Auto merge of #57140 - estebank:str-err, r=varkor

Tweaks to format string diagnostics

Add label spans and fix incorrect spans.

Fix #55155, fix #55350.

1 files changed, 9 insertions, 2 deletions

diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 9d29e2b0fb6..95bb8c886ab 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -860,7 +860,9 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
     }
 
     let arg_spans = parser.arg_places.iter()
-        .map(|&(start, end)| fmt.span.from_inner_byte_pos(start, end))
+        .map(|&(parse::SpanIndex(start), parse::SpanIndex(end))| {
+            fmt.span.from_inner_byte_pos(start, end)
+        })
         .collect();
 
     let mut cx = Context {
@@ -954,13 +956,18 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
         let mut diag = {
             if errs_len == 1 {
                 let (sp, msg) = errs.into_iter().next().unwrap();
-                cx.ecx.struct_span_err(sp, msg)
+                let mut diag = cx.ecx.struct_span_err(sp, msg);
+                diag.span_label(sp, msg);
+                diag
             } else {
                 let mut diag = cx.ecx.struct_span_err(
                     errs.iter().map(|&(sp, _)| sp).collect::<Vec<Span>>(),
                     "multiple unused formatting arguments",
                 );
                 diag.span_label(cx.fmtsp, "multiple missing formatting specifiers");
+                for (sp, msg) in errs {
+                    diag.span_label(sp, msg);
+                }
                 diag
             }
         };