From a730970dffe84711b8be66c38080acf1b1109982 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Sun, 24 Jan 2021 14:15:15 +0100
Subject: [PATCH] Only call span.rust_2021() when necessary.

---
 compiler/rustc_builtin_macros/src/assert.rs | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/compiler/rustc_builtin_macros/src/assert.rs b/compiler/rustc_builtin_macros/src/assert.rs
index 3cffc7a75ee..f82269c4eee 100644
--- a/compiler/rustc_builtin_macros/src/assert.rs
+++ b/compiler/rustc_builtin_macros/src/assert.rs
@@ -12,25 +12,23 @@ use rustc_span::{Span, DUMMY_SP};
 
 pub fn expand_assert<'cx>(
     cx: &'cx mut ExtCtxt<'_>,
-    sp: Span,
+    span: Span,
     tts: TokenStream,
 ) -> Box<dyn MacResult + 'cx> {
-    let Assert { cond_expr, custom_message } = match parse_assert(cx, sp, tts) {
+    let Assert { cond_expr, custom_message } = match parse_assert(cx, span, tts) {
         Ok(assert) => assert,
         Err(mut err) => {
             err.emit();
-            return DummyResult::any(sp);
+            return DummyResult::any(span);
         }
     };
 
-    let is_2021 = sp.rust_2021();
-
     // `core::panic` and `std::panic` are different macros, so we use call-site
     // context to pick up whichever is currently in scope.
-    let sp = cx.with_call_site_ctxt(sp);
+    let sp = cx.with_call_site_ctxt(span);
 
     let panic_call = if let Some(tokens) = custom_message {
-        let path = if is_2021 {
+        let path = if span.rust_2021() {
             // On edition 2021, we always call `$crate::panic!()`.
             Path {
                 span: sp,