[Parser] Perform CachedTokens update dependent on token consume request

[bruno]

Summary

In the context where we break one tok::greatergreater into two tok::greater in order to correctly update the cached tokens; update the CachedTokens with two tok::greater only if ParseGreaterThanInTemplateList clients asks to consume the last token. Otherwise we only need to add one because the second is already added later on, as the current token.

This is a follow up from r259311.

[bruno]

Forgot to add cfe-commits.

[doug.gregor]

LGTM!

lib/Parse/ParseTemplate.cpp

bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc,
 
   // The advance from '>>' to '>' in a ObjectiveC template argument list needs
   // to be properly reflected in the token cache to allow correct interaction
   // between annotation and backtracking.
   if (ObjCGenericList && PrevTok.getKind() == tok::greatergreater &&
       RemainingToken == tok::greater && PP.IsPreviousCachedToken(PrevTok)) {
     PrevTok.setKind(RemainingToken);
     PrevTok.setLength(1);
-    Token NewToks[] = {PrevTok, Tok};
-    PP.ReplacePreviousCachedToken(NewToks);
+    // Break tok::greatergreater into two tok::greater but only add the second
+    // one in case the client asks to consume the last token.
+    if (ConsumeLastToken)
+      PP.ReplacePreviousCachedToken({PrevTok, Tok});
+    else
+      PP.ReplacePreviousCachedToken({PrevTok});
   }
 
   if (!ConsumeLastToken) {
     // Since we're not supposed to consume the '>' token, we need to push
     // this token and revert the current token back to the '>'.
     PP.EnterToken(Tok);
     Tok.setKind(tok::greater);
     Tok.setLength(1);

test/Parser/objcxx11-protocol-in-template.mm

 
 @protocol PA;
 @protocol PB;
 
 @class NSArray<ObjectType>;
 typedef int some_t;
 
 id<PA> FA(NSArray<id<PB>> *h, some_t group);
+
+template <typename Functor> void F(Functor functor) {}
+
+void z() {
+  id<P> x = 0;
+  (void)x;
+  F( [ x = vector<id<P>>{} ] {} );
+}