Uplift and start using check_args_compatible more liberally

4 files changed, 7 insertions, 48 deletions

diff --git a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
index 66688893235..d8aeadd07b3 100644
--- a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
@@ -1,4 +1,4 @@
-use crate::traits::{check_args_compatible, specialization_graph};
+use crate::traits::specialization_graph;
 
 use super::assembly::structural_traits::AsyncCallableRelevantTypes;
 use super::assembly::{self, structural_traits, Candidate};
@@ -247,7 +247,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
                 assoc_def.defining_node,
             );
 
-            if !check_args_compatible(tcx, assoc_def.item, args) {
+            if !tcx.check_args_compatible(assoc_def.item.def_id, args) {
                 return error_response(
                     ecx,
                     "associated item has mismatched generic item arguments",
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 3ab4872fffe..2c8116b779b 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -61,12 +61,12 @@ pub use self::specialize::{
 pub use self::structural_match::search_for_structural_match_violation;
 pub use self::structural_normalize::StructurallyNormalizeExt;
 pub use self::util::elaborate;
-pub use self::util::{
-    check_args_compatible, supertrait_def_ids, supertraits, transitive_bounds,
-    transitive_bounds_that_define_assoc_item, SupertraitDefIds,
-};
 pub use self::util::{expand_trait_aliases, TraitAliasExpander, TraitAliasExpansionInfo};
 pub use self::util::{get_vtable_index_of_object_method, impl_item_is_final, upcast_choices};
+pub use self::util::{
+    supertrait_def_ids, supertraits, transitive_bounds, transitive_bounds_that_define_assoc_item,
+    SupertraitDefIds,
+};
 pub use self::util::{with_replaced_escaping_bound_vars, BoundVarReplacer, PlaceholderReplacer};
 
 pub use rustc_infer::traits::*;
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index c33e24b1094..9d744d9a032 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -2,7 +2,6 @@
 
 use std::ops::ControlFlow;
 
-use super::check_args_compatible;
 use super::specialization_graph;
 use super::translate_args;
 use super::util;
@@ -2030,7 +2029,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
     } else {
         ty.map_bound(|ty| ty.into())
     };
-    if !check_args_compatible(tcx, assoc_ty.item, args) {
+    if !tcx.check_args_compatible(assoc_ty.item.def_id, args) {
         let err = Ty::new_error_with_message(
             tcx,
             obligation.cause.span,
diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs
index 50cc0ed90fb..d29fc7921bc 100644
--- a/compiler/rustc_trait_selection/src/traits/util.rs
+++ b/compiler/rustc_trait_selection/src/traits/util.rs
@@ -344,46 +344,6 @@ pub enum TupleArgumentsFlag {
     No,
 }
 
-// Verify that the trait item and its implementation have compatible args lists
-pub fn check_args_compatible<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    assoc_item: ty::AssocItem,
-    args: ty::GenericArgsRef<'tcx>,
-) -> bool {
-    fn check_args_compatible_inner<'tcx>(
-        tcx: TyCtxt<'tcx>,
-        generics: &'tcx ty::Generics,
-        args: &'tcx [ty::GenericArg<'tcx>],
-    ) -> bool {
-        if generics.count() != args.len() {
-            return false;
-        }
-
-        let (parent_args, own_args) = args.split_at(generics.parent_count);
-
-        if let Some(parent) = generics.parent
-            && let parent_generics = tcx.generics_of(parent)
-            && !check_args_compatible_inner(tcx, parent_generics, parent_args)
-        {
-            return false;
-        }
-
-        for (param, arg) in std::iter::zip(&generics.params, own_args) {
-            match (&param.kind, arg.unpack()) {
-                (ty::GenericParamDefKind::Type { .. }, ty::GenericArgKind::Type(_))
-                | (ty::GenericParamDefKind::Lifetime, ty::GenericArgKind::Lifetime(_))
-                | (ty::GenericParamDefKind::Const { .. }, ty::GenericArgKind::Const(_)) => {}
-                _ => return false,
-            }
-        }
-
-        true
-    }
-
-    let generics = tcx.generics_of(assoc_item.def_id);
-    check_args_compatible_inner(tcx, generics, args)
-}
-
 /// Executes `f` on `value` after replacing all escaping bound variables with placeholders
 /// and then replaces these placeholders with the original bound variables in the result.
 ///