Specify macro is invalid in certain contexts

1 files changed, 21 insertions, 16 deletions

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index c3cf6437afa..3eed3ed9e1b 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -2591,6 +2591,7 @@ impl<'a> Parser<'a> {
     pub(crate) fn maybe_recover_unexpected_comma(
         &mut self,
         lo: Span,
+        is_mac_invoc: bool,
         rt: CommaRecoveryMode,
     ) -> PResult<'a, ()> {
         if self.token != token::Comma {
@@ -2611,24 +2612,28 @@ impl<'a> Parser<'a> {
         let seq_span = lo.to(self.prev_token.span);
         let mut err = self.struct_span_err(comma_span, "unexpected `,` in pattern");
         if let Ok(seq_snippet) = self.span_to_snippet(seq_span) {
-            err.multipart_suggestion(
-                format!(
-                    "try adding parentheses to match on a tuple{}",
-                    if let CommaRecoveryMode::LikelyTuple = rt { "" } else { "..." },
-                ),
-                vec![
-                    (seq_span.shrink_to_lo(), "(".to_string()),
-                    (seq_span.shrink_to_hi(), ")".to_string()),
-                ],
-                Applicability::MachineApplicable,
-            );
-            if let CommaRecoveryMode::EitherTupleOrPipe = rt {
-                err.span_suggestion(
-                    seq_span,
-                    "...or a vertical bar to match on multiple alternatives",
-                    seq_snippet.replace(',', " |"),
+            if is_mac_invoc {
+                err.note(fluent::parse_macro_expands_to_match_arm);
+            } else {
+                err.multipart_suggestion(
+                    format!(
+                        "try adding parentheses to match on a tuple{}",
+                        if let CommaRecoveryMode::LikelyTuple = rt { "" } else { "..." },
+                    ),
+                    vec![
+                        (seq_span.shrink_to_lo(), "(".to_string()),
+                        (seq_span.shrink_to_hi(), ")".to_string()),
+                    ],
                     Applicability::MachineApplicable,
                 );
+                if let CommaRecoveryMode::EitherTupleOrPipe = rt {
+                    err.span_suggestion(
+                        seq_span,
+                        "...or a vertical bar to match on multiple alternatives",
+                        seq_snippet.replace(',', " |"),
+                        Applicability::MachineApplicable,
+                    );
+                }
             }
         }
         Err(err)