Fix a Sema invariant bug that I recently introduced involving

the template instantiation of statement-expressions.

I think it was jyasskin who had a crashing testcase in this area;
hopefully this fixes it and he can find his testcase and check it in.

llvm-svn: 154189

2 files changed, 11 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 709b944447e..82d23783f91 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -8567,6 +8567,9 @@ void Sema::ActOnStartStmtExpr() {
 }
 
 void Sema::ActOnStmtExprError() {
+  // Note that function is also called by TreeTransform when leaving a
+  // StmtExpr scope without rebuilding anything.
+
   DiscardCleanupsInEvaluationContext();
   PopExpressionEvaluationContext();
 }
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index f16b667a658..fdb861eea51 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -6736,14 +6736,20 @@ TreeTransform<Derived>::TransformAddrLabelExpr(AddrLabelExpr *E) {
 template<typename Derived>
 ExprResult 
 TreeTransform<Derived>::TransformStmtExpr(StmtExpr *E) {
+  SemaRef.ActOnStartStmtExpr();
   StmtResult SubStmt
     = getDerived().TransformCompoundStmt(E->getSubStmt(), true);
-  if (SubStmt.isInvalid())
+  if (SubStmt.isInvalid()) {
+    SemaRef.ActOnStmtExprError();
     return ExprError();
+  }
 
   if (!getDerived().AlwaysRebuild() &&
-      SubStmt.get() == E->getSubStmt())
+      SubStmt.get() == E->getSubStmt()) {
+    // Calling this an 'error' is unintuitive, but it does the right thing.
+    SemaRef.ActOnStmtExprError();
     return SemaRef.MaybeBindToTemporary(E);
+  }
 
   return getDerived().RebuildStmtExpr(E->getLParenLoc(),
                                       SubStmt.get(),