d26b417112
Merge `impl_polarity` and `impl_trait_ref` queries Hopefully this is perf neutral. I want to finish https://github.com/rust-lang/rust/pull/120835 and stop using the HIR in `coherent_trait`, which should then give us a perf improvement.
2877 lines
116 KiB
Rust
2877 lines
116 KiB
Rust
//! Conversion from AST representation of types to the `ty.rs` representation.
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//! The main routine here is `ast_ty_to_ty()`; each use is parameterized by an
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//! instance of `AstConv`.
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mod bounds;
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mod errors;
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pub mod generics;
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mod lint;
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mod object_safety;
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use crate::astconv::errors::prohibit_assoc_ty_binding;
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use crate::astconv::generics::{check_generic_arg_count, create_args_for_parent_generic_args};
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use crate::bounds::Bounds;
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use crate::collect::HirPlaceholderCollector;
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use crate::errors::AmbiguousLifetimeBound;
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use crate::middle::resolve_bound_vars as rbv;
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use crate::require_c_abi_if_c_variadic;
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use rustc_ast::TraitObjectSyntax;
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_errors::{
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codes::*, struct_span_code_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
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FatalError, MultiSpan,
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};
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use rustc_hir as hir;
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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};
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use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
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use rustc_infer::traits::ObligationCause;
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use rustc_middle::middle::stability::AllowUnstable;
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use rustc_middle::ty::{
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self, Const, GenericArgKind, GenericArgsRef, GenericParamDefKind, ParamEnv, Ty, TyCtxt,
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TypeVisitableExt,
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};
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use rustc_session::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
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use rustc_span::edit_distance::find_best_match_for_name;
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use rustc_span::source_map::{respan, Spanned};
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use rustc_span::symbol::{kw, Ident, Symbol};
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use rustc_span::{sym, BytePos, Span, DUMMY_SP};
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use rustc_target::spec::abi;
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use rustc_trait_selection::traits::wf::object_region_bounds;
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use rustc_trait_selection::traits::{self, ObligationCtxt};
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use std::fmt::Display;
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use std::slice;
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#[derive(Debug)]
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pub struct PathSeg(pub DefId, pub usize);
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#[derive(Copy, Clone, Debug)]
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pub struct OnlySelfBounds(pub bool);
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#[derive(Copy, Clone, Debug)]
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pub enum PredicateFilter {
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/// All predicates may be implied by the trait.
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All,
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/// Only traits that reference `Self: ..` are implied by the trait.
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SelfOnly,
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/// Only traits that reference `Self: ..` and define an associated type
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/// with the given ident are implied by the trait.
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SelfThatDefines(Ident),
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/// Only traits that reference `Self: ..` and their associated type bounds.
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/// For example, given `Self: Tr<A: B>`, this would expand to `Self: Tr`
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/// and `<Self as Tr>::A: B`.
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SelfAndAssociatedTypeBounds,
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}
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pub trait AstConv<'tcx> {
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fn tcx(&self) -> TyCtxt<'tcx>;
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fn item_def_id(&self) -> DefId;
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/// Returns predicates in scope of the form `X: Foo<T>`, where `X`
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/// is a type parameter `X` with the given id `def_id` and T
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/// matches `assoc_name`. This is a subset of the full set of
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/// predicates.
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///
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/// This is used for one specific purpose: resolving "short-hand"
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/// associated type references like `T::Item`. In principle, we
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/// would do that by first getting the full set of predicates in
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/// scope and then filtering down to find those that apply to `T`,
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/// but this can lead to cycle errors. The problem is that we have
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/// to do this resolution *in order to create the predicates in
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/// the first place*. Hence, we have this "special pass".
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fn get_type_parameter_bounds(
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&self,
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span: Span,
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def_id: LocalDefId,
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assoc_name: Ident,
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) -> ty::GenericPredicates<'tcx>;
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/// Returns the lifetime to use when a lifetime is omitted (and not elided).
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fn re_infer(&self, param: Option<&ty::GenericParamDef>, span: Span)
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-> Option<ty::Region<'tcx>>;
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/// Returns the type to use when a type is omitted.
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fn ty_infer(&self, param: Option<&ty::GenericParamDef>, span: Span) -> Ty<'tcx>;
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/// Returns `true` if `_` is allowed in type signatures in the current context.
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fn allow_ty_infer(&self) -> bool;
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/// Returns the const to use when a const is omitted.
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fn ct_infer(
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&self,
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ty: Ty<'tcx>,
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param: Option<&ty::GenericParamDef>,
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span: Span,
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) -> Const<'tcx>;
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/// Projecting an associated type from a (potentially)
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/// higher-ranked trait reference is more complicated, because of
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/// the possibility of late-bound regions appearing in the
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/// associated type binding. This is not legal in function
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/// signatures for that reason. In a function body, we can always
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/// handle it because we can use inference variables to remove the
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/// late-bound regions.
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fn projected_ty_from_poly_trait_ref(
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&self,
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span: Span,
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item_def_id: DefId,
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item_segment: &hir::PathSegment<'tcx>,
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poly_trait_ref: ty::PolyTraitRef<'tcx>,
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) -> Ty<'tcx>;
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/// Returns `AdtDef` if `ty` is an ADT.
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/// Note that `ty` might be a projection type that needs normalization.
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/// This used to get the enum variants in scope of the type.
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/// For example, `Self::A` could refer to an associated type
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/// or to an enum variant depending on the result of this function.
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fn probe_adt(&self, span: Span, ty: Ty<'tcx>) -> Option<ty::AdtDef<'tcx>>;
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/// Invoked when we encounter an error from some prior pass
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/// (e.g., resolve) that is translated into a ty-error. This is
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/// used to help suppress derived errors typeck might otherwise
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/// report.
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fn set_tainted_by_errors(&self, e: ErrorGuaranteed);
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fn record_ty(&self, hir_id: hir::HirId, ty: Ty<'tcx>, span: Span);
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fn astconv(&self) -> &dyn AstConv<'tcx>
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where
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Self: Sized,
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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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struct ConvertedBinding<'a, 'tcx> {
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hir_id: hir::HirId,
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item_name: Ident,
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kind: ConvertedBindingKind<'a, 'tcx>,
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gen_args: &'tcx GenericArgs<'tcx>,
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span: Span,
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}
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#[derive(Debug)]
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enum ConvertedBindingKind<'a, 'tcx> {
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Equality(Spanned<ty::Term<'tcx>>),
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Constraint(&'a [hir::GenericBound<'tcx>]),
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}
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/// New-typed boolean indicating whether explicit late-bound lifetimes
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/// are present in a set of generic arguments.
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///
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/// For example if we have some method `fn f<'a>(&'a self)` implemented
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/// for some type `T`, although `f` is generic in the lifetime `'a`, `'a`
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/// is late-bound so should not be provided explicitly. Thus, if `f` is
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/// instantiated with some generic arguments providing `'a` explicitly,
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/// we taint those arguments with `ExplicitLateBound::Yes` so that we
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/// can provide an appropriate diagnostic later.
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#[derive(Copy, Clone, PartialEq, Debug)]
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pub enum ExplicitLateBound {
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Yes,
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No,
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}
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#[derive(Copy, Clone, PartialEq)]
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pub enum IsMethodCall {
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Yes,
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No,
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}
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/// Denotes the "position" of a generic argument, indicating if it is a generic type,
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/// generic function or generic method call.
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#[derive(Copy, Clone, PartialEq)]
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pub(crate) enum GenericArgPosition {
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Type,
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Value, // e.g., functions
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MethodCall,
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}
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/// A marker denoting that the generic arguments that were
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/// provided did not match the respective generic parameters.
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#[derive(Clone, Default, Debug)]
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pub struct GenericArgCountMismatch {
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/// Indicates whether a fatal error was reported (`Some`), or just a lint (`None`).
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pub reported: Option<ErrorGuaranteed>,
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/// A list of spans of arguments provided that were not valid.
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pub invalid_args: Vec<Span>,
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}
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/// Decorates the result of a generic argument count mismatch
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/// check with whether explicit late bounds were provided.
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#[derive(Clone, Debug)]
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pub struct GenericArgCountResult {
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pub explicit_late_bound: ExplicitLateBound,
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pub correct: Result<(), GenericArgCountMismatch>,
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}
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pub trait CreateInstantiationsForGenericArgsCtxt<'a, 'tcx> {
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fn args_for_def_id(&mut self, def_id: DefId) -> (Option<&'a GenericArgs<'tcx>>, bool);
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fn provided_kind(
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&mut self,
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param: &ty::GenericParamDef,
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arg: &GenericArg<'tcx>,
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) -> ty::GenericArg<'tcx>;
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fn inferred_kind(
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&mut self,
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args: Option<&[ty::GenericArg<'tcx>]>,
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param: &ty::GenericParamDef,
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infer_args: bool,
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) -> ty::GenericArg<'tcx>;
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}
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impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
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#[instrument(level = "debug", skip(self), ret)]
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pub fn ast_region_to_region(
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&self,
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lifetime: &hir::Lifetime,
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def: Option<&ty::GenericParamDef>,
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) -> ty::Region<'tcx> {
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let tcx = self.tcx();
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let lifetime_name = |def_id| tcx.hir().name(tcx.local_def_id_to_hir_id(def_id));
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match tcx.named_bound_var(lifetime.hir_id) {
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Some(rbv::ResolvedArg::StaticLifetime) => tcx.lifetimes.re_static,
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Some(rbv::ResolvedArg::LateBound(debruijn, index, def_id)) => {
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let name = lifetime_name(def_id.expect_local());
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let br = ty::BoundRegion {
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var: ty::BoundVar::from_u32(index),
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kind: ty::BrNamed(def_id, name),
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};
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ty::Region::new_bound(tcx, debruijn, br)
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}
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Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
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let name = tcx.hir().ty_param_name(def_id.expect_local());
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let item_def_id = tcx.hir().ty_param_owner(def_id.expect_local());
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let generics = tcx.generics_of(item_def_id);
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let index = generics.param_def_id_to_index[&def_id];
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ty::Region::new_early_param(tcx, ty::EarlyParamRegion { def_id, index, name })
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}
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Some(rbv::ResolvedArg::Free(scope, id)) => {
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let name = lifetime_name(id.expect_local());
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ty::Region::new_late_param(tcx, scope, ty::BrNamed(id, name))
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// (*) -- not late-bound, won't change
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}
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Some(rbv::ResolvedArg::Error(guar)) => ty::Region::new_error(tcx, guar),
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None => {
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self.re_infer(def, lifetime.ident.span).unwrap_or_else(|| {
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debug!(?lifetime, "unelided lifetime in signature");
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// This indicates an illegal lifetime
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// elision. `resolve_lifetime` should have
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// reported an error in this case -- but if
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// not, let's error out.
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ty::Region::new_error_with_message(
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tcx,
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lifetime.ident.span,
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"unelided lifetime in signature",
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)
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})
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}
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}
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}
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/// Given a path `path` that refers to an item `I` with the declared generics `decl_generics`,
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/// returns an appropriate set of generic arguments for this particular reference to `I`.
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pub fn ast_path_args_for_ty(
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&self,
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span: Span,
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def_id: DefId,
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item_segment: &hir::PathSegment<'tcx>,
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) -> GenericArgsRef<'tcx> {
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let (args, _) = self.create_args_for_ast_path(
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span,
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def_id,
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&[],
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item_segment,
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item_segment.args(),
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item_segment.infer_args,
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None,
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ty::BoundConstness::NotConst,
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);
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if let Some(b) = item_segment.args().bindings.first() {
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prohibit_assoc_ty_binding(self.tcx(), b.span, Some((item_segment, span)));
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}
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args
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}
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/// Given the type/lifetime/const arguments provided to some path (along with
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/// an implicit `Self`, if this is a trait reference), returns the complete
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/// set of generic arguments. This may involve applying defaulted type parameters.
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/// Constraints on associated types are created from `create_assoc_bindings_for_generic_args`.
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///
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/// Example:
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///
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/// ```ignore (illustrative)
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/// T: std::ops::Index<usize, Output = u32>
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/// // ^1 ^^^^^^^^^^^^^^2 ^^^^3 ^^^^^^^^^^^4
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/// ```
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///
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/// 1. The `self_ty` here would refer to the type `T`.
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/// 2. The path in question is the path to the trait `std::ops::Index`,
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/// which will have been resolved to a `def_id`
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/// 3. The `generic_args` contains info on the `<...>` contents. The `usize` type
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/// parameters are returned in the `GenericArgsRef`, the associated type bindings like
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/// `Output = u32` are returned from `create_assoc_bindings_for_generic_args`.
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///
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/// Note that the type listing given here is *exactly* what the user provided.
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///
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/// For (generic) associated types
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///
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/// ```ignore (illustrative)
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/// <Vec<u8> as Iterable<u8>>::Iter::<'a>
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/// ```
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///
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/// We have the parent args are the args for the parent trait:
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/// `[Vec<u8>, u8]` and `generic_args` are the arguments for the associated
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/// type itself: `['a]`. The returned `GenericArgsRef` concatenates these two
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/// lists: `[Vec<u8>, u8, 'a]`.
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#[instrument(level = "debug", skip(self, span), ret)]
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fn create_args_for_ast_path<'a>(
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&self,
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span: Span,
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def_id: DefId,
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parent_args: &[ty::GenericArg<'tcx>],
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seg: &hir::PathSegment<'_>,
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generic_args: &'a hir::GenericArgs<'tcx>,
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infer_args: bool,
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self_ty: Option<Ty<'tcx>>,
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constness: ty::BoundConstness,
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) -> (GenericArgsRef<'tcx>, GenericArgCountResult) {
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// If the type is parameterized by this region, then replace this
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// region with the current anon region binding (in other words,
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// whatever & would get replaced with).
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let tcx = self.tcx();
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let generics = tcx.generics_of(def_id);
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debug!("generics: {:?}", generics);
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if generics.has_self {
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if generics.parent.is_some() {
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// The parent is a trait so it should have at least one
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// generic parameter for the `Self` type.
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assert!(!parent_args.is_empty())
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} else {
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// This item (presumably a trait) needs a self-type.
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assert!(self_ty.is_some());
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}
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} else {
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assert!(self_ty.is_none());
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}
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|
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|
let mut arg_count = check_generic_arg_count(
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tcx,
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def_id,
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seg,
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generics,
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generic_args,
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|
GenericArgPosition::Type,
|
|
self_ty.is_some(),
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|
infer_args,
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|
);
|
|
|
|
if let Err(err) = &arg_count.correct
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&& let Some(reported) = err.reported
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{
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self.set_tainted_by_errors(reported);
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}
|
|
|
|
// Skip processing if type has no generic parameters.
|
|
// Traits always have `Self` as a generic parameter, which means they will not return early
|
|
// here and so associated type bindings will be handled regardless of whether there are any
|
|
// non-`Self` generic parameters.
|
|
if generics.params.is_empty() {
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return (tcx.mk_args(parent_args), arg_count);
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|
}
|
|
|
|
struct InstantiationsForAstPathCtxt<'a, 'tcx> {
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|
astconv: &'a (dyn AstConv<'tcx> + 'a),
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|
def_id: DefId,
|
|
generic_args: &'a GenericArgs<'tcx>,
|
|
span: Span,
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|
inferred_params: Vec<Span>,
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|
infer_args: bool,
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|
}
|
|
|
|
impl<'a, 'tcx> CreateInstantiationsForGenericArgsCtxt<'a, 'tcx>
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|
for InstantiationsForAstPathCtxt<'a, 'tcx>
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|
{
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|
fn args_for_def_id(&mut self, did: DefId) -> (Option<&'a GenericArgs<'tcx>>, bool) {
|
|
if did == self.def_id {
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|
(Some(self.generic_args), self.infer_args)
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|
} else {
|
|
// The last component of this tuple is unimportant.
|
|
(None, false)
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|
}
|
|
}
|
|
|
|
fn provided_kind(
|
|
&mut self,
|
|
param: &ty::GenericParamDef,
|
|
arg: &GenericArg<'tcx>,
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|
) -> ty::GenericArg<'tcx> {
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|
let tcx = self.astconv.tcx();
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|
|
|
let mut handle_ty_args = |has_default, ty: &hir::Ty<'tcx>| {
|
|
if has_default {
|
|
tcx.check_optional_stability(
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|
param.def_id,
|
|
Some(arg.hir_id()),
|
|
arg.span(),
|
|
None,
|
|
AllowUnstable::No,
|
|
|_, _| {
|
|
// Default generic parameters may not be marked
|
|
// with stability attributes, i.e. when the
|
|
// default parameter was defined at the same time
|
|
// as the rest of the type. As such, we ignore missing
|
|
// stability attributes.
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|
},
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|
);
|
|
}
|
|
if let (hir::TyKind::Infer, false) = (&ty.kind, self.astconv.allow_ty_infer()) {
|
|
self.inferred_params.push(ty.span);
|
|
Ty::new_misc_error(tcx).into()
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|
} else {
|
|
self.astconv.ast_ty_to_ty(ty).into()
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|
}
|
|
};
|
|
|
|
match (¶m.kind, arg) {
|
|
(GenericParamDefKind::Lifetime, GenericArg::Lifetime(lt)) => {
|
|
self.astconv.ast_region_to_region(lt, Some(param)).into()
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|
}
|
|
(&GenericParamDefKind::Type { has_default, .. }, GenericArg::Type(ty)) => {
|
|
handle_ty_args(has_default, ty)
|
|
}
|
|
(&GenericParamDefKind::Type { has_default, .. }, GenericArg::Infer(inf)) => {
|
|
handle_ty_args(has_default, &inf.to_ty())
|
|
}
|
|
(GenericParamDefKind::Const { .. }, GenericArg::Const(ct)) => {
|
|
let did = ct.value.def_id;
|
|
tcx.feed_anon_const_type(did, tcx.type_of(param.def_id));
|
|
ty::Const::from_anon_const(tcx, did).into()
|
|
}
|
|
(&GenericParamDefKind::Const { .. }, hir::GenericArg::Infer(inf)) => {
|
|
let ty = tcx
|
|
.at(self.span)
|
|
.type_of(param.def_id)
|
|
.no_bound_vars()
|
|
.expect("const parameter types cannot be generic");
|
|
if self.astconv.allow_ty_infer() {
|
|
self.astconv.ct_infer(ty, Some(param), inf.span).into()
|
|
} else {
|
|
self.inferred_params.push(inf.span);
|
|
ty::Const::new_misc_error(tcx, ty).into()
|
|
}
|
|
}
|
|
(kind, arg) => span_bug!(
|
|
self.span,
|
|
"mismatched path argument for kind {kind:?}: found arg {arg:?}"
|
|
),
|
|
}
|
|
}
|
|
|
|
fn inferred_kind(
|
|
&mut self,
|
|
args: Option<&[ty::GenericArg<'tcx>]>,
|
|
param: &ty::GenericParamDef,
|
|
infer_args: bool,
|
|
) -> ty::GenericArg<'tcx> {
|
|
let tcx = self.astconv.tcx();
|
|
match param.kind {
|
|
GenericParamDefKind::Lifetime => self
|
|
.astconv
|
|
.re_infer(Some(param), self.span)
|
|
.unwrap_or_else(|| {
|
|
debug!(?param, "unelided lifetime in signature");
|
|
|
|
// This indicates an illegal lifetime in a non-assoc-trait position
|
|
ty::Region::new_error_with_message(
|
|
tcx,
|
|
self.span,
|
|
"unelided lifetime in signature",
|
|
)
|
|
})
|
|
.into(),
|
|
GenericParamDefKind::Type { has_default, .. } => {
|
|
if !infer_args && has_default {
|
|
// No type parameter provided, but a default exists.
|
|
let args = args.unwrap();
|
|
if args.iter().any(|arg| match arg.unpack() {
|
|
GenericArgKind::Type(ty) => ty.references_error(),
|
|
_ => false,
|
|
}) {
|
|
// Avoid ICE #86756 when type error recovery goes awry.
|
|
return Ty::new_misc_error(tcx).into();
|
|
}
|
|
tcx.at(self.span).type_of(param.def_id).instantiate(tcx, args).into()
|
|
} else if infer_args {
|
|
self.astconv.ty_infer(Some(param), self.span).into()
|
|
} else {
|
|
// We've already errored above about the mismatch.
|
|
Ty::new_misc_error(tcx).into()
|
|
}
|
|
}
|
|
GenericParamDefKind::Const { has_default, .. } => {
|
|
let ty = tcx
|
|
.at(self.span)
|
|
.type_of(param.def_id)
|
|
.no_bound_vars()
|
|
.expect("const parameter types cannot be generic");
|
|
if let Err(guar) = ty.error_reported() {
|
|
return ty::Const::new_error(tcx, guar, ty).into();
|
|
}
|
|
// FIXME(effects) see if we should special case effect params here
|
|
if !infer_args && has_default {
|
|
tcx.const_param_default(param.def_id)
|
|
.instantiate(tcx, args.unwrap())
|
|
.into()
|
|
} else {
|
|
if infer_args {
|
|
self.astconv.ct_infer(ty, Some(param), self.span).into()
|
|
} else {
|
|
// We've already errored above about the mismatch.
|
|
ty::Const::new_misc_error(tcx, ty).into()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
let mut args_ctx = InstantiationsForAstPathCtxt {
|
|
astconv: self,
|
|
def_id,
|
|
span,
|
|
generic_args,
|
|
inferred_params: vec![],
|
|
infer_args,
|
|
};
|
|
if let ty::BoundConstness::Const | ty::BoundConstness::ConstIfConst = constness
|
|
&& generics.has_self
|
|
&& !tcx.has_attr(def_id, sym::const_trait)
|
|
{
|
|
let e = tcx.dcx().emit_err(crate::errors::ConstBoundForNonConstTrait {
|
|
span,
|
|
modifier: constness.as_str(),
|
|
});
|
|
self.set_tainted_by_errors(e);
|
|
arg_count.correct =
|
|
Err(GenericArgCountMismatch { reported: Some(e), invalid_args: vec![] });
|
|
}
|
|
let args = create_args_for_parent_generic_args(
|
|
tcx,
|
|
def_id,
|
|
parent_args,
|
|
self_ty.is_some(),
|
|
self_ty,
|
|
&arg_count,
|
|
&mut args_ctx,
|
|
);
|
|
|
|
(args, arg_count)
|
|
}
|
|
|
|
fn create_assoc_bindings_for_generic_args<'a>(
|
|
&self,
|
|
generic_args: &'a hir::GenericArgs<'tcx>,
|
|
) -> Vec<ConvertedBinding<'a, 'tcx>> {
|
|
// Convert associated-type bindings or constraints into a separate vector.
|
|
// Example: Given this:
|
|
//
|
|
// T: Iterator<Item = u32>
|
|
//
|
|
// The `T` is passed in as a self-type; the `Item = u32` is
|
|
// not a "type parameter" of the `Iterator` trait, but rather
|
|
// a restriction on `<T as Iterator>::Item`, so it is passed
|
|
// back separately.
|
|
let assoc_bindings = generic_args
|
|
.bindings
|
|
.iter()
|
|
.map(|binding| {
|
|
let kind = match &binding.kind {
|
|
hir::TypeBindingKind::Equality { term } => match term {
|
|
hir::Term::Ty(ty) => ConvertedBindingKind::Equality(respan(
|
|
ty.span,
|
|
self.ast_ty_to_ty(ty).into(),
|
|
)),
|
|
hir::Term::Const(c) => {
|
|
let span = self.tcx().def_span(c.def_id);
|
|
let c = Const::from_anon_const(self.tcx(), c.def_id);
|
|
ConvertedBindingKind::Equality(respan(span, c.into()))
|
|
}
|
|
},
|
|
hir::TypeBindingKind::Constraint { bounds } => {
|
|
ConvertedBindingKind::Constraint(bounds)
|
|
}
|
|
};
|
|
ConvertedBinding {
|
|
hir_id: binding.hir_id,
|
|
item_name: binding.ident,
|
|
kind,
|
|
gen_args: binding.gen_args,
|
|
span: binding.span,
|
|
}
|
|
})
|
|
.collect();
|
|
|
|
assoc_bindings
|
|
}
|
|
|
|
pub fn create_args_for_associated_item(
|
|
&self,
|
|
span: Span,
|
|
item_def_id: DefId,
|
|
item_segment: &hir::PathSegment<'tcx>,
|
|
parent_args: GenericArgsRef<'tcx>,
|
|
) -> GenericArgsRef<'tcx> {
|
|
debug!(
|
|
"create_args_for_associated_item(span: {:?}, item_def_id: {:?}, item_segment: {:?}",
|
|
span, item_def_id, item_segment
|
|
);
|
|
let (args, _) = self.create_args_for_ast_path(
|
|
span,
|
|
item_def_id,
|
|
parent_args,
|
|
item_segment,
|
|
item_segment.args(),
|
|
item_segment.infer_args,
|
|
None,
|
|
ty::BoundConstness::NotConst,
|
|
);
|
|
|
|
if let Some(b) = item_segment.args().bindings.first() {
|
|
prohibit_assoc_ty_binding(self.tcx(), b.span, Some((item_segment, span)));
|
|
}
|
|
|
|
args
|
|
}
|
|
|
|
/// Instantiates the path for the given trait reference, assuming that it's
|
|
/// bound to a valid trait type. Returns the `DefId` of the defining trait.
|
|
/// The type _cannot_ be a type other than a trait type.
|
|
///
|
|
/// If the `projections` argument is `None`, then assoc type bindings like `Foo<T = X>`
|
|
/// are disallowed. Otherwise, they are pushed onto the vector given.
|
|
pub fn instantiate_mono_trait_ref(
|
|
&self,
|
|
trait_ref: &hir::TraitRef<'tcx>,
|
|
self_ty: Ty<'tcx>,
|
|
) -> ty::TraitRef<'tcx> {
|
|
self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {});
|
|
|
|
self.ast_path_to_mono_trait_ref(
|
|
trait_ref.path.span,
|
|
trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise()),
|
|
self_ty,
|
|
trait_ref.path.segments.last().unwrap(),
|
|
true,
|
|
ty::BoundConstness::NotConst,
|
|
)
|
|
}
|
|
|
|
/// Given a trait bound like `Debug`, applies that trait bound the given self-type to construct
|
|
/// a full trait reference. The resulting trait reference is returned. This may also generate
|
|
/// auxiliary bounds, which are added to `bounds`.
|
|
///
|
|
/// Example:
|
|
///
|
|
/// ```ignore (illustrative)
|
|
/// poly_trait_ref = Iterator<Item = u32>
|
|
/// self_ty = Foo
|
|
/// ```
|
|
///
|
|
/// this would return `Foo: Iterator` and add `<Foo as Iterator>::Item = u32` into `bounds`.
|
|
///
|
|
/// **A note on binders:** against our usual convention, there is an implied binder around
|
|
/// the `self_ty` and `poly_trait_ref` parameters here. So they may reference bound regions.
|
|
/// If for example you had `for<'a> Foo<'a>: Bar<'a>`, then the `self_ty` would be `Foo<'a>`
|
|
/// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be
|
|
/// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly,
|
|
/// however.
|
|
#[instrument(level = "debug", skip(self, span, constness, bounds, speculative))]
|
|
pub(crate) fn instantiate_poly_trait_ref(
|
|
&self,
|
|
trait_ref: &hir::TraitRef<'tcx>,
|
|
span: Span,
|
|
constness: ty::BoundConstness,
|
|
polarity: ty::ImplPolarity,
|
|
self_ty: Ty<'tcx>,
|
|
bounds: &mut Bounds<'tcx>,
|
|
speculative: bool,
|
|
only_self_bounds: OnlySelfBounds,
|
|
) -> GenericArgCountResult {
|
|
let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise());
|
|
let trait_segment = trait_ref.path.segments.last().unwrap();
|
|
let args = trait_segment.args();
|
|
|
|
self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {});
|
|
self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, false);
|
|
|
|
let (generic_args, arg_count) = self.create_args_for_ast_path(
|
|
trait_ref.path.span,
|
|
trait_def_id,
|
|
&[],
|
|
trait_segment,
|
|
args,
|
|
trait_segment.infer_args,
|
|
Some(self_ty),
|
|
constness,
|
|
);
|
|
|
|
let tcx = self.tcx();
|
|
let bound_vars = tcx.late_bound_vars(trait_ref.hir_ref_id);
|
|
debug!(?bound_vars);
|
|
|
|
let assoc_bindings = self.create_assoc_bindings_for_generic_args(args);
|
|
|
|
let poly_trait_ref = ty::Binder::bind_with_vars(
|
|
ty::TraitRef::new(tcx, trait_def_id, generic_args),
|
|
bound_vars,
|
|
);
|
|
|
|
debug!(?poly_trait_ref, ?assoc_bindings);
|
|
bounds.push_trait_bound(tcx, poly_trait_ref, span, polarity);
|
|
|
|
let mut dup_bindings = FxHashMap::default();
|
|
for binding in &assoc_bindings {
|
|
// Don't register additional associated type bounds for negative bounds,
|
|
// since we should have emitten an error for them earlier, and they will
|
|
// not be well-formed!
|
|
if polarity == ty::ImplPolarity::Negative {
|
|
self.tcx().dcx().span_delayed_bug(
|
|
binding.span,
|
|
"negative trait bounds should not have bindings",
|
|
);
|
|
continue;
|
|
}
|
|
|
|
// Specify type to assert that error was already reported in `Err` case.
|
|
let _: Result<_, ErrorGuaranteed> = self.add_predicates_for_ast_type_binding(
|
|
trait_ref.hir_ref_id,
|
|
poly_trait_ref,
|
|
binding,
|
|
bounds,
|
|
speculative,
|
|
&mut dup_bindings,
|
|
binding.span,
|
|
only_self_bounds,
|
|
);
|
|
// Okay to ignore `Err` because of `ErrorGuaranteed` (see above).
|
|
}
|
|
|
|
arg_count
|
|
}
|
|
|
|
fn ast_path_to_mono_trait_ref(
|
|
&self,
|
|
span: Span,
|
|
trait_def_id: DefId,
|
|
self_ty: Ty<'tcx>,
|
|
trait_segment: &hir::PathSegment<'tcx>,
|
|
is_impl: bool,
|
|
// FIXME(effects) move all host param things in astconv to hir lowering
|
|
constness: ty::BoundConstness,
|
|
) -> ty::TraitRef<'tcx> {
|
|
let (generic_args, _) = self.create_args_for_ast_trait_ref(
|
|
span,
|
|
trait_def_id,
|
|
self_ty,
|
|
trait_segment,
|
|
is_impl,
|
|
constness,
|
|
);
|
|
if let Some(b) = trait_segment.args().bindings.first() {
|
|
prohibit_assoc_ty_binding(self.tcx(), b.span, Some((trait_segment, span)));
|
|
}
|
|
ty::TraitRef::new(self.tcx(), trait_def_id, generic_args)
|
|
}
|
|
|
|
#[instrument(level = "debug", skip(self, span))]
|
|
fn create_args_for_ast_trait_ref<'a>(
|
|
&self,
|
|
span: Span,
|
|
trait_def_id: DefId,
|
|
self_ty: Ty<'tcx>,
|
|
trait_segment: &'a hir::PathSegment<'tcx>,
|
|
is_impl: bool,
|
|
constness: ty::BoundConstness,
|
|
) -> (GenericArgsRef<'tcx>, GenericArgCountResult) {
|
|
self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, is_impl);
|
|
|
|
self.create_args_for_ast_path(
|
|
span,
|
|
trait_def_id,
|
|
&[],
|
|
trait_segment,
|
|
trait_segment.args(),
|
|
trait_segment.infer_args,
|
|
Some(self_ty),
|
|
constness,
|
|
)
|
|
}
|
|
|
|
fn trait_defines_associated_item_named(
|
|
&self,
|
|
trait_def_id: DefId,
|
|
assoc_kind: ty::AssocKind,
|
|
assoc_name: Ident,
|
|
) -> bool {
|
|
self.tcx()
|
|
.associated_items(trait_def_id)
|
|
.find_by_name_and_kind(self.tcx(), assoc_name, assoc_kind, trait_def_id)
|
|
.is_some()
|
|
}
|
|
|
|
fn ast_path_to_ty(
|
|
&self,
|
|
span: Span,
|
|
did: DefId,
|
|
item_segment: &hir::PathSegment<'tcx>,
|
|
) -> Ty<'tcx> {
|
|
let tcx = self.tcx();
|
|
let args = self.ast_path_args_for_ty(span, did, item_segment);
|
|
|
|
if let DefKind::TyAlias = tcx.def_kind(did)
|
|
&& tcx.type_alias_is_lazy(did)
|
|
{
|
|
// Type aliases defined in crates that have the
|
|
// feature `lazy_type_alias` enabled get encoded as a type alias that normalization will
|
|
// then actually instantiate the where bounds of.
|
|
let alias_ty = ty::AliasTy::new(tcx, did, args);
|
|
Ty::new_alias(tcx, ty::Weak, alias_ty)
|
|
} else {
|
|
tcx.at(span).type_of(did).instantiate(tcx, args)
|
|
}
|
|
}
|
|
|
|
fn report_ambiguous_associated_type(
|
|
&self,
|
|
span: Span,
|
|
types: &[String],
|
|
traits: &[String],
|
|
name: Symbol,
|
|
) -> ErrorGuaranteed {
|
|
let mut err =
|
|
struct_span_code_err!(self.tcx().dcx(), span, E0223, "ambiguous associated type");
|
|
if self
|
|
.tcx()
|
|
.resolutions(())
|
|
.confused_type_with_std_module
|
|
.keys()
|
|
.any(|full_span| full_span.contains(span))
|
|
{
|
|
err.span_suggestion_verbose(
|
|
span.shrink_to_lo(),
|
|
"you are looking for the module in `std`, not the primitive type",
|
|
"std::",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
} else {
|
|
let mut types = types.to_vec();
|
|
types.sort();
|
|
let mut traits = traits.to_vec();
|
|
traits.sort();
|
|
match (&types[..], &traits[..]) {
|
|
([], []) => {
|
|
err.span_suggestion_verbose(
|
|
span,
|
|
format!(
|
|
"if there were a type named `Type` that implements a trait named \
|
|
`Trait` with associated type `{name}`, you could use the \
|
|
fully-qualified path",
|
|
),
|
|
format!("<Type as Trait>::{name}"),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
([], [trait_str]) => {
|
|
err.span_suggestion_verbose(
|
|
span,
|
|
format!(
|
|
"if there were a type named `Example` that implemented `{trait_str}`, \
|
|
you could use the fully-qualified path",
|
|
),
|
|
format!("<Example as {trait_str}>::{name}"),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
([], traits) => {
|
|
err.span_suggestions(
|
|
span,
|
|
format!(
|
|
"if there were a type named `Example` that implemented one of the \
|
|
traits with associated type `{name}`, you could use the \
|
|
fully-qualified path",
|
|
),
|
|
traits
|
|
.iter()
|
|
.map(|trait_str| format!("<Example as {trait_str}>::{name}"))
|
|
.collect::<Vec<_>>(),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
([type_str], []) => {
|
|
err.span_suggestion_verbose(
|
|
span,
|
|
format!(
|
|
"if there were a trait named `Example` with associated type `{name}` \
|
|
implemented for `{type_str}`, you could use the fully-qualified path",
|
|
),
|
|
format!("<{type_str} as Example>::{name}"),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
(types, []) => {
|
|
err.span_suggestions(
|
|
span,
|
|
format!(
|
|
"if there were a trait named `Example` with associated type `{name}` \
|
|
implemented for one of the types, you could use the fully-qualified \
|
|
path",
|
|
),
|
|
types
|
|
.into_iter()
|
|
.map(|type_str| format!("<{type_str} as Example>::{name}")),
|
|
Applicability::HasPlaceholders,
|
|
);
|
|
}
|
|
(types, traits) => {
|
|
let mut suggestions = vec![];
|
|
for type_str in types {
|
|
for trait_str in traits {
|
|
suggestions.push(format!("<{type_str} as {trait_str}>::{name}"));
|
|
}
|
|
}
|
|
err.span_suggestions(
|
|
span,
|
|
"use fully-qualified syntax",
|
|
suggestions,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
let reported = err.emit();
|
|
self.set_tainted_by_errors(reported);
|
|
reported
|
|
}
|
|
|
|
// Search for a bound on a type parameter which includes the associated item
|
|
// given by `assoc_name`. `ty_param_def_id` is the `DefId` of the type parameter
|
|
// This function will fail if there are no suitable bounds or there is
|
|
// any ambiguity.
|
|
fn find_bound_for_assoc_item(
|
|
&self,
|
|
ty_param_def_id: LocalDefId,
|
|
assoc_name: Ident,
|
|
span: Span,
|
|
) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed> {
|
|
let tcx = self.tcx();
|
|
|
|
debug!(
|
|
"find_bound_for_assoc_item(ty_param_def_id={:?}, assoc_name={:?}, span={:?})",
|
|
ty_param_def_id, assoc_name, span,
|
|
);
|
|
|
|
let predicates =
|
|
&self.get_type_parameter_bounds(span, ty_param_def_id, assoc_name).predicates;
|
|
|
|
debug!("find_bound_for_assoc_item: predicates={:#?}", predicates);
|
|
|
|
let param_name = tcx.hir().ty_param_name(ty_param_def_id);
|
|
self.one_bound_for_assoc_item(
|
|
|| {
|
|
traits::transitive_bounds_that_define_assoc_item(
|
|
tcx,
|
|
predicates
|
|
.iter()
|
|
.filter_map(|(p, _)| Some(p.as_trait_clause()?.map_bound(|t| t.trait_ref))),
|
|
assoc_name,
|
|
)
|
|
},
|
|
param_name,
|
|
Some(ty_param_def_id),
|
|
ty::AssocKind::Type,
|
|
assoc_name,
|
|
span,
|
|
None,
|
|
)
|
|
}
|
|
|
|
// Checks that `bounds` contains exactly one element and reports appropriate
|
|
// errors otherwise.
|
|
#[instrument(level = "debug", skip(self, all_candidates, ty_param_name, binding), ret)]
|
|
fn one_bound_for_assoc_item<I>(
|
|
&self,
|
|
all_candidates: impl Fn() -> I,
|
|
ty_param_name: impl Display,
|
|
ty_param_def_id: Option<LocalDefId>,
|
|
assoc_kind: ty::AssocKind,
|
|
assoc_name: Ident,
|
|
span: Span,
|
|
binding: Option<&ConvertedBinding<'_, 'tcx>>,
|
|
) -> Result<ty::PolyTraitRef<'tcx>, ErrorGuaranteed>
|
|
where
|
|
I: Iterator<Item = ty::PolyTraitRef<'tcx>>,
|
|
{
|
|
let tcx = self.tcx();
|
|
|
|
let mut matching_candidates = all_candidates().filter(|r| {
|
|
self.trait_defines_associated_item_named(r.def_id(), assoc_kind, assoc_name)
|
|
});
|
|
|
|
let Some(bound) = matching_candidates.next() else {
|
|
let reported = self.complain_about_assoc_item_not_found(
|
|
all_candidates,
|
|
&ty_param_name.to_string(),
|
|
ty_param_def_id,
|
|
assoc_kind,
|
|
assoc_name,
|
|
span,
|
|
binding,
|
|
);
|
|
self.set_tainted_by_errors(reported);
|
|
return Err(reported);
|
|
};
|
|
debug!(?bound);
|
|
|
|
if let Some(bound2) = matching_candidates.next() {
|
|
debug!(?bound2);
|
|
|
|
let assoc_kind_str = assoc_kind_str(assoc_kind);
|
|
let ty_param_name = &ty_param_name.to_string();
|
|
let mut err = tcx.dcx().create_err(crate::errors::AmbiguousAssocItem {
|
|
span,
|
|
assoc_kind: assoc_kind_str,
|
|
assoc_name,
|
|
ty_param_name,
|
|
});
|
|
// Provide a more specific error code index entry for equality bindings.
|
|
err.code(
|
|
if let Some(binding) = binding
|
|
&& let ConvertedBindingKind::Equality(_) = binding.kind
|
|
{
|
|
E0222
|
|
} else {
|
|
E0221
|
|
},
|
|
);
|
|
|
|
// FIXME(#97583): Resugar equality bounds to type/const bindings.
|
|
// FIXME: Turn this into a structured, translateable & more actionable suggestion.
|
|
let mut where_bounds = vec![];
|
|
for bound in [bound, bound2].into_iter().chain(matching_candidates) {
|
|
let bound_id = bound.def_id();
|
|
let bound_span = tcx
|
|
.associated_items(bound_id)
|
|
.find_by_name_and_kind(tcx, assoc_name, assoc_kind, bound_id)
|
|
.and_then(|item| tcx.hir().span_if_local(item.def_id));
|
|
|
|
if let Some(bound_span) = bound_span {
|
|
err.span_label(
|
|
bound_span,
|
|
format!("ambiguous `{assoc_name}` from `{}`", bound.print_trait_sugared(),),
|
|
);
|
|
if let Some(binding) = binding {
|
|
match binding.kind {
|
|
ConvertedBindingKind::Equality(term) => {
|
|
// FIXME(#97583): This isn't syntactically well-formed!
|
|
where_bounds.push(format!(
|
|
" T: {trait}::{assoc_name} = {term}",
|
|
trait = bound.print_only_trait_path(),
|
|
term = term.node,
|
|
));
|
|
}
|
|
// FIXME: Provide a suggestion.
|
|
ConvertedBindingKind::Constraint(_bounds) => {}
|
|
}
|
|
} else {
|
|
err.span_suggestion_verbose(
|
|
span.with_hi(assoc_name.span.lo()),
|
|
"use fully-qualified syntax to disambiguate",
|
|
format!("<{ty_param_name} as {}>::", bound.print_only_trait_path()),
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
} else {
|
|
err.note(format!(
|
|
"associated {assoc_kind_str} `{assoc_name}` could derive from `{}`",
|
|
bound.print_only_trait_path(),
|
|
));
|
|
}
|
|
}
|
|
if !where_bounds.is_empty() {
|
|
err.help(format!(
|
|
"consider introducing a new type parameter `T` and adding `where` constraints:\
|
|
\n where\n T: {ty_param_name},\n{}",
|
|
where_bounds.join(",\n"),
|
|
));
|
|
}
|
|
let reported = err.emit();
|
|
self.set_tainted_by_errors(reported);
|
|
if !where_bounds.is_empty() {
|
|
return Err(reported);
|
|
}
|
|
}
|
|
|
|
Ok(bound)
|
|
}
|
|
|
|
// Create a type from a path to an associated type or to an enum variant.
|
|
// For a path `A::B::C::D`, `qself_ty` and `qself_def` are the type and def for `A::B::C`
|
|
// and item_segment is the path segment for `D`. We return a type and a def for
|
|
// the whole path.
|
|
// Will fail except for `T::A` and `Self::A`; i.e., if `qself_ty`/`qself_def` are not a type
|
|
// parameter or `Self`.
|
|
// NOTE: When this function starts resolving `Trait::AssocTy` successfully
|
|
// it should also start reporting the `BARE_TRAIT_OBJECTS` lint.
|
|
#[instrument(level = "debug", skip(self, hir_ref_id, span, qself, assoc_segment), fields(assoc_ident=?assoc_segment.ident), ret)]
|
|
pub fn associated_path_to_ty(
|
|
&self,
|
|
hir_ref_id: hir::HirId,
|
|
span: Span,
|
|
qself_ty: Ty<'tcx>,
|
|
qself: &hir::Ty<'_>,
|
|
assoc_segment: &hir::PathSegment<'tcx>,
|
|
permit_variants: bool,
|
|
) -> Result<(Ty<'tcx>, DefKind, DefId), ErrorGuaranteed> {
|
|
let tcx = self.tcx();
|
|
let assoc_ident = assoc_segment.ident;
|
|
let qself_res = if let hir::TyKind::Path(hir::QPath::Resolved(_, path)) = &qself.kind {
|
|
path.res
|
|
} else {
|
|
Res::Err
|
|
};
|
|
|
|
// Check if we have an enum variant or an inherent associated type.
|
|
let mut variant_resolution = None;
|
|
if let Some(adt_def) = self.probe_adt(span, qself_ty) {
|
|
if adt_def.is_enum() {
|
|
let variant_def = adt_def
|
|
.variants()
|
|
.iter()
|
|
.find(|vd| tcx.hygienic_eq(assoc_ident, vd.ident(tcx), adt_def.did()));
|
|
if let Some(variant_def) = variant_def {
|
|
if permit_variants {
|
|
tcx.check_stability(variant_def.def_id, Some(hir_ref_id), span, None);
|
|
self.prohibit_generics(slice::from_ref(assoc_segment).iter(), |err| {
|
|
err.note("enum variants can't have type parameters");
|
|
let type_name = tcx.item_name(adt_def.did());
|
|
let msg = format!(
|
|
"you might have meant to specify type parameters on enum \
|
|
`{type_name}`"
|
|
);
|
|
let Some(args) = assoc_segment.args else {
|
|
return;
|
|
};
|
|
// Get the span of the generics args *including* the leading `::`.
|
|
// We do so by stretching args.span_ext to the left by 2. Earlier
|
|
// it was done based on the end of assoc segment but that sometimes
|
|
// led to impossible spans and caused issues like #116473
|
|
let args_span = args.span_ext.with_lo(args.span_ext.lo() - BytePos(2));
|
|
if tcx.generics_of(adt_def.did()).count() == 0 {
|
|
// FIXME(estebank): we could also verify that the arguments being
|
|
// work for the `enum`, instead of just looking if it takes *any*.
|
|
err.span_suggestion_verbose(
|
|
args_span,
|
|
format!("{type_name} doesn't have generic parameters"),
|
|
"",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
return;
|
|
}
|
|
let Ok(snippet) = tcx.sess.source_map().span_to_snippet(args_span)
|
|
else {
|
|
err.note(msg);
|
|
return;
|
|
};
|
|
let (qself_sugg_span, is_self) =
|
|
if let hir::TyKind::Path(hir::QPath::Resolved(_, path)) =
|
|
&qself.kind
|
|
{
|
|
// If the path segment already has type params, we want to overwrite
|
|
// them.
|
|
match &path.segments {
|
|
// `segment` is the previous to last element on the path,
|
|
// which would normally be the `enum` itself, while the last
|
|
// `_` `PathSegment` corresponds to the variant.
|
|
[
|
|
..,
|
|
hir::PathSegment {
|
|
ident,
|
|
args,
|
|
res: Res::Def(DefKind::Enum, _),
|
|
..
|
|
},
|
|
_,
|
|
] => (
|
|
// We need to include the `::` in `Type::Variant::<Args>`
|
|
// to point the span to `::<Args>`, not just `<Args>`.
|
|
ident.span.shrink_to_hi().to(args
|
|
.map_or(ident.span.shrink_to_hi(), |a| a.span_ext)),
|
|
false,
|
|
),
|
|
[segment] => (
|
|
// We need to include the `::` in `Type::Variant::<Args>`
|
|
// to point the span to `::<Args>`, not just `<Args>`.
|
|
segment.ident.span.shrink_to_hi().to(segment
|
|
.args
|
|
.map_or(segment.ident.span.shrink_to_hi(), |a| {
|
|
a.span_ext
|
|
})),
|
|
kw::SelfUpper == segment.ident.name,
|
|
),
|
|
_ => {
|
|
err.note(msg);
|
|
return;
|
|
}
|
|
}
|
|
} else {
|
|
err.note(msg);
|
|
return;
|
|
};
|
|
let suggestion = vec![
|
|
if is_self {
|
|
// Account for people writing `Self::Variant::<Args>`, where
|
|
// `Self` is the enum, and suggest replacing `Self` with the
|
|
// appropriate type: `Type::<Args>::Variant`.
|
|
(qself.span, format!("{type_name}{snippet}"))
|
|
} else {
|
|
(qself_sugg_span, snippet)
|
|
},
|
|
(args_span, String::new()),
|
|
];
|
|
err.multipart_suggestion_verbose(
|
|
msg,
|
|
suggestion,
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
});
|
|
return Ok((qself_ty, DefKind::Variant, variant_def.def_id));
|
|
} else {
|
|
variant_resolution = Some(variant_def.def_id);
|
|
}
|
|
}
|
|
}
|
|
|
|
if let Some((ty, did)) = self.lookup_inherent_assoc_ty(
|
|
assoc_ident,
|
|
assoc_segment,
|
|
adt_def.did(),
|
|
qself_ty,
|
|
hir_ref_id,
|
|
span,
|
|
)? {
|
|
return Ok((ty, DefKind::AssocTy, did));
|
|
}
|
|
}
|
|
|
|
// Find the type of the associated item, and the trait where the associated
|
|
// item is declared.
|
|
let bound = match (&qself_ty.kind(), qself_res) {
|
|
(_, Res::SelfTyAlias { alias_to: impl_def_id, is_trait_impl: true, .. }) => {
|
|
// `Self` in an impl of a trait -- we have a concrete self type and a
|
|
// trait reference.
|
|
let Some(trait_ref) = tcx.impl_trait_ref(impl_def_id) else {
|
|
// A cycle error occurred, most likely.
|
|
let guar = tcx.dcx().span_delayed_bug(span, "expected cycle error");
|
|
return Err(guar);
|
|
};
|
|
|
|
self.one_bound_for_assoc_item(
|
|
|| {
|
|
traits::supertraits(
|
|
tcx,
|
|
ty::Binder::dummy(trait_ref.instantiate_identity()),
|
|
)
|
|
},
|
|
kw::SelfUpper,
|
|
None,
|
|
ty::AssocKind::Type,
|
|
assoc_ident,
|
|
span,
|
|
None,
|
|
)?
|
|
}
|
|
(
|
|
&ty::Param(_),
|
|
Res::SelfTyParam { trait_: param_did } | Res::Def(DefKind::TyParam, param_did),
|
|
) => self.find_bound_for_assoc_item(param_did.expect_local(), assoc_ident, span)?,
|
|
_ => {
|
|
let reported = if variant_resolution.is_some() {
|
|
// Variant in type position
|
|
let msg = format!("expected type, found variant `{assoc_ident}`");
|
|
tcx.dcx().span_err(span, msg)
|
|
} else if qself_ty.is_enum() {
|
|
let mut err = struct_span_code_err!(
|
|
tcx.dcx(),
|
|
assoc_ident.span,
|
|
E0599,
|
|
"no variant named `{}` found for enum `{}`",
|
|
assoc_ident,
|
|
qself_ty,
|
|
);
|
|
|
|
let adt_def = qself_ty.ty_adt_def().expect("enum is not an ADT");
|
|
if let Some(suggested_name) = find_best_match_for_name(
|
|
&adt_def
|
|
.variants()
|
|
.iter()
|
|
.map(|variant| variant.name)
|
|
.collect::<Vec<Symbol>>(),
|
|
assoc_ident.name,
|
|
None,
|
|
) {
|
|
err.span_suggestion(
|
|
assoc_ident.span,
|
|
"there is a variant with a similar name",
|
|
suggested_name,
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
} else {
|
|
err.span_label(
|
|
assoc_ident.span,
|
|
format!("variant not found in `{qself_ty}`"),
|
|
);
|
|
}
|
|
|
|
if let Some(sp) = tcx.hir().span_if_local(adt_def.did()) {
|
|
err.span_label(sp, format!("variant `{assoc_ident}` not found here"));
|
|
}
|
|
|
|
err.emit()
|
|
} else if let Err(reported) = qself_ty.error_reported() {
|
|
reported
|
|
} else if let ty::Alias(ty::Opaque, alias_ty) = qself_ty.kind() {
|
|
// `<impl Trait as OtherTrait>::Assoc` makes no sense.
|
|
struct_span_code_err!(
|
|
tcx.dcx(),
|
|
tcx.def_span(alias_ty.def_id),
|
|
E0667,
|
|
"`impl Trait` is not allowed in path parameters"
|
|
)
|
|
.emit() // Already reported in an earlier stage.
|
|
} else {
|
|
self.maybe_report_similar_assoc_fn(span, qself_ty, qself)?;
|
|
|
|
let traits: Vec<_> =
|
|
self.probe_traits_that_match_assoc_ty(qself_ty, assoc_ident);
|
|
|
|
// Don't print `ty::Error` to the user.
|
|
self.report_ambiguous_associated_type(
|
|
span,
|
|
&[qself_ty.to_string()],
|
|
&traits,
|
|
assoc_ident.name,
|
|
)
|
|
};
|
|
self.set_tainted_by_errors(reported);
|
|
return Err(reported);
|
|
}
|
|
};
|
|
|
|
let trait_did = bound.def_id();
|
|
let assoc_ty_did = self.lookup_assoc_ty(assoc_ident, hir_ref_id, span, trait_did).unwrap();
|
|
let ty = self.projected_ty_from_poly_trait_ref(span, assoc_ty_did, assoc_segment, bound);
|
|
|
|
if let Some(variant_def_id) = variant_resolution {
|
|
tcx.node_span_lint(
|
|
AMBIGUOUS_ASSOCIATED_ITEMS,
|
|
hir_ref_id,
|
|
span,
|
|
"ambiguous associated item",
|
|
|lint| {
|
|
let mut could_refer_to = |kind: DefKind, def_id, also| {
|
|
let note_msg = format!(
|
|
"`{}` could{} refer to the {} defined here",
|
|
assoc_ident,
|
|
also,
|
|
tcx.def_kind_descr(kind, def_id)
|
|
);
|
|
lint.span_note(tcx.def_span(def_id), note_msg);
|
|
};
|
|
|
|
could_refer_to(DefKind::Variant, variant_def_id, "");
|
|
could_refer_to(DefKind::AssocTy, assoc_ty_did, " also");
|
|
|
|
lint.span_suggestion(
|
|
span,
|
|
"use fully-qualified syntax",
|
|
format!("<{} as {}>::{}", qself_ty, tcx.item_name(trait_did), assoc_ident),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
},
|
|
);
|
|
}
|
|
Ok((ty, DefKind::AssocTy, assoc_ty_did))
|
|
}
|
|
|
|
fn lookup_inherent_assoc_ty(
|
|
&self,
|
|
name: Ident,
|
|
segment: &hir::PathSegment<'tcx>,
|
|
adt_did: DefId,
|
|
self_ty: Ty<'tcx>,
|
|
block: hir::HirId,
|
|
span: Span,
|
|
) -> Result<Option<(Ty<'tcx>, DefId)>, ErrorGuaranteed> {
|
|
let tcx = self.tcx();
|
|
|
|
// Don't attempt to look up inherent associated types when the feature is not enabled.
|
|
// Theoretically it'd be fine to do so since we feature-gate their definition site.
|
|
// However, due to current limitations of the implementation (caused by us performing
|
|
// selection in AstConv), IATs can lead to cycle errors (#108491, #110106) which mask the
|
|
// feature-gate error, needlessly confusing users that use IATs by accident (#113265).
|
|
if !tcx.features().inherent_associated_types {
|
|
return Ok(None);
|
|
}
|
|
|
|
let candidates: Vec<_> = tcx
|
|
.inherent_impls(adt_did)?
|
|
.iter()
|
|
.filter_map(|&impl_| Some((impl_, self.lookup_assoc_ty_unchecked(name, block, impl_)?)))
|
|
.collect();
|
|
|
|
if candidates.is_empty() {
|
|
return Ok(None);
|
|
}
|
|
|
|
//
|
|
// Select applicable inherent associated type candidates modulo regions.
|
|
//
|
|
|
|
// 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 = match self.infcx() {
|
|
Some(infcx) => infcx,
|
|
None => {
|
|
assert!(!self_ty.has_infer());
|
|
infcx_ = tcx.infer_ctxt().ignoring_regions().build();
|
|
&infcx_
|
|
}
|
|
};
|
|
|
|
// FIXME(inherent_associated_types): Acquiring the ParamEnv this early leads to cycle errors
|
|
// when inside of an ADT (#108491) or where clause.
|
|
let param_env = tcx.param_env(block.owner);
|
|
|
|
let mut universes = if self_ty.has_escaping_bound_vars() {
|
|
vec![None; self_ty.outer_exclusive_binder().as_usize()]
|
|
} else {
|
|
vec![]
|
|
};
|
|
|
|
let (impl_, (assoc_item, def_scope)) =
|
|
crate::traits::project::with_replaced_escaping_bound_vars(
|
|
infcx,
|
|
&mut universes,
|
|
self_ty,
|
|
|self_ty| {
|
|
self.select_inherent_assoc_type_candidates(
|
|
infcx, name, span, self_ty, param_env, candidates,
|
|
)
|
|
},
|
|
)?;
|
|
|
|
self.check_assoc_ty(assoc_item, name, def_scope, block, span);
|
|
|
|
// FIXME(fmease): Currently creating throwaway `parent_args` to please
|
|
// `create_args_for_associated_item`. Modify the latter instead (or sth. similar) to
|
|
// not require the parent args logic.
|
|
let parent_args = ty::GenericArgs::identity_for_item(tcx, impl_);
|
|
let args = self.create_args_for_associated_item(span, assoc_item, segment, parent_args);
|
|
let args = tcx.mk_args_from_iter(
|
|
std::iter::once(ty::GenericArg::from(self_ty))
|
|
.chain(args.into_iter().skip(parent_args.len())),
|
|
);
|
|
|
|
let ty = Ty::new_alias(tcx, ty::Inherent, ty::AliasTy::new(tcx, assoc_item, args));
|
|
|
|
Ok(Some((ty, assoc_item)))
|
|
}
|
|
|
|
fn select_inherent_assoc_type_candidates(
|
|
&self,
|
|
infcx: &InferCtxt<'tcx>,
|
|
name: Ident,
|
|
span: Span,
|
|
self_ty: Ty<'tcx>,
|
|
param_env: ParamEnv<'tcx>,
|
|
candidates: Vec<(DefId, (DefId, DefId))>,
|
|
) -> Result<(DefId, (DefId, DefId)), ErrorGuaranteed> {
|
|
let tcx = self.tcx();
|
|
let mut fulfillment_errors = Vec::new();
|
|
|
|
let applicable_candidates: Vec<_> = candidates
|
|
.iter()
|
|
.copied()
|
|
.filter(|&(impl_, _)| {
|
|
infcx.probe(|_| {
|
|
let ocx = ObligationCtxt::new(infcx);
|
|
let self_ty = ocx.normalize(&ObligationCause::dummy(), param_env, self_ty);
|
|
|
|
let impl_args = infcx.fresh_args_for_item(span, impl_);
|
|
let impl_ty = tcx.type_of(impl_).instantiate(tcx, impl_args);
|
|
let impl_ty = ocx.normalize(&ObligationCause::dummy(), param_env, impl_ty);
|
|
|
|
// Check that the self types can be related.
|
|
if ocx.eq(&ObligationCause::dummy(), param_env, impl_ty, self_ty).is_err() {
|
|
return false;
|
|
}
|
|
|
|
// Check whether the impl imposes obligations we have to worry about.
|
|
let impl_bounds = tcx.predicates_of(impl_).instantiate(tcx, impl_args);
|
|
let impl_bounds =
|
|
ocx.normalize(&ObligationCause::dummy(), param_env, impl_bounds);
|
|
let impl_obligations = traits::predicates_for_generics(
|
|
|_, _| ObligationCause::dummy(),
|
|
param_env,
|
|
impl_bounds,
|
|
);
|
|
ocx.register_obligations(impl_obligations);
|
|
|
|
let mut errors = ocx.select_where_possible();
|
|
if !errors.is_empty() {
|
|
fulfillment_errors.append(&mut errors);
|
|
return false;
|
|
}
|
|
|
|
true
|
|
})
|
|
})
|
|
.collect();
|
|
|
|
match &applicable_candidates[..] {
|
|
&[] => Err(self.complain_about_inherent_assoc_type_not_found(
|
|
name,
|
|
self_ty,
|
|
candidates,
|
|
fulfillment_errors,
|
|
span,
|
|
)),
|
|
|
|
&[applicable_candidate] => Ok(applicable_candidate),
|
|
|
|
&[_, ..] => Err(self.complain_about_ambiguous_inherent_assoc_type(
|
|
name,
|
|
applicable_candidates.into_iter().map(|(_, (candidate, _))| candidate).collect(),
|
|
span,
|
|
)),
|
|
}
|
|
}
|
|
|
|
fn lookup_assoc_ty(
|
|
&self,
|
|
name: Ident,
|
|
block: hir::HirId,
|
|
span: Span,
|
|
scope: DefId,
|
|
) -> Option<DefId> {
|
|
let (item, def_scope) = self.lookup_assoc_ty_unchecked(name, block, scope)?;
|
|
self.check_assoc_ty(item, name, def_scope, block, span);
|
|
Some(item)
|
|
}
|
|
|
|
fn lookup_assoc_ty_unchecked(
|
|
&self,
|
|
name: Ident,
|
|
block: hir::HirId,
|
|
scope: DefId,
|
|
) -> Option<(DefId, DefId)> {
|
|
let tcx = self.tcx();
|
|
let (ident, def_scope) = tcx.adjust_ident_and_get_scope(name, scope, block);
|
|
|
|
// We have already adjusted the item name above, so compare with `.normalize_to_macros_2_0()`
|
|
// instead of calling `filter_by_name_and_kind` which would needlessly normalize the
|
|
// `ident` again and again.
|
|
let item = tcx.associated_items(scope).in_definition_order().find(|i| {
|
|
i.kind.namespace() == Namespace::TypeNS
|
|
&& i.ident(tcx).normalize_to_macros_2_0() == ident
|
|
})?;
|
|
|
|
Some((item.def_id, def_scope))
|
|
}
|
|
|
|
fn check_assoc_ty(
|
|
&self,
|
|
item: DefId,
|
|
name: Ident,
|
|
def_scope: DefId,
|
|
block: hir::HirId,
|
|
span: Span,
|
|
) {
|
|
let tcx = self.tcx();
|
|
let kind = DefKind::AssocTy;
|
|
|
|
if !tcx.visibility(item).is_accessible_from(def_scope, tcx) {
|
|
let kind = tcx.def_kind_descr(kind, item);
|
|
let msg = format!("{kind} `{name}` is private");
|
|
let def_span = tcx.def_span(item);
|
|
let reported = tcx
|
|
.dcx()
|
|
.struct_span_err(span, msg)
|
|
.with_code(E0624)
|
|
.with_span_label(span, format!("private {kind}"))
|
|
.with_span_label(def_span, format!("{kind} defined here"))
|
|
.emit();
|
|
self.set_tainted_by_errors(reported);
|
|
}
|
|
tcx.check_stability(item, Some(block), span, None);
|
|
}
|
|
|
|
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.has_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 impl_header = tcx.impl_trait_header(impl_def_id);
|
|
impl_header.is_some_and(|header| {
|
|
let header = header.instantiate(
|
|
tcx,
|
|
infcx.fresh_args_for_item(DUMMY_SP, impl_def_id),
|
|
);
|
|
let value = tcx.fold_regions(qself_ty, |_, _| tcx.lifetimes.re_erased);
|
|
// FIXME: Don't bother dealing with non-lifetime binders here...
|
|
if value.has_escaping_bound_vars() {
|
|
return false;
|
|
}
|
|
infcx
|
|
.can_eq(
|
|
ty::ParamEnv::empty(),
|
|
header.trait_ref.self_ty(),
|
|
value,
|
|
) && header.polarity != ty::ImplPolarity::Negative
|
|
})
|
|
})
|
|
})
|
|
.map(|trait_def_id| tcx.def_path_str(trait_def_id))
|
|
.collect()
|
|
}
|
|
|
|
fn qpath_to_ty(
|
|
&self,
|
|
span: Span,
|
|
opt_self_ty: Option<Ty<'tcx>>,
|
|
item_def_id: DefId,
|
|
trait_segment: &hir::PathSegment<'tcx>,
|
|
item_segment: &hir::PathSegment<'tcx>,
|
|
constness: ty::BoundConstness,
|
|
) -> Ty<'tcx> {
|
|
let tcx = self.tcx();
|
|
|
|
let trait_def_id = tcx.parent(item_def_id);
|
|
|
|
debug!("qpath_to_ty: trait_def_id={:?}", trait_def_id);
|
|
|
|
let Some(self_ty) = opt_self_ty else {
|
|
let path_str = tcx.def_path_str(trait_def_id);
|
|
|
|
let def_id = self.item_def_id();
|
|
|
|
debug!("qpath_to_ty: self.item_def_id()={:?}", def_id);
|
|
|
|
let parent_def_id = def_id
|
|
.as_local()
|
|
.map(|def_id| tcx.local_def_id_to_hir_id(def_id))
|
|
.map(|hir_id| tcx.hir().get_parent_item(hir_id).to_def_id());
|
|
|
|
debug!("qpath_to_ty: parent_def_id={:?}", parent_def_id);
|
|
|
|
// If the trait in segment is the same as the trait defining the item,
|
|
// use the `<Self as ..>` syntax in the error.
|
|
let is_part_of_self_trait_constraints = def_id == trait_def_id;
|
|
let is_part_of_fn_in_self_trait = parent_def_id == Some(trait_def_id);
|
|
|
|
let type_names = if is_part_of_self_trait_constraints || is_part_of_fn_in_self_trait {
|
|
vec!["Self".to_string()]
|
|
} else {
|
|
// Find all the types that have an `impl` for the trait.
|
|
tcx.all_impls(trait_def_id)
|
|
.filter_map(|impl_def_id| tcx.impl_trait_header(impl_def_id))
|
|
.filter(|header| {
|
|
// Consider only accessible traits
|
|
tcx.visibility(trait_def_id).is_accessible_from(self.item_def_id(), tcx)
|
|
&& header.skip_binder().polarity != ty::ImplPolarity::Negative
|
|
})
|
|
.map(|header| header.instantiate_identity().trait_ref.self_ty())
|
|
// We don't care about blanket impls.
|
|
.filter(|self_ty| !self_ty.has_non_region_param())
|
|
.map(|self_ty| tcx.erase_regions(self_ty).to_string())
|
|
.collect()
|
|
};
|
|
// FIXME: also look at `tcx.generics_of(self.item_def_id()).params` any that
|
|
// references the trait. Relevant for the first case in
|
|
// `src/test/ui/associated-types/associated-types-in-ambiguous-context.rs`
|
|
let reported = self.report_ambiguous_associated_type(
|
|
span,
|
|
&type_names,
|
|
&[path_str],
|
|
item_segment.ident.name,
|
|
);
|
|
return Ty::new_error(tcx, reported);
|
|
};
|
|
|
|
debug!("qpath_to_ty: self_type={:?}", self_ty);
|
|
|
|
let trait_ref = self.ast_path_to_mono_trait_ref(
|
|
span,
|
|
trait_def_id,
|
|
self_ty,
|
|
trait_segment,
|
|
false,
|
|
constness,
|
|
);
|
|
|
|
let item_args =
|
|
self.create_args_for_associated_item(span, item_def_id, item_segment, trait_ref.args);
|
|
|
|
debug!("qpath_to_ty: trait_ref={:?}", trait_ref);
|
|
|
|
Ty::new_projection(tcx, item_def_id, item_args)
|
|
}
|
|
|
|
pub fn prohibit_generics<'a>(
|
|
&self,
|
|
segments: impl Iterator<Item = &'a hir::PathSegment<'a>> + Clone,
|
|
extend: impl Fn(&mut Diagnostic),
|
|
) -> bool {
|
|
let args = segments.clone().flat_map(|segment| segment.args().args);
|
|
|
|
let (lt, ty, ct, inf) =
|
|
args.clone().fold((false, false, false, false), |(lt, ty, ct, inf), arg| match arg {
|
|
hir::GenericArg::Lifetime(_) => (true, ty, ct, inf),
|
|
hir::GenericArg::Type(_) => (lt, true, ct, inf),
|
|
hir::GenericArg::Const(_) => (lt, ty, true, inf),
|
|
hir::GenericArg::Infer(_) => (lt, ty, ct, true),
|
|
});
|
|
let mut emitted = false;
|
|
if lt || ty || ct || inf {
|
|
let types_and_spans: Vec<_> = segments
|
|
.clone()
|
|
.flat_map(|segment| {
|
|
if segment.args().args.is_empty() {
|
|
None
|
|
} else {
|
|
Some((
|
|
match segment.res {
|
|
Res::PrimTy(ty) => {
|
|
format!("{} `{}`", segment.res.descr(), ty.name())
|
|
}
|
|
Res::Def(_, def_id)
|
|
if let Some(name) = self.tcx().opt_item_name(def_id) =>
|
|
{
|
|
format!("{} `{name}`", segment.res.descr())
|
|
}
|
|
Res::Err => "this type".to_string(),
|
|
_ => segment.res.descr().to_string(),
|
|
},
|
|
segment.ident.span,
|
|
))
|
|
}
|
|
})
|
|
.collect();
|
|
let this_type = match &types_and_spans[..] {
|
|
[.., _, (last, _)] => format!(
|
|
"{} and {last}",
|
|
types_and_spans[..types_and_spans.len() - 1]
|
|
.iter()
|
|
.map(|(x, _)| x.as_str())
|
|
.intersperse(", ")
|
|
.collect::<String>()
|
|
),
|
|
[(only, _)] => only.to_string(),
|
|
[] => "this type".to_string(),
|
|
};
|
|
|
|
let arg_spans: Vec<Span> = args.map(|arg| arg.span()).collect();
|
|
|
|
let mut kinds = Vec::with_capacity(4);
|
|
if lt {
|
|
kinds.push("lifetime");
|
|
}
|
|
if ty {
|
|
kinds.push("type");
|
|
}
|
|
if ct {
|
|
kinds.push("const");
|
|
}
|
|
if inf {
|
|
kinds.push("generic");
|
|
}
|
|
let (kind, s) = match kinds[..] {
|
|
[.., _, last] => (
|
|
format!(
|
|
"{} and {last}",
|
|
kinds[..kinds.len() - 1]
|
|
.iter()
|
|
.map(|&x| x)
|
|
.intersperse(", ")
|
|
.collect::<String>()
|
|
),
|
|
"s",
|
|
),
|
|
[only] => (only.to_string(), ""),
|
|
[] => unreachable!("expected at least one generic to prohibit"),
|
|
};
|
|
let last_span = *arg_spans.last().unwrap();
|
|
let span: MultiSpan = arg_spans.into();
|
|
let mut err = struct_span_code_err!(
|
|
self.tcx().dcx(),
|
|
span,
|
|
E0109,
|
|
"{kind} arguments are not allowed on {this_type}",
|
|
);
|
|
err.span_label(last_span, format!("{kind} argument{s} not allowed"));
|
|
for (what, span) in types_and_spans {
|
|
err.span_label(span, format!("not allowed on {what}"));
|
|
}
|
|
extend(&mut err);
|
|
self.set_tainted_by_errors(err.emit());
|
|
emitted = true;
|
|
}
|
|
|
|
for segment in segments {
|
|
// Only emit the first error to avoid overloading the user with error messages.
|
|
if let Some(b) = segment.args().bindings.first() {
|
|
prohibit_assoc_ty_binding(self.tcx(), b.span, None);
|
|
return true;
|
|
}
|
|
}
|
|
emitted
|
|
}
|
|
|
|
// FIXME(eddyb, varkor) handle type paths here too, not just value ones.
|
|
pub fn def_ids_for_value_path_segments(
|
|
&self,
|
|
segments: &[hir::PathSegment<'_>],
|
|
self_ty: Option<Ty<'tcx>>,
|
|
kind: DefKind,
|
|
def_id: DefId,
|
|
span: Span,
|
|
) -> Vec<PathSeg> {
|
|
// We need to extract the type parameters supplied by the user in
|
|
// the path `path`. Due to the current setup, this is a bit of a
|
|
// tricky-process; the problem is that resolve only tells us the
|
|
// end-point of the path resolution, and not the intermediate steps.
|
|
// Luckily, we can (at least for now) deduce the intermediate steps
|
|
// just from the end-point.
|
|
//
|
|
// There are basically five cases to consider:
|
|
//
|
|
// 1. Reference to a constructor of a struct:
|
|
//
|
|
// struct Foo<T>(...)
|
|
//
|
|
// In this case, the parameters are declared in the type space.
|
|
//
|
|
// 2. Reference to a constructor of an enum variant:
|
|
//
|
|
// enum E<T> { Foo(...) }
|
|
//
|
|
// In this case, the parameters are defined in the type space,
|
|
// but may be specified either on the type or the variant.
|
|
//
|
|
// 3. Reference to a fn item or a free constant:
|
|
//
|
|
// fn foo<T>() { }
|
|
//
|
|
// In this case, the path will again always have the form
|
|
// `a::b::foo::<T>` where only the final segment should have
|
|
// type parameters. However, in this case, those parameters are
|
|
// declared on a value, and hence are in the `FnSpace`.
|
|
//
|
|
// 4. Reference to a method or an associated constant:
|
|
//
|
|
// impl<A> SomeStruct<A> {
|
|
// fn foo<B>(...)
|
|
// }
|
|
//
|
|
// Here we can have a path like
|
|
// `a::b::SomeStruct::<A>::foo::<B>`, in which case parameters
|
|
// may appear in two places. The penultimate segment,
|
|
// `SomeStruct::<A>`, contains parameters in TypeSpace, and the
|
|
// final segment, `foo::<B>` contains parameters in fn space.
|
|
//
|
|
// The first step then is to categorize the segments appropriately.
|
|
|
|
let tcx = self.tcx();
|
|
|
|
assert!(!segments.is_empty());
|
|
let last = segments.len() - 1;
|
|
|
|
let mut path_segs = vec![];
|
|
|
|
match kind {
|
|
// Case 1. Reference to a struct constructor.
|
|
DefKind::Ctor(CtorOf::Struct, ..) => {
|
|
// Everything but the final segment should have no
|
|
// parameters at all.
|
|
let generics = tcx.generics_of(def_id);
|
|
// Variant and struct constructors use the
|
|
// generics of their parent type definition.
|
|
let generics_def_id = generics.parent.unwrap_or(def_id);
|
|
path_segs.push(PathSeg(generics_def_id, last));
|
|
}
|
|
|
|
// Case 2. Reference to a variant constructor.
|
|
DefKind::Ctor(CtorOf::Variant, ..) | DefKind::Variant => {
|
|
let (generics_def_id, index) = if let Some(self_ty) = self_ty {
|
|
let adt_def = self.probe_adt(span, self_ty).unwrap();
|
|
debug_assert!(adt_def.is_enum());
|
|
(adt_def.did(), last)
|
|
} else if last >= 1 && segments[last - 1].args.is_some() {
|
|
// Everything but the penultimate segment should have no
|
|
// parameters at all.
|
|
let mut def_id = def_id;
|
|
|
|
// `DefKind::Ctor` -> `DefKind::Variant`
|
|
if let DefKind::Ctor(..) = kind {
|
|
def_id = tcx.parent(def_id);
|
|
}
|
|
|
|
// `DefKind::Variant` -> `DefKind::Enum`
|
|
let enum_def_id = tcx.parent(def_id);
|
|
(enum_def_id, last - 1)
|
|
} else {
|
|
// FIXME: lint here recommending `Enum::<...>::Variant` form
|
|
// instead of `Enum::Variant::<...>` form.
|
|
|
|
// Everything but the final segment should have no
|
|
// parameters at all.
|
|
let generics = tcx.generics_of(def_id);
|
|
// Variant and struct constructors use the
|
|
// generics of their parent type definition.
|
|
(generics.parent.unwrap_or(def_id), last)
|
|
};
|
|
path_segs.push(PathSeg(generics_def_id, index));
|
|
}
|
|
|
|
// Case 3. Reference to a top-level value.
|
|
DefKind::Fn | DefKind::Const | DefKind::ConstParam | DefKind::Static(_) => {
|
|
path_segs.push(PathSeg(def_id, last));
|
|
}
|
|
|
|
// Case 4. Reference to a method or associated const.
|
|
DefKind::AssocFn | DefKind::AssocConst => {
|
|
if segments.len() >= 2 {
|
|
let generics = tcx.generics_of(def_id);
|
|
path_segs.push(PathSeg(generics.parent.unwrap(), last - 1));
|
|
}
|
|
path_segs.push(PathSeg(def_id, last));
|
|
}
|
|
|
|
kind => bug!("unexpected definition kind {:?} for {:?}", kind, def_id),
|
|
}
|
|
|
|
debug!("path_segs = {:?}", path_segs);
|
|
|
|
path_segs
|
|
}
|
|
|
|
/// Check a type `Path` and convert it to a `Ty`.
|
|
pub fn res_to_ty(
|
|
&self,
|
|
opt_self_ty: Option<Ty<'tcx>>,
|
|
path: &hir::Path<'tcx>,
|
|
hir_id: hir::HirId,
|
|
permit_variants: bool,
|
|
) -> Ty<'tcx> {
|
|
let tcx = self.tcx();
|
|
|
|
debug!(
|
|
"res_to_ty(res={:?}, opt_self_ty={:?}, path_segments={:?})",
|
|
path.res, opt_self_ty, path.segments
|
|
);
|
|
|
|
let span = path.span;
|
|
match path.res {
|
|
Res::Def(DefKind::OpaqueTy, did) => {
|
|
// Check for desugared `impl Trait`.
|
|
assert!(tcx.is_type_alias_impl_trait(did));
|
|
let item_segment = path.segments.split_last().unwrap();
|
|
self.prohibit_generics(item_segment.1.iter(), |err| {
|
|
err.note("`impl Trait` types can't have type parameters");
|
|
});
|
|
let args = self.ast_path_args_for_ty(span, did, item_segment.0);
|
|
Ty::new_opaque(tcx, did, args)
|
|
}
|
|
Res::Def(
|
|
DefKind::Enum
|
|
| DefKind::TyAlias
|
|
| DefKind::Struct
|
|
| DefKind::Union
|
|
| DefKind::ForeignTy,
|
|
did,
|
|
) => {
|
|
assert_eq!(opt_self_ty, None);
|
|
self.prohibit_generics(path.segments.split_last().unwrap().1.iter(), |_| {});
|
|
self.ast_path_to_ty(span, did, path.segments.last().unwrap())
|
|
}
|
|
Res::Def(kind @ DefKind::Variant, def_id) if permit_variants => {
|
|
// Convert "variant type" as if it were a real type.
|
|
// The resulting `Ty` is type of the variant's enum for now.
|
|
assert_eq!(opt_self_ty, None);
|
|
|
|
let path_segs =
|
|
self.def_ids_for_value_path_segments(path.segments, None, kind, def_id, span);
|
|
let generic_segs: FxHashSet<_> =
|
|
path_segs.iter().map(|PathSeg(_, index)| index).collect();
|
|
self.prohibit_generics(
|
|
path.segments.iter().enumerate().filter_map(|(index, seg)| {
|
|
if !generic_segs.contains(&index) { Some(seg) } else { None }
|
|
}),
|
|
|err| {
|
|
err.note("enum variants can't have type parameters");
|
|
},
|
|
);
|
|
|
|
let PathSeg(def_id, index) = path_segs.last().unwrap();
|
|
self.ast_path_to_ty(span, *def_id, &path.segments[*index])
|
|
}
|
|
Res::Def(DefKind::TyParam, def_id) => {
|
|
assert_eq!(opt_self_ty, None);
|
|
self.prohibit_generics(path.segments.iter(), |err| {
|
|
if let Some(span) = tcx.def_ident_span(def_id) {
|
|
let name = tcx.item_name(def_id);
|
|
err.span_note(span, format!("type parameter `{name}` defined here"));
|
|
}
|
|
});
|
|
self.hir_id_to_bound_ty(hir_id)
|
|
}
|
|
Res::SelfTyParam { .. } => {
|
|
// `Self` in trait or type alias.
|
|
assert_eq!(opt_self_ty, None);
|
|
self.prohibit_generics(path.segments.iter(), |err| {
|
|
if let [hir::PathSegment { args: Some(args), ident, .. }] = &path.segments {
|
|
err.span_suggestion_verbose(
|
|
ident.span.shrink_to_hi().to(args.span_ext),
|
|
"the `Self` type doesn't accept type parameters",
|
|
"",
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
});
|
|
tcx.types.self_param
|
|
}
|
|
Res::SelfTyAlias { alias_to: def_id, forbid_generic, .. } => {
|
|
// `Self` in impl (we know the concrete type).
|
|
assert_eq!(opt_self_ty, None);
|
|
// Try to evaluate any array length constants.
|
|
let ty = tcx.at(span).type_of(def_id).instantiate_identity();
|
|
let span_of_impl = tcx.span_of_impl(def_id);
|
|
self.prohibit_generics(path.segments.iter(), |err| {
|
|
let def_id = match *ty.kind() {
|
|
ty::Adt(self_def, _) => self_def.did(),
|
|
_ => return,
|
|
};
|
|
|
|
let type_name = tcx.item_name(def_id);
|
|
let span_of_ty = tcx.def_ident_span(def_id);
|
|
let generics = tcx.generics_of(def_id).count();
|
|
|
|
let msg = format!("`Self` is of type `{ty}`");
|
|
if let (Ok(i_sp), Some(t_sp)) = (span_of_impl, span_of_ty) {
|
|
let mut span: MultiSpan = vec![t_sp].into();
|
|
span.push_span_label(
|
|
i_sp,
|
|
format!("`Self` is on type `{type_name}` in this `impl`"),
|
|
);
|
|
let mut postfix = "";
|
|
if generics == 0 {
|
|
postfix = ", which doesn't have generic parameters";
|
|
}
|
|
span.push_span_label(
|
|
t_sp,
|
|
format!("`Self` corresponds to this type{postfix}"),
|
|
);
|
|
err.span_note(span, msg);
|
|
} else {
|
|
err.note(msg);
|
|
}
|
|
for segment in path.segments {
|
|
if let Some(args) = segment.args
|
|
&& segment.ident.name == kw::SelfUpper
|
|
{
|
|
if generics == 0 {
|
|
// FIXME(estebank): we could also verify that the arguments being
|
|
// work for the `enum`, instead of just looking if it takes *any*.
|
|
err.span_suggestion_verbose(
|
|
segment.ident.span.shrink_to_hi().to(args.span_ext),
|
|
"the `Self` type doesn't accept type parameters",
|
|
"",
|
|
Applicability::MachineApplicable,
|
|
);
|
|
return;
|
|
} else {
|
|
err.span_suggestion_verbose(
|
|
segment.ident.span,
|
|
format!(
|
|
"the `Self` type doesn't accept type parameters, use the \
|
|
concrete type's name `{type_name}` instead if you want to \
|
|
specify its type parameters"
|
|
),
|
|
type_name,
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
}
|
|
}
|
|
});
|
|
// HACK(min_const_generics): Forbid generic `Self` types
|
|
// here as we can't easily do that during nameres.
|
|
//
|
|
// We do this before normalization as we otherwise allow
|
|
// ```rust
|
|
// trait AlwaysApplicable { type Assoc; }
|
|
// impl<T: ?Sized> AlwaysApplicable for T { type Assoc = usize; }
|
|
//
|
|
// trait BindsParam<T> {
|
|
// type ArrayTy;
|
|
// }
|
|
// impl<T> BindsParam<T> for <T as AlwaysApplicable>::Assoc {
|
|
// type ArrayTy = [u8; Self::MAX];
|
|
// }
|
|
// ```
|
|
// Note that the normalization happens in the param env of
|
|
// the anon const, which is empty. This is why the
|
|
// `AlwaysApplicable` impl needs a `T: ?Sized` bound for
|
|
// this to compile if we were to normalize here.
|
|
if forbid_generic && ty.has_param() {
|
|
let mut err = tcx.dcx().struct_span_err(
|
|
path.span,
|
|
"generic `Self` types are currently not permitted in anonymous constants",
|
|
);
|
|
if let Some(hir::Node::Item(&hir::Item {
|
|
kind: hir::ItemKind::Impl(impl_),
|
|
..
|
|
})) = tcx.hir().get_if_local(def_id)
|
|
{
|
|
err.span_note(impl_.self_ty.span, "not a concrete type");
|
|
}
|
|
let reported = err.emit();
|
|
self.set_tainted_by_errors(reported);
|
|
Ty::new_error(tcx, reported)
|
|
} else {
|
|
ty
|
|
}
|
|
}
|
|
Res::Def(DefKind::AssocTy, def_id) => {
|
|
debug_assert!(path.segments.len() >= 2);
|
|
self.prohibit_generics(path.segments[..path.segments.len() - 2].iter(), |_| {});
|
|
// HACK: until we support `<Type as ~const Trait>`, assume all of them are.
|
|
let constness = if tcx.has_attr(tcx.parent(def_id), sym::const_trait) {
|
|
ty::BoundConstness::ConstIfConst
|
|
} else {
|
|
ty::BoundConstness::NotConst
|
|
};
|
|
self.qpath_to_ty(
|
|
span,
|
|
opt_self_ty,
|
|
def_id,
|
|
&path.segments[path.segments.len() - 2],
|
|
path.segments.last().unwrap(),
|
|
constness,
|
|
)
|
|
}
|
|
Res::PrimTy(prim_ty) => {
|
|
assert_eq!(opt_self_ty, None);
|
|
self.prohibit_generics(path.segments.iter(), |err| {
|
|
let name = prim_ty.name_str();
|
|
for segment in path.segments {
|
|
if let Some(args) = segment.args {
|
|
err.span_suggestion_verbose(
|
|
segment.ident.span.shrink_to_hi().to(args.span_ext),
|
|
format!("primitive type `{name}` doesn't have generic parameters"),
|
|
"",
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
}
|
|
}
|
|
});
|
|
match prim_ty {
|
|
hir::PrimTy::Bool => tcx.types.bool,
|
|
hir::PrimTy::Char => tcx.types.char,
|
|
hir::PrimTy::Int(it) => Ty::new_int(tcx, ty::int_ty(it)),
|
|
hir::PrimTy::Uint(uit) => Ty::new_uint(tcx, ty::uint_ty(uit)),
|
|
hir::PrimTy::Float(ft) => Ty::new_float(tcx, ty::float_ty(ft)),
|
|
hir::PrimTy::Str => tcx.types.str_,
|
|
}
|
|
}
|
|
Res::Err => {
|
|
let e = self
|
|
.tcx()
|
|
.dcx()
|
|
.span_delayed_bug(path.span, "path with `Res::Err` but no error emitted");
|
|
self.set_tainted_by_errors(e);
|
|
Ty::new_error(self.tcx(), e)
|
|
}
|
|
_ => span_bug!(span, "unexpected resolution: {:?}", path.res),
|
|
}
|
|
}
|
|
|
|
// Converts a hir id corresponding to a type parameter to
|
|
// a early-bound `ty::Param` or late-bound `ty::Bound`.
|
|
pub(crate) fn hir_id_to_bound_ty(&self, hir_id: hir::HirId) -> Ty<'tcx> {
|
|
let tcx = self.tcx();
|
|
match tcx.named_bound_var(hir_id) {
|
|
Some(rbv::ResolvedArg::LateBound(debruijn, index, def_id)) => {
|
|
let name = tcx.item_name(def_id);
|
|
let br = ty::BoundTy {
|
|
var: ty::BoundVar::from_u32(index),
|
|
kind: ty::BoundTyKind::Param(def_id, name),
|
|
};
|
|
Ty::new_bound(tcx, debruijn, br)
|
|
}
|
|
Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
|
|
let def_id = def_id.expect_local();
|
|
let item_def_id = tcx.hir().ty_param_owner(def_id);
|
|
let generics = tcx.generics_of(item_def_id);
|
|
let index = generics.param_def_id_to_index[&def_id.to_def_id()];
|
|
Ty::new_param(tcx, index, tcx.hir().ty_param_name(def_id))
|
|
}
|
|
Some(rbv::ResolvedArg::Error(guar)) => Ty::new_error(tcx, guar),
|
|
arg => bug!("unexpected bound var resolution for {hir_id:?}: {arg:?}"),
|
|
}
|
|
}
|
|
|
|
// Converts a hir id corresponding to a const parameter to
|
|
// a early-bound `ConstKind::Param` or late-bound `ConstKind::Bound`.
|
|
pub(crate) fn hir_id_to_bound_const(
|
|
&self,
|
|
hir_id: hir::HirId,
|
|
param_ty: Ty<'tcx>,
|
|
) -> Const<'tcx> {
|
|
let tcx = self.tcx();
|
|
match tcx.named_bound_var(hir_id) {
|
|
Some(rbv::ResolvedArg::EarlyBound(def_id)) => {
|
|
// Find the name and index of the const parameter by indexing the generics of
|
|
// the parent item and construct a `ParamConst`.
|
|
let item_def_id = tcx.parent(def_id);
|
|
let generics = tcx.generics_of(item_def_id);
|
|
let index = generics.param_def_id_to_index[&def_id];
|
|
let name = tcx.item_name(def_id);
|
|
ty::Const::new_param(tcx, ty::ParamConst::new(index, name), param_ty)
|
|
}
|
|
Some(rbv::ResolvedArg::LateBound(debruijn, index, _)) => {
|
|
ty::Const::new_bound(tcx, debruijn, ty::BoundVar::from_u32(index), param_ty)
|
|
}
|
|
Some(rbv::ResolvedArg::Error(guar)) => ty::Const::new_error(tcx, guar, param_ty),
|
|
arg => bug!("unexpected bound var resolution for {:?}: {arg:?}", hir_id),
|
|
}
|
|
}
|
|
|
|
/// Parses the programmer's textual representation of a type into our
|
|
/// internal notion of a type.
|
|
pub fn ast_ty_to_ty(&self, ast_ty: &hir::Ty<'tcx>) -> Ty<'tcx> {
|
|
self.ast_ty_to_ty_inner(ast_ty, false, false)
|
|
}
|
|
|
|
/// Parses the programmer's textual representation of a type into our
|
|
/// internal notion of a type. This is meant to be used within a path.
|
|
pub fn ast_ty_to_ty_in_path(&self, ast_ty: &hir::Ty<'tcx>) -> Ty<'tcx> {
|
|
self.ast_ty_to_ty_inner(ast_ty, false, true)
|
|
}
|
|
|
|
fn check_delegation_constraints(&self, sig_id: DefId, span: Span, emit: bool) -> bool {
|
|
let mut error_occured = false;
|
|
let sig_span = self.tcx().def_span(sig_id);
|
|
let mut try_emit = |descr| {
|
|
if emit {
|
|
self.tcx().dcx().emit_err(crate::errors::NotSupportedDelegation {
|
|
span,
|
|
descr,
|
|
callee_span: sig_span,
|
|
});
|
|
}
|
|
error_occured = true;
|
|
};
|
|
|
|
if let Some(node) = self.tcx().hir().get_if_local(sig_id)
|
|
&& let Some(decl) = node.fn_decl()
|
|
&& let hir::FnRetTy::Return(ty) = decl.output
|
|
&& let hir::TyKind::InferDelegation(_, _) = ty.kind
|
|
{
|
|
try_emit("recursive delegation");
|
|
}
|
|
|
|
let sig = self.tcx().fn_sig(sig_id).instantiate_identity();
|
|
if sig.output().has_opaque_types() {
|
|
try_emit("delegation to a function with opaque type");
|
|
}
|
|
|
|
let sig_generics = self.tcx().generics_of(sig_id);
|
|
let parent = self.tcx().parent(self.item_def_id());
|
|
let parent_generics = self.tcx().generics_of(parent);
|
|
|
|
let parent_is_trait = (self.tcx().def_kind(parent) == DefKind::Trait) as usize;
|
|
let sig_has_self = sig_generics.has_self as usize;
|
|
|
|
if sig_generics.count() > sig_has_self || parent_generics.count() > parent_is_trait {
|
|
try_emit("delegation with early bound generics");
|
|
}
|
|
|
|
if self.tcx().asyncness(sig_id) == ty::Asyncness::Yes {
|
|
try_emit("delegation to async functions");
|
|
}
|
|
|
|
if self.tcx().constness(sig_id) == hir::Constness::Const {
|
|
try_emit("delegation to const functions");
|
|
}
|
|
|
|
if sig.c_variadic() {
|
|
try_emit("delegation to variadic functions");
|
|
// variadic functions are also `unsafe` and `extern "C"`.
|
|
// Do not emit same error multiple times.
|
|
return error_occured;
|
|
}
|
|
|
|
if let hir::Unsafety::Unsafe = sig.unsafety() {
|
|
try_emit("delegation to unsafe functions");
|
|
}
|
|
|
|
if abi::Abi::Rust != sig.abi() {
|
|
try_emit("delegation to non Rust ABI functions");
|
|
}
|
|
|
|
error_occured
|
|
}
|
|
|
|
fn ty_from_delegation(
|
|
&self,
|
|
sig_id: DefId,
|
|
idx: hir::InferDelegationKind,
|
|
span: Span,
|
|
) -> Ty<'tcx> {
|
|
if self.check_delegation_constraints(sig_id, span, idx == hir::InferDelegationKind::Output)
|
|
{
|
|
let e = self.tcx().dcx().span_delayed_bug(span, "not supported delegation case");
|
|
self.set_tainted_by_errors(e);
|
|
return Ty::new_error(self.tcx(), e);
|
|
};
|
|
let sig = self.tcx().fn_sig(sig_id);
|
|
let sig_generics = self.tcx().generics_of(sig_id);
|
|
|
|
let parent = self.tcx().parent(self.item_def_id());
|
|
let parent_def_kind = self.tcx().def_kind(parent);
|
|
|
|
let sig = if let DefKind::Impl { .. } = parent_def_kind
|
|
&& sig_generics.has_self
|
|
{
|
|
// Generic params can't be here except the trait self type.
|
|
// They are not supported yet.
|
|
assert_eq!(sig_generics.count(), 1);
|
|
assert_eq!(self.tcx().generics_of(parent).count(), 0);
|
|
|
|
let self_ty = self.tcx().type_of(parent).instantiate_identity();
|
|
let generic_self_ty = ty::GenericArg::from(self_ty);
|
|
let args = self.tcx().mk_args_from_iter(std::iter::once(generic_self_ty));
|
|
sig.instantiate(self.tcx(), args)
|
|
} else {
|
|
sig.instantiate_identity()
|
|
};
|
|
|
|
// Bound vars are also inherited from `sig_id`. They will be
|
|
// rebinded later in `ty_of_fn`.
|
|
let sig = sig.skip_binder();
|
|
|
|
match idx {
|
|
hir::InferDelegationKind::Input(id) => sig.inputs()[id],
|
|
hir::InferDelegationKind::Output => sig.output(),
|
|
}
|
|
}
|
|
|
|
/// Turns a `hir::Ty` into a `Ty`. For diagnostics' purposes we keep track of whether trait
|
|
/// objects are borrowed like `&dyn Trait` to avoid emitting redundant errors.
|
|
#[instrument(level = "debug", skip(self), ret)]
|
|
fn ast_ty_to_ty_inner(
|
|
&self,
|
|
ast_ty: &hir::Ty<'tcx>,
|
|
borrowed: bool,
|
|
in_path: bool,
|
|
) -> Ty<'tcx> {
|
|
let tcx = self.tcx();
|
|
|
|
let result_ty = match &ast_ty.kind {
|
|
hir::TyKind::InferDelegation(sig_id, idx) => {
|
|
self.ty_from_delegation(*sig_id, *idx, ast_ty.span)
|
|
}
|
|
hir::TyKind::Slice(ty) => Ty::new_slice(tcx, self.ast_ty_to_ty(ty)),
|
|
hir::TyKind::Ptr(mt) => {
|
|
Ty::new_ptr(tcx, ty::TypeAndMut { ty: self.ast_ty_to_ty(mt.ty), mutbl: mt.mutbl })
|
|
}
|
|
hir::TyKind::Ref(region, mt) => {
|
|
let r = self.ast_region_to_region(region, None);
|
|
debug!(?r);
|
|
let t = self.ast_ty_to_ty_inner(mt.ty, true, false);
|
|
Ty::new_ref(tcx, r, ty::TypeAndMut { ty: t, mutbl: mt.mutbl })
|
|
}
|
|
hir::TyKind::Never => tcx.types.never,
|
|
hir::TyKind::Tup(fields) => {
|
|
Ty::new_tup_from_iter(tcx, fields.iter().map(|t| self.ast_ty_to_ty(t)))
|
|
}
|
|
hir::TyKind::AnonAdt(item_id) => {
|
|
let did = item_id.owner_id.def_id;
|
|
let adt_def = tcx.adt_def(did);
|
|
let generics = tcx.generics_of(did);
|
|
|
|
debug!("ast_ty_to_ty_inner(AnonAdt): generics={:?}", generics);
|
|
let args = ty::GenericArgs::for_item(tcx, did.to_def_id(), |param, _| {
|
|
tcx.mk_param_from_def(param)
|
|
});
|
|
debug!("ast_ty_to_ty_inner(AnonAdt): args={:?}", args);
|
|
|
|
Ty::new_adt(tcx, adt_def, tcx.mk_args(args))
|
|
}
|
|
hir::TyKind::BareFn(bf) => {
|
|
require_c_abi_if_c_variadic(tcx, bf.decl, bf.abi, ast_ty.span);
|
|
|
|
Ty::new_fn_ptr(
|
|
tcx,
|
|
self.ty_of_fn(ast_ty.hir_id, bf.unsafety, bf.abi, bf.decl, None, Some(ast_ty)),
|
|
)
|
|
}
|
|
hir::TyKind::TraitObject(bounds, lifetime, repr) => {
|
|
self.maybe_lint_bare_trait(ast_ty, in_path);
|
|
let repr = match repr {
|
|
TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
|
|
TraitObjectSyntax::DynStar => ty::DynStar,
|
|
};
|
|
|
|
self.conv_object_ty_poly_trait_ref(
|
|
ast_ty.span,
|
|
ast_ty.hir_id,
|
|
bounds,
|
|
lifetime,
|
|
borrowed,
|
|
repr,
|
|
)
|
|
}
|
|
hir::TyKind::Path(hir::QPath::Resolved(maybe_qself, path)) => {
|
|
debug!(?maybe_qself, ?path);
|
|
let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself));
|
|
self.res_to_ty(opt_self_ty, path, ast_ty.hir_id, false)
|
|
}
|
|
&hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => {
|
|
let opaque_ty = tcx.hir().item(item_id);
|
|
|
|
match opaque_ty.kind {
|
|
hir::ItemKind::OpaqueTy(&hir::OpaqueTy { .. }) => {
|
|
let local_def_id = item_id.owner_id.def_id;
|
|
// If this is an RPITIT and we are using the new RPITIT lowering scheme, we
|
|
// generate the def_id of an associated type for the trait and return as
|
|
// type a projection.
|
|
let def_id = if in_trait {
|
|
tcx.associated_type_for_impl_trait_in_trait(local_def_id).to_def_id()
|
|
} else {
|
|
local_def_id.to_def_id()
|
|
};
|
|
self.impl_trait_ty_to_ty(def_id, lifetimes, in_trait)
|
|
}
|
|
ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i),
|
|
}
|
|
}
|
|
hir::TyKind::Path(hir::QPath::TypeRelative(qself, segment)) => {
|
|
debug!(?qself, ?segment);
|
|
let ty = self.ast_ty_to_ty_inner(qself, false, true);
|
|
self.associated_path_to_ty(ast_ty.hir_id, ast_ty.span, ty, qself, segment, false)
|
|
.map(|(ty, _, _)| ty)
|
|
.unwrap_or_else(|guar| Ty::new_error(tcx, guar))
|
|
}
|
|
&hir::TyKind::Path(hir::QPath::LangItem(lang_item, span)) => {
|
|
let def_id = tcx.require_lang_item(lang_item, Some(span));
|
|
let (args, _) = self.create_args_for_ast_path(
|
|
span,
|
|
def_id,
|
|
&[],
|
|
&hir::PathSegment::invalid(),
|
|
&GenericArgs::none(),
|
|
true,
|
|
None,
|
|
ty::BoundConstness::NotConst,
|
|
);
|
|
tcx.at(span).type_of(def_id).instantiate(tcx, args)
|
|
}
|
|
hir::TyKind::Array(ty, length) => {
|
|
let length = match length {
|
|
hir::ArrayLen::Infer(inf) => self.ct_infer(tcx.types.usize, None, inf.span),
|
|
hir::ArrayLen::Body(constant) => {
|
|
ty::Const::from_anon_const(tcx, constant.def_id)
|
|
}
|
|
};
|
|
|
|
Ty::new_array_with_const_len(tcx, self.ast_ty_to_ty(ty), length)
|
|
}
|
|
hir::TyKind::Typeof(e) => tcx.type_of(e.def_id).instantiate_identity(),
|
|
hir::TyKind::Infer => {
|
|
// Infer also appears as the type of arguments or return
|
|
// values in an ExprKind::Closure, or as
|
|
// the type of local variables. Both of these cases are
|
|
// handled specially and will not descend into this routine.
|
|
self.ty_infer(None, ast_ty.span)
|
|
}
|
|
hir::TyKind::Err(guar) => Ty::new_error(tcx, *guar),
|
|
};
|
|
|
|
self.record_ty(ast_ty.hir_id, result_ty, ast_ty.span);
|
|
result_ty
|
|
}
|
|
|
|
#[instrument(level = "debug", skip(self), ret)]
|
|
fn impl_trait_ty_to_ty(
|
|
&self,
|
|
def_id: DefId,
|
|
lifetimes: &[hir::GenericArg<'_>],
|
|
in_trait: bool,
|
|
) -> Ty<'tcx> {
|
|
debug!("impl_trait_ty_to_ty(def_id={:?}, lifetimes={:?})", def_id, lifetimes);
|
|
let tcx = self.tcx();
|
|
|
|
let generics = tcx.generics_of(def_id);
|
|
|
|
debug!("impl_trait_ty_to_ty: generics={:?}", generics);
|
|
let args = ty::GenericArgs::for_item(tcx, def_id, |param, _| {
|
|
// We use `generics.count() - lifetimes.len()` here instead of `generics.parent_count`
|
|
// since return-position impl trait in trait squashes all of the generics from its source fn
|
|
// into its own generics, so the opaque's "own" params isn't always just lifetimes.
|
|
if let Some(i) = (param.index as usize).checked_sub(generics.count() - lifetimes.len())
|
|
{
|
|
// Resolve our own lifetime parameters.
|
|
let GenericParamDefKind::Lifetime { .. } = param.kind else {
|
|
span_bug!(
|
|
tcx.def_span(param.def_id),
|
|
"only expected lifetime for opaque's own generics, got {:?}",
|
|
param.kind
|
|
);
|
|
};
|
|
let hir::GenericArg::Lifetime(lifetime) = &lifetimes[i] else {
|
|
bug!(
|
|
"expected lifetime argument for param {param:?}, found {:?}",
|
|
&lifetimes[i]
|
|
)
|
|
};
|
|
self.ast_region_to_region(lifetime, None).into()
|
|
} else {
|
|
tcx.mk_param_from_def(param)
|
|
}
|
|
});
|
|
debug!("impl_trait_ty_to_ty: args={:?}", args);
|
|
|
|
if in_trait {
|
|
Ty::new_projection(tcx, def_id, args)
|
|
} else {
|
|
Ty::new_opaque(tcx, def_id, args)
|
|
}
|
|
}
|
|
|
|
pub fn ty_of_arg(&self, ty: &hir::Ty<'tcx>, expected_ty: Option<Ty<'tcx>>) -> Ty<'tcx> {
|
|
match ty.kind {
|
|
hir::TyKind::Infer if expected_ty.is_some() => {
|
|
self.record_ty(ty.hir_id, expected_ty.unwrap(), ty.span);
|
|
expected_ty.unwrap()
|
|
}
|
|
_ => self.ast_ty_to_ty(ty),
|
|
}
|
|
}
|
|
|
|
#[instrument(level = "debug", skip(self, hir_id, unsafety, abi, decl, generics, hir_ty), ret)]
|
|
pub fn ty_of_fn(
|
|
&self,
|
|
hir_id: hir::HirId,
|
|
unsafety: hir::Unsafety,
|
|
abi: abi::Abi,
|
|
decl: &hir::FnDecl<'tcx>,
|
|
generics: Option<&hir::Generics<'_>>,
|
|
hir_ty: Option<&hir::Ty<'_>>,
|
|
) -> ty::PolyFnSig<'tcx> {
|
|
let tcx = self.tcx();
|
|
let bound_vars = if let hir::FnRetTy::Return(ret_ty) = decl.output
|
|
&& let hir::TyKind::InferDelegation(sig_id, _) = ret_ty.kind
|
|
{
|
|
tcx.fn_sig(sig_id).skip_binder().bound_vars()
|
|
} else {
|
|
tcx.late_bound_vars(hir_id)
|
|
};
|
|
debug!(?bound_vars);
|
|
|
|
// We proactively collect all the inferred type params to emit a single error per fn def.
|
|
let mut visitor = HirPlaceholderCollector::default();
|
|
let mut infer_replacements = vec![];
|
|
|
|
if let Some(generics) = generics {
|
|
walk_generics(&mut visitor, generics);
|
|
}
|
|
|
|
let input_tys: Vec<_> = decl
|
|
.inputs
|
|
.iter()
|
|
.enumerate()
|
|
.map(|(i, a)| {
|
|
if let hir::TyKind::Infer = a.kind
|
|
&& !self.allow_ty_infer()
|
|
{
|
|
if let Some(suggested_ty) =
|
|
self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, Some(i))
|
|
{
|
|
infer_replacements.push((a.span, suggested_ty.to_string()));
|
|
return Ty::new_error_with_message(
|
|
self.tcx(),
|
|
a.span,
|
|
suggested_ty.to_string(),
|
|
);
|
|
}
|
|
}
|
|
|
|
// Only visit the type looking for `_` if we didn't fix the type above
|
|
visitor.visit_ty(a);
|
|
self.ty_of_arg(a, None)
|
|
})
|
|
.collect();
|
|
|
|
let output_ty = match decl.output {
|
|
hir::FnRetTy::Return(output) => {
|
|
if let hir::TyKind::Infer = output.kind
|
|
&& !self.allow_ty_infer()
|
|
&& let Some(suggested_ty) =
|
|
self.suggest_trait_fn_ty_for_impl_fn_infer(hir_id, None)
|
|
{
|
|
infer_replacements.push((output.span, suggested_ty.to_string()));
|
|
Ty::new_error_with_message(self.tcx(), output.span, suggested_ty.to_string())
|
|
} else {
|
|
visitor.visit_ty(output);
|
|
self.ast_ty_to_ty(output)
|
|
}
|
|
}
|
|
hir::FnRetTy::DefaultReturn(..) => Ty::new_unit(tcx),
|
|
};
|
|
|
|
debug!(?output_ty);
|
|
|
|
let fn_ty = tcx.mk_fn_sig(input_tys, output_ty, decl.c_variadic, unsafety, abi);
|
|
let bare_fn_ty = ty::Binder::bind_with_vars(fn_ty, bound_vars);
|
|
|
|
if !self.allow_ty_infer() && !(visitor.0.is_empty() && infer_replacements.is_empty()) {
|
|
// We always collect the spans for placeholder types when evaluating `fn`s, but we
|
|
// only want to emit an error complaining about them if infer types (`_`) are not
|
|
// allowed. `allow_ty_infer` gates this behavior. We check for the presence of
|
|
// `ident_span` to not emit an error twice when we have `fn foo(_: fn() -> _)`.
|
|
|
|
let mut diag = crate::collect::placeholder_type_error_diag(
|
|
tcx,
|
|
generics,
|
|
visitor.0,
|
|
infer_replacements.iter().map(|(s, _)| *s).collect(),
|
|
true,
|
|
hir_ty,
|
|
"function",
|
|
);
|
|
|
|
if !infer_replacements.is_empty() {
|
|
diag.multipart_suggestion(
|
|
format!(
|
|
"try replacing `_` with the type{} in the corresponding trait method signature",
|
|
rustc_errors::pluralize!(infer_replacements.len()),
|
|
),
|
|
infer_replacements,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
|
|
self.set_tainted_by_errors(diag.emit());
|
|
}
|
|
|
|
// Find any late-bound regions declared in return type that do
|
|
// not appear in the arguments. These are not well-formed.
|
|
//
|
|
// Example:
|
|
// for<'a> fn() -> &'a str <-- 'a is bad
|
|
// for<'a> fn(&'a String) -> &'a str <-- 'a is ok
|
|
let inputs = bare_fn_ty.inputs();
|
|
let late_bound_in_args =
|
|
tcx.collect_constrained_late_bound_regions(&inputs.map_bound(|i| i.to_owned()));
|
|
let output = bare_fn_ty.output();
|
|
let late_bound_in_ret = tcx.collect_referenced_late_bound_regions(&output);
|
|
|
|
self.validate_late_bound_regions(late_bound_in_args, late_bound_in_ret, |br_name| {
|
|
struct_span_code_err!(
|
|
tcx.dcx(),
|
|
decl.output.span(),
|
|
E0581,
|
|
"return type references {}, which is not constrained by the fn input types",
|
|
br_name
|
|
)
|
|
});
|
|
|
|
bare_fn_ty
|
|
}
|
|
|
|
/// Given a fn_hir_id for a impl function, suggest the type that is found on the
|
|
/// corresponding function in the trait that the impl implements, if it exists.
|
|
/// If arg_idx is Some, then it corresponds to an input type index, otherwise it
|
|
/// corresponds to the return type.
|
|
fn suggest_trait_fn_ty_for_impl_fn_infer(
|
|
&self,
|
|
fn_hir_id: hir::HirId,
|
|
arg_idx: Option<usize>,
|
|
) -> Option<Ty<'tcx>> {
|
|
let tcx = self.tcx();
|
|
let hir::Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Fn(..), ident, .. }) =
|
|
tcx.hir_node(fn_hir_id)
|
|
else {
|
|
return None;
|
|
};
|
|
let i = tcx.parent_hir_node(fn_hir_id).expect_item().expect_impl();
|
|
|
|
let trait_ref =
|
|
self.instantiate_mono_trait_ref(i.of_trait.as_ref()?, self.ast_ty_to_ty(i.self_ty));
|
|
|
|
let assoc = tcx.associated_items(trait_ref.def_id).find_by_name_and_kind(
|
|
tcx,
|
|
*ident,
|
|
ty::AssocKind::Fn,
|
|
trait_ref.def_id,
|
|
)?;
|
|
|
|
let fn_sig = tcx.fn_sig(assoc.def_id).instantiate(
|
|
tcx,
|
|
trait_ref.args.extend_to(tcx, assoc.def_id, |param, _| tcx.mk_param_from_def(param)),
|
|
);
|
|
let fn_sig = tcx.liberate_late_bound_regions(fn_hir_id.expect_owner().to_def_id(), fn_sig);
|
|
|
|
Some(if let Some(arg_idx) = arg_idx {
|
|
*fn_sig.inputs().get(arg_idx)?
|
|
} else {
|
|
fn_sig.output()
|
|
})
|
|
}
|
|
|
|
#[instrument(level = "trace", skip(self, generate_err))]
|
|
fn validate_late_bound_regions(
|
|
&self,
|
|
constrained_regions: FxHashSet<ty::BoundRegionKind>,
|
|
referenced_regions: FxHashSet<ty::BoundRegionKind>,
|
|
generate_err: impl Fn(&str) -> DiagnosticBuilder<'tcx>,
|
|
) {
|
|
for br in referenced_regions.difference(&constrained_regions) {
|
|
let br_name = match *br {
|
|
ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon | ty::BrEnv => {
|
|
"an anonymous lifetime".to_string()
|
|
}
|
|
ty::BrNamed(_, name) => format!("lifetime `{name}`"),
|
|
};
|
|
|
|
let mut err = generate_err(&br_name);
|
|
|
|
if let ty::BrNamed(_, kw::UnderscoreLifetime) | ty::BrAnon = *br {
|
|
// The only way for an anonymous lifetime to wind up
|
|
// in the return type but **also** be unconstrained is
|
|
// if it only appears in "associated types" in the
|
|
// input. See #47511 and #62200 for examples. In this case,
|
|
// though we can easily give a hint that ought to be
|
|
// relevant.
|
|
err.note(
|
|
"lifetimes appearing in an associated or opaque type are not considered constrained",
|
|
);
|
|
err.note("consider introducing a named lifetime parameter");
|
|
}
|
|
|
|
self.set_tainted_by_errors(err.emit());
|
|
}
|
|
}
|
|
|
|
/// Given the bounds on an object, determines what single region bound (if any) we can
|
|
/// use to summarize this type. The basic idea is that we will use the bound the user
|
|
/// provided, if they provided one, and otherwise search the supertypes of trait bounds
|
|
/// for region bounds. It may be that we can derive no bound at all, in which case
|
|
/// we return `None`.
|
|
#[instrument(level = "debug", skip(self, span), ret)]
|
|
fn compute_object_lifetime_bound(
|
|
&self,
|
|
span: Span,
|
|
existential_predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
|
|
) -> Option<ty::Region<'tcx>> // if None, use the default
|
|
{
|
|
let tcx = self.tcx();
|
|
|
|
// No explicit region bound specified. Therefore, examine trait
|
|
// bounds and see if we can derive region bounds from those.
|
|
let derived_region_bounds = object_region_bounds(tcx, existential_predicates);
|
|
|
|
// If there are no derived region bounds, then report back that we
|
|
// can find no region bound. The caller will use the default.
|
|
if derived_region_bounds.is_empty() {
|
|
return None;
|
|
}
|
|
|
|
// If any of the derived region bounds are 'static, that is always
|
|
// the best choice.
|
|
if derived_region_bounds.iter().any(|r| r.is_static()) {
|
|
return Some(tcx.lifetimes.re_static);
|
|
}
|
|
|
|
// Determine whether there is exactly one unique region in the set
|
|
// of derived region bounds. If so, use that. Otherwise, report an
|
|
// error.
|
|
let r = derived_region_bounds[0];
|
|
if derived_region_bounds[1..].iter().any(|r1| r != *r1) {
|
|
self.set_tainted_by_errors(tcx.dcx().emit_err(AmbiguousLifetimeBound { span }));
|
|
}
|
|
Some(r)
|
|
}
|
|
}
|
|
|
|
fn assoc_kind_str(kind: ty::AssocKind) -> &'static str {
|
|
match kind {
|
|
ty::AssocKind::Fn => "function",
|
|
ty::AssocKind::Const => "constant",
|
|
ty::AssocKind::Type => "type",
|
|
}
|
|
}
|