Tweak variant_id_for_adt

Author: Nadrieril

crates/hir-ty/src/diagnostics/match_check/pat_analysis.rs

@@ -75,18 +75,15 @@ impl<'p> MatchCheckCtx<'p> {
         }
     }
 
-    fn variant_id_for_adt(&self, ctor: &Constructor<Self>, adt: hir_def::AdtId) -> VariantId {
+    fn variant_id_for_adt(ctor: &Constructor<Self>, adt: hir_def::AdtId) -> Option<VariantId> {
         match ctor {
-            &Variant(id) => id.into(),
-            Struct | UnionField => {
-                assert!(!matches!(adt, hir_def::AdtId::EnumId(_)));
-                match adt {
-                    hir_def::AdtId::EnumId(_) => unreachable!(),
-                    hir_def::AdtId::StructId(id) => id.into(),
-                    hir_def::AdtId::UnionId(id) => id.into(),
-                }
-            }
-            _ => panic!("bad constructor {self:?} for adt {adt:?}"),
+            &Variant(id) => Some(id.into()),
+            Struct | UnionField => match adt {
+                hir_def::AdtId::EnumId(_) => None,
+                hir_def::AdtId::StructId(id) => Some(id.into()),
+                hir_def::AdtId::UnionId(id) => Some(id.into()),
+            },
+            _ => panic!("bad constructor {ctor:?} for adt {adt:?}"),
         }
     }
 
@@ -200,7 +197,7 @@ impl<'p> MatchCheckCtx<'p> {
                                 Wildcard
                             }
                         };
-                        let variant = self.variant_id_for_adt(&ctor, adt.0);
+                        let variant = Self::variant_id_for_adt(&ctor, adt.0).unwrap();
                         let fields_len = variant.variant_data(self.db.upcast()).fields().len();
                         // For each field in the variant, we store the relevant index into `self.fields` if any.
                         let mut field_id_to_id: Vec<Option<usize>> = vec![None; fields_len];
@@ -266,7 +263,7 @@ impl<'p> MatchCheckCtx<'p> {
                     PatKind::Deref { subpattern: subpatterns.next().unwrap() }
                 }
                 TyKind::Adt(adt, substs) => {
-                    let variant = self.variant_id_for_adt(pat.ctor(), adt.0);
+                    let variant = Self::variant_id_for_adt(pat.ctor(), adt.0).unwrap();
                     let subpatterns = self
                         .list_variant_nonhidden_fields(pat.ty(), variant)
                         .zip(subpatterns)
@@ -327,7 +324,7 @@ impl<'p> TypeCx for MatchCheckCtx<'p> {
                         // patterns. If we're here we can assume this is a box pattern.
                         1
                     } else {
-                        let variant = self.variant_id_for_adt(ctor, adt);
+                        let variant = Self::variant_id_for_adt(ctor, adt).unwrap();
                         self.list_variant_nonhidden_fields(ty, variant).count()
                     }
                 }
@@ -370,7 +367,7 @@ impl<'p> TypeCx for MatchCheckCtx<'p> {
                         let subst_ty = substs.at(Interner, 0).assert_ty_ref(Interner).clone();
                         alloc(self, once(subst_ty))
                     } else {
-                        let variant = self.variant_id_for_adt(ctor, adt);
+                        let variant = Self::variant_id_for_adt(ctor, adt).unwrap();
                         let tys = self.list_variant_nonhidden_fields(ty, variant).map(|(_, ty)| ty);
                         alloc(self, tys)
                     }