1 files changed, 1820 insertions, 0 deletions
diff --git a/Test/test21/test3_AddMethod_conv.bpl b/Test/test21/test3_AddMethod_conv.bpl
new file mode 100644
index 00000000..1382fdeb
--- /dev/null
+++ b/Test/test21/test3_AddMethod_conv.bpl
@@ -0,0 +1,1820 @@
+// Spec# program verifier version 0.90, Copyright (c) 2003-2008, Microsoft.
+// Command Line Options: /print:debug.txt AddMethod.dll
+
+type real;
+
+type elements;
+
+type struct;
+
+type name;
+type any;
+
+type exposeVersionType;
+
+type Field a;
+type Heap = <x>[ref,Field x]x;
+
+var $Heap: Heap where IsHeap($Heap);
+
+type ActivityType;
+
+var $ActivityIndicator: ActivityType;
+
+function IsHeap(h: Heap) returns (bool);
+
+const unique $allocated: Field bool;
+
+const unique $elements: Field elements;
+
+function DeclType222<a>(Field a) returns (name);
+
+axiom DeclType222($elements) == System.Object;
+
+const unique $inv: Field name;
+
+const unique $localinv: Field name;
+
+const unique $exposeVersion: Field exposeVersionType;
+
+axiom DeclType222($exposeVersion) == System.Object;
+
+const unique $sharingMode: Field any;
+
+const unique $SharingMode_Unshared: any;
+
+const unique $SharingMode_LockProtected: any;
+
+const unique $ownerRef: Field ref;
+
+const unique $ownerFrame: Field name;
+
+const unique $PeerGroupPlaceholder: name;
+
+function ClassRepr(class: name) returns (ref);
+
+function ClassReprInv(ref) returns (name);
+
+axiom (forall c: name :: { ClassRepr(c) } ClassReprInv(ClassRepr(c)) == c);
+
+axiom (forall T: name :: !($typeof(ClassRepr(T)) <: System.Object));
+
+axiom (forall T: name :: ClassRepr(T) != null);
+
+axiom (forall T: name, h: Heap :: { h[ClassRepr(T), $ownerFrame] } IsHeap(h) ==> h[ClassRepr(T), $ownerFrame] == $PeerGroupPlaceholder);
+
+function IncludeInMainFrameCondition<a>(f: Field a) returns (bool);
+
+axiom IncludeInMainFrameCondition($allocated);
+
+axiom IncludeInMainFrameCondition($elements);
+
+axiom !IncludeInMainFrameCondition($inv);
+
+axiom !IncludeInMainFrameCondition($localinv);
+
+axiom IncludeInMainFrameCondition($ownerRef);
+
+axiom IncludeInMainFrameCondition($ownerFrame);
+
+axiom IncludeInMainFrameCondition($exposeVersion);
+
+axiom !IncludeInMainFrameCondition($FirstConsistentOwner);
+
+function IsStaticField<a>(f: Field a) returns (bool);
+
+axiom !IsStaticField($allocated);
+
+axiom !IsStaticField($elements);
+
+axiom !IsStaticField($inv);
+
+axiom !IsStaticField($localinv);
+
+axiom !IsStaticField($exposeVersion);
+
+function $IncludedInModifiesStar<a>(f: Field a) returns (bool);
+
+axiom !$IncludedInModifiesStar($ownerRef);
+
+axiom !$IncludedInModifiesStar($ownerFrame);
+
+axiom $IncludedInModifiesStar($exposeVersion);
+
+axiom $IncludedInModifiesStar($elements);
+
+function ValueArrayGet(elements, int) returns (any);
+
+function ValueArraySet(elements, int, any) returns (elements);
+
+function IntArrayGet(elements, int) returns (int);
+
+function IntArraySet(elements, int, int) returns (elements);
+
+function RefArrayGet(elements, int) returns (ref);
+
+function RefArraySet(elements, int, ref) returns (elements);
+
+axiom (forall A: elements, i: int, x: any :: ValueArrayGet(ValueArraySet(A, i, x), i) == x);
+
+axiom (forall A: elements, i: int, j: int, x: any :: i != j ==> ValueArrayGet(ValueArraySet(A, i, x), j) == ValueArrayGet(A, j));
+
+axiom (forall A: elements, i: int, x: int :: IntArrayGet(IntArraySet(A, i, x), i) == x);
+
+axiom (forall A: elements, i: int, j: int, x: int :: i != j ==> IntArrayGet(IntArraySet(A, i, x), j) == IntArrayGet(A, j));
+
+axiom (forall A: elements, i: int, x: ref :: RefArrayGet(RefArraySet(A, i, x), i) == x);
+
+axiom (forall A: elements, i: int, j: int, x: ref :: i != j ==> RefArrayGet(RefArraySet(A, i, x), j) == RefArrayGet(A, j));
+
+function ArrayIndex(arr: ref, dim: int, indexAtDim: int, remainingIndexContribution: int) returns (int);
+
+function ArrayIndexInvX(arrayIndex: int) returns (indexAtDim: int);
+
+function ArrayIndexInvY(arrayIndex: int) returns (remainingIndexContribution: int);
+
+axiom (forall a: ref, d: int, x: int, y: int :: { ArrayIndex(a, d, x, y) } ArrayIndexInvX(ArrayIndex(a, d, x, y)) == x);
+
+axiom (forall a: ref, d: int, x: int, y: int :: { ArrayIndex(a, d, x, y) } ArrayIndexInvY(ArrayIndex(a, d, x, y)) == y);
+
+axiom (forall a: ref, i: int, heap: Heap :: { IntArrayGet(heap[a, $elements], i) } IsHeap(heap) ==> InRange(IntArrayGet(heap[a, $elements], i), $ElementType($typeof(a))));
+
+axiom (forall a: ref, i: int, heap: Heap :: { $typeof(RefArrayGet(heap[a, $elements], i)) } IsHeap(heap) && RefArrayGet(heap[a, $elements], i) != null ==> $typeof(RefArrayGet(heap[a, $elements], i)) <: $ElementType($typeof(a)));
+
+axiom (forall a: ref, T: name, i: int, r: int, heap: Heap :: { $typeof(a) <: NonNullRefArray(T, r), RefArrayGet(heap[a, $elements], i) } IsHeap(heap) && $typeof(a) <: NonNullRefArray(T, r) ==> RefArrayGet(heap[a, $elements], i) != null);
+
+function $Rank(ref) returns (int);
+
+axiom (forall a: ref :: 1 <= $Rank(a));
+
+axiom (forall a: ref, T: name, r: int :: { $typeof(a) <: RefArray(T, r) } a != null && $typeof(a) <: RefArray(T, r) ==> $Rank(a) == r);
+
+axiom (forall a: ref, T: name, r: int :: { $typeof(a) <: NonNullRefArray(T, r) } a != null && $typeof(a) <: NonNullRefArray(T, r) ==> $Rank(a) == r);
+
+axiom (forall a: ref, T: name, r: int :: { $typeof(a) <: ValueArray(T, r) } a != null && $typeof(a) <: ValueArray(T, r) ==> $Rank(a) == r);
+
+axiom (forall a: ref, T: name, r: int :: { $typeof(a) <: IntArray(T, r) } a != null && $typeof(a) <: IntArray(T, r) ==> $Rank(a) == r);
+
+function $Length(ref) returns (int);
+
+axiom (forall a: ref :: { $Length(a) } 0 <= $Length(a) && $Length(a) <= int#2147483647);
+
+function $DimLength(ref, int) returns (int);
+
+axiom (forall a: ref, i: int :: 0 <= $DimLength(a, i));
+
+axiom (forall a: ref :: { $DimLength(a, 0) } $Rank(a) == 1 ==> $DimLength(a, 0) == $Length(a));
+
+function $LBound(ref, int) returns (int);
+
+function $UBound(ref, int) returns (int);
+
+axiom (forall a: ref, i: int :: { $LBound(a, i) } $LBound(a, i) == 0);
+
+axiom (forall a: ref, i: int :: { $UBound(a, i) } $UBound(a, i) == $DimLength(a, i) - 1);
+
+const unique $ArrayCategoryValue: name;
+
+const unique $ArrayCategoryInt: name;
+
+const unique $ArrayCategoryRef: name;
+
+const unique $ArrayCategoryNonNullRef: name;
+
+function $ArrayCategory(arrayType: name) returns (arrayCategory: name);
+
+axiom (forall T: name, ET: name, r: int :: { T <: ValueArray(ET, r) } T <: ValueArray(ET, r) ==> $ArrayCategory(T) == $ArrayCategoryValue);
+
+axiom (forall T: name, ET: name, r: int :: { T <: IntArray(ET, r) } T <: IntArray(ET, r) ==> $ArrayCategory(T) == $ArrayCategoryInt);
+
+axiom (forall T: name, ET: name, r: int :: { T <: RefArray(ET, r) } T <: RefArray(ET, r) ==> $ArrayCategory(T) == $ArrayCategoryRef);
+
+axiom (forall T: name, ET: name, r: int :: { T <: NonNullRefArray(ET, r) } T <: NonNullRefArray(ET, r) ==> $ArrayCategory(T) == $ArrayCategoryNonNullRef);
+
+const unique System.Array: name;
+
+axiom System.Array <: System.Object;
+
+function $ElementType(name) returns (name);
+
+function ValueArray(elementType: name, rank: int) returns (name);
+
+axiom (forall T: name, r: int :: { ValueArray(T, r) } ValueArray(T, r) <: ValueArray(T, r) && ValueArray(T, r) <: System.Array);
+
+function IntArray(elementType: name, rank: int) returns (name);
+
+axiom (forall T: name, r: int :: { IntArray(T, r) } IntArray(T, r) <: IntArray(T, r) && IntArray(T, r) <: System.Array);
+
+function RefArray(elementType: name, rank: int) returns (name);
+
+axiom (forall T: name, r: int :: { RefArray(T, r) } RefArray(T, r) <: RefArray(T, r) && RefArray(T, r) <: System.Array);
+
+function NonNullRefArray(elementType: name, rank: int) returns (name);
+
+axiom (forall T: name, r: int :: { NonNullRefArray(T, r) } NonNullRefArray(T, r) <: NonNullRefArray(T, r) && NonNullRefArray(T, r) <: System.Array);
+
+function NonNullRefArrayRaw(array: ref, elementType: name, rank: int) returns (bool);
+
+axiom (forall array: ref, elementType: name, rank: int :: { NonNullRefArrayRaw(array, elementType, rank) } NonNullRefArrayRaw(array, elementType, rank) ==> $typeof(array) <: System.Array && $Rank(array) == rank && elementType <: $ElementType($typeof(array)));
+
+axiom (forall T: name, U: name, r: int :: U <: T ==> RefArray(U, r) <: RefArray(T, r));
+
+axiom (forall T: name, U: name, r: int :: U <: T ==> NonNullRefArray(U, r) <: NonNullRefArray(T, r));
+
+axiom (forall A: name, r: int :: $ElementType(ValueArray(A, r)) == A);
+
+axiom (forall A: name, r: int :: $ElementType(IntArray(A, r)) == A);
+
+axiom (forall A: name, r: int :: $ElementType(RefArray(A, r)) == A);
+
+axiom (forall A: name, r: int :: $ElementType(NonNullRefArray(A, r)) == A);
+
+axiom (forall A: name, r: int, T: name :: { T <: RefArray(A, r) } T <: RefArray(A, r) ==> T != A && T == RefArray($ElementType(T), r) && $ElementType(T) <: A);
+
+axiom (forall A: name, r: int, T: name :: { T <: NonNullRefArray(A, r) } T <: NonNullRefArray(A, r) ==> T != A && T == NonNullRefArray($ElementType(T), r) && $ElementType(T) <: A);
+
+axiom (forall A: name, r: int, T: name :: { T <: ValueArray(A, r) } T <: ValueArray(A, r) ==> T == ValueArray(A, r));
+
+axiom (forall A: name, r: int, T: name :: { T <: IntArray(A, r) } T <: IntArray(A, r) ==> T == IntArray(A, r));
+
+axiom (forall A: name, r: int, T: name :: { RefArray(A, r) <: T } RefArray(A, r) <: T ==> System.Array <: T || (T == RefArray($ElementType(T), r) && A <: $ElementType(T)));
+
+axiom (forall A: name, r: int, T: name :: { NonNullRefArray(A, r) <: T } NonNullRefArray(A, r) <: T ==> System.Array <: T || (T == NonNullRefArray($ElementType(T), r) && A <: $ElementType(T)));
+
+axiom (forall A: name, r: int, T: name :: { ValueArray(A, r) <: T } ValueArray(A, r) <: T ==> System.Array <: T || T == ValueArray(A, r));
+
+axiom (forall A: name, r: int, T: name :: { IntArray(A, r) <: T } IntArray(A, r) <: T ==> System.Array <: T || T == IntArray(A, r));
+
+function $ArrayPtr(elementType: name) returns (name);
+
+function $ElementProxy(ref, int) returns (ref);
+
+function $ElementProxyStruct(struct, int) returns (ref);
+
+axiom (forall a: ref, i: int, heap: Heap :: { heap[RefArrayGet(heap[a, $elements], i), $ownerRef] } { heap[RefArrayGet(heap[a, $elements], i), $ownerFrame] } IsHeap(heap) && $typeof(a) <: System.Array ==> RefArrayGet(heap[a, $elements], i) == null || $IsImmutable($typeof(RefArrayGet(heap[a, $elements], i))) || (heap[RefArrayGet(heap[a, $elements], i), $ownerRef] == heap[$ElementProxy(a, 0 - 1), $ownerRef] && heap[RefArrayGet(heap[a, $elements], i), $ownerFrame] == heap[$ElementProxy(a, 0 - 1), $ownerFrame]));
+
+axiom (forall a: ref, heap: Heap :: { IsAllocated(heap, a) } IsHeap(heap) && IsAllocated(heap, a) && $typeof(a) <: System.Array ==> IsAllocated(heap, $ElementProxy(a, 0 - 1)));
+
+axiom (forall o: ref, pos: int :: { $typeof($ElementProxy(o, pos)) } $typeof($ElementProxy(o, pos)) == System.Object);
+
+axiom (forall o: struct, pos: int :: { $typeof($ElementProxyStruct(o, pos)) } $typeof($ElementProxyStruct(o, pos)) == System.Object);
+
+function $StructGet(struct, name) returns (any);
+
+function $StructSet(struct, name, any) returns (struct);
+
+axiom (forall s: struct, f: name, x: any :: $StructGet($StructSet(s, f, x), f) == x);
+
+axiom (forall s: struct, f: name, f': name, x: any :: f != f' ==> $StructGet($StructSet(s, f, x), f') == $StructGet(s, f'));
+
+function ZeroInit(s: struct, typ: name) returns (bool);
+
+function $typeof(ref) returns (name);
+
+function $BaseClass(sub: name) returns (base: name);
+
+axiom (forall T: name :: { $BaseClass(T) } T <: $BaseClass(T) && (T != System.Object ==> T != $BaseClass(T)));
+
+function AsDirectSubClass(sub: name, base: name) returns (sub': name);
+
+function OneClassDown(sub: name, base: name) returns (directSub: name);
+
+axiom (forall A: name, B: name, C: name :: { C <: AsDirectSubClass(B, A) } C <: AsDirectSubClass(B, A) ==> OneClassDown(C, A) == B);
+
+function $IsValueType(name) returns (bool);
+
+axiom (forall T: name :: $IsValueType(T) ==> (forall U: name :: T <: U ==> T == U) && (forall U: name :: U <: T ==> T == U));
+
+const unique System.Boolean: name;
+
+axiom $IsValueType(System.Boolean);
+
+const unique System.Object: name;
+
+function $IsTokenForType(struct, name) returns (bool);
+
+function TypeObject(name) returns (ref);
+
+const unique System.Type: name;
+
+axiom System.Type <: System.Object;
+
+axiom (forall T: name :: { TypeObject(T) } $IsNotNull(TypeObject(T), System.Type));
+
+function TypeName(ref) returns (name);
+
+axiom (forall T: name :: { TypeObject(T) } TypeName(TypeObject(T)) == T);
+
+function $Is(ref, name) returns (bool);
+
+axiom (forall o: ref, T: name :: { $Is(o, T) } $Is(o, T) <==> o == null || $typeof(o) <: T);
+
+function $IsNotNull(ref, name) returns (bool);
+
+axiom (forall o: ref, T: name :: { $IsNotNull(o, T) } $IsNotNull(o, T) <==> o != null && $Is(o, T));
+
+function $As(ref, name) returns (ref);
+
+axiom (forall o: ref, T: name :: $Is(o, T) ==> $As(o, T) == o);
+
+axiom (forall o: ref, T: name :: !$Is(o, T) ==> $As(o, T) == null);
+
+axiom (forall h: Heap, o: ref :: { $typeof(o) <: System.Array, h[o, $inv] } IsHeap(h) && o != null && $typeof(o) <: System.Array ==> h[o, $inv] == $typeof(o) && h[o, $localinv] == $typeof(o));
+
+function IsAllocated<a>(h: Heap, o: a) returns (bool);
+
+axiom (forall<a> h: Heap, o: ref, f: Field a :: { IsAllocated(h, h[o, f]) } IsHeap(h) && h[o, $allocated] ==> IsAllocated(h, h[o, f]));
+
+axiom (forall h: Heap, o: ref, f: Field ref :: { h[h[o, f], $allocated] } IsHeap(h) && h[o, $allocated] ==> h[h[o, f], $allocated]);
+
+axiom (forall h: Heap, s: struct, f: name :: { IsAllocated(h, $StructGet(s, f)) } IsAllocated(h, s) ==> IsAllocated(h, $StructGet(s, f)));
+
+axiom (forall h: Heap, e: elements, i: int :: { IsAllocated(h, RefArrayGet(e, i)) } IsAllocated(h, e) ==> IsAllocated(h, RefArrayGet(e, i)));
+
+axiom (forall h: Heap, e: elements, i: int :: { IsAllocated(h, ValueArrayGet(e, i)) } IsAllocated(h, e) ==> IsAllocated(h, ValueArrayGet(e, i)));
+
+axiom (forall h: Heap, o: ref :: { h[o, $allocated] } IsAllocated(h, o) ==> h[o, $allocated]);
+
+axiom (forall h: Heap, c: name :: { h[ClassRepr(c), $allocated] } IsHeap(h) ==> h[ClassRepr(c), $allocated]);
+
+const $BeingConstructed: ref;
+
+const unique $NonNullFieldsAreInitialized: Field bool;
+
+const $PurityAxiomsCanBeAssumed: bool;
+
+axiom DeclType222($NonNullFieldsAreInitialized) == System.Object;
+
+
+
+function AsNonNullRefField(field: Field ref, T: name) returns (f: Field ref);
+
+function AsRefField(field: Field ref, T: name) returns (f: Field ref);
+
+function AsRangeField(field: Field int, T: name) returns (f: Field int);
+
+axiom (forall f: Field ref, T: name :: { AsNonNullRefField(f, T) } AsNonNullRefField(f, T) == f ==> AsRefField(f, T) == f);
+
+axiom (forall h: Heap, o: ref, f: Field ref, T: name :: { h[o, AsRefField(f, T)] } IsHeap(h) ==> $Is(h[o, AsRefField(f, T)], T));
+
+axiom (forall h: Heap, o: ref, f: Field ref, T: name :: { h[o, AsNonNullRefField(f, T)] } IsHeap(h) && o != null && (o != $BeingConstructed || h[$BeingConstructed, $NonNullFieldsAreInitialized] == true) ==> h[o, AsNonNullRefField(f, T)] != null);
+
+axiom (forall h: Heap, o: ref, f: Field int, T: name :: { h[o, AsRangeField(f, T)] } IsHeap(h) ==> InRange(h[o, AsRangeField(f, T)], T));
+
+function $IsMemberlessType(name) returns (bool);
+
+axiom (forall o: ref :: { $IsMemberlessType($typeof(o)) } !$IsMemberlessType($typeof(o)));
+
+function $AsInterface(name) returns (name);
+
+axiom (forall $J: name, s: any, b: ref :: { UnboxedType(Box(s, b)) <: $AsInterface($J) } $AsInterface($J) == $J && Box(s, b) == b && UnboxedType(Box(s, b)) <: $AsInterface($J) ==> $typeof(b) <: $J);
+
+function $HeapSucc(oldHeap: Heap, newHeap: Heap) returns (bool);
+
+function $IsImmutable(T: name) returns (bool);
+
+axiom !$IsImmutable(System.Object);
+
+function $AsImmutable(T: name) returns (theType: name);
+
+function $AsMutable(T: name) returns (theType: name);
+
+axiom (forall T: name, U: name :: { U <: $AsImmutable(T) } U <: $AsImmutable(T) ==> $IsImmutable(U) && $AsImmutable(U) == U);
+
+axiom (forall T: name, U: name :: { U <: $AsMutable(T) } U <: $AsMutable(T) ==> !$IsImmutable(U) && $AsMutable(U) == U);
+
+function AsOwner(string: ref, owner: ref) returns (theString: ref);
+
+axiom (forall o: ref, T: name :: { $typeof(o) <: $AsImmutable(T) } o != null && o != $BeingConstructed && $typeof(o) <: $AsImmutable(T) ==> (forall h: Heap :: { IsHeap(h) } IsHeap(h) ==> h[o, $inv] == $typeof(o) && h[o, $localinv] == $typeof(o) && h[o, $ownerFrame] == $PeerGroupPlaceholder && AsOwner(o, h[o, $ownerRef]) == o && (forall t: ref :: { AsOwner(o, h[t, $ownerRef]) } AsOwner(o, h[t, $ownerRef]) == o ==> t == o || h[t, $ownerFrame] != $PeerGroupPlaceholder)));
+
+const unique System.String: name;
+
+function $StringLength(ref) returns (int);
+
+axiom (forall s: ref :: { $StringLength(s) } 0 <= $StringLength(s));
+
+function AsRepField(f: Field ref, declaringType: name) returns (theField: Field ref);
+
+axiom (forall h: Heap, o: ref, f: Field ref, T: name :: { h[o, AsRepField(f, T)] } IsHeap(h) && h[o, AsRepField(f, T)] != null ==> h[h[o, AsRepField(f, T)], $ownerRef] == o && h[h[o, AsRepField(f, T)], $ownerFrame] == T);
+
+function AsPeerField(f: Field ref) returns (theField: Field ref);
+
+axiom (forall h: Heap, o: ref, f: Field ref :: { h[o, AsPeerField(f)] } IsHeap(h) && h[o, AsPeerField(f)] != null ==> h[h[o, AsPeerField(f)], $ownerRef] == h[o, $ownerRef] && h[h[o, AsPeerField(f)], $ownerFrame] == h[o, $ownerFrame]);
+
+function AsElementsRepField(f: Field ref, declaringType: name, position: int) returns (theField: Field ref);
+
+axiom (forall h: Heap, o: ref, f: Field ref, T: name, i: int :: { h[o, AsElementsRepField(f, T, i)] } IsHeap(h) && h[o, AsElementsRepField(f, T, i)] != null ==> h[$ElementProxy(h[o, AsElementsRepField(f, T, i)], i), $ownerRef] == o && h[$ElementProxy(h[o, AsElementsRepField(f, T, i)], i), $ownerFrame] == T);
+
+function AsElementsPeerField(f: Field ref, position: int) returns (theField: Field ref);
+
+axiom (forall h: Heap, o: ref, f: Field ref, i: int :: { h[o, AsElementsPeerField(f, i)] } IsHeap(h) && h[o, AsElementsPeerField(f, i)] != null ==> h[$ElementProxy(h[o, AsElementsPeerField(f, i)], i), $ownerRef] == h[o, $ownerRef] && h[$ElementProxy(h[o, AsElementsPeerField(f, i)], i), $ownerFrame] == h[o, $ownerFrame]);
+
+axiom (forall h: Heap, o: ref :: { h[h[o, $ownerRef], $inv] <: h[o, $ownerFrame] } IsHeap(h) && h[o, $ownerFrame] != $PeerGroupPlaceholder && h[h[o, $ownerRef], $inv] <: h[o, $ownerFrame] && h[h[o, $ownerRef], $localinv] != $BaseClass(h[o, $ownerFrame]) ==> h[o, $inv] == $typeof(o) && h[o, $localinv] == $typeof(o));
+
+procedure $SetOwner(o: ref, ow: ref, fr: name);
+  modifies $Heap;
+  ensures (forall<a> p: ref, F: Field a :: { $Heap[p, F] } (F != $ownerRef && F != $ownerFrame) || old($Heap[p, $ownerRef] != $Heap[o, $ownerRef]) || old($Heap[p, $ownerFrame] != $Heap[o, $ownerFrame]) ==> old($Heap[p, F]) == $Heap[p, F]);
+  ensures (forall p: ref :: { $Heap[p, $ownerRef] } { $Heap[p, $ownerFrame] } old($Heap[p, $ownerRef] == $Heap[o, $ownerRef]) && old($Heap[p, $ownerFrame] == $Heap[o, $ownerFrame]) ==> $Heap[p, $ownerRef] == ow && $Heap[p, $ownerFrame] == fr);
+  free ensures $HeapSucc(old($Heap), $Heap);
+
+
+
+procedure $UpdateOwnersForRep(o: ref, T: name, e: ref);
+  modifies $Heap;
+  ensures (forall<a> p: ref, F: Field a :: { $Heap[p, F] } (F != $ownerRef && F != $ownerFrame) || old($Heap[p, $ownerRef] != $Heap[e, $ownerRef]) || old($Heap[p, $ownerFrame] != $Heap[e, $ownerFrame]) ==> old($Heap[p, F]) == $Heap[p, F]);
+  ensures e == null ==> $Heap == old($Heap);
+  ensures e != null ==> (forall p: ref :: { $Heap[p, $ownerRef] } { $Heap[p, $ownerFrame] } old($Heap[p, $ownerRef] == $Heap[e, $ownerRef]) && old($Heap[p, $ownerFrame] == $Heap[e, $ownerFrame]) ==> $Heap[p, $ownerRef] == o && $Heap[p, $ownerFrame] == T);
+  free ensures $HeapSucc(old($Heap), $Heap);
+
+
+
+procedure $UpdateOwnersForPeer(c: ref, d: ref);
+  modifies $Heap;
+  ensures (forall<a> p: ref, F: Field a :: { $Heap[p, F] } (F != $ownerRef && F != $ownerFrame) || old($Heap[p, $ownerRef] != $Heap[d, $ownerRef] || $Heap[p, $ownerFrame] != $Heap[d, $ownerFrame]) ==> old($Heap[p, F]) == $Heap[p, F]);
+  ensures d == null ==> $Heap == old($Heap);
+  ensures d != null ==> (forall p: ref :: { $Heap[p, $ownerRef] } { $Heap[p, $ownerFrame] } old($Heap[p, $ownerRef] == $Heap[d, $ownerRef] && $Heap[p, $ownerFrame] == $Heap[d, $ownerFrame]) ==> $Heap[p, $ownerRef] == old($Heap)[c, $ownerRef] && $Heap[p, $ownerFrame] == old($Heap)[c, $ownerFrame]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+
+
+
+const unique $FirstConsistentOwner: Field ref;
+
+function $AsPureObject(ref) returns (ref);
+
+function ##FieldDependsOnFCO<a>(o: ref, f: Field a, ev: exposeVersionType) returns (value: any);
+
+axiom (forall<a> o: ref, f: Field a, h: Heap :: { h[$AsPureObject(o), f] } IsHeap(h) && o != null && h[o, $allocated] == true && $AsPureObject(o) == o && h[o, $ownerFrame] != $PeerGroupPlaceholder && h[h[o, $ownerRef], $inv] <: h[o, $ownerFrame] && h[h[o, $ownerRef], $localinv] != $BaseClass(h[o, $ownerFrame]) ==> h[o, f] == ##FieldDependsOnFCO(o, f, h[h[o, $FirstConsistentOwner], $exposeVersion]));
+
+axiom (forall o: ref, h: Heap :: { h[o, $FirstConsistentOwner] } IsHeap(h) && o != null && h[o, $allocated] == true && h[o, $ownerFrame] != $PeerGroupPlaceholder && h[h[o, $ownerRef], $inv] <: h[o, $ownerFrame] && h[h[o, $ownerRef], $localinv] != $BaseClass(h[o, $ownerFrame]) ==> h[o, $FirstConsistentOwner] != null && h[h[o, $FirstConsistentOwner], $allocated] == true && (h[h[o, $FirstConsistentOwner], $ownerFrame] == $PeerGroupPlaceholder || !(h[h[h[o, $FirstConsistentOwner], $ownerRef], $inv] <: h[h[o, $FirstConsistentOwner], $ownerFrame]) || h[h[h[o, $FirstConsistentOwner], $ownerRef], $localinv] == $BaseClass(h[h[o, $FirstConsistentOwner], $ownerFrame])));
+
+function Box<a>(a, ref) returns (ref);
+
+function Unbox(ref) returns (any);
+
+type NondetType;
+
+function MeldNondets(NondetType, any) returns (NondetType);
+
+function BoxFunc<a>(value: a, typ: name) returns (boxedValue: ref);
+
+function AllocFunc(typ: name) returns (newValue: ref);
+
+function NewInstance(object: ref, occurrence: NondetType, activity: ActivityType) returns (newInstance: ref);
+
+axiom (forall value: any, typ: name, occurrence: NondetType, activity: ActivityType :: { NewInstance(BoxFunc(value, typ), occurrence, activity) } Box(value, NewInstance(BoxFunc(value, typ), occurrence, activity)) == NewInstance(BoxFunc(value, typ), occurrence, activity) && UnboxedType(NewInstance(BoxFunc(value, typ), occurrence, activity)) == typ);
+
+axiom (forall x: ref, typ: name, occurrence: NondetType, activity: ActivityType :: !$IsValueType(UnboxedType(x)) ==> NewInstance(BoxFunc(x, typ), occurrence, activity) == x);
+
+axiom (forall x: any, p: ref :: { Unbox(Box(x, p)) } Unbox(Box(x, p)) == x);
+
+function UnboxedType(ref) returns (name);
+
+axiom (forall p: ref :: { $IsValueType(UnboxedType(p)) } $IsValueType(UnboxedType(p)) ==> (forall heap: Heap, x: any :: { heap[Box(x, p), $inv] } IsHeap(heap) ==> heap[Box(x, p), $inv] == $typeof(Box(x, p)) && heap[Box(x, p), $localinv] == $typeof(Box(x, p))));
+
+axiom (forall<a> x: a, p: ref :: { UnboxedType(Box(x, p)) <: System.Object } UnboxedType(Box(x, p)) <: System.Object && Box(x, p) == p ==> x == p);
+
+function BoxTester(p: ref, typ: name) returns (ref);
+
+axiom (forall p: ref, typ: name :: { BoxTester(p, typ) } UnboxedType(p) == typ <==> BoxTester(p, typ) != null);
+
+axiom (forall p: ref, typ: name :: { BoxTester(p, typ) } BoxTester(p, typ) != null ==> Box(Unbox(p), p) == p);
+
+axiom (forall typ: name, occurrence: NondetType, activity: ActivityType :: { NewInstance(AllocFunc(typ), occurrence, activity) } $typeof(NewInstance(AllocFunc(typ), occurrence, activity)) == typ && NewInstance(AllocFunc(typ), occurrence, activity) != null);
+
+axiom (forall typ: name, occurrence: NondetType, activity: ActivityType, heap: Heap :: { heap[NewInstance(AllocFunc(typ), occurrence, activity), $allocated] } IsHeap(heap) ==> heap[NewInstance(AllocFunc(typ), occurrence, activity), $allocated]);
+
+const unique System.SByte: name;
+
+axiom $IsValueType(System.SByte);
+
+const unique System.Byte: name;
+
+axiom $IsValueType(System.Byte);
+
+const unique System.Int16: name;
+
+axiom $IsValueType(System.Int16);
+
+const unique System.UInt16: name;
+
+axiom $IsValueType(System.UInt16);
+
+const unique System.Int32: name;
+
+axiom $IsValueType(System.Int32);
+
+const unique System.UInt32: name;
+
+axiom $IsValueType(System.UInt32);
+
+const unique System.Int64: name;
+
+axiom $IsValueType(System.Int64);
+
+const unique System.UInt64: name;
+
+axiom $IsValueType(System.UInt64);
+
+const unique System.Char: name;
+
+axiom $IsValueType(System.Char);
+
+const unique System.UIntPtr: name;
+
+axiom $IsValueType(System.UIntPtr);
+
+const unique System.IntPtr: name;
+
+axiom $IsValueType(System.IntPtr);
+
+const int#m2147483648: int;
+
+const int#2147483647: int;
+
+const int#4294967295: int;
+
+const int#m9223372036854775808: int;
+
+const int#9223372036854775807: int;
+
+const int#18446744073709551615: int;
+
+axiom int#m9223372036854775808 < int#m2147483648;
+
+axiom int#m2147483648 < 0 - 100000;
+
+axiom 100000 < int#2147483647;
+
+axiom int#2147483647 < int#4294967295;
+
+axiom int#4294967295 < int#9223372036854775807;
+
+axiom int#9223372036854775807 < int#18446744073709551615;
+
+axiom int#m9223372036854775808 + 1 == 0 - int#9223372036854775807;
+
+axiom int#m2147483648 + 1 == 0 - int#2147483647;
+
+function InRange(i: int, T: name) returns (bool);
+
+axiom (forall i: int :: InRange(i, System.SByte) <==> 0 - 128 <= i && i < 128);
+
+axiom (forall i: int :: InRange(i, System.Byte) <==> 0 <= i && i < 256);
+
+axiom (forall i: int :: InRange(i, System.Int16) <==> 0 - 32768 <= i && i < 32768);
+
+axiom (forall i: int :: InRange(i, System.UInt16) <==> 0 <= i && i < 65536);
+
+axiom (forall i: int :: InRange(i, System.Int32) <==> int#m2147483648 <= i && i <= int#2147483647);
+
+axiom (forall i: int :: InRange(i, System.UInt32) <==> 0 <= i && i <= int#4294967295);
+
+axiom (forall i: int :: InRange(i, System.Int64) <==> int#m9223372036854775808 <= i && i <= int#9223372036854775807);
+
+axiom (forall i: int :: InRange(i, System.UInt64) <==> 0 <= i && i <= int#18446744073709551615);
+
+axiom (forall i: int :: InRange(i, System.Char) <==> 0 <= i && i < 65536);
+
+function $IntToInt(val: int, fromType: name, toType: name) returns (int);
+
+function $IntToReal(int, fromType: name, toType: name) returns (real);
+
+function $RealToInt(real, fromType: name, toType: name) returns (int);
+
+function $RealToReal(val: real, fromType: name, toType: name) returns (real);
+
+axiom (forall z: int, B: name, C: name :: InRange(z, C) ==> $IntToInt(z, B, C) == z);
+
+function $SizeIs(name, int) returns (bool);
+
+function $IfThenElse(bool, any, any) returns (any);
+
+axiom (forall b: bool, x: any, y: any :: { $IfThenElse(b, x, y) } b ==> $IfThenElse(b, x, y) == x);
+
+axiom (forall b: bool, x: any, y: any :: { $IfThenElse(b, x, y) } !b ==> $IfThenElse(b, x, y) == y);
+
+function #neg(int) returns (int);
+
+function #and(int, int) returns (int);
+
+function #or(int, int) returns (int);
+
+function #xor(int, int) returns (int);
+
+function #shl(int, int) returns (int);
+
+function #shr(int, int) returns (int);
+
+function #rneg(real) returns (real);
+
+function #radd(real, real) returns (real);
+
+function #rsub(real, real) returns (real);
+
+function #rmul(real, real) returns (real);
+
+function #rdiv(real, real) returns (real);
+
+function #rmod(real, real) returns (real);
+
+function #rLess(real, real) returns (bool);
+
+function #rAtmost(real, real) returns (bool);
+
+function #rEq(real, real) returns (bool);
+
+function #rNeq(real, real) returns (bool);
+
+function #rAtleast(real, real) returns (bool);
+
+function #rGreater(real, real) returns (bool);
+
+axiom (forall x: int, y: int :: { x % y } { x / y } x % y == x - x / y * y);
+
+axiom (forall x: int, y: int :: { x % y } 0 <= x && 0 < y ==> 0 <= x % y && x % y < y);
+
+axiom (forall x: int, y: int :: { x % y } 0 <= x && y < 0 ==> 0 <= x % y && x % y < 0 - y);
+
+axiom (forall x: int, y: int :: { x % y } x <= 0 && 0 < y ==> 0 - y < x % y && x % y <= 0);
+
+axiom (forall x: int, y: int :: { x % y } x <= 0 && y < 0 ==> y < x % y && x % y <= 0);
+
+axiom (forall x: int, y: int :: { (x + y) % y } 0 <= x && 0 <= y ==> (x + y) % y == x % y);
+
+axiom (forall x: int, y: int :: { (y + x) % y } 0 <= x && 0 <= y ==> (y + x) % y == x % y);
+
+axiom (forall x: int, y: int :: { (x - y) % y } 0 <= x - y && 0 <= y ==> (x - y) % y == x % y);
+
+axiom (forall a: int, b: int, d: int :: { a % d, b % d } 2 <= d && a % d == b % d && a < b ==> a + d <= b);
+
+axiom (forall x: int, y: int :: { #and(x, y) } 0 <= x || 0 <= y ==> 0 <= #and(x, y));
+
+axiom (forall x: int, y: int :: { #or(x, y) } 0 <= x && 0 <= y ==> 0 <= #or(x, y) && #or(x, y) <= x + y);
+
+axiom (forall i: int :: { #shl(i, 0) } #shl(i, 0) == i);
+
+axiom (forall i: int, j: int :: { #shl(i, j) } 1 <= j ==> #shl(i, j) == #shl(i, j - 1) * 2);
+
+axiom (forall i: int, j: int :: { #shl(i, j) } 0 <= i && i < 32768 && 0 <= j && j <= 16 ==> 0 <= #shl(i, j) && #shl(i, j) <= int#2147483647);
+
+axiom (forall i: int :: { #shr(i, 0) } #shr(i, 0) == i);
+
+axiom (forall i: int, j: int :: { #shr(i, j) } 1 <= j ==> #shr(i, j) == #shr(i, j - 1) / 2);
+
+function #min(int, int) returns (int);
+
+function #max(int, int) returns (int);
+
+axiom (forall x: int, y: int :: { #min(x, y) } (#min(x, y) == x || #min(x, y) == y) && #min(x, y) <= x && #min(x, y) <= y);
+
+axiom (forall x: int, y: int :: { #max(x, y) } (#max(x, y) == x || #max(x, y) == y) && x <= #max(x, y) && y <= #max(x, y));
+
+function #System.String.IsInterned$System.String$notnull(Heap, ref) returns (ref);
+
+function #System.String.Equals$System.String(Heap, ref, ref) returns (bool);
+
+function #System.String.Equals$System.String$System.String(Heap, ref, ref) returns (bool);
+
+function ##StringEquals(ref, ref) returns (bool);
+
+axiom (forall h: Heap, a: ref, b: ref :: { #System.String.Equals$System.String(h, a, b) } #System.String.Equals$System.String(h, a, b) == #System.String.Equals$System.String$System.String(h, a, b));
+
+axiom (forall h: Heap, a: ref, b: ref :: { #System.String.Equals$System.String$System.String(h, a, b) } #System.String.Equals$System.String$System.String(h, a, b) == ##StringEquals(a, b) && #System.String.Equals$System.String$System.String(h, a, b) == ##StringEquals(b, a) && (a == b ==> ##StringEquals(a, b)));
+
+axiom (forall a: ref, b: ref, c: ref :: ##StringEquals(a, b) && ##StringEquals(b, c) ==> ##StringEquals(a, c));
+
+axiom (forall h: Heap, a: ref, b: ref :: { #System.String.Equals$System.String$System.String(h, a, b) } a != null && b != null && #System.String.Equals$System.String$System.String(h, a, b) ==> #System.String.IsInterned$System.String$notnull(h, a) == #System.String.IsInterned$System.String$notnull(h, b));
+
+const $UnknownRef: ref;
+
+const unique Bag.a: Field ref;
+
+const unique Bag.n: Field int;
+
+const unique Microsoft.Contracts.GuardException: name;
+
+const unique System.ICloneable: name;
+
+const unique Microsoft.Contracts.ObjectInvariantException: name;
+
+const unique System.Exception: name;
+
+const unique System.Collections.IEnumerable: name;
+
+const unique System.Collections.IList: name;
+
+const unique Microsoft.Contracts.ICheckedException: name;
+
+const unique System.Reflection.MemberInfo: name;
+
+const unique Bag: name;
+
+const unique System.Reflection.IReflect: name;
+
+const unique System.Runtime.InteropServices._MemberInfo: name;
+
+const unique System.Runtime.InteropServices._Type: name;
+
+const unique System.Collections.ICollection: name;
+
+const unique System.Runtime.InteropServices._Exception: name;
+
+const unique System.Runtime.Serialization.ISerializable: name;
+
+const unique System.Reflection.ICustomAttributeProvider: name;
+
+axiom !IsStaticField(Bag.n);
+
+axiom IncludeInMainFrameCondition(Bag.n);
+
+axiom $IncludedInModifiesStar(Bag.n);
+
+axiom DeclType222(Bag.n) == Bag;
+
+axiom AsRangeField(Bag.n, System.Int32) == Bag.n;
+
+axiom !IsStaticField(Bag.a);
+
+axiom IncludeInMainFrameCondition(Bag.a);
+
+axiom $IncludedInModifiesStar(Bag.a);
+
+axiom AsRepField(Bag.a, Bag) == Bag.a;
+
+axiom DeclType222(Bag.a) == Bag;
+
+axiom AsNonNullRefField(Bag.a, IntArray(System.Int32, 1)) == Bag.a;
+
+axiom Bag <: Bag;
+
+axiom $BaseClass(Bag) == System.Object && AsDirectSubClass(Bag, $BaseClass(Bag)) == Bag;
+
+axiom !$IsImmutable(Bag) && $AsMutable(Bag) == Bag;
+
+axiom System.Array <: System.Array;
+
+axiom $BaseClass(System.Array) == System.Object && AsDirectSubClass(System.Array, $BaseClass(System.Array)) == System.Array;
+
+axiom !$IsImmutable(System.Array) && $AsMutable(System.Array) == System.Array;
+
+axiom System.ICloneable <: System.ICloneable;
+
+axiom System.ICloneable <: System.Object;
+
+axiom $IsMemberlessType(System.ICloneable);
+
+axiom $AsInterface(System.ICloneable) == System.ICloneable;
+
+axiom System.Array <: System.ICloneable;
+
+axiom System.Collections.IList <: System.Collections.IList;
+
+axiom System.Collections.IList <: System.Object;
+
+axiom System.Collections.ICollection <: System.Collections.ICollection;
+
+axiom System.Collections.ICollection <: System.Object;
+
+axiom System.Collections.IEnumerable <: System.Collections.IEnumerable;
+
+axiom System.Collections.IEnumerable <: System.Object;
+
+axiom $IsMemberlessType(System.Collections.IEnumerable);
+
+axiom $AsInterface(System.Collections.IEnumerable) == System.Collections.IEnumerable;
+
+axiom System.Collections.ICollection <: System.Collections.IEnumerable;
+
+axiom $IsMemberlessType(System.Collections.ICollection);
+
+axiom $AsInterface(System.Collections.ICollection) == System.Collections.ICollection;
+
+axiom System.Collections.IList <: System.Collections.ICollection;
+
+axiom System.Collections.IList <: System.Collections.IEnumerable;
+
+axiom $IsMemberlessType(System.Collections.IList);
+
+axiom $AsInterface(System.Collections.IList) == System.Collections.IList;
+
+axiom System.Array <: System.Collections.IList;
+
+axiom System.Array <: System.Collections.ICollection;
+
+axiom System.Array <: System.Collections.IEnumerable;
+
+axiom $IsMemberlessType(System.Array);
+
+// System.Array object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: System.Array } IsHeap($h) && $h[$oi, $inv] <: System.Array && $h[$oi, $localinv] != $BaseClass(System.Array) ==> true);
+
+// Bag object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: Bag } IsHeap($h) && $h[$oi, $inv] <: Bag && $h[$oi, $localinv] != $BaseClass(Bag) ==> 0 <= $h[$oi, Bag.n] && $h[$oi, Bag.n] <= $Length($h[$oi, Bag.a]));
+
+procedure Bag.SpecSharp.CheckInvariant$System.Boolean(this: ref where $IsNotNull(this, Bag) && $Heap[this, $allocated], throwException$in: bool where true) returns ($result: bool where true);
+  // user-declared preconditions
+  requires ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == System.Object && $Heap[this, $localinv] == $typeof(this) && (forall $p: ref :: $p != null && $Heap[$p, $allocated] && $Heap[$p, $ownerRef] == this && $Heap[$p, $ownerFrame] == Bag ==> $Heap[$p, $inv] == $typeof($p) && $Heap[$p, $localinv] == $typeof($p));
+  free requires $BeingConstructed == null;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && old($o != this || !($typeof(this) <: DeclType222($f)) || !$IncludedInModifiesStar($f)) && old(true) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+implementation Bag.SpecSharp.CheckInvariant$System.Boolean(this: ref, throwException$in: bool) returns ($result: bool)
+{
+  var throwException: bool where true, stack0i: int, stack1i: int, stack0b: bool, stack1o: ref, return.value: bool where true, stack50000o: ref, stack0o: ref, SS$Display.Return.Local: bool where true;
+
+  entry:
+    throwException := throwException$in;
+    goto block2380;
+
+  block2380:
+    goto block2482;
+
+  block2482:
+    // ----- nop
+    // ----- load constant 0
+    stack0i := 0;
+    // ----- load field
+    assert this != null;
+    stack1i := $Heap[this, Bag.n];
+    // ----- binary operator
+    // ----- branch
+    goto true2482to2550, false2482to2414;
+
+  true2482to2550:
+    assume stack0i > stack1i;
+    goto block2550;
+
+  false2482to2414:
+    assume stack0i <= stack1i;
+    goto block2414;
+
+  block2550:
+    // ----- copy
+    stack0b := throwException;
+    // ----- unary operator
+    // ----- branch
+    goto true2550to2584, false2550to2601;
+
+  block2414:
+    // ----- load field
+    assert this != null;
+    stack0i := $Heap[this, Bag.n];
+    // ----- load field
+    assert this != null;
+    stack1o := $Heap[this, Bag.a];
+    // ----- unary operator
+    assert stack1o != null;
+    stack1i := $Length(stack1o);
+    // ----- unary operator
+    stack1i := $IntToInt(stack1i, System.UIntPtr, System.Int32);
+    // ----- binary operator
+    // ----- branch
+    goto true2414to2550, false2414to2465;
+
+  true2414to2550:
+    assume stack0i > stack1i;
+    goto block2550;
+
+  false2414to2465:
+    assume stack0i <= stack1i;
+    goto block2465;
+
+  block2465:
+    // ----- branch
+    goto block2448;
+
+  true2550to2584:
+    assume !stack0b;
+    goto block2584;
+
+  false2550to2601:
+    assume stack0b;
+    goto block2601;
+
+  block2584:
+    // ----- load constant 0
+    return.value := false;
+    // ----- branch
+    goto block2567;
+
+  block2601:
+    assume false;
+    // ----- new object
+    havoc stack50000o;
+    assume $Heap[stack50000o, $allocated] == false && stack50000o != null && $typeof(stack50000o) == Microsoft.Contracts.ObjectInvariantException;
+    assume $Heap[stack50000o, $ownerRef] == stack50000o && $Heap[stack50000o, $ownerFrame] == $PeerGroupPlaceholder;
+    // ----- call
+    assert stack50000o != null;
+    call Microsoft.Contracts.ObjectInvariantException..ctor(stack50000o);
+    // ----- copy
+    stack0o := stack50000o;
+    // ----- throw
+    assert stack0o != null;
+    assume false;
+    return;
+
+  block2448:
+    // ----- load constant 1
+    return.value := true;
+    // ----- branch
+    goto block2567;
+
+  block2567:
+    // ----- copy
+    SS$Display.Return.Local := return.value;
+    // ----- copy
+    stack0b := return.value;
+    // ----- return
+    $result := stack0b;
+    return;
+}
+
+
+
+axiom Microsoft.Contracts.ObjectInvariantException <: Microsoft.Contracts.ObjectInvariantException;
+
+axiom Microsoft.Contracts.GuardException <: Microsoft.Contracts.GuardException;
+
+axiom System.Exception <: System.Exception;
+
+axiom $BaseClass(System.Exception) == System.Object && AsDirectSubClass(System.Exception, $BaseClass(System.Exception)) == System.Exception;
+
+axiom !$IsImmutable(System.Exception) && $AsMutable(System.Exception) == System.Exception;
+
+axiom System.Runtime.Serialization.ISerializable <: System.Runtime.Serialization.ISerializable;
+
+axiom System.Runtime.Serialization.ISerializable <: System.Object;
+
+axiom $IsMemberlessType(System.Runtime.Serialization.ISerializable);
+
+axiom $AsInterface(System.Runtime.Serialization.ISerializable) == System.Runtime.Serialization.ISerializable;
+
+axiom System.Exception <: System.Runtime.Serialization.ISerializable;
+
+axiom System.Runtime.InteropServices._Exception <: System.Runtime.InteropServices._Exception;
+
+axiom System.Runtime.InteropServices._Exception <: System.Object;
+
+axiom $IsMemberlessType(System.Runtime.InteropServices._Exception);
+
+axiom $AsInterface(System.Runtime.InteropServices._Exception) == System.Runtime.InteropServices._Exception;
+
+axiom System.Exception <: System.Runtime.InteropServices._Exception;
+
+// System.Exception object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: System.Exception } IsHeap($h) && $h[$oi, $inv] <: System.Exception && $h[$oi, $localinv] != $BaseClass(System.Exception) ==> true);
+
+axiom $BaseClass(Microsoft.Contracts.GuardException) == System.Exception && AsDirectSubClass(Microsoft.Contracts.GuardException, $BaseClass(Microsoft.Contracts.GuardException)) == Microsoft.Contracts.GuardException;
+
+axiom !$IsImmutable(Microsoft.Contracts.GuardException) && $AsMutable(Microsoft.Contracts.GuardException) == Microsoft.Contracts.GuardException;
+
+// Microsoft.Contracts.GuardException object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: Microsoft.Contracts.GuardException } IsHeap($h) && $h[$oi, $inv] <: Microsoft.Contracts.GuardException && $h[$oi, $localinv] != $BaseClass(Microsoft.Contracts.GuardException) ==> true);
+
+axiom $BaseClass(Microsoft.Contracts.ObjectInvariantException) == Microsoft.Contracts.GuardException && AsDirectSubClass(Microsoft.Contracts.ObjectInvariantException, $BaseClass(Microsoft.Contracts.ObjectInvariantException)) == Microsoft.Contracts.ObjectInvariantException;
+
+axiom !$IsImmutable(Microsoft.Contracts.ObjectInvariantException) && $AsMutable(Microsoft.Contracts.ObjectInvariantException) == Microsoft.Contracts.ObjectInvariantException;
+
+// Microsoft.Contracts.ObjectInvariantException object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: Microsoft.Contracts.ObjectInvariantException } IsHeap($h) && $h[$oi, $inv] <: Microsoft.Contracts.ObjectInvariantException && $h[$oi, $localinv] != $BaseClass(Microsoft.Contracts.ObjectInvariantException) ==> true);
+
+procedure Microsoft.Contracts.ObjectInvariantException..ctor(this: ref where $IsNotNull(this, Microsoft.Contracts.ObjectInvariantException) && $Heap[this, $allocated]);
+  // object is fully unpacked:  this.inv == Object
+  free requires ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == System.Object && $Heap[this, $localinv] == $typeof(this);
+  // nothing is owned by [this,*] and 'this' is alone in its own peer group
+  free requires (forall $o: ref :: $o != this ==> $Heap[$o, $ownerRef] != this) && $Heap[this, $ownerRef] == this && $Heap[this, $ownerFrame] == $PeerGroupPlaceholder;
+  free requires $BeingConstructed == this;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // target object is allocated upon return
+  free ensures $Heap[this, $allocated];
+  // target object is additively exposable for Microsoft.Contracts.ObjectInvariantException
+  ensures ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == Microsoft.Contracts.ObjectInvariantException && $Heap[this, $localinv] == $typeof(this);
+  ensures $Heap[this, $ownerRef] == old($Heap)[this, $ownerRef] && $Heap[this, $ownerFrame] == old($Heap)[this, $ownerFrame];
+  ensures $Heap[this, $sharingMode] == $SharingMode_Unshared;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && ($o != this || !(Microsoft.Contracts.ObjectInvariantException <: DeclType222($f))) && old(true) && old(true) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] && $o != this ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } $o == this || old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+procedure Bag..ctor$System.Int32.array$notnull(this: ref where $IsNotNull(this, Bag) && $Heap[this, $allocated], initialElements$in: ref where $IsNotNull(initialElements$in, IntArray(System.Int32, 1)) && $Heap[initialElements$in, $allocated]);
+  // object is fully unpacked:  this.inv == Object
+  free requires ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == System.Object && $Heap[this, $localinv] == $typeof(this);
+  // initialElements is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[initialElements$in, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[initialElements$in, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // initialElements is peer consistent (owner must not be valid)
+  requires $Heap[initialElements$in, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[initialElements$in, $ownerRef], $inv] <: $Heap[initialElements$in, $ownerFrame]) || $Heap[$Heap[initialElements$in, $ownerRef], $localinv] == $BaseClass($Heap[initialElements$in, $ownerFrame]);
+  // nothing is owned by [this,*] and 'this' is alone in its own peer group
+  free requires (forall $o: ref :: $o != this ==> $Heap[$o, $ownerRef] != this) && $Heap[this, $ownerRef] == this && $Heap[this, $ownerFrame] == $PeerGroupPlaceholder;
+  free requires $BeingConstructed == this;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // target object is allocated upon return
+  free ensures $Heap[this, $allocated];
+  // target object is additively exposable for Bag
+  ensures ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == Bag && $Heap[this, $localinv] == $typeof(this);
+  ensures $Heap[this, $ownerRef] == old($Heap)[this, $ownerRef] && $Heap[this, $ownerFrame] == old($Heap)[this, $ownerFrame];
+  ensures $Heap[this, $sharingMode] == $SharingMode_Unshared;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && ($o != this || !(Bag <: DeclType222($f))) && old(true) && old(true) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] && $o != this ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } $o == this || old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+implementation Bag..ctor$System.Int32.array$notnull(this: ref, initialElements$in: ref)
+{
+  var initialElements: ref where $IsNotNull(initialElements, IntArray(System.Int32, 1)) && $Heap[initialElements, $allocated], stack0o: ref, stack0i: int, temp0: exposeVersionType, temp1: ref, temp2: exposeVersionType, stack1i: int, temp3: ref;
+
+  entry:
+    initialElements := initialElements$in;
+    assume $Heap[this, Bag.n] == 0;
+    goto block3332;
+
+  block3332:
+    goto block3468;
+
+  block3468:
+    // ----- nop
+    // ----- copy  ----- AddMethod.ssc(13,5)
+    stack0o := initialElements;
+    // ----- unary operator  ----- AddMethod.ssc(13,5)
+    assert stack0o != null;
+    stack0i := $Length(stack0o);
+    // ----- unary operator  ----- AddMethod.ssc(13,5)
+    stack0i := $IntToInt(stack0i, System.UIntPtr, System.Int32);
+    // ----- store field  ----- AddMethod.ssc(13,5)
+    assert this != null;
+    assert $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+    havoc temp0;
+    $Heap[this, $exposeVersion] := temp0;
+    $Heap[this, Bag.n] := stack0i;
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || 0 <= $Heap[this, Bag.n];
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || $Heap[this, Bag.n] <= $Length($Heap[this, Bag.a]);
+    assume IsHeap($Heap);
+    // ----- copy  ----- AddMethod.ssc(14,5)
+    stack0o := initialElements;
+    // ----- unary operator  ----- AddMethod.ssc(14,5)
+    assert stack0o != null;
+    stack0i := $Length(stack0o);
+    // ----- unary operator  ----- AddMethod.ssc(14,5)
+    stack0i := $IntToInt(stack0i, System.UIntPtr, System.Int32);
+    // ----- new array  ----- AddMethod.ssc(14,5)
+    assert 0 <= stack0i;
+    havoc temp1;
+    assume $Heap[temp1, $allocated] == false && $Length(temp1) == stack0i;
+    assume $Heap[$ElementProxy(temp1, -1), $allocated] == false && $ElementProxy(temp1, -1) != temp1 && $ElementProxy(temp1, -1) != null;
+    assume temp1 != null;
+    assume $typeof(temp1) == IntArray(System.Int32, 1);
+    assume $Heap[temp1, $ownerRef] == temp1 && $Heap[temp1, $ownerFrame] == $PeerGroupPlaceholder;
+    assume $Heap[$ElementProxy(temp1, -1), $ownerRef] == $ElementProxy(temp1, -1) && $Heap[$ElementProxy(temp1, -1), $ownerFrame] == $PeerGroupPlaceholder;
+    assume $Heap[temp1, $inv] == $typeof(temp1) && $Heap[temp1, $localinv] == $typeof(temp1);
+    assume (forall $i: int :: IntArrayGet($Heap[temp1, $elements], $i) == 0);
+    $Heap[temp1, $allocated] := true;
+    call System.Object..ctor($ElementProxy(temp1, -1));
+    stack0o := temp1;
+    assume IsHeap($Heap);
+    // ----- store field  ----- AddMethod.ssc(14,5)
+    assert this != null;
+    assert $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+    assert ($Heap[stack0o, $ownerRef] == this && $Heap[stack0o, $ownerFrame] == Bag) || $Heap[stack0o, $ownerFrame] == $PeerGroupPlaceholder;
+    assert $Heap[stack0o, $ownerFrame] == $PeerGroupPlaceholder && $Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag) ==> (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[stack0o, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[stack0o, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+    assert $Heap[stack0o, $ownerFrame] == $PeerGroupPlaceholder && $Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag) ==> $Heap[this, $ownerRef] != $Heap[stack0o, $ownerRef] || $Heap[this, $ownerFrame] != $Heap[stack0o, $ownerFrame];
+    call $UpdateOwnersForRep(this, Bag, stack0o);
+    havoc temp2;
+    $Heap[this, $exposeVersion] := temp2;
+    $Heap[this, Bag.a] := stack0o;
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || 0 <= $Heap[this, Bag.n];
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || $Heap[this, Bag.n] <= $Length($Heap[this, Bag.a]);
+    assume IsHeap($Heap);
+    // ----- call  ----- AddMethod.ssc(15,5)
+    assert this != null;
+    call System.Object..ctor(this);
+    $Heap[this, $NonNullFieldsAreInitialized] := true;
+    assume IsHeap($Heap);
+    goto block3417;
+
+  block3417:
+    // ----- load field  ----- AddMethod.ssc(16,5)
+    assert this != null;
+    stack0o := $Heap[this, Bag.a];
+    // ----- load constant 0  ----- AddMethod.ssc(16,5)
+    stack1i := 0;
+    // ----- call  ----- AddMethod.ssc(16,5)
+    assert initialElements != null;
+    call System.Array.CopyTo$System.Array$notnull$System.Int32$.Virtual.$(initialElements, stack0o, stack1i);
+    // ----- FrameGuard processing  ----- AddMethod.ssc(17,3)
+    temp3 := this;
+    // ----- classic pack  ----- AddMethod.ssc(17,3)
+    assert temp3 != null;
+    assert $Heap[temp3, $inv] == System.Object && $Heap[temp3, $localinv] == $typeof(temp3);
+    assert 0 <= $Heap[temp3, Bag.n];
+    assert $Heap[temp3, Bag.n] <= $Length($Heap[temp3, Bag.a]);
+    assert (forall $p: ref :: $p != null && $Heap[$p, $allocated] && $Heap[$p, $ownerRef] == temp3 && $Heap[$p, $ownerFrame] == Bag ==> $Heap[$p, $inv] == $typeof($p) && $Heap[$p, $localinv] == $typeof($p));
+    $Heap[temp3, $inv] := Bag;
+    assume IsHeap($Heap);
+    // ----- return
+    return;
+}
+
+
+
+procedure System.Object..ctor(this: ref where $IsNotNull(this, System.Object) && $Heap[this, $allocated]);
+  // object is fully unpacked:  this.inv == Object
+  free requires ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == System.Object && $Heap[this, $localinv] == $typeof(this);
+  // nothing is owned by [this,*] and 'this' is alone in its own peer group
+  free requires (forall $o: ref :: $o != this ==> $Heap[$o, $ownerRef] != this) && $Heap[this, $ownerRef] == this && $Heap[this, $ownerFrame] == $PeerGroupPlaceholder;
+  free requires $BeingConstructed == this;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // target object is allocated upon return
+  free ensures $Heap[this, $allocated];
+  // target object is additively exposable for System.Object
+  ensures ($Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame])) && $Heap[this, $inv] == System.Object && $Heap[this, $localinv] == $typeof(this);
+  ensures $Heap[this, $ownerRef] == old($Heap)[this, $ownerRef] && $Heap[this, $ownerFrame] == old($Heap)[this, $ownerFrame];
+  ensures $Heap[this, $sharingMode] == $SharingMode_Unshared;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && ($o != this || !(System.Object <: DeclType222($f))) && old(true) && old(true) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] && $o != this ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } $o == this || old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+procedure System.Array.CopyTo$System.Array$notnull$System.Int32$.Virtual.$(this: ref where $IsNotNull(this, System.Array) && $Heap[this, $allocated], array$in: ref where $IsNotNull(array$in, System.Array) && $Heap[array$in, $allocated], index$in: int where InRange(index$in, System.Int32));
+  // user-declared preconditions
+  requires array$in != null;
+  requires $LBound(array$in, 0) <= index$in;
+  requires $Rank(this) == 1;
+  requires $Rank(array$in) == 1;
+  requires $Length(this) <= $UBound(array$in, 0) + 1 - index$in;
+  // target object is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[this, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[this, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // target object is peer consistent (owner must not be valid)
+  requires $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+  // array is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[array$in, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[array$in, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // array is peer consistent (owner must not be valid)
+  requires $Heap[array$in, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[array$in, $ownerRef], $inv] <: $Heap[array$in, $ownerFrame]) || $Heap[$Heap[array$in, $ownerRef], $localinv] == $BaseClass($Heap[array$in, $ownerFrame]);
+  free requires $BeingConstructed == null;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // hard-coded postcondition
+  ensures (forall $k: int :: { ValueArrayGet($Heap[array$in, $elements], $k) } (index$in <= $k && $k < index$in + $Length(this) ==> old(ValueArrayGet($Heap[this, $elements], $k + 0 - index$in)) == ValueArrayGet($Heap[array$in, $elements], $k)) && (!(index$in <= $k && $k < index$in + $Length(this)) ==> old(ValueArrayGet($Heap[array$in, $elements], $k)) == ValueArrayGet($Heap[array$in, $elements], $k)));
+  ensures (forall $k: int :: { IntArrayGet($Heap[array$in, $elements], $k) } (index$in <= $k && $k < index$in + $Length(this) ==> old(IntArrayGet($Heap[this, $elements], $k + 0 - index$in)) == IntArrayGet($Heap[array$in, $elements], $k)) && (!(index$in <= $k && $k < index$in + $Length(this)) ==> old(IntArrayGet($Heap[array$in, $elements], $k)) == IntArrayGet($Heap[array$in, $elements], $k)));
+  ensures (forall $k: int :: { RefArrayGet($Heap[array$in, $elements], $k) } (index$in <= $k && $k < index$in + $Length(this) ==> old(RefArrayGet($Heap[this, $elements], $k + 0 - index$in)) == RefArrayGet($Heap[array$in, $elements], $k)) && (!(index$in <= $k && $k < index$in + $Length(this)) ==> old(RefArrayGet($Heap[array$in, $elements], $k)) == RefArrayGet($Heap[array$in, $elements], $k)));
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && old($o != array$in || !($typeof(array$in) <: DeclType222($f)) || !$IncludedInModifiesStar($f)) && old($o != array$in || $f != $exposeVersion) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+procedure Bag.Add$System.Int32(this: ref where $IsNotNull(this, Bag) && $Heap[this, $allocated], x$in: int where InRange(x$in, System.Int32));
+  // target object is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[this, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[this, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // target object is peer consistent (owner must not be valid)
+  requires $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+  free requires $BeingConstructed == null;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && old($o != this || !($typeof(this) <: DeclType222($f)) || !$IncludedInModifiesStar($f)) && old($o != this || $f != $exposeVersion) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+implementation Bag.Add$System.Int32(this: ref, x$in: int)
+{
+  var x: int where InRange(x, System.Int32), temp0: ref, stack1s: struct, stack1o: ref, temp1: exposeVersionType, local2: ref where $Is(local2, System.Exception) && $Heap[local2, $allocated], stack0i: int, stack1i: int, stack0b: bool, b: ref where $Is(b, IntArray(System.Int32, 1)) && $Heap[b, $allocated], temp2: ref, stack0o: ref, stack2o: ref, stack3i: int, stack4o: ref, stack4i: int, temp3: exposeVersionType, local4: int where InRange(local4, System.Int32), temp4: exposeVersionType, stack0s: struct;
+
+  entry:
+    x := x$in;
+    goto block4335;
+
+  block4335:
+    goto block4488;
+
+  block4488:
+    // ----- nop
+    // ----- FrameGuard processing  ----- AddMethod.ssc(22,13)
+    temp0 := this;
+    // ----- load token  ----- AddMethod.ssc(22,13)
+    havoc stack1s;
+    assume $IsTokenForType(stack1s, Bag);
+    // ----- statically resolved GetTypeFromHandle call  ----- AddMethod.ssc(22,13)
+    stack1o := TypeObject(Bag);
+    // ----- local unpack  ----- AddMethod.ssc(22,13)
+    assert temp0 != null;
+    assert ($Heap[temp0, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[temp0, $ownerRef], $inv] <: $Heap[temp0, $ownerFrame]) || $Heap[$Heap[temp0, $ownerRef], $localinv] == $BaseClass($Heap[temp0, $ownerFrame])) && $Heap[temp0, $inv] <: Bag && $Heap[temp0, $localinv] == $typeof(temp0);
+    $Heap[temp0, $localinv] := System.Object;
+    havoc temp1;
+    $Heap[temp0, $exposeVersion] := temp1;
+    assume IsHeap($Heap);
+    local2 := null;
+    goto block4505;
+
+  block4505:
+    // ----- load field  ----- AddMethod.ssc(24,7)
+    assert this != null;
+    stack0i := $Heap[this, Bag.n];
+    // ----- load field  ----- AddMethod.ssc(24,7)
+    assert this != null;
+    stack1o := $Heap[this, Bag.a];
+    // ----- unary operator  ----- AddMethod.ssc(24,7)
+    assert stack1o != null;
+    stack1i := $Length(stack1o);
+    // ----- unary operator  ----- AddMethod.ssc(24,7)
+    stack1i := $IntToInt(stack1i, System.UIntPtr, System.Int32);
+    // ----- binary operator  ----- AddMethod.ssc(24,7)
+    // ----- branch  ----- AddMethod.ssc(24,7)
+    goto true4505to4539, false4505to4522;
+
+  true4505to4539:
+    assume stack0i != stack1i;
+    goto block4539;
+
+  false4505to4522:
+    assume stack0i == stack1i;
+    goto block4522;
+
+  block4539:
+    // ----- load field  ----- AddMethod.ssc(30,7)
+    assert this != null;
+    stack0o := $Heap[this, Bag.a];
+    // ----- load field  ----- AddMethod.ssc(30,7)
+    assert this != null;
+    stack1i := $Heap[this, Bag.n];
+    // ----- store element  ----- AddMethod.ssc(30,7)
+    assert stack0o != null;
+    assert 0 <= stack1i;
+    assert stack1i < $Length(stack0o);
+    assert $Heap[stack0o, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[stack0o, $ownerRef], $inv] <: $Heap[stack0o, $ownerFrame]) || $Heap[$Heap[stack0o, $ownerRef], $localinv] == $BaseClass($Heap[stack0o, $ownerFrame]);
+    $Heap[stack0o, $elements] := IntArraySet($Heap[stack0o, $elements], stack1i, x);
+    assume IsHeap($Heap);
+    // ----- load field  ----- AddMethod.ssc(31,7)
+    assert this != null;
+    local4 := $Heap[this, Bag.n];
+    // ----- load constant 1  ----- AddMethod.ssc(31,7)
+    stack0i := 1;
+    // ----- binary operator  ----- AddMethod.ssc(31,7)
+    stack0i := local4 + stack0i;
+    // ----- store field  ----- AddMethod.ssc(31,7)
+    assert this != null;
+    assert $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+    havoc temp4;
+    $Heap[this, $exposeVersion] := temp4;
+    $Heap[this, Bag.n] := stack0i;
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || 0 <= $Heap[this, Bag.n];
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || $Heap[this, Bag.n] <= $Length($Heap[this, Bag.a]);
+    assume IsHeap($Heap);
+    // ----- copy
+    stack0i := local4;
+    // ----- branch
+    goto block4658;
+
+  block4522:
+    // ----- load constant 2  ----- AddMethod.ssc(26,15)
+    stack0i := 2;
+    // ----- load field  ----- AddMethod.ssc(26,15)
+    assert this != null;
+    stack1o := $Heap[this, Bag.a];
+    // ----- unary operator  ----- AddMethod.ssc(26,15)
+    assert stack1o != null;
+    stack1i := $Length(stack1o);
+    // ----- unary operator  ----- AddMethod.ssc(26,15)
+    stack1i := $IntToInt(stack1i, System.UIntPtr, System.Int32);
+    // ----- binary operator  ----- AddMethod.ssc(26,15)
+    stack0i := stack0i * stack1i;
+    // ----- load constant 1  ----- AddMethod.ssc(26,15)
+    stack1i := 1;
+    // ----- binary operator  ----- AddMethod.ssc(26,15)
+    stack0i := stack0i + stack1i;
+    // ----- new array  ----- AddMethod.ssc(26,15)
+    assert 0 <= stack0i;
+    havoc temp2;
+    assume $Heap[temp2, $allocated] == false && $Length(temp2) == stack0i;
+    assume $Heap[$ElementProxy(temp2, -1), $allocated] == false && $ElementProxy(temp2, -1) != temp2 && $ElementProxy(temp2, -1) != null;
+    assume temp2 != null;
+    assume $typeof(temp2) == IntArray(System.Int32, 1);
+    assume $Heap[temp2, $ownerRef] == temp2 && $Heap[temp2, $ownerFrame] == $PeerGroupPlaceholder;
+    assume $Heap[$ElementProxy(temp2, -1), $ownerRef] == $ElementProxy(temp2, -1) && $Heap[$ElementProxy(temp2, -1), $ownerFrame] == $PeerGroupPlaceholder;
+    assume $Heap[temp2, $inv] == $typeof(temp2) && $Heap[temp2, $localinv] == $typeof(temp2);
+    assume (forall $i: int :: IntArrayGet($Heap[temp2, $elements], $i) == 0);
+    $Heap[temp2, $allocated] := true;
+    call System.Object..ctor($ElementProxy(temp2, -1));
+    b := temp2;
+    assume IsHeap($Heap);
+    // ----- load field  ----- AddMethod.ssc(27,9)
+    assert this != null;
+    stack0o := $Heap[this, Bag.a];
+    // ----- load constant 0  ----- AddMethod.ssc(27,9)
+    stack1i := 0;
+    // ----- copy  ----- AddMethod.ssc(27,9)
+    stack2o := b;
+    // ----- load constant 0  ----- AddMethod.ssc(27,9)
+    stack3i := 0;
+    // ----- load field  ----- AddMethod.ssc(27,9)
+    assert this != null;
+    stack4o := $Heap[this, Bag.a];
+    // ----- unary operator  ----- AddMethod.ssc(27,9)
+    assert stack4o != null;
+    stack4i := $Length(stack4o);
+    // ----- unary operator  ----- AddMethod.ssc(27,9)
+    stack4i := $IntToInt(stack4i, System.UIntPtr, System.Int32);
+    // ----- call  ----- AddMethod.ssc(27,9)
+    call System.Array.Copy$System.Array$notnull$System.Int32$System.Array$notnull$System.Int32$System.Int32(stack0o, stack1i, stack2o, stack3i, stack4i);
+    // ----- store field  ----- AddMethod.ssc(28,9)
+    assert this != null;
+    assert $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+    assert ($Heap[b, $ownerRef] == this && $Heap[b, $ownerFrame] == Bag) || $Heap[b, $ownerFrame] == $PeerGroupPlaceholder;
+    assert $Heap[b, $ownerFrame] == $PeerGroupPlaceholder && $Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag) ==> (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[b, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[b, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+    assert $Heap[b, $ownerFrame] == $PeerGroupPlaceholder && $Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag) ==> $Heap[this, $ownerRef] != $Heap[b, $ownerRef] || $Heap[this, $ownerFrame] != $Heap[b, $ownerFrame];
+    call $UpdateOwnersForRep(this, Bag, b);
+    havoc temp3;
+    $Heap[this, $exposeVersion] := temp3;
+    $Heap[this, Bag.a] := b;
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || 0 <= $Heap[this, Bag.n];
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || $Heap[this, Bag.n] <= $Length($Heap[this, Bag.a]);
+    assume IsHeap($Heap);
+    goto block4539;
+
+  block4658:
+    stack0o := null;
+    // ----- binary operator
+    // ----- branch
+    goto true4658to4624, false4658to4641;
+
+  true4658to4624:
+    assume local2 == stack0o;
+    goto block4624;
+
+  false4658to4641:
+    assume local2 != stack0o;
+    goto block4641;
+
+  block4624:
+    // ----- load token  ----- AddMethod.ssc(32,5)
+    havoc stack0s;
+    assume $IsTokenForType(stack0s, Bag);
+    // ----- statically resolved GetTypeFromHandle call  ----- AddMethod.ssc(32,5)
+    stack0o := TypeObject(Bag);
+    // ----- local pack  ----- AddMethod.ssc(32,5)
+    assert temp0 != null;
+    assert $Heap[temp0, $localinv] == System.Object;
+    assert 0 <= $Heap[temp0, Bag.n];
+    assert $Heap[temp0, Bag.n] <= $Length($Heap[temp0, Bag.a]);
+    assert (forall $p: ref :: $p != null && $Heap[$p, $allocated] && $Heap[$p, $ownerRef] == temp0 && $Heap[$p, $ownerFrame] == Bag ==> $Heap[$p, $inv] == $typeof($p) && $Heap[$p, $localinv] == $typeof($p));
+    $Heap[temp0, $localinv] := $typeof(temp0);
+    assume IsHeap($Heap);
+    goto block4726;
+
+  block4641:
+    // ----- is instance
+    // ----- branch
+    goto true4641to4624, false4641to4692;
+
+  true4641to4624:
+    assume $As(local2, Microsoft.Contracts.ICheckedException) != null;
+    goto block4624;
+
+  false4641to4692:
+    assume $As(local2, Microsoft.Contracts.ICheckedException) == null;
+    goto block4692;
+
+  block4692:
+    // ----- branch
+    goto block4726;
+
+  block4726:
+    // ----- nop
+    // ----- branch
+    goto block4590;
+
+  block4590:
+    // ----- return
+    return;
+}
+
+
+
+axiom System.Type <: System.Type;
+
+axiom System.Reflection.MemberInfo <: System.Reflection.MemberInfo;
+
+axiom $BaseClass(System.Reflection.MemberInfo) == System.Object && AsDirectSubClass(System.Reflection.MemberInfo, $BaseClass(System.Reflection.MemberInfo)) == System.Reflection.MemberInfo;
+
+axiom $IsImmutable(System.Reflection.MemberInfo) && $AsImmutable(System.Reflection.MemberInfo) == System.Reflection.MemberInfo;
+
+axiom System.Reflection.ICustomAttributeProvider <: System.Reflection.ICustomAttributeProvider;
+
+axiom System.Reflection.ICustomAttributeProvider <: System.Object;
+
+axiom $IsMemberlessType(System.Reflection.ICustomAttributeProvider);
+
+axiom $AsInterface(System.Reflection.ICustomAttributeProvider) == System.Reflection.ICustomAttributeProvider;
+
+axiom System.Reflection.MemberInfo <: System.Reflection.ICustomAttributeProvider;
+
+axiom System.Runtime.InteropServices._MemberInfo <: System.Runtime.InteropServices._MemberInfo;
+
+axiom System.Runtime.InteropServices._MemberInfo <: System.Object;
+
+axiom $IsMemberlessType(System.Runtime.InteropServices._MemberInfo);
+
+axiom $AsInterface(System.Runtime.InteropServices._MemberInfo) == System.Runtime.InteropServices._MemberInfo;
+
+axiom System.Reflection.MemberInfo <: System.Runtime.InteropServices._MemberInfo;
+
+axiom $IsMemberlessType(System.Reflection.MemberInfo);
+
+// System.Reflection.MemberInfo object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: System.Reflection.MemberInfo } IsHeap($h) && $h[$oi, $inv] <: System.Reflection.MemberInfo && $h[$oi, $localinv] != $BaseClass(System.Reflection.MemberInfo) ==> true);
+
+axiom $BaseClass(System.Type) == System.Reflection.MemberInfo && AsDirectSubClass(System.Type, $BaseClass(System.Type)) == System.Type;
+
+axiom $IsImmutable(System.Type) && $AsImmutable(System.Type) == System.Type;
+
+axiom System.Runtime.InteropServices._Type <: System.Runtime.InteropServices._Type;
+
+axiom System.Runtime.InteropServices._Type <: System.Object;
+
+axiom $IsMemberlessType(System.Runtime.InteropServices._Type);
+
+axiom $AsInterface(System.Runtime.InteropServices._Type) == System.Runtime.InteropServices._Type;
+
+axiom System.Type <: System.Runtime.InteropServices._Type;
+
+axiom System.Reflection.IReflect <: System.Reflection.IReflect;
+
+axiom System.Reflection.IReflect <: System.Object;
+
+axiom $IsMemberlessType(System.Reflection.IReflect);
+
+axiom $AsInterface(System.Reflection.IReflect) == System.Reflection.IReflect;
+
+axiom System.Type <: System.Reflection.IReflect;
+
+axiom $IsMemberlessType(System.Type);
+
+// System.Type object invariant
+axiom (forall $oi: ref, $h: Heap :: { $h[$oi, $inv] <: System.Type } IsHeap($h) && $h[$oi, $inv] <: System.Type && $h[$oi, $localinv] != $BaseClass(System.Type) ==> true);
+
+procedure System.Array.Copy$System.Array$notnull$System.Int32$System.Array$notnull$System.Int32$System.Int32(sourceArray$in: ref where $IsNotNull(sourceArray$in, System.Array) && $Heap[sourceArray$in, $allocated], sourceIndex$in: int where InRange(sourceIndex$in, System.Int32), destinationArray$in: ref where $IsNotNull(destinationArray$in, System.Array) && $Heap[destinationArray$in, $allocated], destinationIndex$in: int where InRange(destinationIndex$in, System.Int32), length$in: int where InRange(length$in, System.Int32));
+  // user-declared preconditions
+  requires sourceArray$in != null;
+  requires destinationArray$in != null;
+  requires $Rank(sourceArray$in) == $Rank(destinationArray$in);
+  requires sourceIndex$in >= $LBound(sourceArray$in, 0);
+  requires destinationIndex$in >= $LBound(destinationArray$in, 0);
+  requires length$in >= 0;
+  requires sourceIndex$in + length$in <= $LBound(sourceArray$in, 0) + $Length(sourceArray$in);
+  requires destinationIndex$in + length$in <= $LBound(destinationArray$in, 0) + $Length(destinationArray$in);
+  // sourceArray is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[sourceArray$in, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[sourceArray$in, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // sourceArray is peer consistent (owner must not be valid)
+  requires $Heap[sourceArray$in, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[sourceArray$in, $ownerRef], $inv] <: $Heap[sourceArray$in, $ownerFrame]) || $Heap[$Heap[sourceArray$in, $ownerRef], $localinv] == $BaseClass($Heap[sourceArray$in, $ownerFrame]);
+  // destinationArray is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[destinationArray$in, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[destinationArray$in, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // destinationArray is peer consistent (owner must not be valid)
+  requires $Heap[destinationArray$in, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[destinationArray$in, $ownerRef], $inv] <: $Heap[destinationArray$in, $ownerFrame]) || $Heap[$Heap[destinationArray$in, $ownerRef], $localinv] == $BaseClass($Heap[destinationArray$in, $ownerFrame]);
+  free requires $BeingConstructed == null;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // hard-coded postcondition
+  ensures (forall $k: int :: { ValueArrayGet($Heap[destinationArray$in, $elements], $k) } (destinationIndex$in <= $k && $k < destinationIndex$in + length$in ==> old(ValueArrayGet($Heap[sourceArray$in, $elements], $k + sourceIndex$in - destinationIndex$in)) == ValueArrayGet($Heap[destinationArray$in, $elements], $k)) && (!(destinationIndex$in <= $k && $k < destinationIndex$in + length$in) ==> old(ValueArrayGet($Heap[destinationArray$in, $elements], $k)) == ValueArrayGet($Heap[destinationArray$in, $elements], $k)));
+  ensures (forall $k: int :: { IntArrayGet($Heap[destinationArray$in, $elements], $k) } (destinationIndex$in <= $k && $k < destinationIndex$in + length$in ==> old(IntArrayGet($Heap[sourceArray$in, $elements], $k + sourceIndex$in - destinationIndex$in)) == IntArrayGet($Heap[destinationArray$in, $elements], $k)) && (!(destinationIndex$in <= $k && $k < destinationIndex$in + length$in) ==> old(IntArrayGet($Heap[destinationArray$in, $elements], $k)) == IntArrayGet($Heap[destinationArray$in, $elements], $k)));
+  ensures (forall $k: int :: { RefArrayGet($Heap[destinationArray$in, $elements], $k) } (destinationIndex$in <= $k && $k < destinationIndex$in + length$in ==> old(RefArrayGet($Heap[sourceArray$in, $elements], $k + sourceIndex$in - destinationIndex$in)) == RefArrayGet($Heap[destinationArray$in, $elements], $k)) && (!(destinationIndex$in <= $k && $k < destinationIndex$in + length$in) ==> old(RefArrayGet($Heap[destinationArray$in, $elements], $k)) == RefArrayGet($Heap[destinationArray$in, $elements], $k)));
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && old($o != destinationArray$in || !($typeof(destinationArray$in) <: DeclType222($f)) || !$IncludedInModifiesStar($f)) && old($o != destinationArray$in || $f != $exposeVersion) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+axiom Microsoft.Contracts.ICheckedException <: Microsoft.Contracts.ICheckedException;
+
+axiom Microsoft.Contracts.ICheckedException <: System.Object;
+
+axiom $IsMemberlessType(Microsoft.Contracts.ICheckedException);
+
+axiom $AsInterface(Microsoft.Contracts.ICheckedException) == Microsoft.Contracts.ICheckedException;
+
+procedure Bag.AddAgain$System.Int32(this: ref where $IsNotNull(this, Bag) && $Heap[this, $allocated], x$in: int where InRange(x$in, System.Int32));
+  // target object is peer consistent
+  requires (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[this, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[this, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+  // target object is peer consistent (owner must not be valid)
+  requires $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+  free requires $BeingConstructed == null;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && old($o != this || !($typeof(this) <: DeclType222($f)) || !$IncludedInModifiesStar($f)) && old($o != this || $f != $exposeVersion) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+implementation Bag.AddAgain$System.Int32(this: ref, x$in: int)
+{
+  var x: int where InRange(x, System.Int32), temp0: ref, stack1s: struct, stack1o: ref, temp1: exposeVersionType, local2: ref where $Is(local2, System.Exception) && $Heap[local2, $allocated], stack0i: int, stack1i: int, stack0b: bool, stack0o: ref, local4: int where InRange(local4, System.Int32), temp2: exposeVersionType, b: ref where $Is(b, IntArray(System.Int32, 1)) && $Heap[b, $allocated], temp3: ref, stack2i: int, temp4: exposeVersionType, stack0s: struct;
+
+  entry:
+    x := x$in;
+    goto block6188;
+
+  block6188:
+    goto block6341;
+
+  block6341:
+    // ----- nop
+    // ----- FrameGuard processing  ----- AddMethod.ssc(38,13)
+    temp0 := this;
+    // ----- load token  ----- AddMethod.ssc(38,13)
+    havoc stack1s;
+    assume $IsTokenForType(stack1s, Bag);
+    // ----- statically resolved GetTypeFromHandle call  ----- AddMethod.ssc(38,13)
+    stack1o := TypeObject(Bag);
+    // ----- local unpack  ----- AddMethod.ssc(38,13)
+    assert temp0 != null;
+    assert ($Heap[temp0, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[temp0, $ownerRef], $inv] <: $Heap[temp0, $ownerFrame]) || $Heap[$Heap[temp0, $ownerRef], $localinv] == $BaseClass($Heap[temp0, $ownerFrame])) && $Heap[temp0, $inv] <: Bag && $Heap[temp0, $localinv] == $typeof(temp0);
+    $Heap[temp0, $localinv] := System.Object;
+    havoc temp1;
+    $Heap[temp0, $exposeVersion] := temp1;
+    assume IsHeap($Heap);
+    local2 := null;
+    goto block6358;
+
+  block6358:
+    // ----- load field  ----- AddMethod.ssc(40,7)
+    assert this != null;
+    stack0i := $Heap[this, Bag.n];
+    // ----- load field  ----- AddMethod.ssc(40,7)
+    assert this != null;
+    stack1o := $Heap[this, Bag.a];
+    // ----- unary operator  ----- AddMethod.ssc(40,7)
+    assert stack1o != null;
+    stack1i := $Length(stack1o);
+    // ----- unary operator  ----- AddMethod.ssc(40,7)
+    stack1i := $IntToInt(stack1i, System.UIntPtr, System.Int32);
+    // ----- binary operator  ----- AddMethod.ssc(40,7)
+    // ----- branch  ----- AddMethod.ssc(40,7)
+    goto true6358to6392, false6358to6375;
+
+  true6358to6392:
+    assume stack0i != stack1i;
+    goto block6392;
+
+  false6358to6375:
+    assume stack0i == stack1i;
+    goto block6375;
+
+  block6392:
+    // ----- load field  ----- AddMethod.ssc(46,7)
+    assert this != null;
+    stack0o := $Heap[this, Bag.a];
+    // ----- load field  ----- AddMethod.ssc(46,7)
+    assert this != null;
+    stack1i := $Heap[this, Bag.n];
+    // ----- store element  ----- AddMethod.ssc(46,7)
+    assert stack0o != null;
+    assert 0 <= stack1i;
+    assert stack1i < $Length(stack0o);
+    assert $Heap[stack0o, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[stack0o, $ownerRef], $inv] <: $Heap[stack0o, $ownerFrame]) || $Heap[$Heap[stack0o, $ownerRef], $localinv] == $BaseClass($Heap[stack0o, $ownerFrame]);
+    $Heap[stack0o, $elements] := IntArraySet($Heap[stack0o, $elements], stack1i, x);
+    assume IsHeap($Heap);
+    // ----- load field  ----- AddMethod.ssc(47,7)
+    assert this != null;
+    local4 := $Heap[this, Bag.n];
+    // ----- load constant 1  ----- AddMethod.ssc(47,7)
+    stack0i := 1;
+    // ----- binary operator  ----- AddMethod.ssc(47,7)
+    stack0i := local4 + stack0i;
+    // ----- store field  ----- AddMethod.ssc(47,7)
+    assert this != null;
+    assert $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+    havoc temp2;
+    $Heap[this, $exposeVersion] := temp2;
+    $Heap[this, Bag.n] := stack0i;
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || 0 <= $Heap[this, Bag.n];
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || $Heap[this, Bag.n] <= $Length($Heap[this, Bag.a]);
+    assume IsHeap($Heap);
+    // ----- copy
+    stack0i := local4;
+    // ----- branch
+    goto block6562;
+
+  block6375:
+    // ----- load constant 2  ----- AddMethod.ssc(42,15)
+    stack0i := 2;
+    // ----- load field  ----- AddMethod.ssc(42,15)
+    assert this != null;
+    stack1o := $Heap[this, Bag.a];
+    // ----- unary operator  ----- AddMethod.ssc(42,15)
+    assert stack1o != null;
+    stack1i := $Length(stack1o);
+    // ----- unary operator  ----- AddMethod.ssc(42,15)
+    stack1i := $IntToInt(stack1i, System.UIntPtr, System.Int32);
+    // ----- binary operator  ----- AddMethod.ssc(42,15)
+    stack0i := stack0i * stack1i;
+    // ----- load constant 1  ----- AddMethod.ssc(42,15)
+    stack1i := 1;
+    // ----- binary operator  ----- AddMethod.ssc(42,15)
+    stack0i := stack0i + stack1i;
+    // ----- new array  ----- AddMethod.ssc(42,15)
+    assert 0 <= stack0i;
+    havoc temp3;
+    assume $Heap[temp3, $allocated] == false && $Length(temp3) == stack0i;
+    assume $Heap[$ElementProxy(temp3, -1), $allocated] == false && $ElementProxy(temp3, -1) != temp3 && $ElementProxy(temp3, -1) != null;
+    assume temp3 != null;
+    assume $typeof(temp3) == IntArray(System.Int32, 1);
+    assume $Heap[temp3, $ownerRef] == temp3 && $Heap[temp3, $ownerFrame] == $PeerGroupPlaceholder;
+    assume $Heap[$ElementProxy(temp3, -1), $ownerRef] == $ElementProxy(temp3, -1) && $Heap[$ElementProxy(temp3, -1), $ownerFrame] == $PeerGroupPlaceholder;
+    assume $Heap[temp3, $inv] == $typeof(temp3) && $Heap[temp3, $localinv] == $typeof(temp3);
+    assume (forall $i: int :: IntArrayGet($Heap[temp3, $elements], $i) == 0);
+    $Heap[temp3, $allocated] := true;
+    call System.Object..ctor($ElementProxy(temp3, -1));
+    b := temp3;
+    assume IsHeap($Heap);
+    // ----- load field  ----- AddMethod.ssc(43,9)
+    assert this != null;
+    stack0o := $Heap[this, Bag.a];
+    // ----- copy  ----- AddMethod.ssc(43,9)
+    stack1o := b;
+    // ----- load constant 0  ----- AddMethod.ssc(43,9)
+    stack2i := 0;
+    // ----- call  ----- AddMethod.ssc(43,9)
+    assert stack0o != null;
+    call System.Array.CopyTo$System.Array$notnull$System.Int32$.Virtual.$(stack0o, stack1o, stack2i);
+    // ----- store field  ----- AddMethod.ssc(44,9)
+    assert this != null;
+    assert $Heap[this, $ownerFrame] == $PeerGroupPlaceholder || !($Heap[$Heap[this, $ownerRef], $inv] <: $Heap[this, $ownerFrame]) || $Heap[$Heap[this, $ownerRef], $localinv] == $BaseClass($Heap[this, $ownerFrame]);
+    assert ($Heap[b, $ownerRef] == this && $Heap[b, $ownerFrame] == Bag) || $Heap[b, $ownerFrame] == $PeerGroupPlaceholder;
+    assert $Heap[b, $ownerFrame] == $PeerGroupPlaceholder && $Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag) ==> (forall $pc: ref :: { $typeof($pc) } { $Heap[$pc, $localinv] } { $Heap[$pc, $inv] } { $Heap[$pc, $ownerFrame] } { $Heap[$pc, $ownerRef] } $pc != null && $Heap[$pc, $allocated] && $Heap[$pc, $ownerRef] == $Heap[b, $ownerRef] && $Heap[$pc, $ownerFrame] == $Heap[b, $ownerFrame] ==> $Heap[$pc, $inv] == $typeof($pc) && $Heap[$pc, $localinv] == $typeof($pc));
+    assert $Heap[b, $ownerFrame] == $PeerGroupPlaceholder && $Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag) ==> $Heap[this, $ownerRef] != $Heap[b, $ownerRef] || $Heap[this, $ownerFrame] != $Heap[b, $ownerFrame];
+    call $UpdateOwnersForRep(this, Bag, b);
+    havoc temp4;
+    $Heap[this, $exposeVersion] := temp4;
+    $Heap[this, Bag.a] := b;
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || 0 <= $Heap[this, Bag.n];
+    assert !($Heap[this, $inv] <: Bag && $Heap[this, $localinv] != $BaseClass(Bag)) || $Heap[this, Bag.n] <= $Length($Heap[this, Bag.a]);
+    assume IsHeap($Heap);
+    goto block6392;
+
+  block6562:
+    stack0o := null;
+    // ----- binary operator
+    // ----- branch
+    goto true6562to6477, false6562to6579;
+
+  true6562to6477:
+    assume local2 == stack0o;
+    goto block6477;
+
+  false6562to6579:
+    assume local2 != stack0o;
+    goto block6579;
+
+  block6477:
+    // ----- load token  ----- AddMethod.ssc(48,5)
+    havoc stack0s;
+    assume $IsTokenForType(stack0s, Bag);
+    // ----- statically resolved GetTypeFromHandle call  ----- AddMethod.ssc(48,5)
+    stack0o := TypeObject(Bag);
+    // ----- local pack  ----- AddMethod.ssc(48,5)
+    assert temp0 != null;
+    assert $Heap[temp0, $localinv] == System.Object;
+    assert 0 <= $Heap[temp0, Bag.n];
+    assert $Heap[temp0, Bag.n] <= $Length($Heap[temp0, Bag.a]);
+    assert (forall $p: ref :: $p != null && $Heap[$p, $allocated] && $Heap[$p, $ownerRef] == temp0 && $Heap[$p, $ownerFrame] == Bag ==> $Heap[$p, $inv] == $typeof($p) && $Heap[$p, $localinv] == $typeof($p));
+    $Heap[temp0, $localinv] := $typeof(temp0);
+    assume IsHeap($Heap);
+    goto block6545;
+
+  block6579:
+    // ----- is instance
+    // ----- branch
+    goto true6579to6477, false6579to6528;
+
+  true6579to6477:
+    assume $As(local2, Microsoft.Contracts.ICheckedException) != null;
+    goto block6477;
+
+  false6579to6528:
+    assume $As(local2, Microsoft.Contracts.ICheckedException) == null;
+    goto block6528;
+
+  block6528:
+    // ----- branch
+    goto block6545;
+
+  block6545:
+    // ----- nop
+    // ----- branch
+    goto block6443;
+
+  block6443:
+    // ----- return
+    return;
+}
+
+
+
+procedure Bag..cctor();
+  free requires $BeingConstructed == null;
+  free requires $PurityAxiomsCanBeAssumed;
+  modifies $Heap, $ActivityIndicator;
+  // newly allocated objects are fully valid
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } $o != null && !old($Heap)[$o, $allocated] && $Heap[$o, $allocated] ==> $Heap[$o, $inv] == $typeof($o) && $Heap[$o, $localinv] == $typeof($o));
+  // first consistent owner unchanged if its exposeVersion is
+  free ensures (forall $o: ref :: { $Heap[$o, $FirstConsistentOwner] } old($Heap)[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] == $Heap[old($Heap)[$o, $FirstConsistentOwner], $exposeVersion] ==> old($Heap)[$o, $FirstConsistentOwner] == $Heap[$o, $FirstConsistentOwner]);
+  // frame condition
+  ensures (forall<a> $o: ref, $f: Field a :: { $Heap[$o, $f] } IncludeInMainFrameCondition($f) && $o != null && old($Heap)[$o, $allocated] && (old($Heap)[$o, $ownerFrame] == $PeerGroupPlaceholder || !(old($Heap)[old($Heap)[$o, $ownerRef], $inv] <: old($Heap)[$o, $ownerFrame]) || old($Heap)[old($Heap)[$o, $ownerRef], $localinv] == $BaseClass(old($Heap)[$o, $ownerFrame])) && old(true) && old(true) ==> old($Heap)[$o, $f] == $Heap[$o, $f]);
+  free ensures $HeapSucc(old($Heap), $Heap);
+  // inv/localinv change only in blocks
+  free ensures (forall $o: ref :: { $Heap[$o, $localinv] } { $Heap[$o, $inv] } old($Heap)[$o, $allocated] ==> old($Heap)[$o, $inv] == $Heap[$o, $inv] && old($Heap)[$o, $localinv] == $Heap[$o, $localinv]);
+  free ensures (forall $o: ref :: { $Heap[$o, $allocated] } old($Heap)[$o, $allocated] ==> $Heap[$o, $allocated]) && (forall $ot: ref :: { $Heap[$ot, $ownerFrame] } { $Heap[$ot, $ownerRef] } old($Heap)[$ot, $allocated] && old($Heap)[$ot, $ownerFrame] != $PeerGroupPlaceholder ==> $Heap[$ot, $ownerRef] == old($Heap)[$ot, $ownerRef] && $Heap[$ot, $ownerFrame] == old($Heap)[$ot, $ownerFrame]) && old($Heap)[$BeingConstructed, $NonNullFieldsAreInitialized] == $Heap[$BeingConstructed, $NonNullFieldsAreInitialized];
+  free ensures (forall $o: ref :: { $Heap[$o, $sharingMode] } old($Heap[$o, $sharingMode]) == $Heap[$o, $sharingMode]);
+
+
+
+implementation Bag..cctor()
+{
+
+  entry:
+    goto block7650;
+
+  block7650:
+    goto block7701;
+
+  block7701:
+    // ----- nop
+    // ----- return
+    return;
+}
+
+