Merge

1 files changed, 4 insertions, 2 deletions

diff --git a/Source/Dafny/DafnyAst.cs b/Source/Dafny/DafnyAst.cs
index 792274f8..be2bbe33 100644
--- a/Source/Dafny/DafnyAst.cs
+++ b/Source/Dafny/DafnyAst.cs
@@ -5226,12 +5226,14 @@ namespace Microsoft.Dafny {
       return e;

     }

 

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

+    public static Expression VarSubstituter(List<NonglobalVariable> oldVars, List<BoundVar> newVars, Expression e, Dictionary<TypeParameter, Type> typeMap=null) {

       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>();

+      if (typeMap == null) {

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

+      }

 

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

         var id = new IdentifierExpr(newVars[i].tok, newVars[i].Name);