Rollup merge of #42368 - estebank:call-site, r=nikomatsakis

Use callsite's span for macro calls on suggestion

When suggesting an appropriate mutability for a macro call, use the call
span instead of the expanded macro's span.

```
error[E0308]: mismatched types
  --> $DIR/coerce-suggestions.rs:48:9
   |
48 |     s = format!("foo");
   |         ^^^^^^^^^^^^^^ expected mutable reference, found struct `std::string::String`
   |
   = note: expected type `&mut std::string::String`
              found type `std::string::String`
   = help: try with `&mut format!("foo")`
   = note: this error originates in a macro outside of the current crate
```
Fix #41858.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index bbe5bd4a10c..830a457df74 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -563,6 +563,15 @@ impl CodeMapper for CodeMap {
     fn merge_spans(&self, sp_lhs: Span, sp_rhs: Span) -> Option<Span> {
         self.merge_spans(sp_lhs, sp_rhs)
     }
+    fn call_span_if_macro(&self, sp: Span) -> Span {
+        if self.span_to_filename(sp.clone()).contains("macros>") {
+            let v = sp.macro_backtrace();
+            if let Some(use_site) = v.last() {
+                return use_site.call_site;
+            }
+        }
+        sp
+    }
 }
 
 #[derive(Clone)]