[clang] [clang] Support `__is_trivially_copyable(int()&)==false` (PR #81298)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic updated https://github.com/llvm/llvm-project/pull/81298

>From d59c262b31937fdd2b907ec11d7f08e4a385007c Mon Sep 17 00:00:00 2001
From: Amirreza Ashouri <ar.ashouri999 at gmail.com>
Date: Fri, 9 Feb 2024 21:55:03 +0330
Subject: [PATCH 1/4] [clang] Support `__is_trivially_copyable(int()&)==false`

IMHO it would be productive to make a similar change for `typeid`,
in `ParseCXXTypeid`, in order to improve Clang's error message for
https://godbolt.org/z/oKKWxeYra
But that might be better done by adding a new DeclaratorContext
specifically for TypeidArg, instead of pretending that the argument
to `typeid` is a template argument, because I don't know what else
that change might affect.

Fixes https://github.com/llvm/llvm-project/issues/77585
---
 clang/lib/Parse/ParseExprCXX.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index fd262ff31e661a..746a8b2286ac4c 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -3899,7 +3899,9 @@ ExprResult Parser::ParseTypeTrait() {
   SmallVector<ParsedType, 2> Args;
   do {
     // Parse the next type.
-    TypeResult Ty = ParseTypeName();
+    TypeResult Ty = ParseTypeName(nullptr, getLangOpts().CPlusPlus
+                                               ? DeclaratorContext::TemplateArg
+                                               : DeclaratorContext::TypeName);
     if (Ty.isInvalid()) {
       Parens.skipToEnd();
       return ExprError();
@@ -3941,7 +3943,7 @@ ExprResult Parser::ParseArrayTypeTrait() {
   if (T.expectAndConsume())
     return ExprError();
 
-  TypeResult Ty = ParseTypeName();
+  TypeResult Ty = ParseTypeName(nullptr, DeclaratorContext::TemplateArg);
   if (Ty.isInvalid()) {
     SkipUntil(tok::comma, StopAtSemi);
     SkipUntil(tok::r_paren, StopAtSemi);

>From 4c58f4f351a17cf4bf3c9d0ccfa118d0fe3a52de Mon Sep 17 00:00:00 2001
From: Amirreza Ashouri <ar.ashouri999 at gmail.com>
Date: Sun, 11 Feb 2024 20:35:04 +0330
Subject: [PATCH 2/4] [clang] Fix the failing test in #81298

---
 clang/test/Sema/static-assert.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/test/Sema/static-assert.c b/clang/test/Sema/static-assert.c
index 4e9e6b7ee558bd..7e1ce135cbd995 100644
--- a/clang/test/Sema/static-assert.c
+++ b/clang/test/Sema/static-assert.c
@@ -57,7 +57,7 @@ UNION(char[2], short) u2 = { .one = { 'a', 'b' } }; // ext-warning 3 {{'_Static_
 typedef UNION(char, short) U3; // expected-error {{static assertion failed due to requirement 'sizeof(char) == sizeof(short)': type size mismatch}} \
                                // expected-note{{evaluates to '1 == 2'}} \
                                // ext-warning 3 {{'_Static_assert' is a C11 extension}}
-typedef UNION(float, 0.5f) U4; // expected-error {{expected a type}} \
+typedef UNION(float, 0.5f) U4; // expected-error-re {{{{type name requires a specifier or qualifier|expected a type}}}} \
                                // ext-warning 3 {{'_Static_assert' is a C11 extension}}
 
 // After defining the assert macro in MS-compatibility mode, we should

>From 03c2cfb73fc291ecfc5318077b295a6e38cd9869 Mon Sep 17 00:00:00 2001
From: Amirreza Ashouri <ar.ashouri999 at gmail.com>
Date: Mon, 12 Feb 2024 23:47:33 +0330
Subject: [PATCH 3/4] Add a release note.

---
 clang/docs/ReleaseNotes.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 32440ee64e3ebe..0beb10af709804 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -217,6 +217,8 @@ Bug Fixes to C++ Support
   Fixes (`#80971 ICE when explicit object parameter be a function parameter pack`)
 - Fixed a bug where abbreviated function templates would append their invented template parameters to
   an empty template parameter lists.
+- Fix parsing of abominable function types inside type traits. 
+  Fixes (`#77585 <https://github.com/llvm/llvm-project/issues/77585>`_)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

>From 0de0aa09fb5f45fcde688d988377582b9257b6b8 Mon Sep 17 00:00:00 2001
From: Amirreza Ashouri <ar.ashouri999 at gmail.com>
Date: Tue, 13 Feb 2024 01:19:27 +0330
Subject: [PATCH 4/4] Remove trailing white space in ReleaseNotes.rst.

---
 clang/docs/ReleaseNotes.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 0beb10af709804..55f3faea365a07 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -217,7 +217,7 @@ Bug Fixes to C++ Support
   Fixes (`#80971 ICE when explicit object parameter be a function parameter pack`)
 - Fixed a bug where abbreviated function templates would append their invented template parameters to
   an empty template parameter lists.
-- Fix parsing of abominable function types inside type traits. 
+- Fix parsing of abominable function types inside type traits.
   Fixes (`#77585 <https://github.com/llvm/llvm-project/issues/77585>`_)
 
 Bug Fixes to AST Handling