Uplift and start using check_args_compatible more liberally

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.
 ///