Fix infinite recursion for invalid declaration, by Dmitry Polukhin

Fix for a case found by fuzzing PR23057 (comment #25 https://llvm.org/bugs/show_bug.cgi?id=23057#c25).
Differential Revision: http://reviews.llvm.org/D16065

llvm-svn: 257461

clang/lib/AST/Decl.cpp

@@ -1184,7 +1184,7 @@ static LinkageInfo getLVForLocalDecl(const NamedDecl *D,
     return LinkageInfo::none();
 
   const Decl *OuterD = getOutermostFuncOrBlockContext(D);
-  if (!OuterD)
+  if (!OuterD || OuterD->isInvalidDecl())
     return LinkageInfo::none();
 
   LinkageInfo LV;

clang/test/SemaCXX/linkage-invalid-decl.cpp

@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// This invalid declaration used to call infinite recursion in linkage
+// calculation for enum as a function argument.
+inline foo(A)(enum E;
+// expected-error@-1 {{unknown type name 'foo'}}
+// expected-error@-2 {{ISO C++ forbids forward references to 'enum' types}}
+// expected-error@-3 {{expected ')'}}
+// expected-note@-4 {{to match this '('}}