1 files changed, 5 insertions, 4 deletions
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index 10b2b9f07e2..2ed11204ef6 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -68,17 +68,18 @@ fn emit_frag_parse_err(
     arm_span: Span,
     kind: AstFragmentKind,
 ) {
-    if parser.token == token::Eof && e.message().ends_with(", found `<eof>`") {
+    // FIXME(davidtwco): avoid depending on the error message text
+    if parser.token == token::Eof && e.message().as_str().ends_with(", found `<eof>`") {
         if !e.span.is_dummy() {
             // early end of macro arm (#52866)
             e.replace_span_with(parser.sess.source_map().next_point(parser.token.span));
         }
         let msg = &e.message[0];
         e.message[0] = (
-            format!(
+            rustc_errors::DiagnosticMessage::Str(format!(
                 "macro expansion ends with an incomplete expression: {}",
-                msg.0.replace(", found `<eof>`", ""),
-            ),
+                msg.0.as_str().replace(", found `<eof>`", ""),
+            )),
             msg.1,
         );
     }