[CodeCompletion] Enable signature help when initializing class/struct/union members.

Summary:
Factors out member decleration gathering and uses it in parsing to call signature
help. Doesn't support signature help for base class constructors, the code was too
coupled with diagnostic handling, but still can be factored out but just needs
more afford.

Reviewers: sammccall, ilya-biryukov, ioeric

Reviewed By: ilya-biryukov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D51917

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@341949 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 1 deletions

diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 17dd246122..a86f7ed864 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -3449,6 +3449,7 @@ MemInitResult Parser::ParseMemInitializer(Decl *ConstructorDecl) {
   if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) {
     Diag(Tok, diag::warn_cxx98_compat_generalized_initializer_lists);
 
+    // FIXME: Add support for signature help inside initializer lists.
     ExprResult InitList = ParseBraceInitializer();
     if (InitList.isInvalid())
       return true;
@@ -3466,7 +3467,20 @@ MemInitResult Parser::ParseMemInitializer(Decl *ConstructorDecl) {
     // Parse the optional expression-list.
     ExprVector ArgExprs;
     CommaLocsTy CommaLocs;
-    if (Tok.isNot(tok::r_paren) && ParseExpressionList(ArgExprs, CommaLocs)) {
+    if (Tok.isNot(tok::r_paren) &&
+        ParseExpressionList(ArgExprs, CommaLocs, [&] {
+          QualType PreferredType = Actions.ProduceCtorInitMemberSignatureHelp(
+              getCurScope(), ConstructorDecl, SS, TemplateTypeTy, ArgExprs, II,
+              T.getOpenLocation());
+          CalledSignatureHelp = true;
+          Actions.CodeCompleteExpression(getCurScope(), PreferredType);
+        })) {
+      if (PP.isCodeCompletionReached() && !CalledSignatureHelp) {
+        Actions.ProduceCtorInitMemberSignatureHelp(
+            getCurScope(), ConstructorDecl, SS, TemplateTypeTy, ArgExprs, II,
+            T.getOpenLocation());
+        CalledSignatureHelp = true;
+      }
       SkipUntil(tok::r_paren, StopAtSemi);
       return true;
     }