[libclang] Fix a crash with invalid code, while skip function bodies is enabled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175860 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index a77c034..71a7b2c 100644
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -1974,7 +1974,7 @@
   assert(Tok.is(tok::l_brace));
   SourceLocation LBraceLoc = Tok.getLocation();
 
-  if (SkipFunctionBodies && Actions.canSkipFunctionBody(Decl) &&
+  if (SkipFunctionBodies && (!Decl || Actions.canSkipFunctionBody(Decl)) &&
       trySkippingFunctionBody()) {
     BodyScope.Exit();
     return Actions.ActOnSkippedFunctionBody(Decl);