[VLA] Handle VLA size expression in a full-expression context.

Summary: Previously the cleanups (e.g. dtor calls) are inserted into the
outer scope (e.g. function body scope), instead of it's own scope. After
the fix, the cleanups are inserted right after getting the size value.

This fixes pr30306.

Reviewers: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24333

llvm-svn: 295123

2 files changed, 11 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index a0e4d2999d9..f7db189de84 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -3864,6 +3864,8 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
     if (Body.isInvalid())
       Function->setInvalidDecl();
 
+    // FIXME: finishing the function body while in an expression evaluation
+    // context seems wrong. Investigate more.
     ActOnFinishFunctionBody(Function, Body.get(),
                             /*IsInstantiation=*/true);
 
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index ef349c395f8..8a63d354746 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -4603,8 +4603,15 @@ TreeTransform<Derived>::TransformVariableArrayType(TypeLocBuilder &TLB,
   if (ElementType.isNull())
     return QualType();
 
-  ExprResult SizeResult
-    = getDerived().TransformExpr(T->getSizeExpr());
+  ExprResult SizeResult;
+  {
+    EnterExpressionEvaluationContext Context(SemaRef,
+                                             Sema::PotentiallyEvaluated);
+    SizeResult = getDerived().TransformExpr(T->getSizeExpr());
+  }
+  if (SizeResult.isInvalid())
+    return QualType();
+  SizeResult = SemaRef.ActOnFinishFullExpr(SizeResult.get());
   if (SizeResult.isInvalid())
     return QualType();