[CodeComplete] Propagate preferred type for function arguments in more cases

Summary:
See the added test for some new cases.
This change also removes special code completion calls inside the
ParseExpressionList function now that we properly propagate expected
type to the function responsible for parsing elements of the expression list
(ParseAssignmentExpression).

Reviewers: kadircet

Reviewed By: kadircet

Subscribers: xbolva00, jdoerfert, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D58541

llvm-svn: 354864
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index a8d5e28..895aa02 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -3481,20 +3481,20 @@
     // Parse the optional expression-list.
     ExprVector ArgExprs;
     CommaLocsTy CommaLocs;
+    auto RunSignatureHelp = [&] {
+      QualType PreferredType = Actions.ProduceCtorInitMemberSignatureHelp(
+          getCurScope(), ConstructorDecl, SS, TemplateTypeTy, ArgExprs, II,
+          T.getOpenLocation());
+      CalledSignatureHelp = true;
+      return PreferredType;
+    };
     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);
+          PreferredType.enterFunctionArgument(Tok.getLocation(),
+                                              RunSignatureHelp);
         })) {
-      if (PP.isCodeCompletionReached() && !CalledSignatureHelp) {
-        Actions.ProduceCtorInitMemberSignatureHelp(
-            getCurScope(), ConstructorDecl, SS, TemplateTypeTy, ArgExprs, II,
-            T.getOpenLocation());
-        CalledSignatureHelp = true;
-      }
+      if (PP.isCodeCompletionReached() && !CalledSignatureHelp)
+        RunSignatureHelp();
       SkipUntil(tok::r_paren, StopAtSemi);
       return true;
     }