Use proper InferCtxt when probing for associated types in astconv
This commit is contained in:
Michael Goulet
parent
c8e6a9e8b6
commit
da3ecb09d8
5 changed files with 97 additions and 46 deletions
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@ -27,7 +27,7 @@ use rustc_hir::def::{CtorOf, DefKind, Namespace, Res};
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use rustc_hir::def_id::{DefId, LocalDefId};
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use rustc_hir::intravisit::{walk_generics, Visitor as _};
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use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin};
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use rustc_infer::infer::TyCtxtInferExt;
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use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
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use rustc_middle::middle::stability::AllowUnstable;
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use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
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use rustc_middle::ty::GenericParamDefKind;
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@ -37,7 +37,7 @@ use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, BARE_TRAIT_OBJECT
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use rustc_span::edition::Edition;
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use rustc_span::lev_distance::find_best_match_for_name;
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use rustc_span::symbol::{kw, Ident, Symbol};
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use rustc_span::{sym, Span};
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use rustc_span::{sym, Span, DUMMY_SP};
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use rustc_target::spec::abi;
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use rustc_trait_selection::traits;
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use rustc_trait_selection::traits::astconv_object_safety_violations;
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@ -54,7 +54,7 @@ use std::slice;
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pub struct PathSeg(pub DefId, pub usize);
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pub trait AstConv<'tcx> {
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fn tcx<'a>(&'a self) -> TyCtxt<'tcx>;
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fn tcx(&self) -> TyCtxt<'tcx>;
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fn item_def_id(&self) -> DefId;
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@ -131,6 +131,8 @@ pub trait AstConv<'tcx> {
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{
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self
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}
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fn infcx(&self) -> Option<&InferCtxt<'tcx>>;
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}
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#[derive(Debug)]
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@ -2132,48 +2134,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
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)
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.emit() // Already reported in an earlier stage.
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} else {
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// Find all the `impl`s that `qself_ty` has for any trait that has the
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// associated type, so that we suggest the right one.
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let infcx = tcx.infer_ctxt().build();
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// We create a fresh `ty::ParamEnv` instead of the one for `self.item_def_id()`
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// to avoid a cycle error in `src/test/ui/resolve/issue-102946.rs`.
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let param_env = ty::ParamEnv::empty();
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let traits: Vec<_> = self
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.tcx()
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.all_traits()
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.filter(|trait_def_id| {
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// Consider only traits with the associated type
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tcx.associated_items(*trait_def_id)
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.in_definition_order()
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.any(|i| {
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i.kind.namespace() == Namespace::TypeNS
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&& i.ident(tcx).normalize_to_macros_2_0() == assoc_ident
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&& matches!(i.kind, ty::AssocKind::Type)
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})
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// Consider only accessible traits
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&& tcx.visibility(*trait_def_id)
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.is_accessible_from(self.item_def_id(), tcx)
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&& tcx.all_impls(*trait_def_id)
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.any(|impl_def_id| {
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let trait_ref = tcx.impl_trait_ref(impl_def_id);
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trait_ref.map_or(false, |trait_ref| {
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let impl_ = trait_ref.subst(
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tcx,
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infcx.fresh_substs_for_item(span, impl_def_id),
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);
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infcx
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.can_eq(
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param_env,
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tcx.erase_regions(impl_.self_ty()),
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tcx.erase_regions(qself_ty),
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)
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.is_ok()
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})
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&& tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative
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})
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})
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.map(|trait_def_id| tcx.def_path_str(trait_def_id))
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.collect();
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let traits: Vec<_> =
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self.probe_traits_that_match_assoc_ty(qself_ty, assoc_ident);
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// Don't print `TyErr` to the user.
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self.report_ambiguous_associated_type(
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@ -2232,6 +2194,60 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
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Ok((ty, DefKind::AssocTy, assoc_ty_did))
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}
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fn probe_traits_that_match_assoc_ty(
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&self,
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qself_ty: Ty<'tcx>,
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assoc_ident: Ident,
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) -> Vec<String> {
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let tcx = self.tcx();
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// In contexts that have no inference context, just make a new one.
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// We do need a local variable to store it, though.
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let infcx_;
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let infcx = if let Some(infcx) = self.infcx() {
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infcx
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} else {
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assert!(!qself_ty.needs_infer());
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infcx_ = tcx.infer_ctxt().build();
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&infcx_
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};
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tcx.all_traits()
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.filter(|trait_def_id| {
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// Consider only traits with the associated type
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tcx.associated_items(*trait_def_id)
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.in_definition_order()
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.any(|i| {
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i.kind.namespace() == Namespace::TypeNS
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&& i.ident(tcx).normalize_to_macros_2_0() == assoc_ident
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&& matches!(i.kind, ty::AssocKind::Type)
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})
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// Consider only accessible traits
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&& tcx.visibility(*trait_def_id)
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.is_accessible_from(self.item_def_id(), tcx)
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&& tcx.all_impls(*trait_def_id)
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.any(|impl_def_id| {
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let trait_ref = tcx.impl_trait_ref(impl_def_id);
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trait_ref.map_or(false, |trait_ref| {
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let impl_ = trait_ref.subst(
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tcx,
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infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id),
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);
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infcx
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.can_eq(
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ty::ParamEnv::empty(),
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tcx.erase_regions(impl_.self_ty()),
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tcx.erase_regions(qself_ty),
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)
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.is_ok()
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})
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&& tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative
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})
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})
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.map(|trait_def_id| tcx.def_path_str(trait_def_id))
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.collect()
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}
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fn lookup_assoc_ty(
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&self,
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ident: Ident,
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