fix broken CI and code review

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -3304,7 +3304,7 @@ fn print_disambiguation_help<'tcx>(
     span: Span,
     item: ty::AssocItem,
 ) -> Option<String> {
-    let trait_impl_type = trait_ref.self_ty();
+    let trait_impl_type = trait_ref.self_ty().peel_refs();
     let trait_ref = if item.fn_has_self_parameter {
         trait_ref.print_only_trait_name().to_string()
     } else {
@@ -3332,9 +3332,53 @@ fn print_disambiguation_help<'tcx>(
                 .get(0)
                 .and_then(|ty| ty.ref_mutability())
                 .map_or("", |mutbl| mutbl.ref_prefix_str());
-            // If the type of first arg of this assoc function is `Self` or current trait impl type, we need to take the receiver as args. Otherwise, we don't.
-            let args = if let Some(t) = first_arg_type
-                && (t.to_string() == "Self" || t == trait_impl_type)
+
+            // this is for `arbitrary_self_types`(egde case), see `tests/ui/methods/method-deref-to-same-trait-object-with-separate-params.rs`
+            // for the following example:
+            //
+            // impl<T: ?Sized> NuisanceFoo for T {
+            //     fn foo(self) {}
+            // }
+            //
+            // type of `self` is T(unspecified), which is not `Self` or current trait impl type, but the receiver still shouble be take as the first arg.
+            let arbitrary_self_types_check =
+                |hir_map: rustc_middle::hir::map::Map<'_>,
+                 local_def_id: Option<rustc_span::def_id::LocalDefId>|
+                 -> bool {
+                    match local_def_id {
+                        Some(local_def_id) => match hir_map.find_by_def_id(local_def_id) {
+                            Some(node) => match node {
+                                Node::ImplItem(it) => match it.kind {
+                                    hir::ImplItemKind::Fn(_, body_id) => {
+                                        let body = hir_map.body(body_id);
+                                        match body.params.get(0) {
+                                            Some(first_param) => {
+                                                if let rustc_hir::PatKind::Binding(_, _, ident, _) =
+                                                    &first_param.pat.kind
+                                                {
+                                                    ident.name.as_str() == "self"
+                                                } else {
+                                                    false
+                                                }
+                                            }
+                                            None => false,
+                                        }
+                                    }
+                                    _ => false,
+                                },
+                                _ => false,
+                            },
+                            None => false,
+                        },
+                        None => false,
+                    }
+                };
+
+            // If the type of first arg of this assoc function is `Self` or current trait impl type or `arbitrary_self_types`, we need to take the receiver as args. Otherwise, we don't.
+            let args = if let Some(first_arg_type) = first_arg_type
+                && (first_arg_type == tcx.types.self_param
+                    || first_arg_type == trait_impl_type
+                    || arbitrary_self_types_check(tcx.hir(), item.def_id.as_local()))
             {
                 std::iter::once(receiver).chain(args.iter()).collect::<Vec<_>>()
             } else {

tests/ui/methods/method-ambiguity-no-rcvr.stderr

@@ -20,12 +20,12 @@ LL |     fn foo() {}
    |     ^^^^^^^^
 help: disambiguate the associated function for candidate #1
    |
-LL |     <Qux as Foo>::foo(Qux);
-   |     ~~~~~~~~~~~~~~~~~~~~~~
+LL |     <Qux as Foo>::foo();
+   |     ~~~~~~~~~~~~~~~~~~~
 help: disambiguate the associated function for candidate #2
    |
-LL |     <Qux as FooBar>::foo(Qux);
-   |     ~~~~~~~~~~~~~~~~~~~~~~~~~
+LL |     <Qux as FooBar>::foo();
+   |     ~~~~~~~~~~~~~~~~~~~~~~
 
 error: aborting due to 1 previous error