Fix return type of self_type_parameter

Author: flodiebold

crates/hir_ty/src/chalk_ext.rs

@@ -199,12 +199,12 @@ impl TyExt for Ty {
                             .map(|pred| pred.clone().substitute(&Interner, &substs))
                             .filter(|wc| match &wc.skip_binders() {
                                 WhereClause::Implemented(tr) => {
-                                    tr.self_type_parameter(&Interner) == self
+                                    &tr.self_type_parameter(&Interner) == self
                                 }
                                 WhereClause::AliasEq(AliasEq {
                                     alias: AliasTy::Projection(proj),
                                     ty: _,
-                                }) => proj.self_type_parameter(&Interner) == self,
+                                }) => &proj.self_type_parameter(&Interner) == self,
                                 _ => false,
                             })
                             .collect::<Vec<_>>();

crates/hir_ty/src/display.rs

@@ -616,12 +616,12 @@ impl HirDisplay for Ty {
                                 .map(|pred| pred.clone().substitute(&Interner, &substs))
                                 .filter(|wc| match &wc.skip_binders() {
                                     WhereClause::Implemented(tr) => {
-                                        tr.self_type_parameter(&Interner) == self
+                                        &tr.self_type_parameter(&Interner) == self
                                     }
                                     WhereClause::AliasEq(AliasEq {
                                         alias: AliasTy::Projection(proj),
                                         ty: _,
-                                    }) => proj.self_type_parameter(&Interner) == self,
+                                    }) => &proj.self_type_parameter(&Interner) == self,
                                     _ => false,
                                 })
                                 .collect::<Vec<_>>();

crates/hir_ty/src/traits/chalk/mapping.rs

@@ -509,7 +509,7 @@ pub(super) fn generic_predicate_to_inline_bound(
     let (pred, binders) = pred.as_ref().into_value_and_skipped_binders();
     match pred {
         WhereClause::Implemented(trait_ref) => {
-            if trait_ref.self_type_parameter(&Interner) != &self_ty_shifted_in {
+            if trait_ref.self_type_parameter(&Interner) != self_ty_shifted_in {
                 // we can only convert predicates back to type bounds if they
                 // have the expected self type
                 return None;
@@ -522,7 +522,7 @@ pub(super) fn generic_predicate_to_inline_bound(
             Some(chalk_ir::Binders::new(binders, rust_ir::InlineBound::TraitBound(trait_bound)))
         }
         WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
-            if projection_ty.self_type_parameter(&Interner) != &self_ty_shifted_in {
+            if projection_ty.self_type_parameter(&Interner) != self_ty_shifted_in {
                 return None;
             }
             let trait_ = projection_ty.trait_(db);

crates/hir_ty/src/types.rs

@@ -30,8 +30,8 @@ pub struct ProjectionTy {
 }
 
 impl ProjectionTy {
-    pub fn self_type_parameter(&self, interner: &Interner) -> &Ty {
-        &self.substitution.interned()[0].assert_ty_ref(interner)
+    pub fn self_type_parameter(&self, interner: &Interner) -> Ty {
+        self.substitution.interned()[0].assert_ty_ref(interner).clone()
     }
 }
 
@@ -413,8 +413,8 @@ pub struct TraitRef {
 }
 
 impl TraitRef {
-    pub fn self_type_parameter(&self, interner: &Interner) -> &Ty {
-        &self.substitution.at(interner, 0).assert_ty_ref(interner)
+    pub fn self_type_parameter(&self, interner: &Interner) -> Ty {
+        self.substitution.at(interner, 0).assert_ty_ref(interner).clone()
     }
 }