Merge

20 files changed, 1489 insertions, 699 deletions

diff --git a/Source/Dafny.sln b/Source/Dafny.sln
index 034dfd7b..40e71952 100644
--- a/Source/Dafny.sln
+++ b/Source/Dafny.sln
@@ -1,6 +1,6 @@
 

-Microsoft Visual Studio Solution File, Format Version 11.00

-# Visual Studio 2010

+Microsoft Visual Studio Solution File, Format Version 12.00

+# Visual Studio 2012

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DafnyDriver", "DafnyDriver\DafnyDriver.csproj", "{63400D1F-05B2-453E-9592-1EAB74B2C9CC}"

 EndProject

 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DafnyPipeline", "Dafny\DafnyPipeline.csproj", "{FE44674A-1633-4917-99F4-57635E6FA740}"

@@ -28,8 +28,8 @@ Global
 		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|.NET.Build.0 = Debug|Any CPU

 		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|Any CPU.Build.0 = Debug|Any CPU

-		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU

-		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU

+		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|Mixed Platforms.ActiveCfg = Checked|Any CPU

+		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Debug|Mixed Platforms.Build.0 = Checked|Any CPU

 		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Release|.NET.ActiveCfg = Release|Any CPU

 		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{63400D1F-05B2-453E-9592-1EAB74B2C9CC}.Release|Any CPU.Build.0 = Release|Any CPU

@@ -45,8 +45,8 @@ Global
 		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|.NET.Build.0 = Debug|Any CPU

 		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|Any CPU.Build.0 = Debug|Any CPU

-		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|Mixed Platforms.ActiveCfg = Debug|Any CPU

-		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|Mixed Platforms.Build.0 = Debug|Any CPU

+		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|Mixed Platforms.ActiveCfg = Checked|Any CPU

+		{FE44674A-1633-4917-99F4-57635E6FA740}.Debug|Mixed Platforms.Build.0 = Checked|Any CPU

 		{FE44674A-1633-4917-99F4-57635E6FA740}.Release|.NET.ActiveCfg = Release|Any CPU

 		{FE44674A-1633-4917-99F4-57635E6FA740}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{FE44674A-1633-4917-99F4-57635E6FA740}.Release|Any CPU.Build.0 = Release|Any CPU

diff --git a/Source/Dafny/Cloner.cs b/Source/Dafny/Cloner.cs
index 699d73d1..99da0774 100644
--- a/Source/Dafny/Cloner.cs
+++ b/Source/Dafny/Cloner.cs
@@ -30,6 +30,9 @@ namespace Microsoft.Dafny
       if (d is ArbitraryTypeDecl) {

         var dd = (ArbitraryTypeDecl)d;

         return new ArbitraryTypeDecl(Tok(dd.tok), dd.Name, m, dd.EqualitySupport, CloneAttributes(dd.Attributes));

+      } else if (d is TupleTypeDecl) {

+        var dd = (TupleTypeDecl)d;

+        return new TupleTypeDecl(dd.Dims, dd.Module);

       } else if (d is IndDatatypeDecl) {

         var dd = (IndDatatypeDecl)d;

         var tps = dd.TypeArgs.ConvertAll(CloneTypeParam);

@@ -61,18 +64,13 @@ namespace Microsoft.Dafny
           body, CloneAttributes(dd.Attributes), dd.SignatureEllipsis);

         return iter;

       } else if (d is ClassDecl) {

+        var dd = (ClassDecl)d;

+        var tps = dd.TypeArgs.ConvertAll(CloneTypeParam);

+        var mm = dd.Members.ConvertAll(CloneMember);

         if (d is DefaultClassDecl) {

-          var dd = (ClassDecl)d;

-          var tps = dd.TypeArgs.ConvertAll(CloneTypeParam);

-          var mm = dd.Members.ConvertAll(CloneMember);

-          var cl = new DefaultClassDecl(m, mm);

-          return cl;

+          return new DefaultClassDecl(m, mm);

         } else {

-          var dd = (ClassDecl)d;

-          var tps = dd.TypeArgs.ConvertAll(CloneTypeParam);

-          var mm = dd.Members.ConvertAll(CloneMember);

-          var cl = new ClassDecl(Tok(dd.tok), dd.Name, m, tps, mm, CloneAttributes(dd.Attributes));

-          return cl;

+          return new ClassDecl(Tok(dd.tok), dd.Name, m, tps, mm, CloneAttributes(dd.Attributes));

         }

       } else if (d is ModuleDecl) {

         if (d is LiteralModuleDecl) {

@@ -355,7 +353,7 @@ namespace Microsoft.Dafny
       } else if (expr is MatchExpr) {

         var e = (MatchExpr)expr;

         return new MatchExpr(Tok(e.tok), CloneExpr(e.Source),

-          e.Cases.ConvertAll(c => new MatchCaseExpr(Tok(c.tok), c.Id, c.Arguments.ConvertAll(CloneBoundVar), CloneExpr(c.Body))));

+          e.Cases.ConvertAll(c => new MatchCaseExpr(Tok(c.tok), c.Id, c.Arguments.ConvertAll(CloneBoundVar), CloneExpr(c.Body))), e.UsesOptionalBraces);

 

       } else if (expr is NegationExpression) {

         var e = (NegationExpression)expr;

@@ -478,7 +476,7 @@ namespace Microsoft.Dafny
       } else if (stmt is MatchStmt) {

         var s = (MatchStmt)stmt;

         r = new MatchStmt(Tok(s.Tok), Tok(s.EndTok), CloneExpr(s.Source),

-          s.Cases.ConvertAll(c => new MatchCaseStmt(Tok(c.tok), c.Id, c.Arguments.ConvertAll(CloneBoundVar), c.Body.ConvertAll(CloneStmt))));

+          s.Cases.ConvertAll(c => new MatchCaseStmt(Tok(c.tok), c.Id, c.Arguments.ConvertAll(CloneBoundVar), c.Body.ConvertAll(CloneStmt))), s.UsesOptionalBraces);

 

       } else if (stmt is AssignSuchThatStmt) {

         var s = (AssignSuchThatStmt)stmt;

diff --git a/Source/Dafny/Compiler.cs b/Source/Dafny/Compiler.cs
index f5e8ff30..fcf8a2ca 100644
--- a/Source/Dafny/Compiler.cs
+++ b/Source/Dafny/Compiler.cs
@@ -107,6 +107,10 @@ namespace Microsoft.Dafny {
           indent += IndentAmount;

         }

         foreach (TopLevelDecl d in m.TopLevelDecls) {

+          bool compileIt = true;

+          if (Attributes.ContainsBool(d.Attributes, "compile", ref compileIt) && !compileIt) {

+            continue;

+          }

           wr.WriteLine();

           if (d is ArbitraryTypeDecl) {

             var at = (ArbitraryTypeDecl)d;

@@ -130,16 +134,16 @@ namespace Microsoft.Dafny {
             //     public T x;  // yield-parameter

             //     public int y;  // yield-parameter

             //     IEnumerator<object> _iter;

-            //   

+            //

             //     public void _MyIteratorExample(T q) {

             //       this.q = q;

             //       _iter = TheIterator();

             //     }

-            //   

+            //

             //     public void MoveNext(out bool more) {

             //       more =_iter.MoveNext();

             //     }

-            //   

+            //

             //     private IEnumerator<object> TheIterator() {

             //       // the translation of the body of the iterator, with each "yield" turning into a "yield return null;"

             //       yield break;

@@ -411,7 +415,12 @@ namespace Microsoft.Dafny {
 

         if (dt is IndDatatypeDecl) {

           Indent(ind); wr.WriteLine("public override string ToString() {");

-          string nm = (dt.Module.IsDefaultModule ? "" : dt.Module.CompileName + ".") + dt.CompileName + "." + ctor.CompileName;

+          string nm;

+          if (dt is TupleTypeDecl) {

+            nm = "";

+          } else {

+            nm = (dt.Module.IsDefaultModule ? "" : dt.Module.CompileName + ".") + dt.CompileName + "." + ctor.CompileName;

+          }

           Indent(ind + IndentAmount); wr.WriteLine("string s = \"{0}\";", nm);

           if (ctor.Formals.Count != 0) {

             Indent(ind + IndentAmount); wr.WriteLine("s += \"(\";");

@@ -538,7 +547,7 @@ namespace Microsoft.Dafny {
         }

       }

       wr.Write(")");

-      

+

       wr.WriteLine(";");

       Indent(ind + 2 * IndentAmount);

       wr.WriteLine("}");

@@ -584,7 +593,7 @@ namespace Microsoft.Dafny {
         Indent(ind);

         wr.WriteLine("}");

       }

-  

+

       // destructors

       foreach (var ctor in dt.Ctors) {

         foreach (var arg in ctor.Formals) {

@@ -1019,6 +1028,11 @@ namespace Microsoft.Dafny {
           if (s.AssumeToken != null) {

             compiler.Error("an assume statement cannot be compiled (line {0})", s.AssumeToken.line);

           }

+        } else if (stmt is ForallStmt) {

+          var s = (ForallStmt)stmt;

+          if (s.Body == null) {

+            compiler.Error("a forall statement without a body cannot be compiled (line {0})", stmt.Tok.line);

+          }

         }

       }

     }

diff --git a/Source/Dafny/Dafny.atg b/Source/Dafny/Dafny.atg
index 74aa4abd..c8f410c9 100644
--- a/Source/Dafny/Dafny.atg
+++ b/Source/Dafny/Dafny.atg
@@ -81,7 +81,7 @@ public static int Parse (string/*!*/ s, string/*!*/ filename, ModuleDecl module,
   parser.Parse();

   return parser.errors.count;

 }

-public Parser(Scanner/*!*/ scanner, Errors/*!*/ errors, ModuleDecl module, BuiltIns builtIns, bool verifyThisFile=true) 

+public Parser(Scanner/*!*/ scanner, Errors/*!*/ errors, ModuleDecl module, BuiltIns builtIns, bool verifyThisFile=true)

   : this(scanner, errors)  // the real work

 {

   // initialize readonly fields

@@ -130,6 +130,14 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
     (e is FunctionCallExpr ||

      (e is IdentifierSequence && ((IdentifierSequence)e).OpenParen != null));

 }

+

+bool CloseOptionalParen(bool usesOptionalParen) {

+  return usesOptionalParen && la.kind == _closeparen;

+}

+

+bool CloseOptionalBrace(bool usesOptionalBrace) {

+  return usesOptionalBrace && la.kind == _rbrace;

+}

 /*--------------------------------------------------------------------------*/

 CHARACTERS

   letter = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".

@@ -172,6 +180,7 @@ TOKENS
   lbrace = '{'.

   rbrace = '}'.

   openparen = '('.

+  closeparen = ')'.

   star = '*'.

   notIn = "!in" CONTEXT (nonidchar).

 COMMENTS FROM "/*" TO "*/" NESTED

@@ -197,9 +206,9 @@ Dafny
                                                       includedFile = Path.Combine(basePath, includedFile);

                                                       fullPath = Path.GetFullPath(includedFile);

                                                     }

-                                                    defaultModule.Includes.Add(new Include(t, includedFile, fullPath)); 

+                                                    defaultModule.Includes.Add(new Include(t, includedFile, fullPath));

                                                    }

-                                                .) 

+                                                .)

   }

   { SubModuleDecl<defaultModule, out submodule> (. defaultModule.TopLevelDecls.Add(submodule); .)

   | ClassDecl<defaultModule, out c>             (. defaultModule.TopLevelDecls.Add(c); .)

@@ -226,7 +235,7 @@ Dafny
   .

 SubModuleDecl<ModuleDefinition parent, out ModuleDecl submodule>

 = (. ClassDecl/*!*/ c; DatatypeDecl/*!*/ dt; ArbitraryTypeDecl at; IteratorDecl iter;

-     Attributes attrs = null;  IToken/*!*/ id; 

+     Attributes attrs = null;  IToken/*!*/ id;

      List<MemberDecl/*!*/> namedModuleDefaultClassMembers = new List<MemberDecl>();;

      List<IToken> idRefined = null, idPath = null, idAssignment = null;

      ModuleDefinition module;

@@ -238,8 +247,8 @@ SubModuleDecl<ModuleDefinition parent, out ModuleDecl submodule>
   ( [ "abstract"  (. isAbstract = true; .) ]

     "module"

     { Attribute<ref attrs> }

-    NoUSIdent<out id>                          

-    

+    NoUSIdent<out id>

+

       [ "refines" QualifiedName<out idRefined> ] (. module = new ModuleDefinition(id, id.val, isAbstract, false, idRefined == null ? null : idRefined, parent, attrs, false); .)

        "{"                                       (. module.BodyStartTok = t; .)

         { SubModuleDecl<module, out sm>                (. module.TopLevelDecls.Add(sm); .)

@@ -252,15 +261,15 @@ SubModuleDecl<ModuleDefinition parent, out ModuleDecl submodule>
       "}"                                  (. module.BodyEndTok = t;

                                               module.TopLevelDecls.Add(new DefaultClassDecl(module, namedModuleDefaultClassMembers));

                                               submodule = new LiteralModuleDecl(module, parent); .)

-  | 

+  |

     "import" ["opened" (.opened = true;.)]

-    NoUSIdent<out id> 

+    NoUSIdent<out id>

     [ "=" QualifiedName<out idPath>

       (. submodule = new AliasModuleDecl(idPath, id, parent, opened); .)

     | "as" QualifiedName<out idPath>  ["default" QualifiedName<out idAssignment> ]

       (. submodule = new ModuleFacadeDecl(idPath, id, parent, idAssignment, opened); .)

     ]

-    [ SYNC ";" 

+    [ SYNC ";"

         // This semi-colon used to be required, but it seems silly to have it.

         // To stage the transition toward not having it at all, let's make it optional for now.  Then,

         // in a next big version of Dafny, including the following warning message:

@@ -342,7 +351,7 @@ DatatypeDecl<ModuleDefinition/*!*/ module, out DatatypeDecl/*!*/ dt>
   "="                                      (. bodyStart = t; .)

   DatatypeMemberDecl<ctors>

   { "|" DatatypeMemberDecl<ctors> }

-  [ SYNC ";" 

+  [ SYNC ";"

       // This semi-colon used to be required, but it seems silly to have it.

       // To stage the transition toward not having it at all, let's make it optional for now.  Then,

       // in a next big version of Dafny, including the following warning message:

@@ -394,7 +403,7 @@ ArbitraryTypeDecl<ModuleDefinition/*!*/ module, out ArbitraryTypeDecl at>
   NoUSIdent<out id>

   [ "(" "==" ")"               (. eqSupport = TypeParameter.EqualitySupportValue.Required; .)

   ]                            (. at = new ArbitraryTypeDecl(id, id.val, module, eqSupport, attrs); .)

-  [ SYNC ";" 

+  [ SYNC ";"

       // This semi-colon used to be required, but it seems silly to have it.

       // To stage the transition toward not having it at all, let's make it optional for now.  Then,

       // in a next big version of Dafny, including the following warning message:

@@ -618,7 +627,7 @@ MethodDecl<MemberModifiers mmod, bool allowConstructor, out Method/*!*/ m>
   { MethodSpec<req, mod, ens, dec, ref decAttrs, ref modAttrs> }

   [ BlockStmt<out body, out bodyStart, out bodyEnd>

   ]

-  (. 

+  (.

      if (Attributes.Contains(attrs, "axiom") && !mmod.IsGhost && !isLemma) {

         SemErr(t, "only ghost methods can have the :axiom attribute");

      }

@@ -730,8 +739,9 @@ Type<out Type/*!*/ ty>
   TypeAndToken<out tok, out ty>

   .

 TypeAndToken<out IToken/*!*/ tok, out Type/*!*/ ty>

-= (. Contract.Ensures(Contract.ValueAtReturn(out tok)!=null); Contract.Ensures(Contract.ValueAtReturn(out ty) != null); tok = Token.NoToken;  ty = new BoolType();  /*keep compiler happy*/

-     List<Type/*!*/>/*!*/ gt;

+= (. Contract.Ensures(Contract.ValueAtReturn(out tok)!=null); Contract.Ensures(Contract.ValueAtReturn(out ty) != null);

+     tok = Token.NoToken;  ty = new BoolType();  /*keep compiler happy*/

+     List<Type> gt;

   .)

   ( "bool"                          (. tok = t; .)

   | "nat"                           (. tok = t;  ty = new NatType(); .)

@@ -765,30 +775,38 @@ TypeAndToken<out IToken/*!*/ tok, out Type/*!*/ ty>
                                          ty = new MapType(gt[0], gt[1]);

                                        }

                                     .)

+  | "("                             (. tok = t; gt = new List<Type>(); .)

+    [ Type<out ty>                  (. gt.Add(ty); .)

+      { "," Type<out ty>            (. gt.Add(ty); .)

+      }

+    ]

+    ")"                             (. if (gt.Count == 1) {

+                                         // just return the type 'ty'

+                                       } else {

+                                         // make sure the nullary tuple type exists

+                                         var dims = gt.Count;

+                                         var tmp = theBuiltIns.TupleType(tok, dims, true);

+                                         ty = new UserDefinedType(tok, BuiltIns.TupleTypeName(dims), gt, new List<IToken>());

+                                       }

+                                    .)

   | ReferenceType<out tok, out ty>

   )

   .

 ReferenceType<out IToken/*!*/ tok, out Type/*!*/ ty>

 = (. Contract.Ensures(Contract.ValueAtReturn(out tok) != null); Contract.Ensures(Contract.ValueAtReturn(out ty) != null);

      tok = Token.NoToken;  ty = new BoolType();  /*keep compiler happy*/

-     List<Type/*!*/>/*!*/ gt;

+     List<Type> gt;

      List<IToken> path;

   .)

   ( "object"                        (. tok = t;  ty = new ObjectType(); .)

-  | arrayToken                      (. tok = t;  gt = new List<Type/*!*/>(); .)

-    GenericInstantiation<gt>        (. if (gt.Count != 1) {

-                                         SemErr("array type expects exactly one type argument");

-                                       }

-                                       int dims = 1;

-                                       if (tok.val.Length != 5) {

-                                         dims = int.Parse(tok.val.Substring(5));

-                                       }

-                                       ty = theBuiltIns.ArrayType(tok, dims, gt[0], true);

+  | arrayToken                      (. tok = t;  gt = new List<Type>(); .)

+    [ GenericInstantiation<gt> ]    (. int dims = tok.val.Length == 5 ? 1 : int.Parse(tok.val.Substring(5));

+                                       ty = theBuiltIns.ArrayType(tok, dims, gt, true);

                                     .)

-  | Ident<out tok>                  (. gt = new List<Type/*!*/>();

+  | Ident<out tok>                  (. gt = new List<Type>();

                                        path = new List<IToken>(); .)

     {                               (. path.Add(tok); .)

-      "." Ident<out tok>           

+      "." Ident<out tok>

     }

     [ GenericInstantiation<gt> ]    (. ty = (tok.val == "real") ? (Type)Microsoft.Dafny.Type.Real : new UserDefinedType(tok, tok.val, gt, path); .)

   )

@@ -1009,7 +1027,7 @@ OneStmt<out Statement/*!*/ s>
     SYNC

     ";"                                (. s = label != null ? new BreakStmt(x, t, label) : new BreakStmt(x, t, breakCount); .)

   | ReturnStmt<out s>

-  | SkeletonStmt<out s> 

+  | SkeletonStmt<out s>

   )

   .

 

@@ -1023,7 +1041,7 @@ SkeletonStmt<out Statement s>
      Ident<out tok>                    (. names.Add(tok); .)

      {"," Ident<out tok>               (. names.Add(tok); .)

      }

-     ":=" 

+     ":="

      Expression<out e, false>          (. exprs.Add(e); .)

      {"," Expression<out e, false>     (. exprs.Add(e); .)

      }

@@ -1031,7 +1049,7 @@ SkeletonStmt<out Statement s>
                                             SemErr(whereTok, exprs.Count < names.Count ? "not enough expressions" : "too many expressions");

                                             names = null; exprs = null;

                                           }

-                                       .) 

+                                       .)

   ]

   ";"

   (. s = new SkeletonStatement(dotdotdot, t, names, exprs); .)

@@ -1111,7 +1129,7 @@ Rhs<out AssignmentRhs r, Expression receiverForInitCall>
     [ "["                              (. ee = new List<Expression>(); .)

       Expressions<ee>

       "]"                              (. // make sure an array class with this dimensionality exists

-                                          UserDefinedType tmp = theBuiltIns.ArrayType(x, ee.Count, new IntType(), true);

+                                          var tmp = theBuiltIns.ArrayType(ee.Count, new IntType(), true);

                                        .)

     |                                  (. x = null; args = new List<Expression/*!*/>(); .)

       [ "." Ident<out x> ]

@@ -1332,14 +1350,20 @@ Guard<out Expression e>   /* null represents demonic-choice */
 MatchStmt<out Statement/*!*/ s>

 = (. Contract.Ensures(Contract.ValueAtReturn(out s) != null);

      Token x;  Expression/*!*/ e;  MatchCaseStmt/*!*/ c;

-     List<MatchCaseStmt/*!*/> cases = new List<MatchCaseStmt/*!*/>(); .)

+     List<MatchCaseStmt/*!*/> cases = new List<MatchCaseStmt/*!*/>();

+     bool usesOptionalBrace = false;

+  .)

   "match"                     (. x = t; .)

   Expression<out e, true>

-  "{"

+  [ "{"                                     (. usesOptionalBrace = true; .)

+  ]

   { CaseStatement<out c>     (. cases.Add(c); .)

   }

-  "}"

-  (. s = new MatchStmt(x, t, e, cases); .)

+  ( IF(CloseOptionalBrace(usesOptionalBrace))

+    "}"

+  |                                         (. if (usesOptionalBrace) { SemErr(t, "expecting close curly brace"); } .)

+  )

+  (. s = new MatchStmt(x, t, e, cases, usesOptionalBrace); .)

   .

 CaseStatement<out MatchCaseStmt/*!*/ c>

 = (. Contract.Ensures(Contract.ValueAtReturn(out c) != null);

@@ -1417,10 +1441,11 @@ ForallStmt<out Statement/*!*/ s>
      var ens = new List<MaybeFreeExpression/*!*/>();

      bool isFree;

      Expression/*!*/ e;

-     BlockStmt/*!*/ block;

+     BlockStmt block = null;

      IToken bodyStart, bodyEnd;

+     IToken tok = Token.NoToken;

   .)

-  ( "forall"                                  (. x = t; .)

+  ( "forall"                                  (. x = t; tok = x; .)

   | "parallel"                                (. x = t;

                                                  errors.Warning(t, "the 'parallel' keyword has been deprecated; the comprehension statement now uses the keyword 'forall' (and the parentheses around the bound variables are now optional)");

                                               .)

@@ -1435,16 +1460,27 @@ ForallStmt<out Statement/*!*/ s>
                                             (. if (bvars == null) { bvars = new List<BoundVar>(); }

                                                if (range == null) { range = new LiteralExpr(x, true); }

                                             .)

-  ( ")"                                     (. if (!usesOptionalParen) { SemErr(t, "found but didn't expect a close parenthesis"); } .)

+  ( IF(CloseOptionalParen(usesOptionalParen))

+    ")"

   |                                         (. if (usesOptionalParen) { SemErr(t, "expecting close parenthesis"); } .)

   )

   {                                         (. isFree = false; .)

     [ "free"                                (. isFree = true; .)

     ]

-    "ensures" Expression<out e, false> ";"  (. ens.Add(new MaybeFreeExpression(e, isFree)); .)

+    "ensures" Expression<out e, false>      (. ens.Add(new MaybeFreeExpression(e, isFree)); .)

+    ";"                                     (. tok = t; .)

   }

-  BlockStmt<out block, out bodyStart, out bodyEnd>

-  (. s = new ForallStmt(x, block.EndTok, bvars, attrs, range, ens, block); .)

+  [ BlockStmt<out block, out bodyStart, out bodyEnd>

+  ]

+  (. if (DafnyOptions.O.DisallowSoundnessCheating && block == null && 0 < ens.Count) {

+        SemErr(t, "a forall statement with an ensures clause must have a body");

+     }

+

+     if (block != null) {

+        tok = block.EndTok;

+     }

+     s = new ForallStmt(x, tok, bvars, attrs, range, ens, block);

+  .)

   .

 

 ModifyStmt<out Statement s>

@@ -1478,9 +1514,9 @@ ModifyStmt<out Statement s>
 CalcStmt<out Statement/*!*/ s>

 = (. Contract.Ensures(Contract.ValueAtReturn(out s) != null);

      Token x;

-     CalcStmt.CalcOp/*!*/ op, calcOp = Microsoft.Dafny.CalcStmt.DefaultOp, resOp = Microsoft.Dafny.CalcStmt.DefaultOp;     

+     CalcStmt.CalcOp/*!*/ op, calcOp = Microsoft.Dafny.CalcStmt.DefaultOp, resOp = Microsoft.Dafny.CalcStmt.DefaultOp;

      var lines = new List<Expression/*!*/>();

-     var hints = new List<BlockStmt/*!*/>(); 

+     var hints = new List<BlockStmt/*!*/>();

      CalcStmt.CalcOp stepOp;

      var stepOps = new List<CalcStmt.CalcOp>();

      CalcStmt.CalcOp maybeOp;

@@ -1494,7 +1530,7 @@ CalcStmt<out Statement/*!*/ s>
                                                              if (maybeOp == null) {

                                                                SemErr(opTok, "the main operator of a calculation must be transitive");

                                                              }

-                                                             resOp = calcOp; 

+                                                             resOp = calcOp;

                                                           .)

   ]

   "{"

@@ -1522,8 +1558,8 @@ CalcStmt<out Statement/*!*/ s>
     if (lines.Count > 0) {

       // Repeat the last line to create a dummy line for the dangling hint

       lines.Add(lines[lines.Count - 1]);

-    }  

-    s = new CalcStmt(x, t, calcOp, lines, hints, stepOps, resOp); 

+    }

+    s = new CalcStmt(x, t, calcOp, lines, hints, stepOps, resOp);

   .)

   .

 CalcOp<out IToken x, out CalcStmt.CalcOp/*!*/ op>

@@ -1543,9 +1579,9 @@ CalcOp<out IToken x, out CalcStmt.CalcOp/*!*/ op>
   | '\u2265'       (. x = t;  binOp = BinaryExpr.Opcode.Ge; .)

   | EquivOp        (. x = t;  binOp = BinaryExpr.Opcode.Iff; .)

   | ImpliesOp      (. x = t;  binOp = BinaryExpr.Opcode.Imp; .)

-  | ExpliesOp      (. x = t;  binOp = BinaryExpr.Opcode.Exp; .) 

+  | ExpliesOp      (. x = t;  binOp = BinaryExpr.Opcode.Exp; .)

   )

-  (. 

+  (.

     if (k == null) {

       op = new Microsoft.Dafny.CalcStmt.BinaryCalcOp(binOp);

     } else {

@@ -1555,7 +1591,7 @@ CalcOp<out IToken x, out CalcStmt.CalcOp/*!*/ op>
   .

 Hint<out BlockStmt s>

 = (. Contract.Ensures(Contract.ValueAtReturn(out s) != null); // returns an empty block statement if the hint is empty

-     var subhints = new List<Statement/*!*/>(); 

+     var subhints = new List<Statement/*!*/>();

      IToken bodyStart, bodyEnd;

      BlockStmt/*!*/ block;

      Statement/*!*/ calc;

@@ -1565,7 +1601,7 @@ Hint<out BlockStmt s>
   { BlockStmt<out block, out bodyStart, out bodyEnd>  (. endTok = block.EndTok; subhints.Add(block); .)

   | CalcStmt<out calc>                                (. endTok = calc.EndTok; subhints.Add(calc); .)

   }

-  (. s = new BlockStmt(x, endTok, subhints); // if the hint is empty x is the first token of the next line, but it doesn't matter cause the block statement is just used as a container 

+  (. s = new BlockStmt(x, endTok, subhints); // if the hint is empty x is the first token of the next line, but it doesn't matter cause the block statement is just used as a container

   .)

   .

 /*------------------------------------------------------------------------*/

@@ -1745,7 +1781,7 @@ RelOp<out IToken/*!*/ x, out BinaryExpr.Opcode op, out Expression k>
     [ "#" "[" Expression<out k, true> "]" ]

   | "in"           (. x = t;  op = BinaryExpr.Opcode.In; .)

   | notIn          (. x = t;  op = BinaryExpr.Opcode.NotIn; .)

-  | /* The next operator is "!!", but we have to scan it as two "!", since the scanner is gready 

+  | /* The next operator is "!!", but we have to scan it as two "!", since the scanner is gready

        so if "!!" is a valid token, we won't be able to scan it as two "!" when needed: */

     "!"            (. x = t;  y = Token.NoToken; .)

     [ "!"          (. y = t; .)

@@ -1849,25 +1885,51 @@ ConstAtomExpression<out Expression e>
   | "|"                                        (. x = t; .)

       Expression<out e, true>                  (. e = new UnaryExpr(x, UnaryExpr.Opcode.SeqLength, e); .)

     "|"

-  | "("                                        (. x = t; .)

-      Expression<out e, true>                  (. e = new ParensExpression(x, e); .)

-    ")"

-  | "real"									   (. x = t; .)

-    "("										   (. IToken openParen = t; .)

-	Expression<out e, true> 

-	")"										   (. IToken classTok = new Token(t.line, t.col); classTok.val = "Real";

-											      IToken fnTok = new Token(t.line, t.col); fnTok.val = "IntToReal";

-											      //e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e }); 

-												  e = new FunctionCallExpr(x, "IntToReal", new StaticReceiverExpr(x, theBuiltIns.RealClass), openParen, new List<Expression/*!*/>() { e });

-												.)

-  | "int"									   (. x = t; .)

-    "("										   (. IToken openParen = t; .)

-	Expression<out e, true> 

-	")"										   (. IToken classTok = new Token(t.line, t.col); classTok.val = "Real";

-											      IToken fnTok = new Token(t.line, t.col); fnTok.val = "RealToInt";

-											      //e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e }); 

-												  e = new FunctionCallExpr(x, "RealToInt", new StaticReceiverExpr(x, theBuiltIns.RealClass), openParen, new List<Expression/*!*/>() { e });

-												.)

+  | ParensExpression<out e>

+  | "real"                                     (. x = t; .)

+    "("                                        (. IToken openParen = t; .)

+    Expression<out e, true>

+    ")"                                        (. IToken classTok = new Token(t.line, t.col); classTok.val = "Real";

+                                                  IToken fnTok = new Token(t.line, t.col); fnTok.val = "IntToReal";

+                                                  //e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e });

+                                                  e = new FunctionCallExpr(x, "IntToReal", new StaticReceiverExpr(x, theBuiltIns.RealClass), openParen, new List<Expression/*!*/>() { e });

+                                               .)

+  | "int"                                      (. x = t; .)

+    "("                                        (. IToken openParen = t; .)

+    Expression<out e, true>

+    ")"                                        (. IToken classTok = new Token(t.line, t.col); classTok.val = "Real";

+                                                  IToken fnTok = new Token(t.line, t.col); fnTok.val = "RealToInt";

+                                                  //e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e });

+                                                  e = new FunctionCallExpr(x, "RealToInt", new StaticReceiverExpr(x, theBuiltIns.RealClass), openParen, new List<Expression/*!*/>() { e });

+                                               .)

+  )

+  .

+ParensExpression<out Expression e>

+= (. IToken x;

+     List<Expression> args = null;

+  .)

+  "("                                 (. x = t; e = null; .)

+  ( ")"                               (. // unit

+                                         // make sure the nullary tuple type exists

+                                         var tmp = theBuiltIns.TupleType(x, 0, true);

+                                         e = new DatatypeValue(x, BuiltIns.TupleTypeName(0), BuiltIns.TupleTypeCtorName, new List<Expression>());

+                                      .)

+  | Expression<out e, true>

+    { ","                             (. if (args == null) {

+                                           args = new List<Expression>();

+                                           args.Add(e);  // add the first argument, which was parsed above

+                                        }

+                                      .)

+      Expression<out e, true>         (. args.Add(e); .)

+    }

+    ")"                               (. if (args == null) {

+                                           e = new ParensExpression(x, e);

+                                         } else {

+                                           // make sure the corresponding tuple type exists

+                                           var tmp = theBuiltIns.TupleType(x, args.Count, true);

+                                           e = new DatatypeValue(x, BuiltIns.TupleTypeName(args.Count), BuiltIns.TupleTypeCtorName, args);

+                                         }

+                                      .)

   )

   .

 DisplayExpr<out Expression e>

@@ -2006,15 +2068,22 @@ NamedExpr<out Expression e, bool allowSemi>
 MatchExpression<out Expression e, bool allowSemi>

 = (. Contract.Ensures(Contract.ValueAtReturn(out e) != null); IToken/*!*/ x;  MatchCaseExpr/*!*/ c;

      List<MatchCaseExpr/*!*/> cases = new List<MatchCaseExpr/*!*/>();

+     bool usesOptionalBrace = false;

   .)

   "match"                     (. x = t; .)

   Expression<out e, allowSemi>

+  [ "{"                                     (. usesOptionalBrace = true; .)

+  ]

   /* Note: The following gives rise to a '"case" is start & successor of deletable structure' error,

      but it's okay, because we want this closer match expression to bind as much as possible--use

      parens around it to limit its scope. */

   { CaseExpression<out c, allowSemi>     (. cases.Add(c); .)

   }

-  (. e = new MatchExpr(x, e, cases); .)

+  ( IF(CloseOptionalBrace(usesOptionalBrace))

+    "}"

+  |                                         (. if (usesOptionalBrace) { SemErr(t, "expecting close curly brace"); } .)

+  )

+  (. e = new MatchExpr(x, e, cases, usesOptionalBrace); .)

   .

 CaseExpression<out MatchCaseExpr c, bool allowSemi>

 = (. Contract.Ensures(Contract.ValueAtReturn(out c) != null); IToken/*!*/ x, id;

@@ -2051,10 +2120,10 @@ CasePattern<out CasePattern pat>
                                           // later if resolution finds the CasePattern to denote a parameter-less constructor), because this

                                           // (in particular, bv.IsGhost) is the place where a LetExpr records whether or not the "ghost"

                                           // keyword was used in the declaration.

-                                          pat = new CasePattern(bv.tok, bv); 

+                                          pat = new CasePattern(bv.tok, bv);

                                        .)

   )

-  

+

   .

 /*------------------------------------------------------------------------*/

 DottedIdentifiersAndFunction<out Expression e>

@@ -2108,9 +2177,9 @@ Suffix<ref Expression e>
                                                     multipleLengths = new List<Expression>();

                                                     multipleLengths.Add(e0);

                                                   }

-                                                  takeRest = true;                                                  

+                                                  takeRest = true;

                                                .)

-            [Expression<out ee, true>          (. multipleLengths.Add(ee); 

+            [Expression<out ee, true>          (. multipleLengths.Add(ee);

                                                   takeRest = false;

                                                .)

             ]

@@ -2130,7 +2199,7 @@ Suffix<ref Expression e>
       (. if (multipleIndices != null) {

            e = new MultiSelectExpr(x, e, multipleIndices);

            // make sure an array class with this dimensionality exists

-           UserDefinedType tmp = theBuiltIns.ArrayType(x, multipleIndices.Count, new IntType(), true);

+           var tmp = theBuiltIns.ArrayType(multipleIndices.Count, new IntType(), true);

          } else {

            if (!anyDots && e0 == null) {

              /* a parsing error occurred */

@@ -2310,7 +2379,7 @@ IdentOrDigitsSuffix<out IToken x, out IToken y>
 // Identifier, disallowing leading underscores

 NoUSIdent<out IToken/*!*/ x>

 = (. Contract.Ensures(Contract.ValueAtReturn(out x) != null); .)

-  ident            (. x = t; 

+  ident            (. x = t;

                       if (x.val.StartsWith("_")) {

                         SemErr("cannot declare identifier beginning with underscore");

                       }

@@ -2320,7 +2389,7 @@ NoUSIdent<out IToken/*!*/ x>
 // Identifier, disallowing leading underscores, except possibly the "wildcard" identifier "_"

 WildIdent<out IToken/*!*/ x, bool allowWildcardId>

 = (. Contract.Ensures(Contract.ValueAtReturn(out x) != null); .)

-  ident            (. x = t; 

+  ident            (. x = t;

                       if (x.val.StartsWith("_")) {

                         if (allowWildcardId && x.val.Length == 1) {

                           t.val = "_v" + anonymousIds++;

@@ -2341,7 +2410,7 @@ Nat<out BigInteger n>
          n = BigInteger.Zero;

        }

     .)

-   |hexdigits 

+   |hexdigits

     (. try {

          // note: leading 0 required when parsing positive hex numbers

          n = BigInteger.Parse("0" + t.val.Substring(2), System.Globalization.NumberStyles.HexNumber);

@@ -2361,7 +2430,7 @@ Dec<out Basetypes.BigDec d>
          SemErr("incorrectly formatted number");

          d = Basetypes.BigDec.ZERO;

        }

-    .)   

+    .)

   )

   .

 END Dafny.

diff --git a/Source/Dafny/DafnyAst.cs b/Source/Dafny/DafnyAst.cs
index 754ae8bc..67806193 100644
--- a/Source/Dafny/DafnyAst.cs
+++ b/Source/Dafny/DafnyAst.cs
@@ -88,16 +88,18 @@ namespace Microsoft.Dafny {
   {

     public readonly ModuleDefinition SystemModule = new ModuleDefinition(Token.NoToken, "_System", false, false, null, null, null, true);

     Dictionary<int, ClassDecl> arrayTypeDecls = new Dictionary<int, ClassDecl>();

+    Dictionary<int, TupleTypeDecl> tupleTypeDecls = new Dictionary<int, TupleTypeDecl>();

     public readonly ClassDecl ObjectDecl;

     public readonly ClassDecl RealClass;

     //public readonly Function RealToInt;

     //public readonly Function IntToReal;

     public BuiltIns() {

       // create class 'object'

-      ObjectDecl = new ClassDecl(Token.NoToken, "object", SystemModule, new List<TypeParameter>(), new List<MemberDecl>(), null);

+      ObjectDecl = new ClassDecl(Token.NoToken, "object", SystemModule, new List<TypeParameter>(), new List<MemberDecl>(), DontCompile());

       SystemModule.TopLevelDecls.Add(ObjectDecl);

       // add one-dimensional arrays, since they may arise during type checking

-      UserDefinedType tmp = ArrayType(Token.NoToken, 1, Type.Int, true);

+      // Arrays of other dimensions may be added during parsing as the parser detects the need for these

+      UserDefinedType tmp = ArrayType(1, Type.Int, true);

       // add real number functions

       Function RealToInt = new Function(Token.NoToken, "RealToInt", true, true, new List<TypeParameter>(), Token.NoToken,

         new List<Formal> { new Formal(Token.NoToken, "x", Type.Real, true, true) }, Type.Int, new List<Expression>(),

@@ -108,28 +110,35 @@ namespace Microsoft.Dafny {
         new List<FrameExpression>(), new List<Expression>(), new Specification<Expression>(new List<Expression>(), null),

         null, null, Token.NoToken);

       RealClass = new ClassDecl(Token.NoToken, "Real", SystemModule, new List<TypeParameter>(),

-        new List<MemberDecl>() { RealToInt, IntToReal }, null);

+        new List<MemberDecl>() { RealToInt, IntToReal }, DontCompile());

       RealToInt.EnclosingClass = RealClass;

       IntToReal.EnclosingClass = RealClass;

       RealToInt.IsBuiltin = true;

       IntToReal.IsBuiltin = true;

       SystemModule.TopLevelDecls.Add(RealClass);

+      // Note, in addition to these types, the _System module contains tuple types.  These tuple types are added to SystemModule

+      // by the parser as the parser detects the need for these.

     }

 

-    public UserDefinedType ArrayType(int dims, Type arg) {

-      return ArrayType(Token.NoToken, dims, arg, false);

+    private Attributes DontCompile() {

+      var flse = new Attributes.Argument(Token.NoToken, Expression.CreateBoolLiteral(Token.NoToken, false));

+      return new Attributes("compile", new List<Attributes.Argument>() { flse }, null);

     }

-    public UserDefinedType ArrayType(IToken tok, int dims, Type arg, bool allowCreationOfNewClass) {

-      Contract.Requires(tok != null);

+

+    public UserDefinedType ArrayType(int dims, Type arg, bool allowCreationOfNewClass = false) {

       Contract.Requires(1 <= dims);

       Contract.Requires(arg != null);

+      return ArrayType(Token.NoToken, dims, new List<Type>() { arg }, allowCreationOfNewClass);

+    }

+    public UserDefinedType ArrayType(IToken tok, int dims, List<Type> typeArgs, bool allowCreationOfNewClass) {

+      Contract.Requires(tok != null);

+      Contract.Requires(1 <= dims);

+      Contract.Requires(typeArgs != null);

       Contract.Ensures(Contract.Result<UserDefinedType>() != null);

 

-      List<Type> typeArgs = new List<Type>();

-      typeArgs.Add(arg);

       UserDefinedType udt = new UserDefinedType(tok, ArrayClassName(dims), typeArgs, null);

       if (allowCreationOfNewClass && !arrayTypeDecls.ContainsKey(dims)) {

-        ArrayClassDecl arrayClass = new ArrayClassDecl(dims, SystemModule);

+        ArrayClassDecl arrayClass = new ArrayClassDecl(dims, SystemModule, DontCompile());

         for (int d = 0; d < dims; d++) {

           string name = dims == 1 ? "Length" : "Length" + d;

           string compiledName = dims == 1 ? "Length" : "GetLength(" + d + ")";

@@ -152,6 +161,30 @@ namespace Microsoft.Dafny {
         return "array" + dims;

       }

     }

+

+    public TupleTypeDecl TupleType(IToken tok, int dims, bool allowCreationOfNewType) {

+      Contract.Requires(tok != null);

+      Contract.Requires(0 <= dims);

+      Contract.Ensures(Contract.Result<TupleTypeDecl>() != null);

+

+      TupleTypeDecl tt;

+      if (!tupleTypeDecls.TryGetValue(dims, out tt)) {

+        Contract.Assume(allowCreationOfNewType);  // the parser should ensure that all needed tuple types exist by the time of resolution

+        tt = new TupleTypeDecl(dims, SystemModule);

+        tupleTypeDecls.Add(dims, tt);

+        SystemModule.TopLevelDecls.Add(tt);

+      }

+      return tt;

+    }

+    public static string TupleTypeName(int dims) {

+      Contract.Requires(0 <= dims);

+      return "_tuple#" + dims;

+    }

+    public static bool IsTupleTypeName(string s) {

+      Contract.Requires(s != null);

+      return s.StartsWith("_tuple#");

+    }

+    public const string TupleTypeCtorName = "_#Make";  // the printer wants this name to be uniquely recognizable

   }

 

   public class Attributes {

@@ -553,9 +586,9 @@ namespace Microsoft.Dafny {
   }

   public class MapType : CollectionType

   {

-    public Type Range { 

-      get { return range; } 

-      set { 

+    public Type Range {

+      get { return range; }

+      set {

         range = Range;

         TypeArgs = new List<Type> { Arg, range };

       }

@@ -573,7 +606,7 @@ namespace Microsoft.Dafny {
     }

     public Type Domain {

       get { return Arg; }

-      set { 

+      set {

         TypeArgs = new List<Type> { Domain, range };

       }

     }

@@ -679,7 +712,7 @@ namespace Microsoft.Dafny {
       else

         this.Path = new List<IToken>();

     }

-    

+

     /// <summary>

     /// This constructor constructs a resolved type parameter

     /// </summary>

@@ -694,7 +727,7 @@ namespace Microsoft.Dafny {
       this.Path = new List<IToken>();

     }

 

-    public UserDefinedType(TypeParameter tp) 

+    public UserDefinedType(TypeParameter tp)

       : this(tp.tok, tp.Name, tp)

     {

       Contract.Requires(tp != null);

@@ -736,8 +769,11 @@ namespace Microsoft.Dafny {
     [Pure]

     public override string TypeName(ModuleDefinition context) {

       Contract.Ensures(Contract.Result<string>() != null);

-      if (ResolvedParam != null) {

+      /* if (ResolvedParam != null) {

         return ResolvedParam.FullName();

+      } else */ 

+      if (BuiltIns.IsTupleTypeName(Name)) {

+        return "(" + Util.Comma(",", TypeArgs, ty => ty.TypeName(context)) + ")";

       } else {

         string s = "";

         foreach (var t in Path) {

@@ -923,7 +959,7 @@ namespace Microsoft.Dafny {
   /// Domain and Range refer to the types of the indexing operation.  That is, in A[i],

   /// i is of type Domain and A[i] is of type Range.

   /// Arg is either Domain or Range, depending on what type it is.  Arg is the type

-  /// one would use in an expression "x in C", whereas 

+  /// one would use in an expression "x in C", whereas

   /// This proxy stands for one of:

   ///   seq(T)       Domain,Range,Arg := int,T,T

   ///   multiset(T)  Domain,Range,Arg := T,int,T

@@ -1050,7 +1086,7 @@ namespace Microsoft.Dafny {
       EqualitySupport = equalitySupport;

     }

 

-    public TypeParameter(IToken tok, string name, int positionalIndex, ParentType parent) 

+    public TypeParameter(IToken tok, string name, int positionalIndex, ParentType parent)

        : this(tok, name)

     {

       PositionalIndex = positionalIndex;

@@ -1107,7 +1143,7 @@ namespace Microsoft.Dafny {
     public ModuleDecl CompileRoot;

     public readonly List<IToken> CompilePath;

     public ModuleSignature OriginalSignature;

-    

+

     public ModuleFacadeDecl(List<IToken> path, IToken name, ModuleDefinition parent, List<IToken> compilePath, bool opened)

       : base(name, name.val, parent, opened) {

       Path = path;

@@ -1117,7 +1153,7 @@ namespace Microsoft.Dafny {
   }

 

   public class ModuleSignature {

-    

+

     public readonly Dictionary<string, TopLevelDecl> TopLevels = new Dictionary<string, TopLevelDecl>();

     public readonly Dictionary<string, Tuple<DatatypeCtor, bool>> Ctors = new Dictionary<string, Tuple<DatatypeCtor, bool>>();

     public readonly Dictionary<string, MemberDecl> StaticMembers = new Dictionary<string, MemberDecl>();

@@ -1138,15 +1174,15 @@ namespace Microsoft.Dafny {
         } else return false;

       } else return false;

     }

-    

-      

+

+

   }

   public class ModuleDefinition : TopLevelDecl {

     public readonly List<IToken> RefinementBaseName;  // null if no refinement base

     public ModuleDecl RefinementBaseRoot; // filled in early during resolution, corresponds to RefinementBaseName[0]

     public ModuleDefinition RefinementBase;  // filled in during resolution (null if no refinement base)

     public List<Include> Includes;

-    

+

     public readonly List<TopLevelDecl> TopLevelDecls = new List<TopLevelDecl>();  // filled in by the parser; readonly after that

     public readonly Graph<ICallable> CallGraph = new Graph<ICallable>();  // filled in during resolution

     public int Height;  // height in the topological sorting of modules; filled in during resolution

@@ -1396,10 +1432,10 @@ namespace Microsoft.Dafny {
 

   public class ArrayClassDecl : ClassDecl {

     public readonly int Dims;

-    public ArrayClassDecl(int dims, ModuleDefinition module)

+    public ArrayClassDecl(int dims, ModuleDefinition module, Attributes attrs)

     : base(Token.NoToken, BuiltIns.ArrayClassName(dims), module,

       new List<TypeParameter>(new TypeParameter[]{new TypeParameter(Token.NoToken, "arg")}),

-      new List<MemberDecl>(), null)

+      new List<MemberDecl>(), attrs)

     {

       Contract.Requires(1 <= dims);

       Contract.Requires(module != null);

@@ -1408,7 +1444,8 @@ namespace Microsoft.Dafny {
     }

   }

 

-  public abstract class DatatypeDecl : TopLevelDecl {

+  public abstract class DatatypeDecl : TopLevelDecl

+  {

     public readonly List<DatatypeCtor> Ctors;

     [ContractInvariantMethod]

     void ObjectInvariant() {

@@ -1454,6 +1491,52 @@ namespace Microsoft.Dafny {
     }

   }

 

+  public class TupleTypeDecl : IndDatatypeDecl

+  {

+    public readonly int Dims;

+    /// <summary>

+    /// Construct a resolved built-in tuple type with "dim" arguments.  "systemModule" is expected to be the _System module.

+    /// </summary>

+    public TupleTypeDecl(int dims, ModuleDefinition systemModule)

+      : this(systemModule, CreateTypeParameters(dims)) {

+      Contract.Requires(0 <= dims);

+      Contract.Requires(systemModule != null);

+    }

+    private TupleTypeDecl(ModuleDefinition systemModule, List<TypeParameter> typeArgs)

+      : base(Token.NoToken, BuiltIns.TupleTypeName(typeArgs.Count), systemModule, typeArgs, CreateConstructors(typeArgs), null) {

+      Contract.Requires(systemModule != null);

+      Contract.Requires(typeArgs != null);

+      Dims = typeArgs.Count;

+      foreach (var ctor in Ctors) {

+        ctor.EnclosingDatatype = this;  // resolve here

+        DefaultCtor = ctor;

+        TypeParametersUsedInConstructionByDefaultCtor = new bool[typeArgs.Count];

+        for (int i = 0; i < typeArgs.Count; i++) {

+          TypeParametersUsedInConstructionByDefaultCtor[i] = true;

+        }

+      }

+    }

+    private static List<TypeParameter> CreateTypeParameters(int dims) {

+      Contract.Requires(0 <= dims);

+      var ts = new List<TypeParameter>();

+      for (int i = 0; i < dims; i++) {

+        ts.Add(new TypeParameter(Token.NoToken, "T" + i));

+      }

+      return ts;

+    }

+    private static List<DatatypeCtor> CreateConstructors(List<TypeParameter> typeArgs) {

+      Contract.Requires(typeArgs != null);

+      var formals = new List<Formal>();

+      for (int i = 0; i < typeArgs.Count; i++) {

+        var tp = typeArgs[i];

+        var f = new Formal(Token.NoToken, i.ToString(), new UserDefinedType(Token.NoToken, tp.Name, tp), true, false);

+        formals.Add(f);

+      }

+      var ctor = new DatatypeCtor(Token.NoToken, BuiltIns.TupleTypeCtorName, formals, null);

+      return new List<DatatypeCtor>() { ctor };

+    }

+  }

+

   public class CoDatatypeDecl : DatatypeDecl

   {

     public CoDatatypeDecl SscRepr;  // filled in during resolution

@@ -1496,7 +1579,7 @@ namespace Microsoft.Dafny {
     }

 

     public string FullName {

-      get {        

+      get {

         Contract.Ensures(Contract.Result<string>() != null);

         Contract.Assume(EnclosingDatatype != null);

 

@@ -1561,9 +1644,9 @@ namespace Microsoft.Dafny {
   public class NoContext : ICodeContext

   {

     public readonly ModuleDefinition Module;

-    public NoContext(ModuleDefinition module) 

+    public NoContext(ModuleDefinition module)

     {

-      this.Module = module;    

+      this.Module = module;

     }

     bool ICodeContext.IsGhost { get { return true; } }

     bool ICodeContext.IsStatic { get { Contract.Assume(false, "should not be called on NoContext"); throw new cce.UnreachableException(); } }

@@ -1959,7 +2042,7 @@ namespace Microsoft.Dafny {
       }

       return UniqueName;

     }

-    static char[] specialChars = new char[] { '\'', '_', '?', '\\' };

+    static char[] specialChars = new char[] { '\'', '_', '?', '\\', '#' };

     public static string CompilerizeName(string nm) {

       if ('0' <= nm[0] && nm[0] <= '9') {

         // the identifier is one that consists of just digits

@@ -1983,6 +2066,7 @@ namespace Microsoft.Dafny {
             case '_': name += "__"; break;

             case '?': name += "_q"; break;

             case '\\': name += "_b"; break;

+            case '#': name += "_h"; break;

             default:

               Contract.Assume(false);  // unexpected character

               break;

@@ -3240,7 +3324,7 @@ namespace Microsoft.Dafny {
       Contract.Invariant(MethodName != null);

       Contract.Invariant(cce.NonNullElements(Lhs));

       Contract.Invariant(cce.NonNullElements(Args));

-      Contract.Invariant(TypeArgumentSubstitutions == null || 

+      Contract.Invariant(TypeArgumentSubstitutions == null ||

         Contract.ForAll(Method.TypeArgs, tp => TypeArgumentSubstitutions.ContainsKey(tp)));

     }

 

@@ -3248,8 +3332,8 @@ namespace Microsoft.Dafny {
     public Expression Receiver;  // non-null after resolution

     public readonly string MethodName;

     public readonly List<Expression> Args;

-    public Dictionary<TypeParameter, Type> TypeArgumentSubstitutions;  

-	// create, initialized, and used by resolution 

+    public Dictionary<TypeParameter, Type> TypeArgumentSubstitutions;

+	// create, initialized, and used by resolution

         // (could be deleted once all of resolution is done)

 	// That's not going to work! It should never be deleted!

     public Method Method;  // filled in by resolution

@@ -3560,7 +3644,6 @@ namespace Microsoft.Dafny {
       Contract.Invariant(Range != null);

       Contract.Invariant(BoundVars.Count != 0 || LiteralExpr.IsTrue(Range));

       Contract.Invariant(Ens != null);

-      Contract.Invariant(Body != null);

     }

 

     public ForallStmt(IToken tok, IToken endTok, List<BoundVar> boundVars, Attributes attrs, Expression range, List<MaybeFreeExpression> ens, Statement body)

@@ -3571,7 +3654,6 @@ namespace Microsoft.Dafny {
       Contract.Requires(range != null);

       Contract.Requires(boundVars.Count != 0 || LiteralExpr.IsTrue(range));

       Contract.Requires(cce.NonNullElements(ens));

-      Contract.Requires(body != null);

       this.BoundVars = boundVars;

       this.Attributes = attrs;

       this.Range = range;

@@ -3605,7 +3687,9 @@ namespace Microsoft.Dafny {
 

     public override IEnumerable<Statement> SubStatements {

       get {

-        yield return Body;

+        if (Body != null) {

+          yield return Body;

+        }

       }

     }

     public override IEnumerable<Expression> SubExpressions {

@@ -3686,8 +3770,8 @@ namespace Microsoft.Dafny {
       public static bool ValidOp(BinaryExpr.Opcode op) {

         return

              op == BinaryExpr.Opcode.Eq || op == BinaryExpr.Opcode.Neq

-          || op == BinaryExpr.Opcode.Lt || op == BinaryExpr.Opcode.Le 

-          || op == BinaryExpr.Opcode.Gt || op == BinaryExpr.Opcode.Ge                    

+          || op == BinaryExpr.Opcode.Lt || op == BinaryExpr.Opcode.Le

+          || op == BinaryExpr.Opcode.Gt || op == BinaryExpr.Opcode.Ge

           || LogicOp(op);

       }

 

@@ -3713,7 +3797,7 @@ namespace Microsoft.Dafny {
         var op2 = other.Op;

         if (op1 == BinaryExpr.Opcode.Neq || op2 == BinaryExpr.Opcode.Neq)

           return op2 == BinaryExpr.Opcode.Eq;

-        if (op1 == op2) 

+        if (op1 == op2)

           return true;

         if (LogicOp(op1) || LogicOp(op2))

           return op2 == BinaryExpr.Opcode.Eq ||

@@ -3805,7 +3889,7 @@ namespace Microsoft.Dafny {
     public readonly List<Expression> Steps;  // expressions li op l<i + 1>, filled in during resolution (last step is dummy)

     public Expression Result;                     // expression l0 ResultOp ln, filled in during resolution

 

-    public static readonly CalcOp DefaultOp = new BinaryCalcOp(BinaryExpr.Opcode.Eq); 

+    public static readonly CalcOp DefaultOp = new BinaryCalcOp(BinaryExpr.Opcode.Eq);

 

     [ContractInvariantMethod]

     void ObjectInvariant()

@@ -3847,7 +3931,7 @@ namespace Microsoft.Dafny {
       } else {

         this.ResultOp = resultOp;

       }

-      this.Steps = new List<Expression>();  

+      this.Steps = new List<Expression>();

       this.Result = null;

     }

 

@@ -3916,8 +4000,9 @@ namespace Microsoft.Dafny {
     public readonly Expression Source;

     public readonly List<MatchCaseStmt> Cases;

     public readonly List<DatatypeCtor> MissingCases = new List<DatatypeCtor>();  // filled in during resolution

+    public readonly bool UsesOptionalBraces;

 

-    public MatchStmt(IToken tok, IToken endTok, Expression source, [Captured] List<MatchCaseStmt> cases)

+    public MatchStmt(IToken tok, IToken endTok, Expression source, [Captured] List<MatchCaseStmt> cases, bool usesOptionalBraces)

       : base(tok, endTok) {

       Contract.Requires(tok != null);

       Contract.Requires(endTok != null);

@@ -3925,6 +4010,7 @@ namespace Microsoft.Dafny {
       Contract.Requires(cce.NonNullElements(cases));

       this.Source = source;

       this.Cases = cases;

+      this.UsesOptionalBraces = usesOptionalBraces;

     }

 

     public override IEnumerable<Statement> SubStatements {

@@ -4014,7 +4100,7 @@ namespace Microsoft.Dafny {
       Contract.Requires(endTok != null);

       NameReplacements = nameReplacements;

       ExprReplacements = exprReplacements;

-      

+

     }

     public override IEnumerable<Statement> SubStatements {

       get {

@@ -4185,6 +4271,20 @@ namespace Microsoft.Dafny {
     }

 

     /// <summary>

+    /// Create a resolved expression of the form "e0 + e1"

+    /// </summary>

+    public static Expression CreateAdd(Expression e0, Expression e1) {

+      Contract.Requires(e0 != null);

+      Contract.Requires(e1 != null);

+      Contract.Requires((e0.Type is IntType && e1.Type is IntType) || (e0.Type is RealType && e1.Type is RealType));

+      Contract.Ensures(Contract.Result<Expression>() != null);

+      var s = new BinaryExpr(e0.tok, BinaryExpr.Opcode.Add, e0, e1);

+      s.ResolvedOp = BinaryExpr.ResolvedOpcode.Add;  // resolve here

+      s.Type = e0.Type;  // resolve here

+      return s;

+    }

+

+    /// <summary>

     /// Create a resolved expression of the form "e0 - e1"

     /// </summary>

     public static Expression CreateSubtract(Expression e0, Expression e1) {

@@ -4209,12 +4309,8 @@ namespace Microsoft.Dafny {
       if (n == 0) {

         return e;

       }

-      var nn = new LiteralExpr(e.tok, n);

-      nn.Type = Type.Int;

-      var p = new BinaryExpr(e.tok, BinaryExpr.Opcode.Add, e, nn);

-      p.ResolvedOp = BinaryExpr.ResolvedOpcode.Add;

-      p.Type = Type.Int;

-      return p;

+      var nn = CreateIntLiteral(e.tok, n);

+      return CreateAdd(e, nn);

     }

 

     /// <summary>

@@ -4228,11 +4324,8 @@ namespace Microsoft.Dafny {
       if (n == 0) {

         return e;

       }

-      var nn = Expression.CreateIntLiteral(e.tok, n);

-      var p = new BinaryExpr(e.tok, BinaryExpr.Opcode.Sub, e, nn);

-      p.ResolvedOp = BinaryExpr.ResolvedOpcode.Sub;

-      p.Type = Type.Int;

-      return p;

+      var nn = CreateIntLiteral(e.tok, n);

+      return CreateSubtract(e, nn);

     }

 

     /// <summary>

@@ -4252,7 +4345,7 @@ namespace Microsoft.Dafny {
 

     /// <summary>

     /// Create a resolved expression for a bool b

-    /// </summary>        

+    /// </summary>

     public static Expression CreateBoolLiteral(IToken tok, bool b) {

       Contract.Requires(tok != null);

       var lit = new LiteralExpr(tok, b);

@@ -4296,6 +4389,26 @@ namespace Microsoft.Dafny {
       return s;

     }

 

+    public static Expression CreateEq(Expression e0, Expression e1, Type ty) {

+      Contract.Requires(e0 != null);

+      Contract.Requires(e1 != null);

+      Contract.Requires(ty != null);

+      var eq = new BinaryExpr(e0.tok, BinaryExpr.Opcode.Eq, e0, e1);

+      if (ty is SetType) {

+        eq.ResolvedOp = BinaryExpr.ResolvedOpcode.SetEq;

+      } else if (ty is SeqType) {

+        eq.ResolvedOp = BinaryExpr.ResolvedOpcode.SeqEq;

+      } else if (ty is MultiSetType) {

+        eq.ResolvedOp = BinaryExpr.ResolvedOpcode.InMultiSet;

+      } else if (ty is MapType) {

+        eq.ResolvedOp = BinaryExpr.ResolvedOpcode.MapEq;

+      } else {

+        eq.ResolvedOp = BinaryExpr.ResolvedOpcode.EqCommon;

+      }

+      eq.type = Type.Bool;

+      return eq;

+    }

+

     /// <summary>

     /// Create a resolved expression of the form "e0 && e1"

     /// </summary>

@@ -4357,7 +4470,7 @@ namespace Microsoft.Dafny {
       Contract.Ensures(Contract.Result<MatchCaseExpr>() != null);

 

       ResolvedCloner cloner = new ResolvedCloner();

-      var newVars = old_case.Arguments.ConvertAll(cloner.CloneBoundVar);   

+      var newVars = old_case.Arguments.ConvertAll(cloner.CloneBoundVar);

       new_body = VarSubstituter(old_case.Arguments.ConvertAll<NonglobalVariable>(x=>(NonglobalVariable)x), newVars, new_body);

 

       var new_case = new MatchCaseExpr(old_case.tok, old_case.Id, newVars, new_body);

@@ -4367,15 +4480,15 @@ namespace Microsoft.Dafny {
     }

 

     /// <summary>

-    /// Create a match expression with a resolved type 

+    /// Create a match expression with a resolved type

     /// </summary>

     public static Expression CreateMatch(IToken tok, Expression src, List<MatchCaseExpr> cases, Type type) {

-      MatchExpr e = new MatchExpr(tok, src, cases);

+      MatchExpr e = new MatchExpr(tok, src, cases, false);

       e.Type = type;  // resolve here

 

       return e;

     }

- 

+

     /// <summary>

     /// Create a let expression with a resolved type and fresh variables

     /// </summary>

@@ -4415,22 +4528,33 @@ namespace Microsoft.Dafny {
       }

 

       body = VarSubstituter(expr.BoundVars.ConvertAll<NonglobalVariable>(x=>(NonglobalVariable)x), newVars, body);

-      

+

       QuantifierExpr q;

       if (forall) {

         q = new ForallExpr(expr.tok, new List<TypeParameter>(), newVars, expr.Range, body, expr.Attributes);

       } else {

         q = new ExistsExpr(expr.tok, new List<TypeParameter>(), newVars, expr.Range, body, expr.Attributes);

-      } 

+      }

       q.Type = Type.Bool;

 

-      return q;           

+      return q;

+    }

+

+    /// <summary>

+    /// Create a resolved IdentifierExpr (whose token is that of the variable)

+    /// </summary>

+    public static Expression CreateIdentExpr(IVariable v) {

+      Contract.Requires(v != null);

+      var e = new IdentifierExpr(v.Tok, v.Name);

+      e.Var = v;  // resolve here

+      e.type = v.Type;  // resolve here

+      return e;

     }

 

     public static Expression VarSubstituter(List<NonglobalVariable> oldVars, List<BoundVar> newVars, Expression e) {

       Contract.Requires(oldVars != null && newVars != null);

       Contract.Requires(oldVars.Count == newVars.Count);

-      

+

       Dictionary<IVariable, Expression/*!*/> substMap = new Dictionary<IVariable, Expression>();

       Dictionary<TypeParameter, Type> typeMap = new Dictionary<TypeParameter, Type>();

 

@@ -4455,7 +4579,7 @@ namespace Microsoft.Dafny {
   {

     public readonly Type UnresolvedType;

 

-    public StaticReceiverExpr(IToken tok, Type t) 

+    public StaticReceiverExpr(IToken tok, Type t)

       : base(tok) {

       Contract.Requires(tok != null);

       Contract.Requires(t != null);

@@ -4525,7 +4649,7 @@ namespace Microsoft.Dafny {
       this.Value = b;

     }

   }

-  

+

   public class DatatypeValue : Expression {

     public readonly string DatatypeName;

     public readonly string MemberName;

@@ -4540,7 +4664,7 @@ namespace Microsoft.Dafny {
       Contract.Invariant(cce.NonNullElements(Arguments));

       Contract.Invariant(cce.NonNullElements(InferredTypeArgs));

       Contract.Invariant(

-	Ctor == null || 

+	Ctor == null ||

 	InferredTypeArgs.Count == Ctor.EnclosingDatatype.TypeArgs.Count);

     }

 

@@ -4638,7 +4762,7 @@ namespace Microsoft.Dafny {
       Contract.Requires(cce.NonNullElements(elements));

     }

   }

-  

+

   public class MultiSetDisplayExpr : DisplayExpression {

     public MultiSetDisplayExpr(IToken tok, List<Expression> elements) : base(tok, elements) {

       Contract.Requires(tok != null);

@@ -4800,7 +4924,7 @@ namespace Microsoft.Dafny {
     public readonly Expression Receiver;

     public readonly IToken OpenParen;  // can be null if Args.Count == 0

     public readonly List<Expression> Args;

-    public Dictionary<TypeParameter, Type> TypeArgumentSubstitutions;  

+    public Dictionary<TypeParameter, Type> TypeArgumentSubstitutions;

 	// created, initialized, and used by resolution (and also used by translation)

     public enum CoCallResolution {

       No,

@@ -4822,7 +4946,7 @@ namespace Microsoft.Dafny {
         Function == null || TypeArgumentSubstitutions == null ||

         Contract.ForAll(

           Function.TypeArgs,

-        	  a => TypeArgumentSubstitutions.ContainsKey(a)) && 

+        	  a => TypeArgumentSubstitutions.ContainsKey(a)) &&

         Contract.ForAll(

           TypeArgumentSubstitutions.Keys,

         	  a => Function.TypeArgs.Contains(a) || Function.EnclosingClass.TypeArgs.Contains(a)));

@@ -5052,6 +5176,18 @@ namespace Microsoft.Dafny {
     public ResolvedOpcode ResolvedOp_PossiblyStillUndetermined {  // offer a way to return _theResolveOp -- for experts only!

       get { return _theResolvedOp; }

     }

+    public static bool IsEqualityOp(ResolvedOpcode op) {

+      switch (op) {

+        case ResolvedOpcode.EqCommon:

+        case ResolvedOpcode.SetEq:

+        case ResolvedOpcode.SeqEq:

+        case ResolvedOpcode.MultiSetEq:

+        case ResolvedOpcode.MapEq:

+          return true;

+        default:

+          return false;

+      }

+    }

 

     public static Opcode ResolvedOp2SyntacticOp(ResolvedOpcode rop) {

       switch (rop) {

@@ -5610,6 +5746,7 @@ namespace Microsoft.Dafny {
     public readonly Expression Source;

     public readonly List<MatchCaseExpr> Cases;

     public readonly List<DatatypeCtor> MissingCases = new List<DatatypeCtor>();  // filled in during resolution

+    public readonly bool UsesOptionalBraces;

 

     [ContractInvariantMethod]

     void ObjectInvariant() {

@@ -5618,13 +5755,14 @@ namespace Microsoft.Dafny {
       Contract.Invariant(cce.NonNullElements(MissingCases));

     }

 

-    public MatchExpr(IToken tok, Expression source, [Captured] List<MatchCaseExpr> cases)

+    public MatchExpr(IToken tok, Expression source, [Captured] List<MatchCaseExpr> cases, bool usesOptionalBraces)

       : base(tok) {

       Contract.Requires(tok != null);

       Contract.Requires(source != null);

       Contract.Requires(cce.NonNullElements(cases));

       this.Source = source;

       this.Cases = cases;

+      this.UsesOptionalBraces = usesOptionalBraces;

     }

 

     public override IEnumerable<Expression> SubExpressions {

@@ -5807,7 +5945,7 @@ namespace Microsoft.Dafny {
   public class MaybeFreeExpression {

     public readonly Expression E;

     public readonly bool IsFree;

-    

+

     [ContractInvariantMethod]

     void ObjectInvariant() {

       Contract.Invariant(E != null);

diff --git a/Source/Dafny/Parser.cs b/Source/Dafny/Parser.cs
index bc89b6f1..750c04d0 100644
--- a/Source/Dafny/Parser.cs
+++ b/Source/Dafny/Parser.cs
@@ -25,8 +25,9 @@ public class Parser {
 	public const int _lbrace = 9;

 	public const int _rbrace = 10;

 	public const int _openparen = 11;

-	public const int _star = 12;

-	public const int _notIn = 13;

+	public const int _closeparen = 12;

+	public const int _star = 13;

+	public const int _notIn = 14;

 	public const int maxT = 126;

 

 	const bool T = true;

@@ -107,7 +108,7 @@ public static int Parse (string/*!*/ s, string/*!*/ filename, ModuleDecl module,
   parser.Parse();

   return parser.errors.count;

 }

-public Parser(Scanner/*!*/ scanner, Errors/*!*/ errors, ModuleDecl module, BuiltIns builtIns, bool verifyThisFile=true) 

+public Parser(Scanner/*!*/ scanner, Errors/*!*/ errors, ModuleDecl module, BuiltIns builtIns, bool verifyThisFile=true)

   : this(scanner, errors)  // the real work

 {

   // initialize readonly fields

@@ -156,6 +157,14 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
     (e is FunctionCallExpr ||

      (e is IdentifierSequence && ((IdentifierSequence)e).OpenParen != null));

 }

+

+bool CloseOptionalParen(bool usesOptionalParen) {

+  return usesOptionalParen && la.kind == _closeparen;

+}

+

+bool CloseOptionalBrace(bool usesOptionalBrace) {

+  return usesOptionalBrace && la.kind == _rbrace;

+}

 /*--------------------------------------------------------------------------*/

 

 

@@ -236,7 +245,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		// theModule should be a DefaultModuleDecl (actually, the singular DefaultModuleDecl)

 		Contract.Assert(defaultModule != null);

 		

-		while (la.kind == 14) {

+		while (la.kind == 15) {

 			Get();

 			Expect(6);

 			{

@@ -248,28 +257,28 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 			  includedFile = Path.Combine(basePath, includedFile);

 			  fullPath = Path.GetFullPath(includedFile);

 			}

-			defaultModule.Includes.Add(new Include(t, includedFile, fullPath)); 

+			defaultModule.Includes.Add(new Include(t, includedFile, fullPath));

 			}

 			

 		}

 		while (StartOf(1)) {

 			switch (la.kind) {

-			case 15: case 16: case 18: {

+			case 16: case 17: case 19: {

 				SubModuleDecl(defaultModule, out submodule);

 				defaultModule.TopLevelDecls.Add(submodule); 

 				break;

 			}

-			case 23: {

+			case 24: {

 				ClassDecl(defaultModule, out c);

 				defaultModule.TopLevelDecls.Add(c); 

 				break;

 			}

-			case 26: case 27: {

+			case 27: case 28: {

 				DatatypeDecl(defaultModule, out dt);

 				defaultModule.TopLevelDecls.Add(dt); 

 				break;

 			}

-			case 31: {

+			case 32: {

 				ArbitraryTypeDecl(defaultModule, out at);

 				defaultModule.TopLevelDecls.Add(at); 

 				break;

@@ -279,7 +288,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 				defaultModule.TopLevelDecls.Add(iter); 

 				break;

 			}

-			case 24: case 25: case 29: case 40: case 41: case 42: case 43: case 44: case 62: case 63: case 64: {

+			case 25: case 26: case 30: case 40: case 41: case 42: case 43: case 44: case 62: case 63: case 64: {

 				ClassMemberDecl(membersDefaultClass, false);

 				break;

 			}

@@ -302,7 +311,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 

 	void SubModuleDecl(ModuleDefinition parent, out ModuleDecl submodule) {

 		ClassDecl/*!*/ c; DatatypeDecl/*!*/ dt; ArbitraryTypeDecl at; IteratorDecl iter;

-		Attributes attrs = null;  IToken/*!*/ id; 

+		Attributes attrs = null;  IToken/*!*/ id;

 		List<MemberDecl/*!*/> namedModuleDefaultClassMembers = new List<MemberDecl>();;

 		List<IToken> idRefined = null, idPath = null, idAssignment = null;

 		ModuleDefinition module;

@@ -311,17 +320,17 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		bool isAbstract = false;

 		bool opened = false;

 		

-		if (la.kind == 15 || la.kind == 16) {

-			if (la.kind == 15) {

+		if (la.kind == 16 || la.kind == 17) {

+			if (la.kind == 16) {

 				Get();

 				isAbstract = true; 

 			}

-			Expect(16);

+			Expect(17);

 			while (la.kind == 9) {

 				Attribute(ref attrs);

 			}

 			NoUSIdent(out id);

-			if (la.kind == 17) {

+			if (la.kind == 18) {

 				Get();

 				QualifiedName(out idRefined);

 			}

@@ -330,22 +339,22 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 			module.BodyStartTok = t; 

 			while (StartOf(1)) {

 				switch (la.kind) {

-				case 15: case 16: case 18: {

+				case 16: case 17: case 19: {

 					SubModuleDecl(module, out sm);

 					module.TopLevelDecls.Add(sm); 

 					break;

 				}

-				case 23: {

+				case 24: {

 					ClassDecl(module, out c);

 					module.TopLevelDecls.Add(c); 

 					break;

 				}

-				case 26: case 27: {

+				case 27: case 28: {

 					DatatypeDecl(module, out dt);

 					module.TopLevelDecls.Add(dt); 

 					break;

 				}

-				case 31: {

+				case 32: {

 					ArbitraryTypeDecl(module, out at);

 					module.TopLevelDecls.Add(at); 

 					break;

@@ -355,7 +364,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 					module.TopLevelDecls.Add(iter); 

 					break;

 				}

-				case 24: case 25: case 29: case 40: case 41: case 42: case 43: case 44: case 62: case 63: case 64: {

+				case 25: case 26: case 30: case 40: case 41: case 42: case 43: case 44: case 62: case 63: case 64: {

 					ClassMemberDecl(namedModuleDefaultClassMembers, false);

 					break;

 				}

@@ -365,22 +374,22 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 			module.BodyEndTok = t;

 			module.TopLevelDecls.Add(new DefaultClassDecl(module, namedModuleDefaultClassMembers));

 			submodule = new LiteralModuleDecl(module, parent); 

-		} else if (la.kind == 18) {

+		} else if (la.kind == 19) {

 			Get();

-			if (la.kind == 19) {

+			if (la.kind == 20) {

 				Get();

 				opened = true;

 			}

 			NoUSIdent(out id);

-			if (la.kind == 20 || la.kind == 21) {

-				if (la.kind == 20) {

+			if (la.kind == 21 || la.kind == 22) {

+				if (la.kind == 21) {

 					Get();

 					QualifiedName(out idPath);

 					submodule = new AliasModuleDecl(idPath, id, parent, opened); 

 				} else {

 					Get();

 					QualifiedName(out idPath);

-					if (la.kind == 22) {

+					if (la.kind == 23) {

 						Get();

 						QualifiedName(out idAssignment);

 					}

@@ -409,8 +418,8 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		List<MemberDecl/*!*/> members = new List<MemberDecl/*!*/>();

 		IToken bodyStart;

 		

-		while (!(la.kind == 0 || la.kind == 23)) {SynErr(129); Get();}

-		Expect(23);

+		while (!(la.kind == 0 || la.kind == 24)) {SynErr(129); Get();}

+		Expect(24);

 		while (la.kind == 9) {

 			Attribute(ref attrs);

 		}

@@ -440,10 +449,10 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		IToken bodyStart = Token.NoToken;  // dummy assignment

 		bool co = false;

 		

-		while (!(la.kind == 0 || la.kind == 26 || la.kind == 27)) {SynErr(130); Get();}

-		if (la.kind == 26) {

+		while (!(la.kind == 0 || la.kind == 27 || la.kind == 28)) {SynErr(130); Get();}

+		if (la.kind == 27) {

 			Get();

-		} else if (la.kind == 27) {

+		} else if (la.kind == 28) {

 			Get();

 			co = true; 

 		} else SynErr(131);

@@ -454,10 +463,10 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		if (la.kind == 38) {

 			GenericParameters(typeArgs);

 		}

-		Expect(20);

+		Expect(21);

 		bodyStart = t; 

 		DatatypeMemberDecl(ctors);

-		while (la.kind == 28) {

+		while (la.kind == 29) {

 			Get();

 			DatatypeMemberDecl(ctors);

 		}

@@ -480,15 +489,15 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		Attributes attrs = null;

 		var eqSupport = TypeParameter.EqualitySupportValue.Unspecified;

 		

-		Expect(31);

+		Expect(32);

 		while (la.kind == 9) {

 			Attribute(ref attrs);

 		}

 		NoUSIdent(out id);

 		if (la.kind == 11) {

 			Get();

-			Expect(32);

 			Expect(33);

+			Expect(12);

 			eqSupport = TypeParameter.EqualitySupportValue.Required; 

 		}

 		at = new ArbitraryTypeDecl(id, id.val, module, eqSupport, attrs); 

@@ -569,8 +578,8 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		Function/*!*/ f;

 		MemberModifiers mmod = new MemberModifiers();

 		

-		while (la.kind == 24 || la.kind == 25) {

-			if (la.kind == 24) {

+		while (la.kind == 25 || la.kind == 26) {

+			if (la.kind == 25) {

 				Get();

 				mmod.IsGhost = true; 

 			} else {

@@ -578,7 +587,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 				mmod.IsStatic = true; 

 			}

 		}

-		if (la.kind == 29) {

+		if (la.kind == 30) {

 			FieldDecl(mmod, mm);

 		} else if (la.kind == 62 || la.kind == 63 || la.kind == 64) {

 			FunctionDecl(mmod, out f);

@@ -598,7 +607,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 	void NoUSIdent(out IToken/*!*/ x) {

 		Contract.Ensures(Contract.ValueAtReturn(out x) != null); 

 		Expect(1);

-		x = t; 

+		x = t;

 		if (x.val.StartsWith("_")) {

 		 SemErr("cannot declare identifier beginning with underscore");

 		}

@@ -669,19 +678,19 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		eqSupport = TypeParameter.EqualitySupportValue.Unspecified; 

 		if (la.kind == 11) {

 			Get();

-			Expect(32);

 			Expect(33);

+			Expect(12);

 			eqSupport = TypeParameter.EqualitySupportValue.Required; 

 		}

 		typeArgs.Add(new TypeParameter(id, id.val, eqSupport)); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			NoUSIdent(out id);

 			eqSupport = TypeParameter.EqualitySupportValue.Unspecified; 

 			if (la.kind == 11) {

 				Get();

-				Expect(32);

 				Expect(33);

+				Expect(12);

 				eqSupport = TypeParameter.EqualitySupportValue.Required; 

 			}

 			typeArgs.Add(new TypeParameter(id, id.val, eqSupport)); 

@@ -694,8 +703,8 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		Attributes attrs = null;

 		IToken/*!*/ id;  Type/*!*/ ty;

 		

-		while (!(la.kind == 0 || la.kind == 29)) {SynErr(138); Get();}

-		Expect(29);

+		while (!(la.kind == 0 || la.kind == 30)) {SynErr(138); Get();}

+		Expect(30);

 		if (mmod.IsStatic) { SemErr(t, "fields cannot be declared 'static'"); }

 		

 		while (la.kind == 9) {

@@ -703,7 +712,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		}

 		FIdentType(out id, out ty);

 		mm.Add(new Field(id, id.val, mmod.IsGhost, ty, attrs)); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			FIdentType(out id, out ty);

 			mm.Add(new Field(id, id.val, mmod.IsGhost, ty, attrs)); 

@@ -984,13 +993,13 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		if (StartOf(9)) {

 			TypeIdentOptional(out id, out name, out ty, out isGhost);

 			formals.Add(new Formal(id, name, ty, true, isGhost)); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				TypeIdentOptional(out id, out name, out ty, out isGhost);

 				formals.Add(new Formal(id, name, ty, true, isGhost)); 

 			}

 		}

-		Expect(33);

+		Expect(12);

 	}

 

 	void FIdentType(out IToken/*!*/ id, out Type/*!*/ ty) {

@@ -1011,7 +1020,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		Contract.Ensures(Contract.ValueAtReturn(out id)!=null);

 		Contract.Ensures(Contract.ValueAtReturn(out ty)!=null);

 		isGhost = false; 

-		if (la.kind == 24) {

+		if (la.kind == 25) {

 			Get();

 			if (allowGhostKeyword) { isGhost = true; } else { SemErr(t, "formal cannot be declared 'ghost' in this context"); } 

 		}

@@ -1028,7 +1037,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 	void WildIdent(out IToken/*!*/ x, bool allowWildcardId) {

 		Contract.Ensures(Contract.ValueAtReturn(out x) != null); 

 		Expect(1);

-		x = t; 

+		x = t;

 		if (x.val.StartsWith("_")) {

 		 if (allowWildcardId && x.val.Length == 1) {

 		   t.val = "_v" + anonymousIds++;

@@ -1074,7 +1083,7 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		Contract.Ensures(Contract.ValueAtReturn(out ty)!=null);

 		Contract.Ensures(Contract.ValueAtReturn(out identName)!=null);

 		string name = null; id = Token.NoToken; ty = new BoolType()/*dummy*/; isGhost = false; 

-		if (la.kind == 24) {

+		if (la.kind == 25) {

 			Get();

 			isGhost = true; 

 		}

@@ -1106,8 +1115,9 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 	}

 

 	void TypeAndToken(out IToken/*!*/ tok, out Type/*!*/ ty) {

-		Contract.Ensures(Contract.ValueAtReturn(out tok)!=null); Contract.Ensures(Contract.ValueAtReturn(out ty) != null); tok = Token.NoToken;  ty = new BoolType();  /*keep compiler happy*/

-		List<Type/*!*/>/*!*/ gt;

+		Contract.Ensures(Contract.ValueAtReturn(out tok)!=null); Contract.Ensures(Contract.ValueAtReturn(out ty) != null);

+		tok = Token.NoToken;  ty = new BoolType();  /*keep compiler happy*/

+		List<Type> gt;

 		

 		switch (la.kind) {

 		case 52: {

@@ -1186,6 +1196,30 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 			

 			break;

 		}

+		case 11: {

+			Get();

+			tok = t; gt = new List<Type>(); 

+			if (StartOf(10)) {

+				Type(out ty);

+				gt.Add(ty); 

+				while (la.kind == 31) {

+					Get();

+					Type(out ty);

+					gt.Add(ty); 

+				}

+			}

+			Expect(12);

+			if (gt.Count == 1) {

+			 // just return the type 'ty'

+			} else {

+			 // make sure the nullary tuple type exists

+			 var dims = gt.Count;

+			 var tmp = theBuiltIns.TupleType(tok, dims, true);

+			 ty = new UserDefinedType(tok, BuiltIns.TupleTypeName(dims), gt, new List<IToken>());

+			}

+			

+			break;

+		}

 		case 1: case 5: case 60: {

 			ReferenceType(out tok, out ty);

 			break;

@@ -1198,16 +1232,16 @@ bool SemiFollowsCall(bool allowSemi, Expression e) {
 		Contract.Requires(cce.NonNullElements(formals)); IToken/*!*/ id;  Type/*!*/ ty;  bool isGhost; 

 		Expect(11);

 		openParen = t; 

-		if (la.kind == 1 || la.kind == 24) {

+		if (la.kind == 1 || la.kind == 25) {

 			GIdentType(allowGhostKeyword, out id, out ty, out isGhost);

 			formals.Add(new Formal(id, id.val, ty, incoming, isGhost)); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				GIdentType(allowGhostKeyword, out id, out ty, out isGhost);

 				formals.Add(new Formal(id, id.val, ty, incoming, isGhost)); 

 			}

 		}

-		Expect(33);

+		Expect(12);

 	}

 

 	void IteratorSpec(List<FrameExpression/*!*/>/*!*/ reads, List<FrameExpression/*!*/>/*!*/ mod, List<Expression/*!*/> decreases,

@@ -1225,7 +1259,7 @@ ref Attributes readsAttrs, ref Attributes modAttrs, ref Attributes decrAttrs) {
 			if (StartOf(12)) {

 				FrameExpression(out fe);

 				reads.Add(fe); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					FrameExpression(out fe);

 					reads.Add(fe); 

@@ -1241,7 +1275,7 @@ ref Attributes readsAttrs, ref Attributes modAttrs, ref Attributes decrAttrs) {
 			if (StartOf(12)) {

 				FrameExpression(out fe);

 				mod.Add(fe); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					FrameExpression(out fe);

 					mod.Add(fe); 

@@ -1323,7 +1357,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			if (StartOf(12)) {

 				FrameExpression(out fe);

 				mod.Add(fe); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					FrameExpression(out fe);

 					mod.Add(fe); 

@@ -1410,7 +1444,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		 decreases.Add(e);

 		}

 		

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			PossiblyWildExpression(out e);

 			if (!allowWildcard && e is WildcardExpr) {

@@ -1427,7 +1461,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		Expect(38);

 		Type(out ty);

 		gt.Add(ty); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			Type(out ty);

 			gt.Add(ty); 

@@ -1438,7 +1472,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 	void ReferenceType(out IToken/*!*/ tok, out Type/*!*/ ty) {

 		Contract.Ensures(Contract.ValueAtReturn(out tok) != null); Contract.Ensures(Contract.ValueAtReturn(out ty) != null);

 		tok = Token.NoToken;  ty = new BoolType();  /*keep compiler happy*/

-		List<Type/*!*/>/*!*/ gt;

+		List<Type> gt;

 		List<IToken> path;

 		

 		if (la.kind == 60) {

@@ -1446,20 +1480,16 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			tok = t;  ty = new ObjectType(); 

 		} else if (la.kind == 5) {

 			Get();

-			tok = t;  gt = new List<Type/*!*/>(); 

-			GenericInstantiation(gt);

-			if (gt.Count != 1) {

-			 SemErr("array type expects exactly one type argument");

-			}

-			int dims = 1;

-			if (tok.val.Length != 5) {

-			 dims = int.Parse(tok.val.Substring(5));

+			tok = t;  gt = new List<Type>(); 

+			if (la.kind == 38) {

+				GenericInstantiation(gt);

 			}

-			ty = theBuiltIns.ArrayType(tok, dims, gt[0], true);

+			int dims = tok.val.Length == 5 ? 1 : int.Parse(tok.val.Substring(5));

+			ty = theBuiltIns.ArrayType(tok, dims, gt, true);

 			

 		} else if (la.kind == 1) {

 			Ident(out tok);

-			gt = new List<Type/*!*/>();

+			gt = new List<Type>();

 			path = new List<IToken>(); 

 			while (la.kind == 61) {

 				path.Add(tok); 

@@ -1490,7 +1520,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			if (StartOf(17)) {

 				PossiblyWildFrameExpression(out fe);

 				reads.Add(fe); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					PossiblyWildFrameExpression(out fe);

 					reads.Add(fe); 

@@ -1528,7 +1558,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 

 	void PossiblyWildFrameExpression(out FrameExpression/*!*/ fe) {

 		Contract.Ensures(Contract.ValueAtReturn(out fe) != null); fe = dummyFrameExpr; 

-		if (la.kind == 12) {

+		if (la.kind == 13) {

 			Get();

 			fe = new FrameExpression(t, new WildcardExpr(t), null); 

 		} else if (StartOf(12)) {

@@ -1539,7 +1569,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 	void PossiblyWildExpression(out Expression/*!*/ e) {

 		Contract.Ensures(Contract.ValueAtReturn(out e)!=null);

 		e = dummyExpr; 

-		if (la.kind == 12) {

+		if (la.kind == 13) {

 			Get();

 			e = new WildcardExpr(t); 

 		} else if (StartOf(16)) {

@@ -1580,11 +1610,11 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			PrintStmt(out s);

 			break;

 		}

-		case 1: case 2: case 3: case 4: case 11: case 28: case 54: case 55: case 113: case 114: case 115: case 116: case 117: case 118: {

+		case 1: case 2: case 3: case 4: case 11: case 29: case 54: case 55: case 113: case 114: case 115: case 116: case 117: case 118: {

 			UpdateStmt(out s);

 			break;

 		}

-		case 24: case 29: {

+		case 25: case 30: {

 			VarDeclStatement(out s);

 			break;

 		}

@@ -1708,7 +1738,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		x = t; 

 		AttributeArg(out arg, false);

 		args.Add(arg); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			AttributeArg(out arg, false);

 			args.Add(arg); 

@@ -1735,9 +1765,9 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			}

 			Expect(8);

 			endTok = t; rhss.Add(new ExprRhs(e, attrs)); 

-		} else if (la.kind == 30 || la.kind == 69 || la.kind == 71) {

+		} else if (la.kind == 31 || la.kind == 69 || la.kind == 71) {

 			lhss.Add(e);  lhs0 = e; 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				Lhs(out e);

 				lhss.Add(e); 

@@ -1747,7 +1777,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 				x = t; 

 				Rhs(out r, lhs0);

 				rhss.Add(r); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					Rhs(out r, lhs0);

 					rhss.Add(r); 

@@ -1790,18 +1820,18 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		Attributes attrs = null;

 		IToken endTok;

 		

-		if (la.kind == 24) {

+		if (la.kind == 25) {

 			Get();

 			isGhost = true;  x = t; 

 		}

-		Expect(29);

+		Expect(30);

 		if (!isGhost) { x = t; } 

 		while (la.kind == 9) {

 			Attribute(ref attrs);

 		}

 		LocalIdentTypeOptional(out d, isGhost);

 		lhss.Add(d); d.Attributes = attrs; attrs = null; 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			while (la.kind == 9) {

 				Attribute(ref attrs);

@@ -1817,7 +1847,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 				

 				Rhs(out r, lhs0);

 				rhss.Add(r); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					Rhs(out r, lhs0);

 					rhss.Add(r); 

@@ -1954,17 +1984,26 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 	void MatchStmt(out Statement/*!*/ s) {

 		Contract.Ensures(Contract.ValueAtReturn(out s) != null);

 		Token x;  Expression/*!*/ e;  MatchCaseStmt/*!*/ c;

-		List<MatchCaseStmt/*!*/> cases = new List<MatchCaseStmt/*!*/>(); 

+		List<MatchCaseStmt/*!*/> cases = new List<MatchCaseStmt/*!*/>();

+		bool usesOptionalBrace = false;

+		

 		Expect(82);

 		x = t; 

 		Expression(out e, true);

-		Expect(9);

+		if (la.kind == 9) {

+			Get();

+			usesOptionalBrace = true; 

+		}

 		while (la.kind == 78) {

 			CaseStatement(out c);

 			cases.Add(c); 

 		}

-		Expect(10);

-		s = new MatchStmt(x, t, e, cases); 

+		if (CloseOptionalBrace(usesOptionalBrace)) {

+			Expect(10);

+		} else if (StartOf(21)) {

+			if (usesOptionalBrace) { SemErr(t, "expecting close curly brace"); } 

+		} else SynErr(187);

+		s = new MatchStmt(x, t, e, cases, usesOptionalBrace); 

 	}

 

 	void ForallStmt(out Statement/*!*/ s) {

@@ -1977,18 +2016,19 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		var ens = new List<MaybeFreeExpression/*!*/>();

 		bool isFree;

 		Expression/*!*/ e;

-		BlockStmt/*!*/ block;

+		BlockStmt block = null;

 		IToken bodyStart, bodyEnd;

+		IToken tok = Token.NoToken;

 		

 		if (la.kind == 85) {

 			Get();

-			x = t; 

+			x = t; tok = x; 

 		} else if (la.kind == 86) {

 			Get();

 			x = t;

 			errors.Warning(t, "the 'parallel' keyword has been deprecated; the comprehension statement now uses the keyword 'forall' (and the parentheses around the bound variables are now optional)");

 			

-		} else SynErr(187);

+		} else SynErr(188);

 		if (la.kind == 11) {

 			Get();

 			usesOptionalParen = true; 

@@ -2002,12 +2042,11 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		if (bvars == null) { bvars = new List<BoundVar>(); }

 		if (range == null) { range = new LiteralExpr(x, true); }

 		

-		if (la.kind == 33) {

-			Get();

-			if (!usesOptionalParen) { SemErr(t, "found but didn't expect a close parenthesis"); } 

-		} else if (la.kind == 9 || la.kind == 46 || la.kind == 48) {

+		if (CloseOptionalParen(usesOptionalParen)) {

+			Expect(12);

+		} else if (StartOf(22)) {

 			if (usesOptionalParen) { SemErr(t, "expecting close parenthesis"); } 

-		} else SynErr(188);

+		} else SynErr(189);

 		while (la.kind == 46 || la.kind == 48) {

 			isFree = false; 

 			if (la.kind == 46) {

@@ -2016,19 +2055,30 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			}

 			Expect(48);

 			Expression(out e, false);

-			Expect(8);

 			ens.Add(new MaybeFreeExpression(e, isFree)); 

+			Expect(8);

+			tok = t; 

+		}

+		if (la.kind == 9) {

+			BlockStmt(out block, out bodyStart, out bodyEnd);

 		}

-		BlockStmt(out block, out bodyStart, out bodyEnd);

-		s = new ForallStmt(x, block.EndTok, bvars, attrs, range, ens, block); 

+		if (DafnyOptions.O.DisallowSoundnessCheating && block == null && 0 < ens.Count) {

+		  SemErr(t, "a forall statement with an ensures clause must have a body");

+		}

+		

+		if (block != null) {

+		  tok = block.EndTok;

+		}

+		s = new ForallStmt(x, tok, bvars, attrs, range, ens, block);

+		

 	}

 

 	void CalcStmt(out Statement/*!*/ s) {

 		Contract.Ensures(Contract.ValueAtReturn(out s) != null);

 		Token x;

-		CalcStmt.CalcOp/*!*/ op, calcOp = Microsoft.Dafny.CalcStmt.DefaultOp, resOp = Microsoft.Dafny.CalcStmt.DefaultOp;     

+		CalcStmt.CalcOp/*!*/ op, calcOp = Microsoft.Dafny.CalcStmt.DefaultOp, resOp = Microsoft.Dafny.CalcStmt.DefaultOp;

 		var lines = new List<Expression/*!*/>();

-		var hints = new List<BlockStmt/*!*/>(); 

+		var hints = new List<BlockStmt/*!*/>();

 		CalcStmt.CalcOp stepOp;

 		var stepOps = new List<CalcStmt.CalcOp>();

 		CalcStmt.CalcOp maybeOp;

@@ -2039,13 +2089,13 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		

 		Expect(88);

 		x = t; 

-		if (StartOf(21)) {

+		if (StartOf(23)) {

 			CalcOp(out opTok, out calcOp);

 			maybeOp = calcOp.ResultOp(calcOp); // guard against non-transitive calcOp (like !=)

 			if (maybeOp == null) {

 			 SemErr(opTok, "the main operator of a calculation must be transitive");

 			}

-			resOp = calcOp; 

+			resOp = calcOp;

 			

 		}

 		Expect(9);

@@ -2053,7 +2103,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Expression(out e, false);

 			lines.Add(e); stepOp = calcOp; danglingOperator = null; 

 			Expect(8);

-			if (StartOf(21)) {

+			if (StartOf(23)) {

 				CalcOp(out opTok, out op);

 				maybeOp = resOp.ResultOp(op);

 				if (maybeOp == null) {

@@ -2078,8 +2128,8 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		if (lines.Count > 0) {

 		 // Repeat the last line to create a dummy line for the dangling hint

 		 lines.Add(lines[lines.Count - 1]);

-		}  

-		s = new CalcStmt(x, t, calcOp, lines, hints, stepOps, resOp); 

+		}

+		s = new CalcStmt(x, t, calcOp, lines, hints, stepOps, resOp);

 		

 	}

 

@@ -2095,11 +2145,11 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		while (IsAttribute()) {

 			Attribute(ref attrs);

 		}

-		if (StartOf(22)) {

+		if (StartOf(24)) {

 			if (StartOf(12)) {

 				FrameExpression(out fe);

 				mod.Add(fe); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					FrameExpression(out fe);

 					mod.Add(fe); 

@@ -2112,10 +2162,10 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		if (la.kind == 9) {

 			BlockStmt(out body, out bodyStart, out endTok);

 		} else if (la.kind == 8) {

-			while (!(la.kind == 0 || la.kind == 8)) {SynErr(189); Get();}

+			while (!(la.kind == 0 || la.kind == 8)) {SynErr(190); Get();}

 			Get();

 			endTok = t; 

-		} else SynErr(190);

+		} else SynErr(191);

 		s = new ModifyStmt(tok, endTok, mod, attrs, body);

 		if (ellipsisToken != null) {

 		 s = new SkeletonStatement(s, ellipsisToken, null);

@@ -2135,11 +2185,11 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		} else if (la.kind == 51) {

 			Get();

 			returnTok = t; isYield = true; 

-		} else SynErr(191);

-		if (StartOf(23)) {

+		} else SynErr(192);

+		if (StartOf(25)) {

 			Rhs(out r, null);

 			rhss = new List<AssignmentRhs>(); rhss.Add(r); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				Rhs(out r, null);

 				rhss.Add(r); 

@@ -2166,7 +2216,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			names = new List<IToken>(); exprs = new List<Expression>(); whereTok = t;

 			Ident(out tok);

 			names.Add(tok); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				Ident(out tok);

 				names.Add(tok); 

@@ -2174,7 +2224,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Expect(69);

 			Expression(out e, false);

 			exprs.Add(e); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				Expression(out e, false);

 				exprs.Add(e); 

@@ -2208,7 +2258,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 					ee = new List<Expression>(); 

 					Expressions(ee);

 					Expect(75);

-					UserDefinedType tmp = theBuiltIns.ArrayType(x, ee.Count, new IntType(), true);

+					var tmp = theBuiltIns.ArrayType(ee.Count, new IntType(), true);

 					

 				} else {

 					x = null; args = new List<Expression/*!*/>(); 

@@ -2220,7 +2270,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 					if (StartOf(16)) {

 						Expressions(args);

 					}

-					Expect(33);

+					Expect(12);

 				}

 			}

 			if (ee != null) {

@@ -2231,13 +2281,13 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			 r = new TypeRhs(newToken, ty);

 			}

 			

-		} else if (la.kind == 12) {

+		} else if (la.kind == 13) {

 			Get();

 			r = new HavocRhs(t); 

 		} else if (StartOf(16)) {

 			Expression(out e, false);

 			r = new ExprRhs(e); 

-		} else SynErr(192);

+		} else SynErr(193);

 		while (la.kind == 9) {

 			Attribute(ref attrs);

 		}

@@ -2252,20 +2302,20 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			while (la.kind == 61 || la.kind == 74) {

 				Suffix(ref e);

 			}

-		} else if (StartOf(24)) {

+		} else if (StartOf(26)) {

 			ConstAtomExpression(out e);

 			Suffix(ref e);

 			while (la.kind == 61 || la.kind == 74) {

 				Suffix(ref e);

 			}

-		} else SynErr(193);

+		} else SynErr(194);

 	}

 

 	void Expressions(List<Expression/*!*/>/*!*/ args) {

 		Contract.Requires(cce.NonNullElements(args)); Expression/*!*/ e; 

 		Expression(out e, true);

 		args.Add(e); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			Expression(out e, true);

 			args.Add(e); 

@@ -2296,18 +2346,18 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 

 	void Guard(out Expression e) {

 		Expression/*!*/ ee;  e = null; 

-		if (la.kind == 12) {

+		if (la.kind == 13) {

 			Get();

 			e = null; 

 		} else if (IsParenStar()) {

 			Expect(11);

+			Expect(13);

 			Expect(12);

-			Expect(33);

 			e = null; 

 		} else if (StartOf(16)) {

 			Expression(out ee, true);

 			e = ee; 

-		} else SynErr(194);

+		} else SynErr(195);

 	}

 

 	void LoopSpec(out List<MaybeFreeExpression/*!*/> invariants, out List<Expression/*!*/> decreases, out List<FrameExpression/*!*/> mod, ref Attributes decAttrs, ref Attributes modAttrs) {

@@ -2317,23 +2367,23 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		decreases = new List<Expression/*!*/>();

 		mod = null;

 		

-		while (StartOf(25)) {

+		while (StartOf(27)) {

 			if (la.kind == 46 || la.kind == 81) {

 				Invariant(out invariant);

-				while (!(la.kind == 0 || la.kind == 8)) {SynErr(195); Get();}

+				while (!(la.kind == 0 || la.kind == 8)) {SynErr(196); Get();}

 				Expect(8);

 				invariants.Add(invariant); 

 			} else if (la.kind == 49) {

-				while (!(la.kind == 0 || la.kind == 49)) {SynErr(196); Get();}

+				while (!(la.kind == 0 || la.kind == 49)) {SynErr(197); Get();}

 				Get();

 				while (IsAttribute()) {

 					Attribute(ref decAttrs);

 				}

 				DecreasesList(decreases, true);

-				while (!(la.kind == 0 || la.kind == 8)) {SynErr(197); Get();}

+				while (!(la.kind == 0 || la.kind == 8)) {SynErr(198); Get();}

 				Expect(8);

 			} else {

-				while (!(la.kind == 0 || la.kind == 45)) {SynErr(198); Get();}

+				while (!(la.kind == 0 || la.kind == 45)) {SynErr(199); Get();}

 				Get();

 				while (IsAttribute()) {

 					Attribute(ref modAttrs);

@@ -2342,13 +2392,13 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 				if (StartOf(12)) {

 					FrameExpression(out fe);

 					mod.Add(fe); 

-					while (la.kind == 30) {

+					while (la.kind == 31) {

 						Get();

 						FrameExpression(out fe);

 						mod.Add(fe); 

 					}

 				}

-				while (!(la.kind == 0 || la.kind == 8)) {SynErr(199); Get();}

+				while (!(la.kind == 0 || la.kind == 8)) {SynErr(200); Get();}

 				Expect(8);

 			}

 		}

@@ -2356,7 +2406,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 

 	void Invariant(out MaybeFreeExpression/*!*/ invariant) {

 		bool isFree = false; Expression/*!*/ e; List<string> ids = new List<string>(); invariant = null; Attributes attrs = null; 

-		while (!(la.kind == 0 || la.kind == 46 || la.kind == 81)) {SynErr(200); Get();}

+		while (!(la.kind == 0 || la.kind == 46 || la.kind == 81)) {SynErr(201); Get();}

 		if (la.kind == 46) {

 			Get();

 			isFree = true; 

@@ -2383,12 +2433,12 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 			IdentTypeOptional(out bv);

 			arguments.Add(bv); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				IdentTypeOptional(out bv);

 				arguments.Add(bv); 

 			}

-			Expect(33);

+			Expect(12);

 		}

 		Expect(79);

 		while (StartOf(14)) {

@@ -2405,7 +2455,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		} else if (StartOf(16)) {

 			Expression(out e, allowSemi);

 			arg = new Attributes.Argument(t, e); 

-		} else SynErr(201);

+		} else SynErr(202);

 	}

 

 	void QuantifierDomain(out List<BoundVar> bvars, out Attributes attrs, out Expression range) {

@@ -2416,7 +2466,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		

 		IdentTypeOptional(out bv);

 		bvars.Add(bv); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			IdentTypeOptional(out bv);

 			bvars.Add(bv); 

@@ -2424,7 +2474,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		while (IsAttribute()) {

 			Attribute(ref attrs);

 		}

-		if (la.kind == 28) {

+		if (la.kind == 29) {

 			Get();

 			Expression(out range, true);

 		}

@@ -2436,7 +2486,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		x = null;

 		

 		switch (la.kind) {

-		case 32: {

+		case 33: {

 			Get();

 			x = t;  binOp = BinaryExpr.Opcode.Eq; 

 			if (la.kind == 89) {

@@ -2502,7 +2552,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			x = t;  binOp = BinaryExpr.Opcode.Exp; 

 			break;

 		}

-		default: SynErr(202); break;

+		default: SynErr(203); break;

 		}

 		if (k == null) {

 		 op = new Microsoft.Dafny.CalcStmt.BinaryCalcOp(binOp);

@@ -2514,7 +2564,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 

 	void Hint(out BlockStmt s) {

 		Contract.Ensures(Contract.ValueAtReturn(out s) != null); // returns an empty block statement if the hint is empty

-		var subhints = new List<Statement/*!*/>(); 

+		var subhints = new List<Statement/*!*/>();

 		IToken bodyStart, bodyEnd;

 		BlockStmt/*!*/ block;

 		Statement/*!*/ calc;

@@ -2530,7 +2580,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 				endTok = calc.EndTok; subhints.Add(calc); 

 			}

 		}

-		s = new BlockStmt(x, endTok, subhints); // if the hint is empty x is the first token of the next line, but it doesn't matter cause the block statement is just used as a container 

+		s = new BlockStmt(x, endTok, subhints); // if the hint is empty x is the first token of the next line, but it doesn't matter cause the block statement is just used as a container

 		

 	}

 

@@ -2539,7 +2589,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 97) {

 			Get();

-		} else SynErr(203);

+		} else SynErr(204);

 	}

 

 	void ImpliesOp() {

@@ -2547,7 +2597,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 99) {

 			Get();

-		} else SynErr(204);

+		} else SynErr(205);

 	}

 

 	void ExpliesOp() {

@@ -2555,7 +2605,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 101) {

 			Get();

-		} else SynErr(205);

+		} else SynErr(206);

 	}

 

 	void EquivExpression(out Expression e0, bool allowSemi) {

@@ -2572,7 +2622,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 	void ImpliesExpliesExpression(out Expression e0, bool allowSemi) {

 		Contract.Ensures(Contract.ValueAtReturn(out e0) != null); IToken/*!*/ x;  Expression/*!*/ e1; 

 		LogicalExpression(out e0, allowSemi);

-		if (StartOf(26)) {

+		if (StartOf(28)) {

 			if (la.kind == 98 || la.kind == 99) {

 				ImpliesOp();

 				x = t; 

@@ -2596,7 +2646,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 	void LogicalExpression(out Expression e0, bool allowSemi) {

 		Contract.Ensures(Contract.ValueAtReturn(out e0) != null); IToken/*!*/ x;  Expression/*!*/ e1; 

 		RelationalExpression(out e0, allowSemi);

-		if (StartOf(27)) {

+		if (StartOf(29)) {

 			if (la.kind == 102 || la.kind == 103) {

 				AndOp();

 				x = t; 

@@ -2650,7 +2700,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		

 		Term(out e0, allowSemi);

 		e = e0; 

-		if (StartOf(28)) {

+		if (StartOf(30)) {

 			RelOp(out x, out op, out k);

 			firstOpTok = x; 

 			Term(out e1, allowSemi);

@@ -2663,7 +2713,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			 e = new TernaryExpr(x, op == BinaryExpr.Opcode.Eq ? TernaryExpr.Opcode.PrefixEqOp : TernaryExpr.Opcode.PrefixNeqOp, k, e0, e1);

 			}

 			

-			while (StartOf(28)) {

+			while (StartOf(30)) {

 				if (chain == null) {

 				 chain = new List<Expression>();

 				 ops = new List<BinaryExpr.Opcode>();

@@ -2740,7 +2790,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 103) {

 			Get();

-		} else SynErr(206);

+		} else SynErr(207);

 	}

 

 	void OrOp() {

@@ -2748,7 +2798,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 105) {

 			Get();

-		} else SynErr(207);

+		} else SynErr(208);

 	}

 

 	void Term(out Expression e0, bool allowSemi) {

@@ -2768,7 +2818,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		k = null;

 		

 		switch (la.kind) {

-		case 32: {

+		case 33: {

 			Get();

 			x = t;  op = BinaryExpr.Opcode.Eq; 

 			if (la.kind == 89) {

@@ -2815,7 +2865,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			x = t;  op = BinaryExpr.Opcode.In; 

 			break;

 		}

-		case 13: {

+		case 14: {

 			Get();

 			x = t;  op = BinaryExpr.Opcode.NotIn; 

 			break;

@@ -2853,14 +2903,14 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			x = t;  op = BinaryExpr.Opcode.Ge; 

 			break;

 		}

-		default: SynErr(208); break;

+		default: SynErr(209); break;

 		}

 	}

 

 	void Factor(out Expression e0, bool allowSemi) {

 		Contract.Ensures(Contract.ValueAtReturn(out e0) != null); IToken/*!*/ x;  Expression/*!*/ e1;  BinaryExpr.Opcode op; 

 		UnaryExpression(out e0, allowSemi);

-		while (la.kind == 12 || la.kind == 110 || la.kind == 111) {

+		while (la.kind == 13 || la.kind == 110 || la.kind == 111) {

 			MulOp(out x, out op);

 			UnaryExpression(out e1, allowSemi);

 			e0 = new BinaryExpr(x, op, e0, e1); 

@@ -2875,7 +2925,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		} else if (la.kind == 109) {

 			Get();

 			x = t;  op = BinaryExpr.Opcode.Sub; 

-		} else SynErr(209);

+		} else SynErr(210);

 	}

 

 	void UnaryExpression(out Expression e, bool allowSemi) {

@@ -2895,7 +2945,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			e = new UnaryExpr(x, UnaryExpr.Opcode.Not, e); 

 			break;

 		}

-		case 24: case 29: case 56: case 66: case 72: case 76: case 82: case 83: case 85: case 88: case 121: case 122: case 123: {

+		case 25: case 30: case 56: case 66: case 72: case 76: case 82: case 83: case 85: case 88: case 121: case 122: case 123: {

 			EndlessExpression(out e, allowSemi);

 			break;

 		}

@@ -2930,25 +2980,25 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 				}

 			} else if (la.kind == 1) {

 				MapComprehensionExpr(x, out e, allowSemi);

-			} else if (StartOf(29)) {

+			} else if (StartOf(31)) {

 				SemErr("map must be followed by literal in brackets or comprehension."); 

-			} else SynErr(210);

+			} else SynErr(211);

 			break;

 		}

-		case 2: case 3: case 4: case 11: case 28: case 54: case 55: case 113: case 114: case 115: case 116: case 117: case 118: {

+		case 2: case 3: case 4: case 11: case 29: case 54: case 55: case 113: case 114: case 115: case 116: case 117: case 118: {

 			ConstAtomExpression(out e);

 			while (la.kind == 61 || la.kind == 74) {

 				Suffix(ref e);

 			}

 			break;

 		}

-		default: SynErr(211); break;

+		default: SynErr(212); break;

 		}

 	}

 

 	void MulOp(out IToken x, out BinaryExpr.Opcode op) {

 		Contract.Ensures(Contract.ValueAtReturn(out x) != null); x = Token.NoToken;  op = BinaryExpr.Opcode.Add/*(dummy)*/; 

-		if (la.kind == 12) {

+		if (la.kind == 13) {

 			Get();

 			x = t;  op = BinaryExpr.Opcode.Mul; 

 		} else if (la.kind == 110) {

@@ -2957,7 +3007,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		} else if (la.kind == 111) {

 			Get();

 			x = t;  op = BinaryExpr.Opcode.Mod; 

-		} else SynErr(212);

+		} else SynErr(213);

 	}

 

 	void NegOp() {

@@ -2965,7 +3015,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 112) {

 			Get();

-		} else SynErr(213);

+		} else SynErr(214);

 	}

 

 	void EndlessExpression(out Expression e, bool allowSemi) {

@@ -3004,7 +3054,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			e = new StmtExpr(s.Tok, s, e); 

 			break;

 		}

-		case 24: case 29: {

+		case 25: case 30: {

 			LetExpr(out e, allowSemi);

 			break;

 		}

@@ -3012,7 +3062,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			NamedExpr(out e, allowSemi);

 			break;

 		}

-		default: SynErr(214); break;

+		default: SynErr(215); break;

 		}

 	}

 

@@ -3044,7 +3094,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			if (StartOf(16)) {

 				Expressions(args);

 			}

-			Expect(33);

+			Expect(12);

 		}

 		e = new IdentifierSequence(idents, openParen, args); 

 	}

@@ -3078,7 +3128,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 				if (StartOf(16)) {

 					Expressions(args);

 				}

-				Expect(33);

+				Expect(12);

 				e = new FunctionCallExpr(id, id.val, e, openParen, args); 

 			}

 			if (!func) { e = new ExprDotName(id, e, id.val); } 

@@ -3106,17 +3156,17 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 						 multipleLengths = new List<Expression>();

 						 multipleLengths.Add(e0);

 						}

-						takeRest = true;                                                  

+						takeRest = true;

 						

 						if (StartOf(16)) {

 							Expression(out ee, true);

-							multipleLengths.Add(ee); 

+							multipleLengths.Add(ee);

 							takeRest = false;

 							

 						}

 					}

-				} else if (la.kind == 30 || la.kind == 75) {

-					while (la.kind == 30) {

+				} else if (la.kind == 31 || la.kind == 75) {

+					while (la.kind == 31) {

 						Get();

 						Expression(out ee, true);

 						if (multipleIndices == null) {

@@ -3126,7 +3176,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 						multipleIndices.Add(ee);

 						

 					}

-				} else SynErr(215);

+				} else SynErr(216);

 			} else if (la.kind == 120) {

 				Get();

 				anyDots = true; 

@@ -3134,11 +3184,11 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 					Expression(out ee, true);

 					e1 = ee; 

 				}

-			} else SynErr(216);

+			} else SynErr(217);

 			if (multipleIndices != null) {

 			 e = new MultiSelectExpr(x, e, multipleIndices);

 			 // make sure an array class with this dimensionality exists

-			 UserDefinedType tmp = theBuiltIns.ArrayType(x, multipleIndices.Count, new IntType(), true);

+			 var tmp = theBuiltIns.ArrayType(multipleIndices.Count, new IntType(), true);

 			} else {

 			 if (!anyDots && e0 == null) {

 			   /* a parsing error occurred */

@@ -3175,7 +3225,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			}

 			

 			Expect(75);

-		} else SynErr(217);

+		} else SynErr(218);

 	}

 

 	void DisplayExpr(out Expression e) {

@@ -3199,7 +3249,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			}

 			e = new SeqDisplayExpr(x, elements); 

 			Expect(75);

-		} else SynErr(218);

+		} else SynErr(219);

 	}

 

 	void MultiSetExpr(out Expression e) {

@@ -3222,10 +3272,10 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			x = t;  elements = new List<Expression/*!*/>(); 

 			Expression(out e, true);

 			e = new MultiSetFormingExpr(x, e); 

-			Expect(33);

-		} else if (StartOf(30)) {

+			Expect(12);

+		} else if (StartOf(32)) {

 			SemErr("multiset must be followed by multiset literal or expression to coerce in parentheses."); 

-		} else SynErr(219);

+		} else SynErr(220);

 	}

 

 	void MapDisplayExpr(IToken/*!*/ mapToken, out Expression e) {

@@ -3250,7 +3300,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		

 		IdentTypeOptional(out bv);

 		bvars.Add(bv); 

-		if (la.kind == 28) {

+		if (la.kind == 29) {

 			Get();

 			Expression(out range, true);

 		}

@@ -3301,7 +3351,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			x = t; 

 			Expect(11);

 			Expression(out e, true);

-			Expect(33);

+			Expect(12);

 			e = new FreshExpr(x, e); 

 			break;

 		}

@@ -3310,24 +3360,20 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			x = t; 

 			Expect(11);

 			Expression(out e, true);

-			Expect(33);

+			Expect(12);

 			e = new OldExpr(x, e); 

 			break;

 		}

-		case 28: {

+		case 29: {

 			Get();

 			x = t; 

 			Expression(out e, true);

 			e = new UnaryExpr(x, UnaryExpr.Opcode.SeqLength, e); 

-			Expect(28);

+			Expect(29);

 			break;

 		}

 		case 11: {

-			Get();

-			x = t; 

-			Expression(out e, true);

-			e = new ParensExpression(x, e); 

-			Expect(33);

+			ParensExpression(out e);

 			break;

 		}

 		case 55: {

@@ -3336,10 +3382,10 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Expect(11);

 			IToken openParen = t; 

 			Expression(out e, true);

-			Expect(33);

+			Expect(12);

 			IToken classTok = new Token(t.line, t.col); classTok.val = "Real";

 			IToken fnTok = new Token(t.line, t.col); fnTok.val = "IntToReal";

-			//e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e }); 

+			//e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e });

 			e = new FunctionCallExpr(x, "IntToReal", new StaticReceiverExpr(x, theBuiltIns.RealClass), openParen, new List<Expression/*!*/>() { e });

 			

 			break;

@@ -3350,15 +3396,15 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Expect(11);

 			IToken openParen = t; 

 			Expression(out e, true);

-			Expect(33);

+			Expect(12);

 			IToken classTok = new Token(t.line, t.col); classTok.val = "Real";

 			IToken fnTok = new Token(t.line, t.col); fnTok.val = "RealToInt";

-			//e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e }); 

+			//e = new IdentifierSequence(new List<IToken>() { classTok, fnTok }, openParen, new List<Expression/*!*/>() { e });

 			e = new FunctionCallExpr(x, "RealToInt", new StaticReceiverExpr(x, theBuiltIns.RealClass), openParen, new List<Expression/*!*/>() { e });

 			

 			break;

 		}

-		default: SynErr(220); break;

+		default: SynErr(221); break;

 		}

 	}

 

@@ -3383,7 +3429,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			 n = BigInteger.Zero;

 			}

 			

-		} else SynErr(221);

+		} else SynErr(222);

 	}

 

 	void Dec(out Basetypes.BigDec d) {

@@ -3398,6 +3444,41 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		

 	}

 

+	void ParensExpression(out Expression e) {

+		IToken x;

+		List<Expression> args = null;

+		

+		Expect(11);

+		x = t; e = null; 

+		if (la.kind == 12) {

+			Get();

+			var tmp = theBuiltIns.TupleType(x, 0, true);

+			e = new DatatypeValue(x, BuiltIns.TupleTypeName(0), BuiltIns.TupleTypeCtorName, new List<Expression>());

+			

+		} else if (StartOf(16)) {

+			Expression(out e, true);

+			while (la.kind == 31) {

+				Get();

+				if (args == null) {

+				 args = new List<Expression>();

+				 args.Add(e);  // add the first argument, which was parsed above

+				}

+				

+				Expression(out e, true);

+				args.Add(e); 

+			}

+			Expect(12);

+			if (args == null) {

+			 e = new ParensExpression(x, e);

+			} else {

+			 // make sure the corresponding tuple type exists

+			 var tmp = theBuiltIns.TupleType(x, args.Count, true);

+			 e = new DatatypeValue(x, BuiltIns.TupleTypeName(args.Count), BuiltIns.TupleTypeCtorName, args);

+			}

+			

+		} else SynErr(223);

+	}

+

 	void MapLiteralExpressions(out List<ExpressionPair> elements) {

 		Expression/*!*/ d, r;

 		elements = new List<ExpressionPair/*!*/>(); 

@@ -3405,7 +3486,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		Expect(69);

 		Expression(out r, true);

 		elements.Add(new ExpressionPair(d,r)); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			Expression(out d, true);

 			Expect(69);

@@ -3419,21 +3500,31 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 125) {

 			Get();

-		} else SynErr(222);

+		} else SynErr(224);

 	}

 

 	void MatchExpression(out Expression e, bool allowSemi) {

 		Contract.Ensures(Contract.ValueAtReturn(out e) != null); IToken/*!*/ x;  MatchCaseExpr/*!*/ c;

 		List<MatchCaseExpr/*!*/> cases = new List<MatchCaseExpr/*!*/>();

+		bool usesOptionalBrace = false;

 		

 		Expect(82);

 		x = t; 

 		Expression(out e, allowSemi);

+		if (la.kind == 9) {

+			Get();

+			usesOptionalBrace = true; 

+		}

 		while (la.kind == 78) {

 			CaseExpression(out c, allowSemi);

 			cases.Add(c); 

 		}

-		e = new MatchExpr(x, e, cases); 

+		if (CloseOptionalBrace(usesOptionalBrace)) {

+			Expect(10);

+		} else if (StartOf(31)) {

+			if (usesOptionalBrace) { SemErr(t, "expecting close curly brace"); } 

+		} else SynErr(225);

+		e = new MatchExpr(x, e, cases, usesOptionalBrace); 

 	}

 

 	void QuantifierGuts(out Expression q, bool allowSemi) {

@@ -3450,7 +3541,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		} else if (la.kind == 122 || la.kind == 123) {

 			Exists();

 			x = t; 

-		} else SynErr(223);

+		} else SynErr(226);

 		QuantifierDomain(out bvars, out attrs, out range);

 		QSep();

 		Expression(out body, allowSemi);

@@ -3474,12 +3565,12 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		x = t; 

 		IdentTypeOptional(out bv);

 		bvars.Add(bv); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			IdentTypeOptional(out bv);

 			bvars.Add(bv); 

 		}

-		Expect(28);

+		Expect(29);

 		Expression(out range, allowSemi);

 		if (la.kind == 124 || la.kind == 125) {

 			QSep();

@@ -3498,7 +3589,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			AssumeStmt(out s);

 		} else if (la.kind == 88) {

 			CalcStmt(out s);

-		} else SynErr(224);

+		} else SynErr(227);

 	}

 

 	void LetExpr(out Expression e, bool allowSemi) {

@@ -3510,17 +3601,17 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		bool exact = true;

 		e = dummyExpr;

 		

-		if (la.kind == 24) {

+		if (la.kind == 25) {

 			Get();

 			isGhost = true;  x = t; 

 		}

-		Expect(29);

+		Expect(30);

 		if (!isGhost) { x = t; } 

 		CasePattern(out pat);

 		if (isGhost) { pat.Vars.Iter(bv => bv.IsGhost = true); }

 		letLHSs.Add(pat);

 		

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			CasePattern(out pat);

 			if (isGhost) { pat.Vars.Iter(bv => bv.IsGhost = true); }

@@ -3538,10 +3629,10 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			 }

 			}

 			

-		} else SynErr(225);

+		} else SynErr(228);

 		Expression(out e, false);

 		letRHSs.Add(e); 

-		while (la.kind == 30) {

+		while (la.kind == 31) {

 			Get();

 			Expression(out e, false);

 			letRHSs.Add(e); 

@@ -3577,19 +3668,19 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			if (la.kind == 1) {

 				CasePattern(out pat);

 				arguments.Add(pat); 

-				while (la.kind == 30) {

+				while (la.kind == 31) {

 					Get();

 					CasePattern(out pat);

 					arguments.Add(pat); 

 				}

 			}

-			Expect(33);

+			Expect(12);

 			pat = new CasePattern(id, id.val, arguments); 

 		} else if (la.kind == 1) {

 			IdentTypeOptional(out bv);

-			pat = new CasePattern(bv.tok, bv); 

+			pat = new CasePattern(bv.tok, bv);

 			

-		} else SynErr(226);

+		} else SynErr(229);

 	}

 

 	void CaseExpression(out MatchCaseExpr c, bool allowSemi) {

@@ -3605,12 +3696,12 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 			IdentTypeOptional(out bv);

 			arguments.Add(bv); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				IdentTypeOptional(out bv);

 				arguments.Add(bv); 

 			}

-			Expect(33);

+			Expect(12);

 		}

 		Expect(79);

 		Expression(out body, allowSemi);

@@ -3622,7 +3713,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 121) {

 			Get();

-		} else SynErr(227);

+		} else SynErr(230);

 	}

 

 	void Exists() {

@@ -3630,7 +3721,7 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 			Get();

 		} else if (la.kind == 123) {

 			Get();

-		} else SynErr(228);

+		} else SynErr(231);

 	}

 

 	void AttributeBody(ref Attributes attrs) {

@@ -3641,10 +3732,10 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 		Expect(7);

 		Expect(1);

 		aName = t.val; 

-		if (StartOf(31)) {

+		if (StartOf(33)) {

 			AttributeArg(out aArg, true);

 			aArgs.Add(aArg); 

-			while (la.kind == 30) {

+			while (la.kind == 31) {

 				Get();

 				AttributeArg(out aArg, true);

 				aArgs.Add(aArg); 

@@ -3666,38 +3757,40 @@ List<Expression/*!*/>/*!*/ decreases, ref Attributes decAttrs, ref Attributes mo
 	}

 

 	static readonly bool[,]/*!*/ set = {

-		{T,T,T,T, T,x,x,x, T,T,x,T, x,x,x,x, x,x,x,x, x,x,x,T, T,x,T,T, T,T,x,x, x,x,T,x, x,T,x,x, T,T,T,T, T,T,T,T, T,T,T,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,x,x, T,T,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

-		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, T,x,T,x, x,x,x,T, T,T,T,T, x,T,x,T, x,x,T,x, x,x,x,x, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,x,x, x,T,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{T,T,T,T, T,x,x,x, T,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,T,x,T, T,T,T,x, x,x,T,x, x,T,x,x, T,T,T,T, T,T,T,T, T,T,T,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,x,x, T,T,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

+		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,x,T, x,x,x,x, T,T,T,T, T,x,T,x, T,x,T,x, x,x,x,x, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,x, x,x,T,x, x,x,x,x, x,x,x,x, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{T,x,x,x, x,x,x,x, x,T,T,T, x,x,x,T, T,x,T,x, x,x,x,T, T,T,T,T, x,T,x,T, x,x,T,x, x,x,T,x, T,T,T,T, T,x,x,T, T,T,T,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{T,x,x,x, x,x,x,x, x,T,T,T, x,x,x,x, T,T,x,T, x,x,x,x, T,T,T,T, T,x,T,x, T,x,T,x, x,x,T,x, T,T,T,T, T,x,x,T, T,T,T,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, T,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,T,T,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,T,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{x,T,T,x, x,T,x,x, x,x,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{x,T,x,x, x,T,x,x, x,x,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,T,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,T,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,T,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,x,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,x,x, T,x,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,x,x, T,x,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

 		{T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, T,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,T,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

-		{T,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,x,x, T,x,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, T,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, T,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

-		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,T,T, T,T,T,T, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,T,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

-		{x,T,T,T, T,x,x,x, x,T,x,T, T,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,T,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

-		{x,x,T,T, T,x,x,x, x,x,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,T,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,T,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{T,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,x,x, T,x,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,T,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,T,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,T,x, T,x,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,T,x, T,x,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,T,x, T,x,x,x, T,x,T,x, T,x,T,T, T,T,T,T, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

+		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,T,T, T,T,T,T, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,T,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{x,T,T,T, T,x,x,x, x,T,x,T, x,T,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,T,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x},

+		{x,x,T,T, T,x,x,x, x,x,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,T,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

 		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

-		{x,x,x,x, x,x,x,T, T,T,T,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,x,T,x, T,T,x,x, x,T,T,T, x,x,x,x, x,T,T,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,x,x, x,x,x,T, x,T,T,T, x,T,x,x, x,x,x,x, x,x,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, x,x,x,x, x,x,x,T, T,x,x,x, T,T,x,x},

-		{x,x,x,x, x,x,x,T, T,T,T,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, T,x,T,x, T,T,x,x, x,T,T,T, x,x,x,x, x,T,T,x, T,T,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,x,x, x,T,x,x, x,x,T,T, x,T,T,T, x,T,x,x, x,x,x,x, x,x,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, x,x,x,x, x,x,x,T, T,x,x,x, T,T,x,x},

-		{x,T,T,T, T,x,T,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, T,x,x,x, T,T,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x}

+		{x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,T,T, x,x,x,x, x,x,x,x, x,x,T,T, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x},

+		{x,T,T,T, T,x,x,T, T,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,T, x,T,x,x, x,T,T,T, x,x,x,x, x,T,T,x, T,T,x,T, x,x,T,T, x,x,x,x, x,x,x,x, x,T,T,T, x,T,T,x, T,x,x,T, T,T,T,T, T,T,T,T, T,T,T,T, T,x,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, x,T,T,T, T,T,T,T, T,x,x,x, T,T,x,x},

+		{x,T,T,T, T,x,x,T, T,T,T,T, T,T,T,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,T, x,T,x,x, x,T,T,T, x,x,x,x, x,T,T,x, T,T,x,T, x,x,T,T, x,x,x,x, x,T,x,x, x,T,T,T, x,T,T,x, T,x,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,x,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, T,T,T,T, x,T,T,T, T,T,T,T, T,x,x,x, T,T,x,x},

+		{x,T,T,T, T,x,T,x, x,T,x,T, x,x,x,x, x,x,x,x, x,x,x,x, x,T,x,x, x,T,T,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,T,T, T,T,x,T, x,x,x,x, x,x,T,x, x,x,x,x, T,x,T,x, T,x,x,x, x,x,T,T, x,T,x,x, T,x,x,x, x,x,x,x, x,x,x,x, x,x,x,x, x,x,x,T, x,T,x,x, T,T,T,T, T,T,T,x, x,T,T,T, x,x,x,x}

 

 	};

 } // end Parser

@@ -3734,28 +3827,28 @@ public class Errors {
 			case 9: s = "lbrace expected"; break;

 			case 10: s = "rbrace expected"; break;

 			case 11: s = "openparen expected"; break;

-			case 12: s = "star expected"; break;

-			case 13: s = "notIn expected"; break;

-			case 14: s = "\"include\" expected"; break;

-			case 15: s = "\"abstract\" expected"; break;

-			case 16: s = "\"module\" expected"; break;

-			case 17: s = "\"refines\" expected"; break;

-			case 18: s = "\"import\" expected"; break;

-			case 19: s = "\"opened\" expected"; break;

-			case 20: s = "\"=\" expected"; break;

-			case 21: s = "\"as\" expected"; break;

-			case 22: s = "\"default\" expected"; break;

-			case 23: s = "\"class\" expected"; break;

-			case 24: s = "\"ghost\" expected"; break;

-			case 25: s = "\"static\" expected"; break;

-			case 26: s = "\"datatype\" expected"; break;

-			case 27: s = "\"codatatype\" expected"; break;

-			case 28: s = "\"|\" expected"; break;

-			case 29: s = "\"var\" expected"; break;

-			case 30: s = "\",\" expected"; break;

-			case 31: s = "\"type\" expected"; break;

-			case 32: s = "\"==\" expected"; break;

-			case 33: s = "\")\" expected"; break;

+			case 12: s = "closeparen expected"; break;

+			case 13: s = "star expected"; break;

+			case 14: s = "notIn expected"; break;

+			case 15: s = "\"include\" expected"; break;

+			case 16: s = "\"abstract\" expected"; break;

+			case 17: s = "\"module\" expected"; break;

+			case 18: s = "\"refines\" expected"; break;

+			case 19: s = "\"import\" expected"; break;

+			case 20: s = "\"opened\" expected"; break;

+			case 21: s = "\"=\" expected"; break;

+			case 22: s = "\"as\" expected"; break;

+			case 23: s = "\"default\" expected"; break;

+			case 24: s = "\"class\" expected"; break;

+			case 25: s = "\"ghost\" expected"; break;

+			case 26: s = "\"static\" expected"; break;

+			case 27: s = "\"datatype\" expected"; break;

+			case 28: s = "\"codatatype\" expected"; break;

+			case 29: s = "\"|\" expected"; break;

+			case 30: s = "\"var\" expected"; break;

+			case 31: s = "\",\" expected"; break;

+			case 32: s = "\"type\" expected"; break;

+			case 33: s = "\"==\" expected"; break;

 			case 34: s = "\"iterator\" expected"; break;

 			case 35: s = "\"yields\" expected"; break;

 			case 36: s = "\"returns\" expected"; break;

@@ -3909,48 +4002,51 @@ public class Errors {
 			case 184: s = "invalid IfStmt"; break;

 			case 185: s = "invalid WhileStmt"; break;

 			case 186: s = "invalid WhileStmt"; break;

-			case 187: s = "invalid ForallStmt"; break;

+			case 187: s = "invalid MatchStmt"; break;

 			case 188: s = "invalid ForallStmt"; break;

-			case 189: s = "this symbol not expected in ModifyStmt"; break;

-			case 190: s = "invalid ModifyStmt"; break;

-			case 191: s = "invalid ReturnStmt"; break;

-			case 192: s = "invalid Rhs"; break;

-			case 193: s = "invalid Lhs"; break;

-			case 194: s = "invalid Guard"; break;

-			case 195: s = "this symbol not expected in LoopSpec"; break;

+			case 189: s = "invalid ForallStmt"; break;

+			case 190: s = "this symbol not expected in ModifyStmt"; break;

+			case 191: s = "invalid ModifyStmt"; break;

+			case 192: s = "invalid ReturnStmt"; break;

+			case 193: s = "invalid Rhs"; break;

+			case 194: s = "invalid Lhs"; break;

+			case 195: s = "invalid Guard"; break;

 			case 196: s = "this symbol not expected in LoopSpec"; break;

 			case 197: s = "this symbol not expected in LoopSpec"; break;

 			case 198: s = "this symbol not expected in LoopSpec"; break;

 			case 199: s = "this symbol not expected in LoopSpec"; break;

-			case 200: s = "this symbol not expected in Invariant"; break;

-			case 201: s = "invalid AttributeArg"; break;

-			case 202: s = "invalid CalcOp"; break;

-			case 203: s = "invalid EquivOp"; break;

-			case 204: s = "invalid ImpliesOp"; break;

-			case 205: s = "invalid ExpliesOp"; break;

-			case 206: s = "invalid AndOp"; break;

-			case 207: s = "invalid OrOp"; break;

-			case 208: s = "invalid RelOp"; break;

-			case 209: s = "invalid AddOp"; break;

-			case 210: s = "invalid UnaryExpression"; break;

+			case 200: s = "this symbol not expected in LoopSpec"; break;

+			case 201: s = "this symbol not expected in Invariant"; break;

+			case 202: s = "invalid AttributeArg"; break;

+			case 203: s = "invalid CalcOp"; break;

+			case 204: s = "invalid EquivOp"; break;

+			case 205: s = "invalid ImpliesOp"; break;

+			case 206: s = "invalid ExpliesOp"; break;

+			case 207: s = "invalid AndOp"; break;

+			case 208: s = "invalid OrOp"; break;

+			case 209: s = "invalid RelOp"; break;

+			case 210: s = "invalid AddOp"; break;

 			case 211: s = "invalid UnaryExpression"; break;

-			case 212: s = "invalid MulOp"; break;

-			case 213: s = "invalid NegOp"; break;

-			case 214: s = "invalid EndlessExpression"; break;

-			case 215: s = "invalid Suffix"; break;

+			case 212: s = "invalid UnaryExpression"; break;

+			case 213: s = "invalid MulOp"; break;

+			case 214: s = "invalid NegOp"; break;

+			case 215: s = "invalid EndlessExpression"; break;

 			case 216: s = "invalid Suffix"; break;

 			case 217: s = "invalid Suffix"; break;

-			case 218: s = "invalid DisplayExpr"; break;

-			case 219: s = "invalid MultiSetExpr"; break;

-			case 220: s = "invalid ConstAtomExpression"; break;

-			case 221: s = "invalid Nat"; break;

-			case 222: s = "invalid QSep"; break;

-			case 223: s = "invalid QuantifierGuts"; break;

-			case 224: s = "invalid StmtInExpr"; break;

-			case 225: s = "invalid LetExpr"; break;

-			case 226: s = "invalid CasePattern"; break;

-			case 227: s = "invalid Forall"; break;

-			case 228: s = "invalid Exists"; break;

+			case 218: s = "invalid Suffix"; break;

+			case 219: s = "invalid DisplayExpr"; break;

+			case 220: s = "invalid MultiSetExpr"; break;

+			case 221: s = "invalid ConstAtomExpression"; break;

+			case 222: s = "invalid Nat"; break;

+			case 223: s = "invalid ParensExpression"; break;

+			case 224: s = "invalid QSep"; break;

+			case 225: s = "invalid MatchExpression"; break;

+			case 226: s = "invalid QuantifierGuts"; break;

+			case 227: s = "invalid StmtInExpr"; break;

+			case 228: s = "invalid LetExpr"; break;

+			case 229: s = "invalid CasePattern"; break;

+			case 230: s = "invalid Forall"; break;

+			case 231: s = "invalid Exists"; break;

 

 			default: s = "error " + n; break;

 		}

diff --git a/Source/Dafny/Printer.cs b/Source/Dafny/Printer.cs
index 706f751c..3a0ab21c 100644
--- a/Source/Dafny/Printer.cs
+++ b/Source/Dafny/Printer.cs
@@ -48,7 +48,7 @@ namespace Microsoft.Dafny {
       Contract.Requires(expr != null);

       using (var wr = new System.IO.StringWriter()) {

         var pr = new Printer(wr);

-        pr.PrintExtendedExpr(expr, 0, true, false);        

+        pr.PrintExtendedExpr(expr, 0, true, false);

         return wr.ToString();

       }

     }

@@ -565,7 +565,7 @@ namespace Microsoft.Dafny {
       }

     }

 

-    internal void PrintSpec(string kind, List<MaybeFreeExpression> ee, int indent) {

+    internal void PrintSpec(string kind, List<MaybeFreeExpression> ee, int indent, bool newLine = true) {

       Contract.Requires(kind != null);

       Contract.Requires(ee != null);

       foreach (MaybeFreeExpression e in ee)

@@ -582,7 +582,11 @@ namespace Microsoft.Dafny {
         wr.Write(" ");

         PrintExpression(e.E, true);

 

-        wr.WriteLine(";");

+        if (newLine) {

+          wr.WriteLine(";");

+        } else {

+          wr.Write(";");

+        }

       }

     }

 

@@ -735,10 +739,12 @@ namespace Microsoft.Dafny {
           wr.Write(" ");

         } else {

           wr.WriteLine();

-          PrintSpec("ensures", s.Ens, indent + IndentAmount);

+          PrintSpec("ensures", s.Ens, indent + IndentAmount, s.Body != null);

           Indent(indent);

         }

-        PrintStatement(s.Body, indent);

+        if (s.Body != null) {

+          PrintStatement(s.Body, indent);

+        }

 

       } else if (stmt is ModifyStmt) {

         var s = (ModifyStmt)stmt;

@@ -789,9 +795,12 @@ namespace Microsoft.Dafny {
         MatchStmt s = (MatchStmt)stmt;

         wr.Write("match ");

         PrintExpression(s.Source, false);

-        wr.WriteLine(" {");

-        int caseInd = indent + IndentAmount;

+        if (s.UsesOptionalBraces) {

+          wr.Write(" {");

+        }

+        int caseInd = indent + (s.UsesOptionalBraces ? IndentAmount : 0);

         foreach (MatchCaseStmt mc in s.Cases) {

+          wr.WriteLine();

           Indent(caseInd);

           wr.Write("case {0}", mc.Id);

           if (mc.Arguments.Count != 0) {

@@ -802,15 +811,18 @@ namespace Microsoft.Dafny {
             }

             wr.Write(")");

           }

-          wr.WriteLine(" =>");

+          wr.Write(" =>");

           foreach (Statement bs in mc.Body) {

+            wr.WriteLine();

             Indent(caseInd + IndentAmount);

             PrintStatement(bs, caseInd + IndentAmount);

-            wr.WriteLine();

           }

         }

-        Indent(indent);

-        wr.Write("}");

+        if (s.UsesOptionalBraces) {

+          wr.WriteLine();

+          Indent(indent);

+          wr.Write("}");

+        }

 

       } else if (stmt is ConcreteUpdateStatement) {

         var s = (ConcreteUpdateStatement)stmt;

@@ -1082,15 +1094,18 @@ namespace Microsoft.Dafny {
       } else if (expr is MatchExpr) {

         var e = (MatchExpr)expr;

         Indent(indent);

-        var parensNeeded = !isRightmost;

+        var parensNeeded = !isRightmost && !e.UsesOptionalBraces;

         if (parensNeeded) { wr.Write("("); }

         wr.Write("match ");

         PrintExpression(e.Source, isRightmost && e.Cases.Count == 0, false);

-        if (parensNeeded && e.Cases.Count == 0) { wr.WriteLine(")"); } else { wr.WriteLine(); }

+        if (e.UsesOptionalBraces) { wr.WriteLine(" {"); }

+        else if (parensNeeded && e.Cases.Count == 0) { wr.WriteLine(")"); }

+        else { wr.WriteLine(); }

         int i = 0;

+        int ind = indent + (e.UsesOptionalBraces ? IndentAmount : 0);

         foreach (var mc in e.Cases) {

           bool isLastCase = i == e.Cases.Count - 1;

-          Indent(indent);

+          Indent(ind);

           wr.Write("case {0}", mc.Id);

           if (mc.Arguments.Count != 0) {

             string sep = "(";

@@ -1101,9 +1116,13 @@ namespace Microsoft.Dafny {
             wr.Write(")");

           }

           wr.WriteLine(" =>");

-          PrintExtendedExpr(mc.Body, indent + IndentAmount, isLastCase, isLastCase && (parensNeeded || endWithCloseParen));

+          PrintExtendedExpr(mc.Body, ind + IndentAmount, isLastCase, isLastCase && (parensNeeded || endWithCloseParen));

           i++;

         }

+        if (e.UsesOptionalBraces) {

+          Indent(indent);

+          wr.WriteLine("}");

+        }

       } else if (expr is ParensExpression) {

         PrintExtendedExpr(((ParensExpression)expr).E, indent, isRightmost, endWithCloseParen);

       } else {

@@ -1184,9 +1203,16 @@ namespace Microsoft.Dafny {
         wr.Write(((IdentifierExpr)expr).Name);

 

       } else if (expr is DatatypeValue) {

-        DatatypeValue dtv = (DatatypeValue)expr;

-        wr.Write("#{0}.{1}", dtv.DatatypeName, dtv.MemberName);

-        if (dtv.Arguments.Count != 0) {

+        var dtv = (DatatypeValue)expr;

+        bool printParens;

+        if (dtv.MemberName == BuiltIns.TupleTypeCtorName) {

+          // we're looking at a tuple, whose printed constructor name is essentially the empty string

+          printParens = true;

+        } else {

+          wr.Write("{0}.{1}", dtv.DatatypeName, dtv.MemberName);

+          printParens = dtv.Arguments.Count != 0;

+        }

+        if (printParens) {

           wr.Write("(");

           PrintExpressionList(dtv.Arguments, false);

           wr.Write(")");

@@ -1651,10 +1677,11 @@ namespace Microsoft.Dafny {
 

       } else if (expr is MatchExpr) {

         var e = (MatchExpr)expr;

-        var parensNeeded = !isRightmost;

+        var parensNeeded = !isRightmost && !e.UsesOptionalBraces;

         if (parensNeeded) { wr.Write("("); }

         wr.Write("match ");

         PrintExpression(e.Source, isRightmost && e.Cases.Count == 0, !parensNeeded && isFollowedBySemicolon);

+        if (e.UsesOptionalBraces) { wr.Write(" {"); }

         int i = 0;

         foreach (var mc in e.Cases) {

           bool isLastCase = i == e.Cases.Count - 1;

@@ -1671,7 +1698,8 @@ namespace Microsoft.Dafny {
           PrintExpression(mc.Body, isRightmost && isLastCase, !parensNeeded && isFollowedBySemicolon);

           i++;

         }

-        if (parensNeeded) { wr.Write(")"); }

+        if (e.UsesOptionalBraces) { wr.Write(" }"); }

+        else if (parensNeeded) { wr.Write(")"); }

 

       } else if (expr is BoxingCastExpr) {

         // this is not expected for a parsed program, but we may be called for /trace purposes in the translator

diff --git a/Source/Dafny/Resolver.cs b/Source/Dafny/Resolver.cs
index c1cbd61a..7115a95f 100644
--- a/Source/Dafny/Resolver.cs
+++ b/Source/Dafny/Resolver.cs
@@ -192,16 +192,17 @@ namespace Microsoft.Dafny
       var refinementTransformer = new RefinementTransformer(this, AdditionalInformationReporter, prog);

       rewriters.Add(refinementTransformer);

       rewriters.Add(new AutoContractsRewriter());

-      var opaqueRewriter = new OpaqueFunctionRewriter();      

+      var opaqueRewriter = new OpaqueFunctionRewriter();

       rewriters.Add(new AutoReqFunctionRewriter(this, opaqueRewriter));

       rewriters.Add(opaqueRewriter);

 

       systemNameInfo = RegisterTopLevelDecls(prog.BuiltIns.SystemModule, false);

+      prog.CompileModules.Add(prog.BuiltIns.SystemModule);

       foreach (var decl in sortedDecls) {

         if (decl is LiteralModuleDecl) {

           // The declaration is a literal module, so it has members and such that we need

           // to resolve. First we do refinement transformation. Then we construct the signature

-          // of the module. This is the public, externally visible signature. Then we add in 

+          // of the module. This is the public, externally visible signature. Then we add in

           // everything that the system defines, as well as any "import" (i.e. "opened" modules)

           // directives (currently not supported, but this is where we would do it.) This signature,

           // which is only used while resolving the members of the module is stored in the (basically)

@@ -894,7 +895,7 @@ namespace Microsoft.Dafny
                   formals.AddRange(cop.Formals.ConvertAll(cloner.CloneFormal));

 

                   List<TypeParameter> tyvars = cop.TypeArgs.ConvertAll(cloner.CloneTypeParam);

-		   

+

 	          /*

                   Dictionary<TypeParameter, Type> su = new Dictionary<TypeParameter, Type>();

                   for (int i = 0; i < tyvars.Count; i++) {

@@ -907,12 +908,12 @@ namespace Microsoft.Dafny
                   // create prefix predicate

                   cop.PrefixPredicate = new PrefixPredicate(cop.tok, extraName, cop.IsStatic,

                     tyvars, cop.OpenParen, k, formals,

-                    cop.Req.ConvertAll(cloner.CloneExpr), 

-                    cop.Reads.ConvertAll(cloner.CloneFrameExpr), 

+                    cop.Req.ConvertAll(cloner.CloneExpr),

+                    cop.Reads.ConvertAll(cloner.CloneFrameExpr),

                     cop.Ens.ConvertAll(cloner.CloneExpr),

                     new Specification<Expression>(new List<Expression>() { new IdentifierExpr(cop.tok, k.Name) }, null),

-                    cop.Body, 

-                    null, 

+                    cop.Body,

+                    null,

                     cop);

                   extraMember = cop.PrefixPredicate;

                   // In the call graph, add an edge from P# to P, since this will have the desired effect of detecting unwanted cycles.

@@ -1035,6 +1036,9 @@ namespace Microsoft.Dafny
       if (d is ArbitraryTypeDecl) {

         var dd = (ArbitraryTypeDecl)d;

         return new ArbitraryTypeDecl(dd.tok, dd.Name, m, dd.EqualitySupport, null);

+      } else if (d is TupleTypeDecl) {

+        var dd = (TupleTypeDecl)d;

+        return new TupleTypeDecl(dd.Dims, dd.Module);

       } else if (d is IndDatatypeDecl) {

         var dd = (IndDatatypeDecl)d;

         var tps = dd.TypeArgs.ConvertAll(CloneTypeParam);

@@ -1353,7 +1357,7 @@ namespace Microsoft.Dafny
       } else if (expr is MatchExpr) {

         var e = (MatchExpr)expr;

         return new MatchExpr(e.tok, CloneExpr(e.Source),

-          e.Cases.ConvertAll(c => new MatchCaseExpr(c.tok, c.Id, c.Arguments.ConvertAll(CloneBoundVar), CloneExpr(c.Body))));

+          e.Cases.ConvertAll(c => new MatchCaseExpr(c.tok, c.Id, c.Arguments.ConvertAll(CloneBoundVar), CloneExpr(c.Body))), e.UsesOptionalBraces);

 

       } else if (expr is NegationExpression) {

         var e = (NegationExpression)expr;

@@ -1949,7 +1953,7 @@ namespace Microsoft.Dafny
           foreach (var p in e.TypeArgumentSubstitutions) {

             if (p.Value.Normalize() is TypeProxy) {

               Error(e.tok, "type variable '{0}' in the function call to '{1}' could not determined{2}", p.Key.Name, e.Name,

-                (e.Name.Contains("reveal_") || e.Name.Contains("_FULL"))  

+                (e.Name.Contains("reveal_") || e.Name.Contains("_FULL"))

                 ? ". If you are making an opaque function, make sure that the function can be called."

                 : ""

               );

@@ -1985,7 +1989,7 @@ namespace Microsoft.Dafny
           return CheckTypeIsDetermined(tok, ((MapType)t).Range, what, aggressive) &&

                  CheckTypeIsDetermined(tok, ((MapType)t).Domain, what, aggressive);

         } else if (aggressive && t is CollectionType) {

-          return CheckTypeIsDetermined(tok, ((CollectionType)t).Arg, what, aggressive); 

+          return CheckTypeIsDetermined(tok, ((CollectionType)t).Arg, what, aggressive);

         } else if (aggressive && t is UserDefinedType) {

           return t.TypeArgs.All(rg => CheckTypeIsDetermined(tok, rg, what, aggressive));

         } else {

@@ -2011,7 +2015,7 @@ namespace Microsoft.Dafny
     /// Note, the current implementation is rather conservative in its analysis; upon need, the

     /// algorithm could be improved.

     /// In the current implementation, "enclosingMethod" is not allowed to be a mutually recursive method.

-    /// 

+    ///

     /// The incoming value of "tailCall" is not used, but it's nevertheless a 'ref' parameter to allow the

     /// body to return the incoming value or to omit assignments to it.

     /// If the return value is CanBeFollowedByAnything, "tailCall" is unchanged.

@@ -2141,7 +2145,10 @@ namespace Microsoft.Dafny
         }

       } else if (stmt is ForallStmt) {

         var s = (ForallStmt)stmt;

-        var status = CheckTailRecursive(s.Body, enclosingMethod, ref tailCall, reportErrors);

+        var status = TailRecursionStatus.NotTailRecursive;

+        if (s.Body != null) {

+          status = CheckTailRecursive(s.Body, enclosingMethod, ref tailCall, reportErrors);

+        }

         if (status != TailRecursionStatus.CanBeFollowedByAnything) {

           if (status == TailRecursionStatus.NotTailRecursive) {

             // an error has already been reported

@@ -2848,13 +2855,13 @@ namespace Microsoft.Dafny
     /// datatype has some value that can be constructed from datatypes in lower stratospheres only.

     /// The algorithm used here is quadratic in the number of datatypes in the SCC.  Since that number is

     /// deemed to be rather small, this seems okay.

-    /// 

+    ///

     /// As a side effect of this checking, the DefaultCtor field is filled in (for every inductive datatype

     /// that passes the check).  It may be that several constructors could be used as the default, but

     /// only the first one encountered as recorded.  This particular choice is slightly more than an

     /// implementation detail, because it affects how certain cycles among inductive datatypes (having

     /// to do with the types used to instantiate type parameters of datatypes) are used.

-    /// 

+    ///

     /// The role of the SCC here is simply to speed up this method.  It would still be correct if the

     /// equivalence classes in the given SCC were unions of actual SCC's.  In particular, this method

     /// would still work if "dependencies" consisted of one large SCC containing all the inductive

@@ -3079,7 +3086,7 @@ namespace Microsoft.Dafny
         if (!allTypeParameters.Push(tp.Name, tp) && emitErrors) {

           Error(tp, "Duplicate type-parameter name: {0}", tp.Name);

         }

-      } 

+      }

     }

 

     /// <summary>

@@ -3302,8 +3309,9 @@ namespace Microsoft.Dafny
     void ResolveCtorSignature(DatatypeCtor ctor, List<TypeParameter> dtTypeArguments) {

       Contract.Requires(ctor != null);

       Contract.Requires(dtTypeArguments != null);

+      ResolveTypeOption option = dtTypeArguments.Count == 0 ? new ResolveTypeOption(ctor) : new ResolveTypeOption(ResolveTypeOptionEnum.AllowPrefix);

       foreach (Formal p in ctor.Formals) {

-        ResolveType(p.tok, p.Type, ResolveTypeOptionEnum.AllowExact, dtTypeArguments);

+        ResolveType(p.tok, p.Type, option, dtTypeArguments);

       }

     }

 

@@ -3551,7 +3559,7 @@ namespace Microsoft.Dafny
       iter.Member_MoveNext.Decreases.Attributes = iter.Decreases.Attributes;

     }

 

-    // Like the ResolveTypeOptionEnum, but iff the case of AllowPrefixExtend, it also 

+    // Like the ResolveTypeOptionEnum, but iff the case of AllowPrefixExtend, it also

     // contains a pointer to its Parent class, to fill in default type parameters properly.

     public class ResolveTypeOption

     {

@@ -3592,10 +3600,6 @@ namespace Microsoft.Dafny
       /// </summary>

       InferTypeProxies,

       /// <summary>

-      /// if exactly defaultTypeArguments.Count type arguments are needed, use defaultTypeArguments

-      /// </summary>

-      AllowExact,

-      /// <summary>

       /// if at most defaultTypeArguments.Count type arguments are needed, use a prefix of defaultTypeArguments

       /// </summary>

       AllowPrefix,

@@ -3610,7 +3614,7 @@ namespace Microsoft.Dafny
     /// See ResolveTypeOption for a description of the option/defaultTypeArguments parameters.

     /// </summary>

     public void ResolveType(IToken tok, Type type, ResolveTypeOptionEnum eopt, List<TypeParameter> defaultTypeArguments) {

-      Contract.Requires(eopt != ResolveTypeOptionEnum.AllowPrefixExtend); 

+      Contract.Requires(eopt != ResolveTypeOptionEnum.AllowPrefixExtend);

       ResolveType(tok, type, new ResolveTypeOption(eopt), defaultTypeArguments);

     }

 

@@ -3717,7 +3721,7 @@ namespace Microsoft.Dafny
           } else {

             Error(t.tok, "Type parameter expects no type arguments: {0}", t.Name);

           }

-        } else if (t.ResolvedClass == null) {  // this test is because 'array' is already resolved; TODO: an alternative would be to pre-populate 'classes' with built-in references types like 'array' (and perhaps in the future 'string')

+        } else {

           TopLevelDecl d = null;

 

           int j;

@@ -3797,9 +3801,12 @@ namespace Microsoft.Dafny
         for (int i = 0; i < n; i++) {

           typeArgs.Add(new InferredTypeProxy());

         }

+      /*

       } else if (option.Opt == ResolveTypeOptionEnum.AllowExact && defaultTypeArguments.Count != n) {

         // the number of default arguments is not exactly what we need, so don't add anything

       } else if (option.Opt == ResolveTypeOptionEnum.AllowPrefix && defaultTypeArguments.Count < n) {

+      */

+      } else if (option.Opt == ResolveTypeOptionEnum.AllowPrefix && defaultTypeArguments.Count < n) {

         // there aren't enough default arguments, so don't do anything

       } else {

         // we'll add arguments

@@ -4074,7 +4081,7 @@ namespace Microsoft.Dafny
           //   set(Arg) or multiset(Arg) or seq(Arg) or map(Arg, anyRange)

           // pb is:

           //   seq(Arg) or multiset(Arg) or map(Domain, Arg), or

-          //   if AllowArray, array(Arg) 

+          //   if AllowArray, array(Arg)

           // Their intersection is:

           if (ib.AllowArray) {

             var c = new IndexableTypeProxy(ib.Domain, ib.Range, ib.Arg, false);

@@ -4587,14 +4594,16 @@ namespace Microsoft.Dafny
         }

         s.IsGhost = bodyMustBeSpecOnly;

 

-        // clear the labels for the duration of checking the body, because break statements are not allowed to leave a forall statement

-        var prevLblStmts = labeledStatements;

-        var prevLoopStack = loopStack;

-        labeledStatements = new Scope<Statement>();

-        loopStack = new List<Statement>();

-        ResolveStatement(s.Body, bodyMustBeSpecOnly, codeContext);

-        labeledStatements = prevLblStmts;

-        loopStack = prevLoopStack;

+        if (s.Body != null) {

+          // clear the labels for the duration of checking the body, because break statements are not allowed to leave a forall statement

+          var prevLblStmts = labeledStatements;

+          var prevLoopStack = loopStack;

+          labeledStatements = new Scope<Statement>();

+          loopStack = new List<Statement>();

+          ResolveStatement(s.Body, bodyMustBeSpecOnly, codeContext);

+          labeledStatements = prevLblStmts;

+          loopStack = prevLoopStack;

+        }

         scope.PopMarker();

 

         if (prevErrorCount == ErrorCount) {

@@ -4631,9 +4640,11 @@ namespace Microsoft.Dafny
               }

             }

           }

-          CheckForallStatementBodyRestrictions(s.Body, s.Kind);

+          if (s.Body != null) {

+            CheckForallStatementBodyRestrictions(s.Body, s.Kind);

+          }

         }

-		

+

       } else if (stmt is ModifyStmt) {

         var s = (ModifyStmt)stmt;

         ResolveAttributes(s.Mod.Attributes, true, codeContext);

@@ -4662,14 +4673,14 @@ namespace Microsoft.Dafny
               if (!UnifyTypes(e0.Type, e1.Type)) {

                 Error(e1, "all lines in a calculation must have the same type (got {0} after {1})", e1.Type, e0.Type);

               } else {

-                var step = s.StepOps[i - 1].StepExpr(e0, e1); // Use custom line operator                

+                var step = s.StepOps[i - 1].StepExpr(e0, e1); // Use custom line operator

                 ResolveExpression(step, true, codeContext);

-                s.Steps.Add(step);            

+                s.Steps.Add(step);

               }

               e0 = e1;

             }

           }

-                  

+

           // clear the labels for the duration of checking the hints, because break statements are not allowed to leave a forall statement

           var prevLblStmts = labeledStatements;

           var prevLoopStack = loopStack;

@@ -4680,7 +4691,7 @@ namespace Microsoft.Dafny
             CheckHintRestrictions(h);

           }

           labeledStatements = prevLblStmts;

-          loopStack = prevLoopStack;          

+          loopStack = prevLoopStack;

 

         }

         if (prevErrorCount == ErrorCount && s.Lines.Count > 0) {

@@ -4690,8 +4701,8 @@ namespace Microsoft.Dafny
           s.Result = CalcStmt.DefaultOp.StepExpr(Expression.CreateIntLiteral(s.Tok, 0), Expression.CreateIntLiteral(s.Tok, 0));

         }

         ResolveExpression(s.Result, true, codeContext);

-        Contract.Assert(s.Result != null);        

-        Contract.Assert(prevErrorCount != ErrorCount || s.Steps.Count == s.Hints.Count);        

+        Contract.Assert(s.Result != null);

+        Contract.Assert(prevErrorCount != ErrorCount || s.Steps.Count == s.Hints.Count);

 

       } else if (stmt is MatchStmt) {

         MatchStmt s = (MatchStmt)stmt;

@@ -5417,7 +5428,7 @@ namespace Microsoft.Dafny
             Contract.Assert(false);  // unexpected kind

             break;

         }

-		

+

       } else if (stmt is CalcStmt) {

           // cool

 

@@ -5536,7 +5547,7 @@ namespace Microsoft.Dafny
             Contract.Assert(false);  // unexpected kind

             break;

         }

-		

+

       } else if (stmt is CalcStmt) {

         var s = (CalcStmt)stmt;

         foreach (var h in s.Hints) {

@@ -6080,10 +6091,10 @@ namespace Microsoft.Dafny
 

         }

         else if (e.Seq.Type is UserDefinedType && ((UserDefinedType)e.Seq.Type).IsDatatype)

-        {          

+        {

           DatatypeDecl dt = ((UserDefinedType)e.Seq.Type).AsDatatype;

 

-          if (!(e.Index is IdentifierSequence || (e.Index is LiteralExpr && ((LiteralExpr)e.Index).Value is BigInteger)))  

+          if (!(e.Index is IdentifierSequence || (e.Index is LiteralExpr && ((LiteralExpr)e.Index).Value is BigInteger)))

           {

             Error(expr, "datatype updates must be to datatype destructors");

           } else {

@@ -6464,7 +6475,7 @@ namespace Microsoft.Dafny
         bool _val = true;

         bool typeQuantifier = Attributes.ContainsBool(e.Attributes, "typeQuantifier", ref _val);

         allTypeParameters.PushMarker();

-        ResolveTypeParameters(e.TypeArgs, true, e); 

+        ResolveTypeParameters(e.TypeArgs, true, e);

         scope.PushMarker();

         foreach (BoundVar v in e.BoundVars) {

           if (!scope.Push(v.Name, v)) {

@@ -7118,7 +7129,7 @@ namespace Microsoft.Dafny
         // ----- root is a local variable, parameter, or bound variable

         r = new IdentifierExpr(id, id.val);

         ResolveExpression(r, twoState, codeContext);

-        r = ResolveSuffix(r, e, 1, twoState, codeContext,  allowMethodCall, out call);

+        r = ResolveSuffix(r, e, 1, twoState, codeContext, allowMethodCall, out call);

 

       } else if (moduleInfo.TopLevels.TryGetValue(id.val, out decl)) {

         if (decl is AmbiguousTopLevelDecl) {

@@ -7126,10 +7137,10 @@ namespace Microsoft.Dafny
         } else if (e.Tokens.Count == 1 && e.Arguments == null) {

           Error(id, "name of type ('{0}') is used as a variable", id.val);

         } else if (e.Tokens.Count == 1 && e.Arguments != null) {

-          // in 

+          // in

           //   datatype Id = Id

           // you cannot refer to the constructor, instead this error message is thrown:

-          // (bug?)         

+          // (bug?)

           Error(id, "name of type ('{0}') is used as a function", id.val);

           // resolve the arguments nonetheless

           foreach (var arg in e.Arguments) {

@@ -7322,7 +7333,7 @@ namespace Microsoft.Dafny
 

       if (p < e.Tokens.Count) {

         Contract.Assert(e.Arguments != null);

-        

+

         bool itIsAMethod = false;

         if (allowMethodCall) {

           var udt = r.Type.Normalize() as UserDefinedType;

diff --git a/Source/Dafny/Scanner.cs b/Source/Dafny/Scanner.cs
index 4b473e9d..87dee5aa 100644
--- a/Source/Dafny/Scanner.cs
+++ b/Source/Dafny/Scanner.cs
@@ -255,21 +255,21 @@ public class Scanner {
 		for (int i = 92; i <= 92; ++i) start[i] = 1;

 		for (int i = 95; i <= 95; ++i) start[i] = 1;

 		for (int i = 98; i <= 122; ++i) start[i] = 1;

-		for (int i = 49; i <= 57; ++i) start[i] = 21;

+		for (int i = 49; i <= 57; ++i) start[i] = 22;

 		for (int i = 34; i <= 34; ++i) start[i] = 11;

-		start[97] = 22; 

-		start[48] = 23; 

+		start[97] = 23; 

+		start[48] = 24; 

 		start[58] = 64; 

 		start[59] = 13; 

 		start[123] = 14; 

 		start[125] = 15; 

 		start[40] = 16; 

-		start[42] = 17; 

+		start[41] = 17; 

+		start[42] = 18; 

 		start[33] = 65; 

 		start[61] = 66; 

 		start[124] = 67; 

-		start[44] = 30; 

-		start[41] = 31; 

+		start[44] = 31; 

 		start[46] = 68; 

 		start[60] = 69; 

 		start[62] = 70; 

@@ -491,21 +491,21 @@ public class Scanner {
 

 	void CheckLiteral() {

 		switch (t.val) {

-			case "include": t.kind = 14; break;

-			case "abstract": t.kind = 15; break;

-			case "module": t.kind = 16; break;

-			case "refines": t.kind = 17; break;

-			case "import": t.kind = 18; break;

-			case "opened": t.kind = 19; break;

-			case "as": t.kind = 21; break;

-			case "default": t.kind = 22; break;

-			case "class": t.kind = 23; break;

-			case "ghost": t.kind = 24; break;

-			case "static": t.kind = 25; break;

-			case "datatype": t.kind = 26; break;

-			case "codatatype": t.kind = 27; break;

-			case "var": t.kind = 29; break;

-			case "type": t.kind = 31; break;

+			case "include": t.kind = 15; break;

+			case "abstract": t.kind = 16; break;

+			case "module": t.kind = 17; break;

+			case "refines": t.kind = 18; break;

+			case "import": t.kind = 19; break;

+			case "opened": t.kind = 20; break;

+			case "as": t.kind = 22; break;

+			case "default": t.kind = 23; break;

+			case "class": t.kind = 24; break;

+			case "ghost": t.kind = 25; break;

+			case "static": t.kind = 26; break;

+			case "datatype": t.kind = 27; break;

+			case "codatatype": t.kind = 28; break;

+			case "var": t.kind = 30; break;

+			case "type": t.kind = 32; break;

 			case "iterator": t.kind = 34; break;

 			case "yields": t.kind = 35; break;

 			case "returns": t.kind = 36; break;

@@ -648,65 +648,65 @@ public class Scanner {
 			case 17:

 				{t.kind = 12; break;}

 			case 18:

-				if (ch == 'n') {AddCh(); goto case 19;}

-				else {goto case 0;}

+				{t.kind = 13; break;}

 			case 19:

-				if (ch <= '&' || ch >= '(' && ch <= '/' || ch >= ':' && ch <= '>' || ch == '@' || ch == '[' || ch >= ']' && ch <= '^' || ch == '`' || ch >= '{' && ch <= 65535) {apx++; AddCh(); goto case 20;}

+				if (ch == 'n') {AddCh(); goto case 20;}

 				else {goto case 0;}

 			case 20:

+				if (ch <= '&' || ch >= '(' && ch <= '/' || ch >= ':' && ch <= '>' || ch == '@' || ch == '[' || ch >= ']' && ch <= '^' || ch == '`' || ch >= '{' && ch <= 65535) {apx++; AddCh(); goto case 21;}

+				else {goto case 0;}

+			case 21:

 				{

 					tlen -= apx;

 					SetScannerBehindT();

-					t.kind = 13; break;}

-			case 21:

+					t.kind = 14; break;}

+			case 22:

 				recEnd = pos; recKind = 2;

-				if (ch >= '0' && ch <= '9') {AddCh(); goto case 21;}

+				if (ch >= '0' && ch <= '9') {AddCh(); goto case 22;}

 				else if (ch == '.') {AddCh(); goto case 9;}

 				else {t.kind = 2; break;}

-			case 22:

+			case 23:

 				recEnd = pos; recKind = 1;

 				if (ch == 39 || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'q' || ch >= 's' && ch <= 'z') {AddCh(); goto case 2;}

-				else if (ch == 'r') {AddCh(); goto case 25;}

+				else if (ch == 'r') {AddCh(); goto case 26;}

 				else {t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t;}

-			case 23:

+			case 24:

 				recEnd = pos; recKind = 2;

-				if (ch >= '0' && ch <= '9') {AddCh(); goto case 21;}

+				if (ch >= '0' && ch <= '9') {AddCh(); goto case 22;}

 				else if (ch == 'x') {AddCh(); goto case 7;}

 				else if (ch == '.') {AddCh(); goto case 9;}

 				else {t.kind = 2; break;}

-			case 24:

+			case 25:

 				recEnd = pos; recKind = 1;

-				if (ch == 39 || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'z') {AddCh(); goto case 24;}

+				if (ch == 39 || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'z') {AddCh(); goto case 25;}

 				else {t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t;}

-			case 25:

+			case 26:

 				recEnd = pos; recKind = 1;

 				if (ch == 39 || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'q' || ch >= 's' && ch <= 'z') {AddCh(); goto case 3;}

-				else if (ch == 'r') {AddCh(); goto case 26;}

+				else if (ch == 'r') {AddCh(); goto case 27;}

 				else {t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t;}

-			case 26:

+			case 27:

 				recEnd = pos; recKind = 1;

 				if (ch == 39 || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'b' && ch <= 'z') {AddCh(); goto case 4;}

-				else if (ch == 'a') {AddCh(); goto case 27;}

+				else if (ch == 'a') {AddCh(); goto case 28;}

 				else {t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t;}

-			case 27:

+			case 28:

 				recEnd = pos; recKind = 1;

 				if (ch == 39 || ch >= '0' && ch <= '9' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'x' || ch == 'z') {AddCh(); goto case 5;}

-				else if (ch == 'y') {AddCh(); goto case 28;}

+				else if (ch == 'y') {AddCh(); goto case 29;}

 				else {t.kind = 1; t.val = new String(tval, 0, tlen); CheckLiteral(); return t;}

-			case 28:

+			case 29:

 				recEnd = pos; recKind = 5;

 				if (ch == 39 || ch == '0' || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'z') {AddCh(); goto case 6;}

-				else if (ch >= '1' && ch <= '9') {AddCh(); goto case 29;}

+				else if (ch >= '1' && ch <= '9') {AddCh(); goto case 30;}

 				else {t.kind = 5; break;}

-			case 29:

+			case 30:

 				recEnd = pos; recKind = 5;

-				if (ch == 39 || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'z') {AddCh(); goto case 24;}

-				else if (ch >= '0' && ch <= '9') {AddCh(); goto case 29;}

+				if (ch == 39 || ch == '?' || ch >= 'A' && ch <= 'Z' || ch == 92 || ch == '_' || ch >= 'a' && ch <= 'z') {AddCh(); goto case 25;}

+				else if (ch >= '0' && ch <= '9') {AddCh(); goto case 30;}

 				else {t.kind = 5; break;}

-			case 30:

-				{t.kind = 30; break;}

 			case 31:

-				{t.kind = 33; break;}

+				{t.kind = 31; break;}

 			case 32:

 				{t.kind = 37; break;}

 			case 33:

@@ -780,18 +780,18 @@ public class Scanner {
 				else {t.kind = 7; break;}

 			case 65:

 				recEnd = pos; recKind = 107;

-				if (ch == 'i') {AddCh(); goto case 18;}

+				if (ch == 'i') {AddCh(); goto case 19;}

 				else if (ch == '=') {AddCh(); goto case 41;}

 				else {t.kind = 107; break;}

 			case 66:

-				recEnd = pos; recKind = 20;

+				recEnd = pos; recKind = 21;

 				if (ch == '=') {AddCh(); goto case 71;}

 				else if (ch == '>') {AddCh(); goto case 38;}

-				else {t.kind = 20; break;}

+				else {t.kind = 21; break;}

 			case 67:

-				recEnd = pos; recKind = 28;

+				recEnd = pos; recKind = 29;

 				if (ch == '|') {AddCh(); goto case 53;}

-				else {t.kind = 28; break;}

+				else {t.kind = 29; break;}

 			case 68:

 				recEnd = pos; recKind = 61;

 				if (ch == '.') {AddCh(); goto case 72;}

@@ -805,9 +805,9 @@ public class Scanner {
 				if (ch == '=') {AddCh(); goto case 40;}

 				else {t.kind = 39; break;}

 			case 71:

-				recEnd = pos; recKind = 32;

+				recEnd = pos; recKind = 33;

 				if (ch == '>') {AddCh(); goto case 47;}

-				else {t.kind = 32; break;}

+				else {t.kind = 33; break;}

 			case 72:

 				recEnd = pos; recKind = 120;

 				if (ch == '.') {AddCh(); goto case 32;}

diff --git a/Source/Dafny/Translator.cs b/Source/Dafny/Translator.cs
index 548547d2..496633a7 100644
--- a/Source/Dafny/Translator.cs
+++ b/Source/Dafny/Translator.cs
@@ -18,6 +18,7 @@ namespace Microsoft.Dafny {
 

     [NotDelayed]

     public Translator() {

+      InsertChecksums = 0 < CommandLineOptions.Clo.VerifySnapshots;

       Bpl.Program boogieProgram = ReadPrelude();

       if (boogieProgram != null) {

         sink = boogieProgram;

@@ -409,13 +410,13 @@ namespace Microsoft.Dafny {
           var impl = decl as Implementation;

           if (impl != null && impl.FindStringAttribute("checksum") == null)

           {

-            impl.AddAttribute("checksum", "dummy");

+            impl.AddAttribute("checksum", "stable");

           }

 

           var func = decl as Bpl.Function;

           if (func != null && func.FindStringAttribute("checksum") == null)

           {

-            func.AddAttribute("checksum", "dummy");

+            func.AddAttribute("checksum", "stable");

           }

         }

       }

@@ -2614,7 +2615,7 @@ namespace Microsoft.Dafny {
     public void InsertUniqueIdForImplementation(Bpl.Declaration decl)

     {

       var impl = decl as Bpl.Implementation;

-      var prefix = UniqueIdPrefix ?? decl.tok.filename;

+      var prefix = UniqueIdPrefix ?? System.Text.RegularExpressions.Regex.Replace(decl.tok.filename, @".v\d+.dfy", ".dfy");

       if (impl != null && !string.IsNullOrEmpty(prefix))

       {

         decl.AddAttribute("id", prefix + ":" + impl.Name + ":0");

@@ -5858,15 +5859,33 @@ namespace Microsoft.Dafny {
       //     assume $HeapSucc(oldHeap, $Heap);

       //     (a)

       //       assume (forall<alpha> o: ref, F: Field alpha ::

+      //         { $Heap[o,F] }

       //         $Heap[o,F] = oldHeap[o,F] ||

       //         (exists x,y :: Range(x,y) && o == E(x,y) && F = f));

-      //       assume (forall x,y ::  Range ==> $Heap[ E[$Heap:=oldHeap], F] == G[$Heap:=oldHeap]);

+      //       assume (forall x,y ::  Range ==> $Heap[ E[$Heap:=oldHeap], F] == G[$Heap:=oldHeap]); (**)

       //     (b)

       //       assume (forall<alpha> o: ref, F: Field alpha ::

+      //         { $Heap[o,F] }

       //         $Heap[o,F] = oldHeap[o,F] ||

       //         (exists x,y :: Range(x,y) && o == A(x,y) && F = Index(I0,I1,...)));

-      //       assume (forall x,y ::  Range ==> $Heap[ A[$Heap:=oldHeap], Index(I0,I1,...)] == G[$Heap:=oldHeap]);

+      //       assume (forall x,y ::  Range ==> $Heap[ A[$Heap:=oldHeap], Index(I0,I1,...)] == G[$Heap:=oldHeap]); (**)

       //   }

+      //

+      // Note: In order to get a good trigger for the quantifiers (**), we will attempt to make the parameters

+      // that select from $Heap in the LHS of the equalities as plain as possible.  This involves taking the inverse

+      // of an expression, which isn't always easy or possible, so we settle for handling some common cases.  In

+      // particular, we change:

+      //   0: forall i | R(i) { F(i).f := E(i); }

+      //   1: forall i | R(i) { A[F(i)] := E(i); }

+      //   2: forall i | R(i) { F(i)[N] := E(i); }

+      // where f is some field and A and N are expressions that do not depend on i, into:

+      //   0: forall j | Q(j) { j.f := E(F-1(j)); }

+      //   1: forall j | Q(j) { A[j] := E(F-1(j)); }

+      //   2: forall j | Q(j) { j[N] := E(F-1(j)); }

+      // where we ensure that, for all i and j:

+      //   R(i) && j == F(i)    <==>    Q(j) && F-1(j) == i

+      // If the transformation succeeds, we use, respectively, j.f, A[j], and j[N] (each evaluated in the new heap) as

+      // the trigger of the quantifier generated.

 

       var substMap = SetupBoundVarsAsLocals(s.BoundVars, definedness, locals, etran);

       Expression range = Substitute(s.Range, null, substMap);

@@ -5932,6 +5951,7 @@ namespace Microsoft.Dafny {
 

       // Here comes:

       //   assume (forall<alpha> o: ref, f: Field alpha ::

+      //     { $Heap[o,f] }

       //     $Heap[o,f] = oldHeap[o,f] ||

       //     (exists x,y :: Range(x,y)[$Heap:=oldHeap] &&

       //                    o == Object(x,y)[$Heap:=oldHeap] && f == Field(x,y)[$Heap:=oldHeap]));

@@ -5940,8 +5960,8 @@ namespace Microsoft.Dafny {
       Bpl.IdentifierExpr o = new Bpl.IdentifierExpr(s.Tok, oVar);

       Bpl.BoundVariable fVar = new Bpl.BoundVariable(s.Tok, new Bpl.TypedIdent(s.Tok, "$f", predef.FieldName(s.Tok, alpha)));

       Bpl.IdentifierExpr f = new Bpl.IdentifierExpr(s.Tok, fVar);

-      Bpl.Expr heapOF = ReadHeap(s.Tok, etran.HeapExpr, o, f);

-      Bpl.Expr oldHeapOF = ReadHeap(s.Tok, prevHeap, o, f);

+      Bpl.Expr heapOF = ExpressionTranslator.ReadHeap(s.Tok, etran.HeapExpr, o, f);

+      Bpl.Expr oldHeapOF = ExpressionTranslator.ReadHeap(s.Tok, prevHeap, o, f);

       List<Variable> xBvars = new List<Variable>();

       var xBody = etran.TrBoundVariables(s.BoundVars, xBvars);

       xBody = BplAnd(xBody, prevEtran.TrExpr(s.Range));

@@ -5951,30 +5971,249 @@ namespace Microsoft.Dafny {
       xBody = BplAnd(xBody, Bpl.Expr.Eq(f, xField));

       Bpl.Expr xObjField = new Bpl.ExistsExpr(s.Tok, xBvars, xBody);

       Bpl.Expr body = Bpl.Expr.Or(Bpl.Expr.Eq(heapOF, oldHeapOF), xObjField);

-      Bpl.Expr qq = new Bpl.ForallExpr(s.Tok, new List<TypeVariable> { alpha }, new List<Variable> { oVar, fVar }, body);

+      var tr = new Trigger(s.Tok, true, new List<Expr>() { heapOF });

+      Bpl.Expr qq = new Bpl.ForallExpr(s.Tok, new List<TypeVariable> { alpha }, new List<Variable> { oVar, fVar }, null, tr, body);

       updater.Add(new Bpl.AssumeCmd(s.Tok, qq));

 

       if (s0.Rhs is ExprRhs) {

-        //   assume (forall x,y :: Range(x,y)[$Heap:=oldHeap] ==>

-        //                         $Heap[ Object(x,y)[$Heap:=oldHeap], Field(x,y)[$Heap:=oldHeap] ] == G[$Heap:=oldHeap] ));

-        xBvars = new List<Variable>();

-        Bpl.Expr xAnte = etran.TrBoundVariables(s.BoundVars, xBvars);

-        xAnte = BplAnd(xAnte, prevEtran.TrExpr(s.Range));

+        Expression Fi = null;

+        Func<Expression,Expression> lhsBuilder = null;

+        lhs = s0.Lhs.Resolved;

+        var i = s.BoundVars[0];

+        if (s.BoundVars.Count == 1) {

+          //var lhsContext = null;

+          // Detect the following cases:

+          //   0: forall i | R(i) { F(i).f := E(i); }

+          //   1: forall i | R(i) { A[F(i)] := E(i); }

+          //   2: forall i | R(i) { F(i)[N] := E(i); }

+          if (lhs is FieldSelectExpr) {

+            var ll = (FieldSelectExpr)lhs;

+            Fi = ll.Obj;

+            lhsBuilder = e => { var l = new FieldSelectExpr(ll.tok, e, ll.FieldName); l.Field = ll.Field; l.Type = ll.Type; return l; };

+          } else if (lhs is SeqSelectExpr) {

+            var ll = (SeqSelectExpr)lhs;

+            Contract.Assert(ll.SelectOne);

+            if (!ContainsFreeVariable(ll.Seq, false, i)) {

+              Fi = ll.E0;

+              lhsBuilder = e => { var l = new SeqSelectExpr(ll.tok, true, ll.Seq, e, null); l.Type = ll.Type; return l; };

+            } else if (!ContainsFreeVariable(ll.E0, false, i)) {

+              Fi = ll.Seq;

+              lhsBuilder = e => { var l = new SeqSelectExpr(ll.tok, true, e, ll.E0, null); l.Type = ll.Type; return l; };

+            }

+          }

+        }

         var rhs = ((ExprRhs)s0.Rhs).Expr;

-        var g = prevEtran.TrExpr(rhs);

-        GetObjFieldDetails(s0.Lhs.Resolved, prevEtran, out xObj, out xField);

-        var xHeapOF = ReadHeap(s.Tok, etran.HeapExpr, xObj, xField);

-

-        Type lhsType;

-        if (lhs is FieldSelectExpr) {

-          lhsType = ((FieldSelectExpr)lhs).Type;

-        } else {

-          lhsType = null;

+        bool usedInversion = false;

+        if (Fi != null) {

+          var j = new BoundVar(i.tok, i.Name + "#inv", Fi.Type);

+          var jj = Expression.CreateIdentExpr(j);

+          var jList = new List<BoundVar>() { j };

+          var vals = InvertExpression(i, j, s.Range, Fi);

+#if DEBUG_PRINT

+          Console.WriteLine("DEBUG: Trying to invert:");

+          Console.WriteLine("DEBUG:   " + Printer.ExprToString(s.Range) + " && " + j.Name + " == " + Printer.ExprToString(Fi));

+          if (vals == null) {

+            Console.WriteLine("DEBUG: Can't");

+          } else {

+            Console.WriteLine("DEBUG: The inverse is the disjunction of the following:");

+            foreach (var val in vals) {

+              Console.WriteLine("DEBUG:   " + Printer.ExprToString(val.Range) + " && " + Printer.ExprToString(val.FInverse) + " == " + i.Name);

+            }

+          }

+#endif

+          if (vals != null) {

+            foreach (var val in vals) {

+              qq = TrForall_NewValueAssumption(s.Tok, jList, val.Range, lhsBuilder(jj), Substitute(rhs, i, val.FInverse), true, etran, prevEtran);

+              updater.Add(new Bpl.AssumeCmd(s.Tok, qq));

+            }

+            usedInversion = true;

+          }

         }

-        g = CondApplyBox(rhs.tok, g, rhs.Type, lhsType);

+        if (!usedInversion) {

+          qq = TrForall_NewValueAssumption(s.Tok, s.BoundVars, s.Range, lhs, rhs, false, etran, prevEtran);

+          updater.Add(new Bpl.AssumeCmd(s.Tok, qq));

+        }

+      }

+    }

+

+    /// <summary>

+    /// Generate:

+    ///   assume (forall x,y :: Range(x,y)[$Heap:=oldHeap] ==>

+    ///                         $Heap[ Object(x,y)[$Heap:=oldHeap], Field(x,y)[$Heap:=oldHeap] ] == G[$Heap:=oldHeap] ));

+    /// where

+    ///   x,y           represent boundVars

+    ///   Object(x,y)   is the first part of lhs

+    ///   Field(x,y)    is the second part of lhs

+    ///   G             is rhs

+    /// If lhsAsTrigger is true, then use the LHS of the equality above as the trigger; otherwise, don't specify any trigger.

+    /// </summary>

+    private Bpl.Expr TrForall_NewValueAssumption(IToken tok, List<BoundVar> boundVars, Expression range, Expression lhs, Expression rhs, bool lhsAsTrigger, ExpressionTranslator etran, ExpressionTranslator prevEtran) {

+      Contract.Requires(tok != null);

+      Contract.Requires(boundVars != null);

+      Contract.Requires(range != null);

+      Contract.Requires(lhs != null);

+      Contract.Requires(rhs != null);

+      Contract.Requires(etran != null);

+      Contract.Requires(prevEtran != null);

+

+      var xBvars = new List<Variable>();

+      Bpl.Expr xAnte = etran.TrBoundVariables(boundVars, xBvars);

+      xAnte = BplAnd(xAnte, prevEtran.TrExpr(range));

+      var g = prevEtran.TrExpr(rhs);

+      Bpl.Expr obj, field;

+      GetObjFieldDetails(lhs, prevEtran, out obj, out field);

+      var xHeapOF = ExpressionTranslator.ReadHeap(tok, etran.HeapExpr, obj, field);

 

-        qq = new Bpl.ForallExpr(s.Tok, xBvars, Bpl.Expr.Imp(xAnte, Bpl.Expr.Eq(xHeapOF, g)));

-        updater.Add(new Bpl.AssumeCmd(s.Tok, qq));

+      Type lhsType = lhs is FieldSelectExpr ? ((FieldSelectExpr)lhs).Type : null;

+      g = CondApplyBox(rhs.tok, g, rhs.Type, lhsType);

+

+      Trigger tr = lhsAsTrigger ? new Trigger(tok, true, new List<Bpl.Expr>() { xHeapOF }) : null;

+      return new Bpl.ForallExpr(tok, xBvars, tr, Bpl.Expr.Imp(xAnte, Bpl.Expr.Eq(xHeapOF, g)));

+    }

+

+    class ForallStmtTranslationValues

+    {

+      public readonly Expression Range;

+      public readonly Expression FInverse;

+      public ForallStmtTranslationValues(Expression range, Expression fInverse) {

+        Contract.Requires(range != null);

+        Contract.Requires(fInverse != null);

+        Range = range;

+        FInverse = fInverse;

+      }

+      public ForallStmtTranslationValues Subst(IVariable j, Expression e, Translator translator) {

+        Contract.Requires(j != null);

+        Contract.Requires(e != null);

+        Contract.Requires(translator != null);

+        var substMap = new Dictionary<IVariable, Expression>();

+        substMap.Add(j, e);

+        var v = new ForallStmtTranslationValues(translator.Substitute(Range, null, substMap), translator.Substitute(FInverse, null, substMap));

+        return v;

+      }

+    }

+

+    /// <summary>

+    /// Find piecewise inverse of F under R.  More precisely, find lists of expressions P and F-1

+    /// such that

+    ///     R(i) && j == F(i)

+    /// holds iff the disjunction of the following predicates holds:

+    ///     P_0(j) && F-1_0(j) == i

+    ///     ...

+    ///     P_{n-1}(j) && F-1_{n-1}(j) == i

+    /// If no such disjunction is found, return null.

+    /// If such a disjunction is found, return for each disjunct:

+    ///     * The predicate P_k(j), which is an expression that may have free occurrences of j (but no free occurrences of i)

+    ///     * The expression F-1_k(j), which also may have free occurrences of j but not of i

+    /// </summary>

+    private List<ForallStmtTranslationValues> InvertExpression(BoundVar i, BoundVar j, Expression R, Expression F) {

+      Contract.Requires(i != null);

+      Contract.Requires(j != null);

+      Contract.Requires(R != null);

+      Contract.Requires(F != null);

+      var vals = new List<ForallStmtTranslationValues>(InvertExpressionIter(i, j, R, F));

+      if (vals.Count == 0) {

+        return null;

+      } else {

+        return vals;

+      }

+    }

+    /// <summary>

+    /// See InvertExpression.

+    /// </summary>

+    private IEnumerable<ForallStmtTranslationValues> InvertExpressionIter(BoundVar i, BoundVar j, Expression R, Expression F) {

+      Contract.Requires(i != null);

+      Contract.Requires(j != null);

+      Contract.Requires(R != null);

+      Contract.Requires(F != null);

+      F = F.Resolved;

+      if (!ContainsFreeVariable(F, false, i)) {

+        // We're looking at R(i) && j == K.

+        // We cannot invert j == K, but if we're lucky, R(i) contains a conjunct i==G.

+        Expression r = Expression.CreateBoolLiteral(R.tok, true);

+        Expression G = null;

+        foreach (var c in Expression.Conjuncts(R)) {

+          if (G == null && c is BinaryExpr) {

+            var bin = (BinaryExpr)c;

+            if (BinaryExpr.IsEqualityOp(bin.ResolvedOp)) {

+              var id = bin.E0.Resolved as IdentifierExpr;

+              if (id != null && id.Var == i) {

+                G = bin.E1;

+                continue;

+              }

+              id = bin.E1.Resolved as IdentifierExpr;

+              if (id != null && id.Var == i) {

+                G = bin.E0;

+                continue;

+              }

+            }

+          }

+          r = Expression.CreateAnd(r, c);

+        }

+        if (G != null) {

+          var jIsK = Expression.CreateEq(Expression.CreateIdentExpr(j), F, j.Type);

+          var rr = Substitute(r, i, G);

+          yield return new ForallStmtTranslationValues(Expression.CreateAnd(rr, jIsK), G);

+        }

+      } else if (F is IdentifierExpr) {

+        var e = (IdentifierExpr)F;

+        if (e.Var == i) {

+          // We're looking at R(i) && j == i, which is particularly easy to invert:  R(j) && j == i

+          var jj = Expression.CreateIdentExpr(j);

+          yield return new ForallStmtTranslationValues(Substitute(R, i, jj), jj);

+        }

+      } else if (F is BinaryExpr) {

+        var bin = (BinaryExpr)F;

+        if (bin.ResolvedOp == BinaryExpr.ResolvedOpcode.Add) {

+          if (!ContainsFreeVariable(bin.E1, false, i)) {

+            // We're looking at:  R(i) && j == f(i) + K.

+            // By a recursive call, we'll ask to invert:  R(i) && j' == f(i).

+            // For each P_0(j') && f-1_0(j') == i we get back, we yield:

+            // P_0(j - K) && f-1_0(j - K) == i

+            var jMinusK = Expression.CreateSubtract(Expression.CreateIdentExpr(j), bin.E1);

+            foreach (var val in InvertExpression(i, j, R, bin.E0)) {

+              yield return val.Subst(j, jMinusK, this);

+            }

+          } else if (!ContainsFreeVariable(bin.E0, false, i)) {

+            // We're looking at:  R(i) && j == K + f(i)

+            // Do as in previous case, but with operands reversed.

+            var jMinusK = Expression.CreateSubtract(Expression.CreateIdentExpr(j), bin.E0);

+            foreach (var val in InvertExpression(i, j, R, bin.E1)) {

+              yield return val.Subst(j, jMinusK, this);

+            }

+          }

+        } else if (bin.ResolvedOp == BinaryExpr.ResolvedOpcode.Sub) {

+          if (!ContainsFreeVariable(bin.E1, false, i)) {

+            // We're looking at:  R(i) && j == f(i) - K

+            // Recurse on f(i) and then replace j := j + K

+            var jPlusK = Expression.CreateAdd(Expression.CreateIdentExpr(j), bin.E1);

+            foreach (var val in InvertExpression(i, j, R, bin.E0)) {

+              yield return val.Subst(j, jPlusK, this);

+            }

+          } else if (!ContainsFreeVariable(bin.E0, false, i)) {

+            // We're looking at:  R(i) && j == K - f(i)

+            // Recurse on f(i) and then replace j := K - j

+            var kMinusJ = Expression.CreateAdd(Expression.CreateIdentExpr(j), bin.E0);

+            foreach (var val in InvertExpression(i, j, R, bin.E1)) {

+              yield return val.Subst(j, kMinusJ, this);

+            }

+          }

+        }

+      } else if (F is ITEExpr) {

+        var ife = (ITEExpr)F;

+        // We're looking at R(i) && j == if A(i) then B(i) else C(i), which is equivalent to the disjunction of:

+        //   R(i) && A(i) && j == B(i)

+        //   R(i) && !A(i) && j == C(i)

+        // We recurse on each one, yielding the results

+        var r = Expression.CreateAnd(R, ife.Test);

+        var valsThen = InvertExpression(i, j, r, ife.Thn);

+        if (valsThen != null) {

+          r = Expression.CreateAnd(R, Expression.CreateNot(ife.tok, ife.Test));

+          var valsElse = InvertExpression(i, j, r, ife.Els);

+          if (valsElse != null) {

+            foreach (var val in valsThen) { yield return val; }

+            foreach (var val in valsElse) { yield return val; }

+          }

+        }

       }

     }

 

@@ -6164,16 +6403,17 @@ namespace Microsoft.Dafny {
       TrStmt_CheckWellformed(s.Range, definedness, locals, etran, false);

       definedness.Add(new Bpl.AssumeCmd(s.Range.tok, etran.TrExpr(s.Range)));

 

-      TrStmt(s.Body, definedness, locals, etran);

+      if (s.Body != null) {

+        TrStmt(s.Body, definedness, locals, etran);

 

-      // check that postconditions hold

-      foreach (var ens in s.Ens) {

-        TrStmt_CheckWellformed(ens.E, definedness, locals, etran, false);

-        if (!ens.IsFree) {

-          bool splitHappened;  // we actually don't care

-          foreach (var split in TrSplitExpr(ens.E, etran, true, out splitHappened)) {

-            if (split.IsChecked) {

-              definedness.Add(Assert(split.E.tok, split.E, "possible violation of postcondition of forall statement"));

+        // check that postconditions hold

+        foreach (var ens in s.Ens) {

+          if (!ens.IsFree) {

+            bool splitHappened;  // we actually don't care

+            foreach (var split in TrSplitExpr(ens.E, etran, true, out splitHappened)) {

+              if (split.IsChecked) {

+                definedness.Add(Assert(split.E.tok, split.E, "possible violation of postcondition of forall statement"));

+              }

             }

           }

         }

@@ -8289,10 +8529,16 @@ namespace Microsoft.Dafny {
         } else if (expr is SeqDisplayExpr) {

           SeqDisplayExpr e = (SeqDisplayExpr)expr;

           Bpl.Expr s = translator.FunctionCall(expr.tok, BuiltinFunction.SeqEmpty, predef.BoxType);

-          foreach (Expression ee in e.Elements) {

-            Bpl.Expr elt = BoxIfNecessary(expr.tok, TrExpr(ee), cce.NonNull(ee.Type));

+          bool isLit = true;

+           foreach (Expression ee in e.Elements) {

+            var rawElement = TrExpr(ee);

+            isLit = isLit && translator.IsLit(rawElement);

+            Bpl.Expr elt = BoxIfNecessary(expr.tok, rawElement, ee.Type);

             s = translator.FunctionCall(expr.tok, BuiltinFunction.SeqBuild, predef.BoxType, s, elt);

           }

+          if (isLit) {

+            s = translator.Lit(s, predef.BoxType);

+          }

           return s;

 

         } else if (expr is MapDisplayExpr) {

@@ -8313,14 +8559,15 @@ namespace Microsoft.Dafny {
           Bpl.Expr result;

           if (e.Field.IsMutable) {

             result = ReadHeap(expr.tok, HeapExpr, obj, new Bpl.IdentifierExpr(expr.tok, translator.GetField(e.Field)));

-          } else {

-            result = new Bpl.NAryExpr(expr.tok, new Bpl.FunctionCall(translator.GetReadonlyField(e.Field)), new List<Bpl.Expr> { obj });

-            if (translator.IsLit(obj)) {

-              result = translator.Lit(result, translator.TrType(expr.Type));

-            }

+            return translator.CondApplyUnbox(expr.tok, result, e.Field.Type, expr.Type);

+           } else {

+             result = new Bpl.NAryExpr(expr.tok, new Bpl.FunctionCall(translator.GetReadonlyField(e.Field)), new List<Bpl.Expr> { obj });

+             result = translator.CondApplyUnbox(expr.tok, result, e.Field.Type, expr.Type);

+             if (translator.IsLit(obj)) {

+               result = translator.Lit(result, translator.TrType(expr.Type));

+             }

+             return result;

           }

-          return translator.CondApplyUnbox(expr.tok, result, e.Field.Type, cce.NonNull(expr.Type));

-

         } else if (expr is SeqSelectExpr) {

           SeqSelectExpr e = (SeqSelectExpr)expr;

           Bpl.Expr seq = TrExpr(e.Seq);

@@ -8366,13 +8613,20 @@ namespace Microsoft.Dafny {
             if (e.Seq.Type.IsArrayType) {

               seq = translator.FunctionCall(expr.tok, BuiltinFunction.SeqFromArray, elType, HeapExpr, seq);

             }

+            var isLit = translator.IsLit(seq);

             if (e1 != null) {

+              isLit = isLit && translator.IsLit(e1);

               seq = translator.FunctionCall(expr.tok, BuiltinFunction.SeqTake, elType, seq, e1);

             }

             if (e0 != null) {

+              isLit = isLit && translator.IsLit(e0);

               seq = translator.FunctionCall(expr.tok, BuiltinFunction.SeqDrop, elType, seq, e0);

             }

             // if e0 == null && e1 == null, then we have the identity operation seq[..] == seq;

+            if (isLit && (e0 != null || e1 != null)) {

+              // Lit-lift the expression

+              seq = translator.Lit(seq, translator.TrType(expr.Type));

+            }

             return seq;

           }

 

@@ -8446,12 +8700,13 @@ namespace Microsoft.Dafny {
           var id = new Bpl.IdentifierExpr(e.tok, e.Function.FullSanitizedName, ty);

           bool returnLit;

           var args = FunctionInvocationArguments(e, layerArgument, out returnLit);

+

           Expr result = new Bpl.NAryExpr(e.tok, new Bpl.FunctionCall(id), args);

+          result = translator.CondApplyUnbox(e.tok, result, e.Function.ResultType, e.Type);

           if (returnLit && !translator.IsOpaqueFunction(e.Function)) {

             result = translator.Lit(result, ty);

           }

-          return translator.CondApplyUnbox(e.tok, result, e.Function.ResultType, e.Type);

-

+          return result;

         } else if (expr is DatatypeValue) {

           DatatypeValue dtv = (DatatypeValue)expr;

           Contract.Assert(dtv.Ctor != null);  // since dtv has been successfully resolved

@@ -8465,7 +8720,7 @@ namespace Microsoft.Dafny {
             args.Add(translator.CondApplyBox(expr.tok, bArg, cce.NonNull(arg.Type), t));

           }

           Bpl.IdentifierExpr id = new Bpl.IdentifierExpr(dtv.tok, dtv.Ctor.FullName, predef.DatatypeType);

-          Expr ret = new Bpl.NAryExpr(dtv.tok, new Bpl.FunctionCall(id), args);

+          Bpl.Expr ret = new Bpl.NAryExpr(dtv.tok, new Bpl.FunctionCall(id), args);

           if (isLit) {

             ret = translator.Lit(ret, predef.DatatypeType);

           }

@@ -8621,13 +8876,13 @@ namespace Microsoft.Dafny {
               typ = Bpl.Type.Bool;

               bOpcode = BinaryOperator.Opcode.Gt; break;

             case BinaryExpr.ResolvedOpcode.Add:

-              typ = Bpl.Type.Int;

+              typ = isReal ? Bpl.Type.Real : Bpl.Type.Int;

               bOpcode = BinaryOperator.Opcode.Add; break;

             case BinaryExpr.ResolvedOpcode.Sub:

-              typ = Bpl.Type.Int;

+              typ = isReal ? Bpl.Type.Real : Bpl.Type.Int;

               bOpcode = BinaryOperator.Opcode.Sub; break;

             case BinaryExpr.ResolvedOpcode.Mul:

-              typ = Bpl.Type.Int;

+              typ = isReal ? Bpl.Type.Real : Bpl.Type.Int;

               bOpcode = BinaryOperator.Opcode.Mul; break;

             case BinaryExpr.ResolvedOpcode.Div:

               if (isReal) {

@@ -8862,9 +9117,9 @@ namespace Microsoft.Dafny {
 

         } else if (expr is ITEExpr) {

           ITEExpr e = (ITEExpr)expr;

-          Bpl.Expr g = translator.RemoveLit(TrExpr(e.Test));

-          Bpl.Expr thn = translator.RemoveLit(TrExpr(e.Thn));

-          Bpl.Expr els = translator.RemoveLit(TrExpr(e.Els));

+          var g = translator.RemoveLit(TrExpr(e.Test));

+          var thn = translator.RemoveLit(TrExpr(e.Thn));

+          var els = translator.RemoveLit(TrExpr(e.Els));

           return new NAryExpr(expr.tok, new IfThenElse(expr.tok), new List<Bpl.Expr> { g, thn, els });

 

         } else if (expr is MatchExpr) {

@@ -9032,6 +9287,24 @@ namespace Microsoft.Dafny {
         return translator.BoxIfNecessary(tok, e, fromType);

       }

 

+      public static Bpl.NAryExpr ReadHeap(IToken tok, Expr heap, Expr r, Expr f) {

+        Contract.Requires(tok != null);

+        Contract.Requires(heap != null);

+        Contract.Requires(r != null);

+        Contract.Requires(f != null);

+        Contract.Ensures(Contract.Result<Bpl.NAryExpr>() != null);

+

+        List<Bpl.Expr> args = new List<Bpl.Expr>();

+        args.Add(heap);

+        args.Add(r);

+        args.Add(f);

+        Bpl.Type t = (f.Type != null) ? f.Type : f.ShallowType;

+        return new Bpl.NAryExpr(tok,

+          new Bpl.FunctionCall(new Bpl.IdentifierExpr(tok, "read", t.AsCtor.Arguments[0])),

+          args);

+      }

+

+

       public static Bpl.NAryExpr UpdateHeap(IToken tok, Expr heap, Expr r, Expr f, Expr v) {

         Contract.Requires(tok != null);

         Contract.Requires(heap != null);

@@ -9193,8 +9466,10 @@ namespace Microsoft.Dafny {
     enum BuiltinFunction

     {

       Lit,

+      LitInt,

+      LitReal,

       LayerSucc,

-

+      

       Is, IsBox,

       IsAlloc, IsAllocBox,

 

@@ -9273,9 +9548,21 @@ namespace Microsoft.Dafny {
     }

 

     Bpl.Expr Lit(Bpl.Expr expr, Bpl.Type typ) {

-      return FunctionCall(expr.tok, BuiltinFunction.Lit, typ, expr);

+      Contract.Requires(expr != null);

+      Contract.Requires(typ != null);

+      // To avoid Boogie's int_2_U and U_2_int conversions, which seem to cause problems with

+      // arithmetic reasoning, we use several Lit functions.  In particular, we use one for

+      // integers, one for reals, and one for everything else.

+      if (typ.IsInt) {

+        return FunctionCall(expr.tok, BuiltinFunction.LitInt, null, expr);

+      } else if (typ.IsReal) {

+        return FunctionCall(expr.tok, BuiltinFunction.LitReal, null, expr);

+      } else {

+        return FunctionCall(expr.tok, BuiltinFunction.Lit, typ, expr);

+      }

     }

 

+

     Bpl.Expr Lit(Bpl.Expr expr) {

       return Lit(expr, expr.Type);

     }

@@ -9283,19 +9570,20 @@ namespace Microsoft.Dafny {
     Bpl.Expr GetLit(Bpl.Expr expr) {

       if (expr is NAryExpr) {

         NAryExpr app = (NAryExpr)expr;

-        if (app.Fun.FunctionName == "Lit") {

-          return app.Args[0];

+        switch (app.Fun.FunctionName) {

+          case "LitInt":

+          case "LitReal":

+          case "Lit":

+            return app.Args[0];

+          default:

+            break;

         }

       }

       return null;

     }

 

     Bpl.Expr RemoveLit(Bpl.Expr expr) {

-      var e = GetLit(expr);

-      if (e == null) {

-        e = expr;

-      }

-      return e;

+      return GetLit(expr) ?? expr;

     }

 

     bool IsLit(Bpl.Expr expr) {

@@ -9311,6 +9599,14 @@ namespace Microsoft.Dafny {
       Contract.Ensures(Contract.Result<Bpl.NAryExpr>() != null);

 

       switch (f) {

+        case BuiltinFunction.LitInt:

+          Contract.Assert(args.Length == 1);

+          Contract.Assert(typeInstantiation == null);

+          return FunctionCall(tok, "LitInt", Bpl.Type.Int, args);

+        case BuiltinFunction.LitReal:

+          Contract.Assert(args.Length == 1);

+          Contract.Assert(typeInstantiation == null);

+          return FunctionCall(tok, "LitReal", Bpl.Type.Real, args);

         case BuiltinFunction.Lit:

           Contract.Assert(args.Length == 1);

           Contract.Assert(typeInstantiation != null);

@@ -10528,6 +10824,19 @@ namespace Microsoft.Dafny {
       }

     }

 

+    /// <summary>

+    /// Returns an expression like "expr", but where free occurrences of "v" have been replaced by "e".

+    /// </summary>

+    public Expression Substitute(Expression expr, IVariable v, Expression e) {

+      Contract.Requires(expr != null);

+      Contract.Requires(v != null);

+      Contract.Requires(e != null);

+      Contract.Ensures(Contract.Result<Expression>() != null);

+      var substMap = new Dictionary<IVariable, Expression>();

+      substMap.Add(v, e);

+      return Substitute(expr, null, substMap);

+    }

+

     public Expression Substitute(Expression expr, Expression receiverReplacement, Dictionary<IVariable, Expression/*!*/>/*!*/ substMap, Dictionary<TypeParameter, Type>/*?*/ typeMap = null) {

       Contract.Requires(expr != null);

       Contract.Requires(cce.NonNullDictionaryAndValues(substMap));

@@ -10836,7 +11145,7 @@ namespace Microsoft.Dafny {
             cases.Add(newCaseExpr);

           }

           if (anythingChanged) {

-            var newME = new MatchExpr(expr.tok, src, cases);

+            var newME = new MatchExpr(expr.tok, src, cases, e.UsesOptionalBraces);

             newME.MissingCases.AddRange(e.MissingCases);

             newExpr = newME;

           }

@@ -11133,7 +11442,7 @@ namespace Microsoft.Dafny {
           r = rr;

         } else if (stmt is MatchStmt) {

           var s = (MatchStmt)stmt;

-          var rr = new MatchStmt(s.Tok, s.EndTok, Substitute(s.Source), s.Cases.ConvertAll(SubstMatchCaseStmt));

+          var rr = new MatchStmt(s.Tok, s.EndTok, Substitute(s.Source), s.Cases.ConvertAll(SubstMatchCaseStmt), s.UsesOptionalBraces);

           rr.MissingCases.AddRange(s.MissingCases);

           r = rr;

         } else if (stmt is AssignSuchThatStmt) {

diff --git a/Source/DafnyDriver/DafnyDriver.cs b/Source/DafnyDriver/DafnyDriver.cs
index 8f5b5300..01ee269e 100644
--- a/Source/DafnyDriver/DafnyDriver.cs
+++ b/Source/DafnyDriver/DafnyDriver.cs
@@ -99,7 +99,7 @@ namespace Microsoft.Dafny
     }

 

 

-    static ExitValue ProcessFiles(List<string/*!*/>/*!*/ fileNames)

+    static ExitValue ProcessFiles(List<string/*!*/>/*!*/ fileNames, bool lookForSnapshots = true)

     {

       Contract.Requires(cce.NonNullElements(fileNames));

 

@@ -110,7 +110,21 @@ namespace Microsoft.Dafny
         {

           Console.WriteLine();

           Console.WriteLine("-------------------- {0} --------------------", f);

-          var ev = ProcessFiles(new List<string> { f });

+          var ev = ProcessFiles(new List<string> { f }, lookForSnapshots);

+          if (exitValue != ev && ev != ExitValue.VERIFIED)

+          {

+            exitValue = ev;

+          }

+        }

+        return exitValue;

+      }

+

+      if (0 < CommandLineOptions.Clo.VerifySnapshots && lookForSnapshots)

+      {

+        var snapshotsByVersion = ExecutionEngine.LookForSnapshots(fileNames);

+        foreach (var s in snapshotsByVersion)

+        {

+          var ev = ProcessFiles(new List<string>(s), false);

           if (exitValue != ev && ev != ExitValue.VERIFIED)

           {

             exitValue = ev;

@@ -213,7 +227,7 @@ namespace Microsoft.Dafny
           ExecutionEngine.CollectModSets(program);

           ExecutionEngine.CoalesceBlocks(program);

           ExecutionEngine.Inline(program);

-          return ExecutionEngine.InferAndVerify(program, stats);

+          return ExecutionEngine.InferAndVerify(program, stats, 1 < Dafny.DafnyOptions.Clo.VerifySnapshots ? "main_program_id" : null);

 

         default:

           Contract.Assert(false); throw new cce.UnreachableException();  // unexpected outcome

diff --git a/Source/DafnyDriver/DafnyDriver.csproj b/Source/DafnyDriver/DafnyDriver.csproj
index 631b0194..cf664364 100644
--- a/Source/DafnyDriver/DafnyDriver.csproj
+++ b/Source/DafnyDriver/DafnyDriver.csproj
@@ -20,7 +20,7 @@
     <OldToolsVersion>3.5</OldToolsVersion>

     <UpgradeBackupLocation />

     <IsWebBootstrapper>false</IsWebBootstrapper>

-    <TargetFrameworkProfile>Client</TargetFrameworkProfile>

+    <TargetFrameworkProfile></TargetFrameworkProfile>

     <PublishUrl>publish\</PublishUrl>

     <Install>true</Install>

     <InstallFrom>Disk</InstallFrom>

diff --git a/Source/DafnyExtension/DafnyDriver.cs b/Source/DafnyExtension/DafnyDriver.cs
index f4eb4fb7..ea21f12b 100644
--- a/Source/DafnyExtension/DafnyDriver.cs
+++ b/Source/DafnyExtension/DafnyDriver.cs
@@ -45,7 +45,7 @@ namespace DafnyLanguage
 

         ExecutionEngine.printer = new DummyPrinter();

         ExecutionEngine.errorInformationFactory = new DafnyErrorInformationFactory();

-        ToggleIncrementalVerification();

+        ChangeIncrementalVerification(1);

       }

     }

 

@@ -215,11 +215,30 @@ namespace DafnyLanguage
       }

     }

 

-    public static bool ToggleIncrementalVerification()

+    public static int IncrementalVerificationMode()

     {

-      // TODO(wuestholz): Change this once there are more than two options.

-      Dafny.DafnyOptions.Clo.VerifySnapshots = (Dafny.DafnyOptions.Clo.VerifySnapshots + 1) % 2;

-      return 0 < Dafny.DafnyOptions.Clo.VerifySnapshots;

+      return Dafny.DafnyOptions.Clo.VerifySnapshots;

+    }

+

+    public static int ChangeIncrementalVerification(int mode)

+    {

+      var old = Dafny.DafnyOptions.Clo.VerifySnapshots;

+      if (mode == 1 && old != 0)

+      {

+        // Disable mode 1.

+        Dafny.DafnyOptions.Clo.VerifySnapshots = 0;

+      }

+      else if (mode == 2 && old == 2)

+      {

+        // Disable mode 2.

+        Dafny.DafnyOptions.Clo.VerifySnapshots = 1;

+      }

+      else

+      {

+        // Enable mode.

+        Dafny.DafnyOptions.Clo.VerifySnapshots = mode;

+      }

+      return Dafny.DafnyOptions.Clo.VerifySnapshots;

     }

 

     public static bool Verify(Dafny.Program dafnyProgram, ResolverTagger resolver, string uniqueIdPrefix, string requestId, ErrorReporterDelegate er) {

@@ -230,7 +249,8 @@ namespace DafnyLanguage
 

       resolver.ReInitializeVerificationErrors(requestId, boogieProgram.TopLevelDeclarations);

 

-      PipelineOutcome oc = BoogiePipeline(boogieProgram, requestId, er);

+      // TODO(wuestholz): Maybe we should use a fixed program ID to limit the memory overhead due to the program cache in Boogie.

+      PipelineOutcome oc = BoogiePipeline(boogieProgram, 1 < Dafny.DafnyOptions.Clo.VerifySnapshots ? uniqueIdPrefix : null, requestId, er);

       switch (oc) {

         case PipelineOutcome.Done:

         case PipelineOutcome.VerificationCompleted:

@@ -248,7 +268,7 @@ namespace DafnyLanguage
     /// else.  Hence, any resolution errors and type checking errors are due to errors in

     /// the translation.

     /// </summary>

-    static PipelineOutcome BoogiePipeline(Bpl.Program/*!*/ program, string requestId, ErrorReporterDelegate er)

+    static PipelineOutcome BoogiePipeline(Bpl.Program/*!*/ program, string programId, string requestId, ErrorReporterDelegate er)

     {

       Contract.Requires(program != null);

 

@@ -257,8 +277,8 @@ namespace DafnyLanguage
         ExecutionEngine.EliminateDeadVariables(program);

         ExecutionEngine.CollectModSets(program);

         ExecutionEngine.CoalesceBlocks(program);

-        ExecutionEngine.Inline(program);  

-        return ExecutionEngine.InferAndVerify(program, new PipelineStatistics(), er, requestId);

+        ExecutionEngine.Inline(program);

+        return ExecutionEngine.InferAndVerify(program, new PipelineStatistics(), programId, er, requestId);

       }

       return oc;

     }

diff --git a/Source/DafnyExtension/MenuProxy.cs b/Source/DafnyExtension/MenuProxy.cs
index a67ba602..11e1287f 100644
--- a/Source/DafnyExtension/MenuProxy.cs
+++ b/Source/DafnyExtension/MenuProxy.cs
@@ -17,9 +17,20 @@ namespace DafnyLanguage
       this.DafnyMenuPackage = DafnyMenuPackage;

     }

 

-    public bool ToggleSnapshotVerification(IWpfTextView activeTextView)

+    public int ToggleSnapshotVerification(IWpfTextView activeTextView)

     {

-      return DafnyDriver.ToggleIncrementalVerification();

+      return DafnyDriver.ChangeIncrementalVerification(1);

+    }

+

+    public int ToggleMoreAdvancedSnapshotVerification(IWpfTextView activeTextView)

+    {

+      return DafnyDriver.ChangeIncrementalVerification(2);

+    }

+

+    public bool MoreAdvancedSnapshotVerificationCommandEnabled(IWpfTextView activeTextView)

+    {

+      return activeTextView != null

+             && 0 < DafnyDriver.IncrementalVerificationMode();

     }

 

     public bool StopVerifierCommandEnabled(IWpfTextView activeTextView)

diff --git a/Source/DafnyExtension/TokenTagger.cs b/Source/DafnyExtension/TokenTagger.cs
index 48f5d1b4..5068354a 100644
--- a/Source/DafnyExtension/TokenTagger.cs
+++ b/Source/DafnyExtension/TokenTagger.cs
@@ -5,6 +5,7 @@ using System.Linq;
 using Microsoft.VisualStudio.Text;

 using Microsoft.VisualStudio.Text.Tagging;

 using Microsoft.VisualStudio.Utilities;

+using System.Diagnostics.Contracts;

 

 

 namespace DafnyLanguage

@@ -69,11 +70,12 @@ namespace DafnyLanguage
     }

   }

 

-  internal sealed class DafnyTokenTagger : ITagger<DafnyTokenTag>

+  internal sealed class DafnyTokenTagger : ITagger<DafnyTokenTag>, IDisposable

   {

     ITextBuffer _buffer;

     ITextSnapshot _snapshot;

     List<TokenRegion> _regions;

+    bool _disposed;

 

     internal DafnyTokenTagger(ITextBuffer buffer) {

       _buffer = buffer;

@@ -83,6 +85,19 @@ namespace DafnyLanguage
       _buffer.Changed += new EventHandler<TextContentChangedEventArgs>(ReparseFile);

     }

 

+    public void Dispose() {

+      lock (this) {

+        if (!_disposed) {

+          _buffer.Changed -= ReparseFile;

+          _buffer = null;

+          _snapshot = null;

+          _regions = null;

+          _disposed = true;

+        }

+      }

+      GC.SuppressFinalize(this);

+    }

+

     public event EventHandler<SnapshotSpanEventArgs> TagsChanged;

 

     public IEnumerable<ITagSpan<DafnyTokenTag>> GetTags(NormalizedSnapshotSpanCollection spans) {

@@ -148,20 +163,24 @@ namespace DafnyLanguage
     private static List<TokenRegion> Rescan(ITextSnapshot newSnapshot) {

       List<TokenRegion> newRegions = new List<TokenRegion>();

 

-      bool stillScanningLongComment = false;

-      SnapshotPoint commentStart = new SnapshotPoint();  // used only when stillScanningLongComment

-      SnapshotPoint commentEndAsWeKnowIt = new SnapshotPoint();  // used only when stillScanningLongComment

+      int longCommentDepth = 0;

+      SnapshotPoint commentStart = new SnapshotPoint();  // used only when longCommentDepth != 0

+      SnapshotPoint commentEndAsWeKnowIt = new SnapshotPoint();  // used only when longCommentDepth != 0

       foreach (ITextSnapshotLine line in newSnapshot.Lines) {

         string txt = line.GetText();  // the current line (without linebreak characters)

         int N = txt.Length;  // length of the current line

         int cur = 0;  // offset into the current line

 

-        if (stillScanningLongComment) {

-          if (ScanForEndOfComment(txt, ref cur)) {

+        if (longCommentDepth != 0) {

+          ScanForEndOfComment(txt, ref longCommentDepth, ref cur);

+          if (longCommentDepth == 0) {

+            // we just finished parsing a long comment

             newRegions.Add(new TokenRegion(commentStart, new SnapshotPoint(newSnapshot, line.Start + cur), DafnyTokenKind.Comment));

-            stillScanningLongComment = false;

           } else {

+            // we're still parsing the long comment

+            Contract.Assert(cur == txt.Length);

             commentEndAsWeKnowIt = new SnapshotPoint(newSnapshot, line.Start + cur);

+            goto OUTER_CONTINUE;

           }

         }

 

@@ -179,9 +198,9 @@ namespace DafnyLanguage
             if ('a' <= ch && ch <= 'z') break;

             if ('A' <= ch && ch <= 'Z') break;

             if ('0' <= ch && ch <= '9') { ty = DafnyTokenKind.Number; break; }

+            if (ch == '\'' || ch == '_' || ch == '?' || ch == '\\') break;  // parts of identifiers

             if (ch == '"') { ty = DafnyTokenKind.String; break; }

             if (ch == '/') { ty = DafnyTokenKind.Comment; break; }

-            if (ch == '\'' || ch == '_' || ch == '?' || ch == '\\') break;  // parts of identifiers

           }

 

           // advance to the end of the token

@@ -211,7 +230,7 @@ namespace DafnyLanguage
               }

             }

           } else if (ty == DafnyTokenKind.Comment) {

-            if (end == N) continue;  // this was not the start of a comment

+            if (end == N) continue;  // this was not the start of a comment; it was just a single "/" and we don't care to color it

             char ch = txt[end];

             if (ch == '/') {

               // a short comment

@@ -220,15 +239,18 @@ namespace DafnyLanguage
               // a long comment; find the matching "*/"

               end++;

               commentStart = new SnapshotPoint(newSnapshot, line.Start + cur);

-              if (ScanForEndOfComment(txt, ref end)) {

+              Contract.Assert(longCommentDepth == 0);

+              longCommentDepth = 1;

+              ScanForEndOfComment(txt, ref longCommentDepth, ref end);

+              if (longCommentDepth == 0) {

+                // we finished scanning a long comment, and "end" is set to right after it

                 newRegions.Add(new TokenRegion(commentStart, new SnapshotPoint(newSnapshot, line.Start + end), DafnyTokenKind.Comment));

               } else {

-                stillScanningLongComment = true;

                 commentEndAsWeKnowIt = new SnapshotPoint(newSnapshot, line.Start + end);

               }

               continue;

             } else {

-              // not a comment

+              // not a comment; it was just a single "/" and we don't care to color it

               continue;

             }

           } else {

@@ -322,7 +344,7 @@ namespace DafnyLanguage
                 #endregion

                   break;

                 default:

-                  continue;  // it was an identifier

+                  continue;  // it was an identifier, so we don't color it

               }

             }

           }

@@ -332,26 +354,40 @@ namespace DafnyLanguage
       OUTER_CONTINUE: ;

       }

 

-      if (stillScanningLongComment) {

+      if (longCommentDepth != 0) {

+        // This was a malformed comment, running to the end of the buffer.  Above, we let "commentEndAsWeKnowIt" be the end of the

+        // last line, so we can use it here.

         newRegions.Add(new TokenRegion(commentStart, commentEndAsWeKnowIt, DafnyTokenKind.Comment));

       }

 

       return newRegions;

     }

 

-    private static bool ScanForEndOfComment(string txt, ref int end) {

-      int N = txt.Length;

-      for (; end < N; end++) {

+    /// <summary>

+    /// Scans "txt" beginning with depth "depth", which is assumed to be non-0.  Any occurrences of "/*" or "*/"

+    /// increment or decrement "depth".  If "depth" ever reaches 0, then "end" returns as the number of characters

+    /// consumed from "txt" (including the last "*/").  If "depth" is still non-0 when the entire "txt" has

+    /// been consumed, then "end" returns as the length of "txt".  (Note, "end" may return as the length of "txt"

+    /// if "depth" is still non-0 or if "depth" became 0 from reading the last characters of "txt".)

+    /// </summary>

+    private static void ScanForEndOfComment(string txt, ref int depth, ref int end) {

+      Contract.Requires(depth > 0);

+

+      int Nminus1 = txt.Length - 1;  // no reason ever to look at the last character of the line, unless the second-to-last character is '*' or '/'

+      for (; end < Nminus1; ) {

         char ch = txt[end];

-        if (ch == '*' && end + 1 < N) {

-          ch = txt[end + 1];

-          if (ch == '/') {

-            end += 2;

-            return true;

-          }

+        if (ch == '*' && txt[end + 1] == '/') {

+          end += 2;

+          depth--;

+          if (depth == 0) { return; }

+        } else if (ch == '/' && txt[end + 1] == '*') {

+          end += 2;

+          depth++;

+        } else {

+          end++;

         }

       }

-      return false;  // hit end-of-line without finding end-of-comment

+      end = txt.Length;  // we didn't look at the last character, but we still consumed all the output

     }

   }

 

diff --git a/Source/DafnyExtension/source.extension.vsixmanifest b/Source/DafnyExtension/source.extension.vsixmanifest
index 3b2316b9..f4f66193 100644
--- a/Source/DafnyExtension/source.extension.vsixmanifest
+++ b/Source/DafnyExtension/source.extension.vsixmanifest
@@ -6,7 +6,7 @@
     <Description xml:space="preserve">This is a language mode for using the Dafny language inside Visual Studio.</Description>

   </Metadata>

   <Installation InstalledByMsi="false">

-    <InstallationTarget Version="[11.0,12.0)" Id="Microsoft.VisualStudio.Pro" />

+    <InstallationTarget Version="[11.0,13.0)" Id="Microsoft.VisualStudio.Pro" />

   </Installation>

   <Dependencies>

     <Dependency Id="Microsoft.Framework.NDP" DisplayName="Microsoft .NET Framework" d:Source="Manual" Version="4.5" />

diff --git a/Source/DafnyMenu/DafnyMenu.vsct b/Source/DafnyMenu/DafnyMenu.vsct
index 0e8c7855..813ccd23 100644
--- a/Source/DafnyMenu/DafnyMenu.vsct
+++ b/Source/DafnyMenu/DafnyMenu.vsct
@@ -103,6 +103,16 @@
         </Strings>

       </Button>

 

+      <Button guid="guidDafnyMenuCmdSet" id="cmdidToggleMoreAdvancedSnapshotVerification" priority="0x0105" type="Button">

+        <Parent guid="guidDafnyMenuCmdSet" id="DafnyMenuGroup" />

+        <CommandFlag>DefaultInvisible</CommandFlag>

+        <CommandFlag>DynamicVisibility</CommandFlag>

+        <CommandFlag>TextChanges</CommandFlag>

+        <Strings>

+          <ButtonText>Enable more advanced on-demand re-verification</ButtonText>

+        </Strings>

+      </Button>

+

       <Button guid="guidDafnyMenuCmdSet" id="cmdidToggleBVD" priority="0x010a" type="Button">

         <Parent guid="guidDafnyMenuCmdSet" id="DafnyMenuGroup" />

         <CommandFlag>DynamicVisibility</CommandFlag>

@@ -144,6 +154,7 @@
       <IDSymbol name="cmdidStopVerifier" value="0x0102" />

       <IDSymbol name="cmdidToggleSnapshotVerification" value="0x0103" />

       <IDSymbol name="cmdidToggleBVD" value="0x0104" />

+      <IDSymbol name="cmdidToggleMoreAdvancedSnapshotVerification" value="0x0105" />

     </GuidSymbol>

 

     <!--

diff --git a/Source/DafnyMenu/DafnyMenuPackage.cs b/Source/DafnyMenu/DafnyMenuPackage.cs
index 114ddf10..58bf2a26 100644
--- a/Source/DafnyMenu/DafnyMenuPackage.cs
+++ b/Source/DafnyMenu/DafnyMenuPackage.cs
@@ -19,7 +19,13 @@ namespace DafnyLanguage.DafnyMenu
 

   public interface IMenuProxy

   {

-    bool ToggleSnapshotVerification(IWpfTextView activeTextView);

+    int ToggleSnapshotVerification(IWpfTextView activeTextView);

+

+

+    int ToggleMoreAdvancedSnapshotVerification(IWpfTextView activeTextView);

+

+

+    bool MoreAdvancedSnapshotVerificationCommandEnabled(IWpfTextView activeTextView);

 

 

     bool StopVerifierCommandEnabled(IWpfTextView activeTextView);

@@ -80,6 +86,7 @@ namespace DafnyLanguage.DafnyMenu
     private OleMenuCommand runVerifierCommand;

     private OleMenuCommand stopVerifierCommand;

     private OleMenuCommand toggleSnapshotVerificationCommand;

+    private OleMenuCommand toggleMoreAdvancedSnapshotVerificationCommand;

     private OleMenuCommand toggleBVDCommand;

 

     bool BVDDisabled;

@@ -138,6 +145,11 @@ namespace DafnyLanguage.DafnyMenu
         toggleSnapshotVerificationCommand = new OleMenuCommand(ToggleSnapshotVerificationCallback, toggleSnapshotVerificationCommandID);

         mcs.AddCommand(toggleSnapshotVerificationCommand);

 

+        var toggleMoreAdvancedSnapshotVerificationCommandID = new CommandID(GuidList.guidDafnyMenuCmdSet, (int)PkgCmdIDList.cmdidToggleMoreAdvancedSnapshotVerification);

+        toggleMoreAdvancedSnapshotVerificationCommand = new OleMenuCommand(ToggleMoreAdvancedSnapshotVerificationCallback, toggleMoreAdvancedSnapshotVerificationCommandID);

+        toggleMoreAdvancedSnapshotVerificationCommand.BeforeQueryStatus += toggleMoreAdvancedSnapshotVerificationCommand_BeforeQueryStatus;

+        mcs.AddCommand(toggleMoreAdvancedSnapshotVerificationCommand);

+

         var showErrorModelCommandID = new CommandID(GuidList.guidDafnyMenuCmdSet, (int)PkgCmdIDList.cmdidToggleBVD);

         toggleBVDCommand = new OleMenuCommand(ToggleBVDCallback, showErrorModelCommandID);

         toggleBVDCommand.Enabled = true;

@@ -191,8 +203,20 @@ namespace DafnyLanguage.DafnyMenu
       var atv = ActiveTextView;

       if (MenuProxy != null && atv != null)

       {

-        var on = MenuProxy.ToggleSnapshotVerification(atv);

-        toggleSnapshotVerificationCommand.Text = (on ? "Disable" : "Enable") + " on-demand re-verification";

+        var mode = MenuProxy.ToggleSnapshotVerification(atv);

+        toggleSnapshotVerificationCommand.Text = (mode == 1 ? "Disable" : "Enable") + " on-demand re-verification";

+        toggleMoreAdvancedSnapshotVerificationCommand.Text = (mode == 2 ? "Disable" : "Enable") + " more advanced on-demand re-verification";

+      }

+    }

+

+    void ToggleMoreAdvancedSnapshotVerificationCallback(object sender, EventArgs e)

+    {

+      var atv = ActiveTextView;

+      if (MenuProxy != null && atv != null)

+      {

+        var mode = MenuProxy.ToggleMoreAdvancedSnapshotVerification(atv);

+        toggleSnapshotVerificationCommand.Text = (mode != 0 ? "Disable" : "Enable") + " on-demand re-verification";

+        toggleMoreAdvancedSnapshotVerificationCommand.Text = (mode == 2 ? "Disable" : "Enable") + " more advanced on-demand re-verification";

       }

     }

 

@@ -276,6 +300,16 @@ namespace DafnyLanguage.DafnyMenu
       }

     }

 

+    private void toggleMoreAdvancedSnapshotVerificationCommand_BeforeQueryStatus(object sender, EventArgs e)

+    {

+      var atv = ActiveTextView;

+      if (MenuProxy != null && atv != null)

+      {

+        var visible = MenuProxy.MoreAdvancedSnapshotVerificationCommandEnabled(atv);

+        toggleMoreAdvancedSnapshotVerificationCommand.Visible = visible;

+      }

+    }

+

     void ToggleBVDCallback(object sender, EventArgs e)

     {

       BVDDisabled = !BVDDisabled;

diff --git a/Source/DafnyMenu/PkgCmdID.cs b/Source/DafnyMenu/PkgCmdID.cs
index f3452cb9..b6f30145 100644
--- a/Source/DafnyMenu/PkgCmdID.cs
+++ b/Source/DafnyMenu/PkgCmdID.cs
@@ -12,5 +12,6 @@ namespace DafnyLanguage.DafnyMenu
     public const uint cmdidMenu = 0x1021;

     public static uint cmdidToggleSnapshotVerification = 0x103;

     public const uint cmdidToggleBVD = 0x104;

+    public static uint cmdidToggleMoreAdvancedSnapshotVerification = 0x105;

   };

 }
\ No newline at end of file
diff --git a/Source/DafnyMenu/source.extension.vsixmanifest b/Source/DafnyMenu/source.extension.vsixmanifest
index 508078d4..7beeb69e 100644
--- a/Source/DafnyMenu/source.extension.vsixmanifest
+++ b/Source/DafnyMenu/source.extension.vsixmanifest
@@ -6,7 +6,7 @@
     <Description xml:space="preserve">This is a menu for interacting with Dafny.</Description>

   </Metadata>

   <Installation InstalledByMsi="false">

-    <InstallationTarget Version="[11.0,12.0)" Id="Microsoft.VisualStudio.Pro" />

+    <InstallationTarget Version="[11.0,13.0)" Id="Microsoft.VisualStudio.Pro" />

   </Installation>

   <Dependencies>

     <Dependency Id="Microsoft.Framework.NDP" DisplayName="Microsoft .NET Framework" d:Source="Manual" Version="4.5" />