Auto merge of #51196 - Havvy:remove-keywords, r=petrochenkov

Implement RFC 2421, 'Keyword unreservations (pure, sizeof, alignof, offsetof)

On my local machine I was getting failures in `test/ui-fulldeps`, but I was also getting them again after reverting the change, so I'm hoping that this works.

I removed the test because that's what the other PR that unreserved a keyword did and I feel that it doesn't make sense/keep value to keep a test for something removed years ago.

1 files changed, 12 insertions, 3 deletions

diff --git a/src/test/parse-fail/removed-syntax-fn-pure.rs b/src/test/run-pass/rfc-2421-unreserve-pure-offsetof-sizeof-alignof.rs
index 83794a70a4f..7d8050a07a3 100644
--- a/src/test/parse-fail/removed-syntax-fn-pure.rs
+++ b/src/test/run-pass/rfc-2421-unreserve-pure-offsetof-sizeof-alignof.rs
@@ -1,4 +1,4 @@
-// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //
@@ -8,6 +8,15 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// compile-flags: -Z parse-only
+// Test that removed keywords are allowed as identifiers.
+fn main () {
+    let offsetof = ();
+    let alignof = ();
+    let sizeof = ();
+    let pure = ();
+}
 
-pure fn f() {} //~ ERROR expected item, found `pure`
+fn offsetof() {}
+fn alignof() {}
+fn sizeof() {}
+fn pure() {}