Fix an edge case of mangling involving the combination of a lambda and typeid.

typeid (and a couple other non-standard places where we can transform an
unevaluated expression into an evaluated expression) is special
because it introduces an an expression evaluation context,
which conflicts with the mechanism to compute the current
lambda mangling context.  PR12123.

I would appreciate if someone would double-check that we get the mangling
correct with this patch.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164658 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 3 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 41985328bb..630281a424 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -10135,6 +10135,14 @@ Sema::PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,
     std::swap(MaybeODRUseExprs, ExprEvalContexts.back().SavedMaybeODRUseExprs);
 }
 
+void
+Sema::PushExpressionEvaluationContext(ExpressionEvaluationContext NewContext,
+                                      ReuseLambdaContextDecl_t,
+                                      bool IsDecltype) {
+  Decl *LambdaContextDecl = ExprEvalContexts.back().LambdaContextDecl;
+  PushExpressionEvaluationContext(NewContext, LambdaContextDecl, IsDecltype);
+}
+
 void Sema::PopExpressionEvaluationContext() {
   ExpressionEvaluationContextRecord& Rec = ExprEvalContexts.back();
 
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 975895dc8e..e0451c4c49 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -4275,7 +4275,8 @@ template<typename Derived>
 QualType TreeTransform<Derived>::TransformTypeOfExprType(TypeLocBuilder &TLB,
                                                       TypeOfExprTypeLoc TL) {
   // typeof expressions are not potentially evaluated contexts
-  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated,
+                                               Sema::ReuseLambdaContextDecl);
 
   ExprResult E = getDerived().TransformExpr(TL.getUnderlyingExpr());
   if (E.isInvalid())
@@ -6266,7 +6267,8 @@ TreeTransform<Derived>::TransformUnaryExprOrTypeTraitExpr(
   // C++0x [expr.sizeof]p1:
   //   The operand is either an expression, which is an unevaluated operand
   //   [...]
-  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated,
+                                               Sema::ReuseLambdaContextDecl);
 
   ExprResult SubExpr = getDerived().TransformExpr(E->getArgumentExpr());
   if (SubExpr.isInvalid())
@@ -7002,7 +7004,8 @@ TreeTransform<Derived>::TransformCXXTypeidExpr(CXXTypeidExpr *E) {
   // after we perform semantic analysis.  We speculatively assume it is
   // unevaluated; it will get fixed later if the subexpression is in fact
   // potentially evaluated.
-  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated);
+  EnterExpressionEvaluationContext Unevaluated(SemaRef, Sema::Unevaluated,
+                                               Sema::ReuseLambdaContextDecl);
 
   ExprResult SubExpr = getDerived().TransformExpr(E->getExprOperand());
   if (SubExpr.isInvalid())