Don't build invalid AST nodes during recovery

A DependentScopeDeclRefExpr should always have a nested name specifier.
During template instantiation, if we found that the named context was
incomplete, we would previously build a DependentScopeDeclRefExpr with
an empty qualifier.

This error recovery path has been asserting for some time. The other
error codepaths use ExprError, so we can do the same.

Fixes PR21864.

llvm-svn: 224451

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 07e3137f845..f2e951e5749 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -2877,7 +2877,7 @@ Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
   if (!(DC = computeDeclContext(SS, false)) ||
       DC->isDependentContext() ||
       RequireCompleteDeclContext(SS, DC))
-    return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
+    return ExprError();
 
   bool MemberOfUnknownSpecialization;
   LookupResult R(*this, NameInfo, LookupOrdinaryName);