[macro_metavar_expr_concat] Dogfooding

Author: c410-f3r

library/std/src/lib.rs

@@ -302,6 +302,7 @@
 #![feature(let_chains)]
 #![feature(link_cfg)]
 #![feature(linkage)]
+#![feature(macro_metavar_expr_concat)]
 #![feature(min_exhaustive_patterns)]
 #![feature(min_specialization)]
 #![feature(must_not_suspend)]

library/std/src/sys/pal/unix/weak.rs

@@ -172,10 +172,7 @@ pub(crate) macro syscall {
                 // (not paths).
                 use libc::*;
 
-                syscall(
-                    concat_idents!(SYS_, $name),
-                    $($arg_name),*
-                ) as $ret
+                syscall(${concat(SYS_, $name)}, $($arg_name),*) as $ret
             }
         }
     )
@@ -189,10 +186,7 @@ pub(crate) macro raw_syscall {
             // (not paths).
             use libc::*;
 
-            syscall(
-                concat_idents!(SYS_, $name),
-                $($arg_name),*
-            ) as $ret
+            syscall(${concat(SYS_, $name)}, $($arg_name),*) as $ret
         }
     )
 }