From c13af7db21c8e7978f5d6bd462a397f5f7a29c8d Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Sun, 10 Mar 2024 18:50:55 +0000
Subject: [PATCH] Some early clean-ups in method probe
---
compiler/rustc_hir_typeck/src/method/probe.rs | 59 +++----------------
1 file changed, 8 insertions(+), 51 deletions(-)
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index 2876e0b49db..7e480d66695 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -21,7 +21,7 @@ use rustc_middle::ty::fast_reject::{simplify_type, TreatParams};
use rustc_middle::ty::AssocItem;
use rustc_middle::ty::GenericParamDefKind;
use rustc_middle::ty::ToPredicate;
-use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
+use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeVisitableExt};
use rustc_middle::ty::{GenericArgs, GenericArgsRef};
use rustc_session::lint;
use rustc_span::def_id::DefId;
@@ -745,7 +745,6 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
let (impl_ty, impl_args) = self.impl_ty_and_args(impl_def_id);
- let impl_ty = impl_ty.instantiate(self.tcx, impl_args);
debug!("impl_ty: {:?}", impl_ty);
@@ -818,7 +817,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
return;
}
- let new_trait_ref = this.instantiate_bound_regions_with_erased(new_trait_ref);
+ let new_trait_ref = this.tcx.instantiate_bound_regions_with_erased(new_trait_ref);
let (xform_self_ty, xform_ret_ty) =
this.xform_self_ty(item, new_trait_ref.self_ty(), new_trait_ref.args);
@@ -929,27 +928,12 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
}
}
- fn matches_return_type(
- &self,
- method: ty::AssocItem,
- self_ty: Option<Ty<'tcx>>,
- expected: Ty<'tcx>,
- ) -> bool {
+ fn matches_return_type(&self, method: ty::AssocItem, expected: Ty<'tcx>) -> bool {
match method.kind {
ty::AssocKind::Fn => self.probe(|_| {
let args = self.fresh_args_for_item(self.span, method.def_id);
let fty = self.tcx.fn_sig(method.def_id).instantiate(self.tcx, args);
let fty = self.instantiate_binder_with_fresh_vars(self.span, infer::FnCall, fty);
-
- if let Some(self_ty) = self_ty {
- if self
- .at(&ObligationCause::dummy(), self.param_env)
- .sup(DefineOpaqueTypes::No, fty.inputs()[0], self_ty)
- .is_err()
- {
- return false;
- }
- }
self.can_sub(self.param_env, fty.output(), expected)
}),
_ => false,
@@ -1040,7 +1024,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
.filter(|candidate| candidate_filter(&candidate.item))
.filter(|candidate| {
if let Some(return_ty) = self.return_type {
- self.matches_return_type(candidate.item, None, return_ty)
+ self.matches_return_type(candidate.item, return_ty)
} else {
true
}
@@ -1894,40 +1878,13 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
fn_sig.instantiate(self.tcx, args)
};
- self.instantiate_bound_regions_with_erased(xform_fn_sig)
+ self.tcx.instantiate_bound_regions_with_erased(xform_fn_sig)
}
/// Gets the type of an impl and generate generic parameters with inference vars.
- fn impl_ty_and_args(
- &self,
- impl_def_id: DefId,
- ) -> (ty::EarlyBinder<Ty<'tcx>>, GenericArgsRef<'tcx>) {
- (self.tcx.type_of(impl_def_id), self.fresh_args_for_item(self.span, impl_def_id))
- }
-
- /// Replaces late-bound-regions bound by `value` with `'static` using
- /// `ty::instantiate_bound_regions_with_erased`.
- ///
- /// This is only a reasonable thing to do during the *probe* phase, not the *confirm* phase, of
- /// method matching. It is reasonable during the probe phase because we don't consider region
- /// relationships at all. Therefore, we can just replace all the region variables with 'static
- /// rather than creating fresh region variables. This is nice for two reasons:
- ///
- /// 1. Because the numbers of the region variables would otherwise be fairly unique to this
- /// particular method call, it winds up creating fewer types overall, which helps for memory
- /// usage. (Admittedly, this is a rather small effect, though measurable.)
- ///
- /// 2. It makes it easier to deal with higher-ranked trait bounds, because we can replace any
- /// late-bound regions with 'static. Otherwise, if we were going to replace late-bound
- /// regions with actual region variables as is proper, we'd have to ensure that the same
- /// region got replaced with the same variable, which requires a bit more coordination
- /// and/or tracking the instantiations and
- /// so forth.
- fn instantiate_bound_regions_with_erased<T>(&self, value: ty::Binder<'tcx, T>) -> T
- where
- T: TypeFoldable<TyCtxt<'tcx>>,
- {
- self.tcx.instantiate_bound_regions_with_erased(value)
+ fn impl_ty_and_args(&self, impl_def_id: DefId) -> (Ty<'tcx>, GenericArgsRef<'tcx>) {
+ let args = self.fresh_args_for_item(self.span, impl_def_id);
+ (self.tcx.type_of(impl_def_id).instantiate(self.tcx, args), args)
}
/// Determine if the given associated item type is relevant in the current context.