Automerge: Diagnose the code with trailing comma in the function call. (#125232)

This patch fixes a regression caused by
llvm/llvm-project#114684 where clang accepts
trailing commas for function calls.

Fixes #125225

(cherry picked from commit 922f339)

Author: hokein

clang/lib/Parse/ParseExpr.cpp

@@ -2237,6 +2237,8 @@ Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
             if (PP.isCodeCompletionReached() && !CalledSignatureHelp)
               RunSignatureHelp();
             LHS = ExprError();
+          } else if (!HasError && HasTrailingComma) {
+            Diag(Tok, diag::err_expected_expression);
           } else if (LHS.isInvalid()) {
             for (auto &E : ArgExprs)
               Actions.CorrectDelayedTyposInExpr(E);

clang/test/Parser/recovery.cpp

@@ -215,3 +215,10 @@ struct ::template foo, struct ::template bar; // expected-error 2 {{expected ide
 struct ::foo struct::; // expected-error {{no struct named 'foo' in the global namespace}} expected-error {{expected identifier}}
 class :: : {} a;  // expected-error {{expected identifier}} expected-error {{expected class name}}
 }
+
+namespace GH125225 {
+void func(int);
+void k() {
+  func(1, ); // expected-error {{expected expression}}
+}
+}