diff options
Diffstat (limited to 'compiler/rustc_hir_analysis/src')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/astconv/mod.rs | 106 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/collect.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/variance/constraints.rs | 8 |
3 files changed, 69 insertions, 51 deletions
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs index 27284f8b983..caf26a75d3c 100644 --- a/compiler/rustc_hir_analysis/src/astconv/mod.rs +++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs @@ -27,7 +27,7 @@ use rustc_hir::def::{CtorOf, DefKind, Namespace, Res}; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::intravisit::{walk_generics, Visitor as _}; use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin}; -use rustc_infer::infer::TyCtxtInferExt; +use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; use rustc_middle::middle::stability::AllowUnstable; use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef}; use rustc_middle::ty::GenericParamDefKind; @@ -37,7 +37,7 @@ use rustc_session::lint::builtin::{AMBIGUOUS_ASSOCIATED_ITEMS, BARE_TRAIT_OBJECT use rustc_span::edition::Edition; use rustc_span::lev_distance::find_best_match_for_name; use rustc_span::symbol::{kw, Ident, Symbol}; -use rustc_span::{sym, Span}; +use rustc_span::{sym, Span, DUMMY_SP}; use rustc_target::spec::abi; use rustc_trait_selection::traits; use rustc_trait_selection::traits::astconv_object_safety_violations; @@ -54,7 +54,7 @@ use std::slice; pub struct PathSeg(pub DefId, pub usize); pub trait AstConv<'tcx> { - fn tcx<'a>(&'a self) -> TyCtxt<'tcx>; + fn tcx(&self) -> TyCtxt<'tcx>; fn item_def_id(&self) -> DefId; @@ -131,6 +131,8 @@ pub trait AstConv<'tcx> { { self } + + fn infcx(&self) -> Option<&InferCtxt<'tcx>>; } #[derive(Debug)] @@ -2132,48 +2134,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { ) .emit() // Already reported in an earlier stage. } else { - // Find all the `impl`s that `qself_ty` has for any trait that has the - // associated type, so that we suggest the right one. - let infcx = tcx.infer_ctxt().build(); - // We create a fresh `ty::ParamEnv` instead of the one for `self.item_def_id()` - // to avoid a cycle error in `src/test/ui/resolve/issue-102946.rs`. - let param_env = ty::ParamEnv::empty(); - let traits: Vec<_> = self - .tcx() - .all_traits() - .filter(|trait_def_id| { - // Consider only traits with the associated type - tcx.associated_items(*trait_def_id) - .in_definition_order() - .any(|i| { - i.kind.namespace() == Namespace::TypeNS - && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident - && matches!(i.kind, ty::AssocKind::Type) - }) - // Consider only accessible traits - && tcx.visibility(*trait_def_id) - .is_accessible_from(self.item_def_id(), tcx) - && tcx.all_impls(*trait_def_id) - .any(|impl_def_id| { - let trait_ref = tcx.impl_trait_ref(impl_def_id); - trait_ref.map_or(false, |trait_ref| { - let impl_ = trait_ref.subst( - tcx, - infcx.fresh_substs_for_item(span, impl_def_id), - ); - infcx - .can_eq( - param_env, - tcx.erase_regions(impl_.self_ty()), - tcx.erase_regions(qself_ty), - ) - .is_ok() - }) - && tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative - }) - }) - .map(|trait_def_id| tcx.def_path_str(trait_def_id)) - .collect(); + let traits: Vec<_> = + self.probe_traits_that_match_assoc_ty(qself_ty, assoc_ident); // Don't print `TyErr` to the user. self.report_ambiguous_associated_type( @@ -2232,6 +2194,60 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { Ok((ty, DefKind::AssocTy, assoc_ty_did)) } + fn probe_traits_that_match_assoc_ty( + &self, + qself_ty: Ty<'tcx>, + assoc_ident: Ident, + ) -> Vec<String> { + let tcx = self.tcx(); + + // In contexts that have no inference context, just make a new one. + // We do need a local variable to store it, though. + let infcx_; + let infcx = if let Some(infcx) = self.infcx() { + infcx + } else { + assert!(!qself_ty.needs_infer()); + infcx_ = tcx.infer_ctxt().build(); + &infcx_ + }; + + tcx.all_traits() + .filter(|trait_def_id| { + // Consider only traits with the associated type + tcx.associated_items(*trait_def_id) + .in_definition_order() + .any(|i| { + i.kind.namespace() == Namespace::TypeNS + && i.ident(tcx).normalize_to_macros_2_0() == assoc_ident + && matches!(i.kind, ty::AssocKind::Type) + }) + // Consider only accessible traits + && tcx.visibility(*trait_def_id) + .is_accessible_from(self.item_def_id(), tcx) + && tcx.all_impls(*trait_def_id) + .any(|impl_def_id| { + let trait_ref = tcx.impl_trait_ref(impl_def_id); + trait_ref.map_or(false, |trait_ref| { + let impl_ = trait_ref.subst( + tcx, + infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id), + ); + infcx + .can_eq( + ty::ParamEnv::empty(), + tcx.erase_regions(impl_.self_ty()), + tcx.erase_regions(qself_ty), + ) + .is_ok() + }) + && tcx.impl_polarity(impl_def_id) != ty::ImplPolarity::Negative + }) + }) + .map(|trait_def_id| tcx.def_path_str(trait_def_id)) + .collect() + } + fn lookup_assoc_ty( &self, ident: Ident, diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs index b73a05ff398..f5a1e51c07b 100644 --- a/compiler/rustc_hir_analysis/src/collect.rs +++ b/compiler/rustc_hir_analysis/src/collect.rs @@ -25,7 +25,7 @@ use rustc_hir as hir; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::{GenericParamKind, Node}; -use rustc_infer::infer::TyCtxtInferExt; +use rustc_infer::infer::{InferCtxt, TyCtxtInferExt}; use rustc_infer::traits::ObligationCause; use rustc_middle::hir::nested_filter; use rustc_middle::ty::query::Providers; @@ -517,6 +517,10 @@ impl<'tcx> AstConv<'tcx> for ItemCtxt<'tcx> { fn record_ty(&self, _hir_id: hir::HirId, _ty: Ty<'tcx>, _span: Span) { // There's no place to record types from signatures? } + + fn infcx(&self) -> Option<&InferCtxt<'tcx>> { + None + } } /// Synthesize a new lifetime name that doesn't clash with any of the lifetimes already present. diff --git a/compiler/rustc_hir_analysis/src/variance/constraints.rs b/compiler/rustc_hir_analysis/src/variance/constraints.rs index a1872822d36..165782f209a 100644 --- a/compiler/rustc_hir_analysis/src/variance/constraints.rs +++ b/compiler/rustc_hir_analysis/src/variance/constraints.rs @@ -225,8 +225,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> { } ty::Ref(region, ty, mutbl) => { - let contra = self.contravariant(variance); - self.add_constraints_from_region(current, region, contra); + self.add_constraints_from_region(current, region, variance); self.add_constraints_from_mt(current, &ty::TypeAndMut { ty, mutbl }, variance); } @@ -258,9 +257,8 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> { } ty::Dynamic(data, r, _) => { - // The type `Foo<T+'a>` is contravariant w/r/t `'a`: - let contra = self.contravariant(variance); - self.add_constraints_from_region(current, r, contra); + // The type `dyn Trait<T> +'a` is covariant w/r/t `'a`: + self.add_constraints_from_region(current, r, variance); if let Some(poly_trait_ref) = data.principal() { self.add_constraints_from_invariant_substs( |