bjoernager/rust
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Remove rustc_middle::ty::util::ExplicitSelf.

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It's an old (2017 or earlier) type that describes a `self` receiver.
It's only used in `rustc_hir_analysis` for two error messages, and much
of the complexity isn't used. I suspect it used to be used for more
things.

This commit removes it, and moves a greatly simplified version of the
`determine` method into `rustc_hir_analysis`, renamed as
`get_self_string`. The big comment on the method is removed because it
no longer seems relevant.
This commit is contained in:
Nicholas Nethercote 2025-03-28 13:44:55 +11:00
parent 217693a1f0
commit 78768361a0
2 changed files with 22 additions and 62 deletions
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35
compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
View file

@ -12,7 +12,6 @@ use rustc_hir::{self as hir, AmbigArg, GenericParamKind, ImplItemKind, intravisi
use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt};
use rustc_infer::traits::util;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
use rustc_middle::ty::util::ExplicitSelf;
use rustc_middle::ty::{
self, BottomUpFolder, GenericArgs, GenericParamDefKind, Ty, TyCtxt, TypeFoldable, TypeFolder,
TypeSuperFoldable, TypeVisitableExt, TypingMode, Upcast,
@ -995,6 +994,26 @@ impl<'tcx> ty::FallibleTypeFolder<TyCtxt<'tcx>> for RemapHiddenTyRegions<'tcx> {
}
}
/// Gets the string for an explicit self declaration, e.g. "self", "&self",
/// etc.
fn get_self_string<'tcx, P>(self_arg_ty: Ty<'tcx>, is_self_ty: P) -> String
where
P: Fn(Ty<'tcx>) -> bool,
{
if is_self_ty(self_arg_ty) {
"self".to_owned()
} else if let ty::Ref(_, ty, mutbl) = self_arg_ty.kind()
&& is_self_ty(*ty)
{
match mutbl {
hir::Mutability::Not => "&self".to_owned(),
hir::Mutability::Mut => "&mut self".to_owned(),
}
} else {
format!("self: {self_arg_ty}")
}
}
fn report_trait_method_mismatch<'tcx>(
infcx: &InferCtxt<'tcx>,
mut cause: ObligationCause<'tcx>,
@ -1020,12 +1039,7 @@ fn report_trait_method_mismatch<'tcx>(
if trait_m.fn_has_self_parameter =>
{
let ty = trait_sig.inputs()[0];
let sugg = match ExplicitSelf::determine(ty, |ty| ty == impl_trait_ref.self_ty()) {
ExplicitSelf::ByValue => "self".to_owned(),
ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(),
ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(),
_ => format!("self: {ty}"),
};
let sugg = get_self_string(ty, |ty| ty == impl_trait_ref.self_ty());
// When the `impl` receiver is an arbitrary self type, like `self: Box<Self>`, the
// span points only at the type `Box<Self`>, but we want to cover the whole
@ -1238,12 +1252,7 @@ fn compare_self_type<'tcx>(
.build_with_typing_env(ty::TypingEnv::non_body_analysis(tcx, method.def_id));
let self_arg_ty = tcx.liberate_late_bound_regions(method.def_id, self_arg_ty);
let can_eq_self = |ty| infcx.can_eq(param_env, untransformed_self_ty, ty);
match ExplicitSelf::determine(self_arg_ty, can_eq_self) {
ExplicitSelf::ByValue => "self".to_owned(),
ExplicitSelf::ByReference(_, hir::Mutability::Not) => "&self".to_owned(),
ExplicitSelf::ByReference(_, hir::Mutability::Mut) => "&mut self".to_owned(),
_ => format!("self: {self_arg_ty}"),
}
get_self_string(self_arg_ty, can_eq_self)
};
match (trait_m.fn_has_self_parameter, impl_m.fn_has_self_parameter) {