Rollup merge of rust-lang#145147 - fee1-dead-contrib:push-mxxpmlpmzmsz, r=compiler-errors

rename `TraitRef::from_method` to `from_assoc`

also add a note to `GenericArgs::truncate_to`

Author: Zalathar

compiler/rustc_const_eval/src/check_consts/ops.rs

@@ -142,7 +142,7 @@ impl<'tcx> NonConstOp<'tcx> for FnCallNonConst<'tcx> {
             |err, self_ty, trait_id| {
                 // FIXME(const_trait_impl): Do we need any of this on the non-const codepath?
 
-                let trait_ref = TraitRef::from_method(tcx, trait_id, self.args);
+                let trait_ref = TraitRef::from_assoc(tcx, trait_id, self.args);
 
                 match self_ty.kind() {
                     Param(param_ty) => {

compiler/rustc_const_eval/src/interpret/call.rs

@@ -732,7 +732,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         let tcx = *self.tcx;
 
         let trait_def_id = tcx.trait_of_assoc(def_id).unwrap();
-        let virtual_trait_ref = ty::TraitRef::from_method(tcx, trait_def_id, virtual_instance.args);
+        let virtual_trait_ref = ty::TraitRef::from_assoc(tcx, trait_def_id, virtual_instance.args);
         let existential_trait_ref = ty::ExistentialTraitRef::erase_self_ty(tcx, virtual_trait_ref);
         let concrete_trait_ref = existential_trait_ref.with_self_ty(tcx, dyn_ty);
 

compiler/rustc_middle/src/ty/context.rs

@@ -290,11 +290,8 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
         debug_assert_matches!(self.def_kind(def_id), DefKind::AssocTy | DefKind::AssocConst);
         let trait_def_id = self.parent(def_id);
         debug_assert_matches!(self.def_kind(trait_def_id), DefKind::Trait);
-        let trait_generics = self.generics_of(trait_def_id);
-        (
-            ty::TraitRef::new_from_args(self, trait_def_id, args.truncate_to(self, trait_generics)),
-            &args[trait_generics.count()..],
-        )
+        let trait_ref = ty::TraitRef::from_assoc(self, trait_def_id, args);
+        (trait_ref, &args[trait_ref.args.len()..])
     }
 
     fn mk_args(self, args: &[Self::GenericArg]) -> ty::GenericArgsRef<'tcx> {

compiler/rustc_middle/src/ty/generic_args.rs

@@ -585,6 +585,9 @@ impl<'tcx> GenericArgs<'tcx> {
         tcx.mk_args_from_iter(target_args.iter().chain(self.iter().skip(defs.count())))
     }
 
+    /// Truncates this list of generic args to have at most the number of args in `generics`.
+    ///
+    /// You might be looking for [`TraitRef::from_assoc`](super::TraitRef::from_assoc).
     pub fn truncate_to(&self, tcx: TyCtxt<'tcx>, generics: &ty::Generics) -> GenericArgsRef<'tcx> {
         tcx.mk_args(&self[..generics.count()])
     }

compiler/rustc_sanitizers/src/cfi/typeid/itanium_cxx_abi/transform.rs

@@ -342,7 +342,7 @@ pub(crate) fn transform_instance<'tcx>(
         let upcast_ty = match tcx.trait_of_assoc(def_id) {
             Some(trait_id) => trait_object_ty(
                 tcx,
-                ty::Binder::dummy(ty::TraitRef::from_method(tcx, trait_id, instance.args)),
+                ty::Binder::dummy(ty::TraitRef::from_assoc(tcx, trait_id, instance.args)),
             ),
             // drop_in_place won't have a defining trait, skip the upcast
             None => instance.args.type_at(0),
@@ -481,7 +481,7 @@ fn implemented_method<'tcx>(
         trait_method = trait_method_bound;
         method_id = instance.def_id();
         trait_id = tcx.trait_of_assoc(method_id)?;
-        trait_ref = ty::EarlyBinder::bind(TraitRef::from_method(tcx, trait_id, instance.args));
+        trait_ref = ty::EarlyBinder::bind(TraitRef::from_assoc(tcx, trait_id, instance.args));
         trait_id
     } else {
         return None;

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -763,7 +763,7 @@ fn instantiate_and_check_impossible_predicates<'tcx>(
     // Specifically check trait fulfillment to avoid an error when trying to resolve
     // associated items.
     if let Some(trait_def_id) = tcx.trait_of_assoc(key.0) {
-        let trait_ref = ty::TraitRef::from_method(tcx, trait_def_id, key.1);
+        let trait_ref = ty::TraitRef::from_assoc(tcx, trait_def_id, key.1);
         predicates.push(trait_ref.upcast(tcx));
     }
 

compiler/rustc_ty_utils/src/instance.rs

@@ -109,7 +109,7 @@ fn resolve_associated_item<'tcx>(
 ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> {
     debug!(?trait_item_id, ?typing_env, ?trait_id, ?rcvr_args, "resolve_associated_item");
 
-    let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_args);
+    let trait_ref = ty::TraitRef::from_assoc(tcx, trait_id, rcvr_args);
 
     let input = typing_env.as_query_input(trait_ref);
     let vtbl = match tcx.codegen_select_candidate(input) {
@@ -238,7 +238,7 @@ fn resolve_associated_item<'tcx>(
             Some(ty::Instance::new_raw(leaf_def.item.def_id, args))
         }
         traits::ImplSource::Builtin(BuiltinImplSource::Object(_), _) => {
-            let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_args);
+            let trait_ref = ty::TraitRef::from_assoc(tcx, trait_id, rcvr_args);
             if trait_ref.has_non_region_infer() || trait_ref.has_non_region_param() {
                 // We only resolve totally substituted vtable entries.
                 None

compiler/rustc_type_ir/src/predicate.rs

@@ -82,7 +82,7 @@ impl<I: Interner> TraitRef<I> {
         Self::new_from_args(interner, trait_def_id, args)
     }
 
-    pub fn from_method(interner: I, trait_id: I::DefId, args: I::GenericArgs) -> TraitRef<I> {
+    pub fn from_assoc(interner: I, trait_id: I::DefId, args: I::GenericArgs) -> TraitRef<I> {
         let generics = interner.generics_of(trait_id);
         TraitRef::new(interner, trait_id, args.iter().take(generics.count()))
     }