Diagnose function template definitions inside functions

The parser can only be tricked into parsing a function template
definition by inserting a typename keyword before the function template
declaration. This used to make us crash, and now it's fixed.

While here, remove an unneeded boolean parameter from ParseDeclGroup.
This boolean always corresponded to non-typedef declarators at file
scope. ParseDeclGroup already has precise diagnostics for the function
definition typedef case, so we can let that through.

Fixes PR21839.

llvm-svn: 224287

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/test/Parser/cxx-template-decl.cpp b/clang/test/Parser/cxx-template-decl.cpp
index bce1b7cbdeb..efa42ad30d0 100644
--- a/clang/test/Parser/cxx-template-decl.cpp
+++ b/clang/test/Parser/cxx-template-decl.cpp
@@ -211,6 +211,19 @@ void Instantiate() {
 
 }
 
+namespace func_tmpl_spec_def_in_func {
+// We failed to diagnose function template specialization definitions inside
+// functions during recovery previously.
+template <class> void FuncTemplate() {}
+void TopLevelFunc() {
+  // expected-error@+2 {{expected a qualified name after 'typename'}}
+  // expected-error@+1 {{function definition is not allowed here}}
+  typename template <> void FuncTemplate<void>() { }
+  // expected-error@+1 {{function definition is not allowed here}}
+  void NonTemplateInner() { }
+}
+}
+
 namespace broken_baseclause {
 template<typename T>
 struct base { };