hir-analysis: make one diagnostic translatable

compiler/rustc_error_messages/locales/en-US/hir_analysis.ftl

@@ -124,3 +124,6 @@ hir_analysis_linkage_type =
 hir_analysis_auto_deref_reached_recursion_limit = reached the recursion limit while auto-dereferencing `{$ty}`
     .label = deref recursion limit reached
     .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]` attribute to your crate (`{$crate_name}`)
+
+hir_analysis_track_caller_on_main = `main` function is not allowed to be `#[track_caller]`
+    .label = `main` function is not allowed to be `#[track_caller]`

compiler/rustc_hir_analysis/src/errors.rs

@@ -312,3 +312,12 @@ pub struct AutoDerefReachedRecursionLimit<'a> {
     pub suggested_limit: rustc_session::Limit,
     pub crate_name: Symbol,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_track_caller_on_main)]
+pub(crate) struct TrackCallerOnMain {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub annotated: Span,
+}

compiler/rustc_hir_analysis/src/lib.rs

@@ -297,10 +297,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
     }
 
     for attr in tcx.get_attrs(main_def_id, sym::track_caller) {
-        tcx.sess
-            .struct_span_err(attr.span, "`main` function is not allowed to be `#[track_caller]`")
-            .span_label(main_span, "`main` function is not allowed to be `#[track_caller]`")
-            .emit();
+        tcx.sess.emit_err(errors::TrackCallerOnMain { span: attr.span, annotated: main_span });
         error = true;
     }