Rollup merge of #113999 - Centri3:macro-arm-expand, r=wesleywiser

Specify macro is invalid in certain contexts

Adds a note when a macro is used where it really shouldn't be.

Closes #113766

compiler/rustc_parse/src/parser/pat.rs

@@ -142,7 +142,11 @@ impl<'a> Parser<'a> {
         // Parse the first pattern (`p_0`).
         let mut first_pat = self.parse_pat_no_top_alt(expected, syntax_loc)?;
         if rc == RecoverComma::Yes {
-            self.maybe_recover_unexpected_comma(first_pat.span, rt)?;
+            self.maybe_recover_unexpected_comma(
+                first_pat.span,
+                matches!(first_pat.kind, PatKind::MacCall(_)),
+                rt,
+            )?;
         }
 
         // If the next token is not a `|`,
@@ -184,7 +188,7 @@ impl<'a> Parser<'a> {
                 err
             })?;
             if rc == RecoverComma::Yes {
-                self.maybe_recover_unexpected_comma(pat.span, rt)?;
+                self.maybe_recover_unexpected_comma(pat.span, false, rt)?;
             }
             pats.push(pat);
         }