fix broken CI and code review

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -33,7 +33,7 @@ use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
 use rustc_middle::ty::print::{with_crate_prefix, with_forced_trimmed_paths};
 use rustc_middle::ty::IsSuggestable;
 use rustc_middle::ty::{self, GenericArgKind, Ty, TyCtxt, TypeVisitableExt};
-use rustc_span::def_id::DefIdSet;
+use rustc_span::def_id::{self, DefIdSet};
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Symbol;
 use rustc_span::{edit_distance, ExpnKind, FileName, MacroKind, Span};
@@ -3312,7 +3312,7 @@ 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 {
@@ -3340,9 +3340,43 @@ 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 = |local_def_id: Option<def_id::LocalDefId>| -> bool {
+                local_def_id.and_then(|id| tcx.opt_hir_node_by_def_id(id)).map_or(false, |node| {
+                    match node {
+                        Node::ImplItem(it) => match it.kind {
+                            hir::ImplItemKind::Fn(_, body_id) => {
+                                let body = tcx.hir().body(body_id);
+                                body.params.get(0).map_or(false, |first_param| {
+                                    match &first_param.pat.kind {
+                                        // check the name of first arg
+                                        rustc_hir::PatKind::Binding(_, _, ident, _) => {
+                                            ident.name.as_str() == "self"
+                                        }
+                                        _ => false,
+                                    }
+                                })
+                            }
+                            _ => false,
+                        },
+                        _ => 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(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