fix: break inside async closure has incorrect span for enclosing closure

Author: linyihai

compiler/rustc_passes/src/loops.rs

@@ -91,6 +91,10 @@ impl<'a, 'hir> Visitor<'hir> for CheckLoopVisitor<'a, 'hir> {
             }) => {
                 let cx = match kind {
                     hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(kind, source)) => {
+                        let fn_decl_span = match self.cx {
+                            Closure(span) => fn_decl_span.with_lo(span.lo()),
+                            _ => fn_decl_span,
+                        };
                         Coroutine { coroutine_span: fn_decl_span, kind, source }
                     }
                     _ => Closure(fn_decl_span),

tests/ui/coroutine/break-inside-coroutine-issue-124495.stderr

@@ -41,10 +41,10 @@ error[E0267]: `break` inside `async` closure
   --> $DIR/break-inside-coroutine-issue-124495.rs:21:24
    |
 LL |     let _ = async || { break; };
-   |                      --^^^^^---
-   |                      | |
-   |                      | cannot `break` inside `async` closure
-   |                      enclosing `async` closure
+   |             -----------^^^^^---
+   |             |          |
+   |             |          cannot `break` inside `async` closure
+   |             enclosing `async` closure
 
 error[E0267]: `break` inside `gen` block
   --> $DIR/break-inside-coroutine-issue-124495.rs:23:19