[clang] Adding __nullptr as a keyword to C (PR #123119)

[Aidan Goldfarb via cfe-commits]

https://github.com/AidanGoldfarb created https://github.com/llvm/llvm-project/pull/123119

This PR resolves #121503. 

>From 51372333df218cfb4fa8dcc0cebee03c0e3ebc5f Mon Sep 17 00:00:00 2001
From: Aidan <aidan.goldfarb at mail.mcgill.ca>
Date: Wed, 15 Jan 2025 15:24:12 -0500
Subject: [PATCH] __nullptr -> KEYALL, added relevant test

---
 clang/include/clang/Basic/TokenKinds.def | 2 +-
 clang/test/Sema/nullptr.c                | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/TokenKinds.def b/clang/include/clang/Basic/TokenKinds.def
index 2c692c999bdff5..8902a20b07ffa8 100644
--- a/clang/include/clang/Basic/TokenKinds.def
+++ b/clang/include/clang/Basic/TokenKinds.def
@@ -707,7 +707,7 @@ ALIAS("__decltype"       , decltype     , KEYCXX)
 ALIAS("__imag__"         , __imag       , KEYALL)
 ALIAS("__inline"         , inline       , KEYALL)
 ALIAS("__inline__"       , inline       , KEYALL)
-ALIAS("__nullptr"        , nullptr      , KEYCXX)
+ALIAS("__nullptr"        , nullptr      , KEYALL)
 ALIAS("__real__"         , __real       , KEYALL)
 ALIAS("__restrict"       , restrict     , KEYALL)
 ALIAS("__restrict__"     , restrict     , KEYALL)
diff --git a/clang/test/Sema/nullptr.c b/clang/test/Sema/nullptr.c
index d11765a9c881a1..64095fc00691cd 100644
--- a/clang/test/Sema/nullptr.c
+++ b/clang/test/Sema/nullptr.c
@@ -108,3 +108,6 @@ void test_f1() {
   int ir = (f1)(nullptr);
 }
 
+// __nullptr keyword in C
+void foo(void *);
+void bar() { foo(__nullptr); }
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