Parse: Don't crash during parsing if we lack a simple-type-specifier

Summary:
Parsing cast expressions during error recovery can put us in a bad
state.  Check to see if the token for a simple-type-specifier makes
sense before further parsing.

Fixes PR17255.

Reviewers: rsmith, doug.gregor, CornedBee, eli.friedman

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1696

llvm-svn: 191159

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/test/Parser/cxx-decl.cpp b/clang/test/Parser/cxx-decl.cpp
index 281e33b20f8..c33a8d561ca 100644
--- a/clang/test/Parser/cxx-decl.cpp
+++ b/clang/test/Parser/cxx-decl.cpp
@@ -209,6 +209,14 @@ namespace PR5066 {
   using T = int (*T)(); // expected-error {{type-id cannot have a name}} expected-warning {{C++11}}
 }
 
+namespace PR17255 {
+void foo() {
+  typename A::template B<>; // expected-error {{use of undeclared identifier 'A'}} \
+                            // expected-error {{expected a qualified name after 'typename'}} \
+                            // expected-warning {{'template' keyword outside of a template}}
+}
+}
+
 // PR8380
 extern ""      // expected-error {{unknown linkage language}}
 test6a { ;// expected-error {{C++ requires a type specifier for all declarations}} \