Fix treatment of types defined in function prototype

Types defined in function prototype are diagnosed earlier in C++ compilation.
They are put into declaration context where the prototype is introduced. Later on,
when FunctionDecl object is created, these types are moved into the function context.

This patch fixes PR19018 and PR18963.

Differential Revision: http://reviews.llvm.org/D4145

llvm-svn: 211718
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 7234d4c..d910a66 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2544,6 +2544,18 @@
     NamedDecl **A = new (getASTContext()) NamedDecl*[NewDecls.size()];
     std::copy(NewDecls.begin(), NewDecls.end(), A);
     DeclsInPrototypeScope = ArrayRef<NamedDecl *>(A, NewDecls.size());
+    // Move declarations introduced in prototype to the function context.
+    for (auto I : NewDecls) {
+      DeclContext *DC = I->getDeclContext();
+      // Forward-declared reference to an enumeration is not added to
+      // declaration scope, so skip declaration that is absent from its
+      // declaration contexts.
+      if (DC->containsDecl(I)) {
+          DC->removeDecl(I);
+          I->setDeclContext(this);
+          addDecl(I);
+      }
+    }
   }
 }