work towards rejecting consts in patterns that do not implement PartialEq

1 files changed, 12 insertions, 2 deletions

diff --git a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
index 00d9fe72cfc..41f31beff77 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/const_to_pat.rs
@@ -16,8 +16,8 @@ use std::cell::Cell;
 
 use super::PatCtxt;
 use crate::errors::{
-    FloatPattern, IndirectStructuralMatch, InvalidPattern, NontrivialStructuralMatch,
-    PointerPattern, TypeNotStructural, UnionPattern, UnsizedPattern,
+    FloatPattern, IndirectStructuralMatch, InvalidPattern, NonPartialEqMatch,
+    NontrivialStructuralMatch, PointerPattern, TypeNotStructural, UnionPattern, UnsizedPattern,
 };
 
 impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
@@ -235,6 +235,16 @@ impl<'tcx> ConstToPat<'tcx> {
                             PointerPattern,
                         );
                     }
+                    _ if !self.type_may_have_partial_eq_impl(cv.ty()) => {
+                        // Value is structural-match but the type doesn't even implement `PartialEq`...
+                        self.saw_const_match_lint.set(true);
+                        self.tcx().emit_spanned_lint(
+                            lint::builtin::MATCH_WITHOUT_PARTIAL_EQ,
+                            self.id,
+                            self.span,
+                            NonPartialEqMatch { non_peq_ty: cv.ty() },
+                        );
+                    }
                     _ => {}
                 }
             }