2590 lines
91 KiB
Rust
2590 lines
91 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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pub use self::Variance::*;
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pub use self::AssociatedItemContainer::*;
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pub use self::BorrowKind::*;
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pub use self::IntVarValue::*;
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pub use self::LvaluePreference::*;
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pub use self::fold::TypeFoldable;
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use hir::{map as hir_map, FreevarMap, TraitMap};
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use hir::def::{Def, CtorKind, ExportMap};
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use hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
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use ich::StableHashingContext;
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use middle::const_val::ConstVal;
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use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
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use middle::privacy::AccessLevels;
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use middle::resolve_lifetime::ObjectLifetimeDefault;
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use mir::Mir;
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use mir::GeneratorLayout;
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use traits;
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use ty;
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use ty::subst::{Subst, Substs};
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use ty::util::IntTypeExt;
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use ty::walk::TypeWalker;
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use util::common::ErrorReported;
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use util::nodemap::{NodeSet, DefIdMap, FxHashMap, FxHashSet};
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use serialize::{self, Encodable, Encoder};
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use std::collections::BTreeMap;
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use std::cmp;
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use std::fmt;
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use std::hash::{Hash, Hasher};
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use std::iter::FromIterator;
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use std::ops::Deref;
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use std::rc::Rc;
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use std::slice;
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use std::vec::IntoIter;
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use std::mem;
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use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
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use syntax::attr;
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use syntax::ext::hygiene::{Mark, SyntaxContext};
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use syntax::symbol::{Symbol, InternedString};
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use syntax_pos::{DUMMY_SP, Span};
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use rustc_const_math::ConstInt;
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use rustc_data_structures::accumulate_vec::IntoIter as AccIntoIter;
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use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
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HashStable};
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use rustc_data_structures::transitive_relation::TransitiveRelation;
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use hir;
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pub use self::sty::{Binder, DebruijnIndex};
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pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
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pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
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pub use self::sty::{ClosureSubsts, GeneratorInterior, TypeAndMut};
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pub use self::sty::{TraitRef, TypeVariants, PolyTraitRef};
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pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
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pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
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pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
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pub use self::sty::RegionKind;
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pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
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pub use self::sty::BoundRegion::*;
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pub use self::sty::InferTy::*;
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pub use self::sty::RegionKind::*;
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pub use self::sty::TypeVariants::*;
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pub use self::binding::BindingMode;
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pub use self::binding::BindingMode::*;
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pub use self::context::{TyCtxt, GlobalArenas, tls, keep_local};
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pub use self::context::{Lift, TypeckTables};
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pub use self::instance::{Instance, InstanceDef};
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pub use self::trait_def::TraitDef;
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pub use self::maps::queries;
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pub mod adjustment;
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pub mod binding;
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pub mod cast;
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pub mod error;
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pub mod fast_reject;
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pub mod fold;
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pub mod inhabitedness;
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pub mod item_path;
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pub mod layout;
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pub mod _match;
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pub mod maps;
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pub mod outlives;
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pub mod relate;
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pub mod steal;
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pub mod subst;
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pub mod trait_def;
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pub mod walk;
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pub mod wf;
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pub mod util;
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mod context;
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mod flags;
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mod instance;
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mod structural_impls;
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mod sty;
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// Data types
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/// The complete set of all analyses described in this module. This is
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/// produced by the driver and fed to trans and later passes.
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///
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/// NB: These contents are being migrated into queries using the
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/// *on-demand* infrastructure.
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#[derive(Clone)]
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pub struct CrateAnalysis {
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pub access_levels: Rc<AccessLevels>,
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pub reachable: Rc<NodeSet>,
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pub name: String,
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pub glob_map: Option<hir::GlobMap>,
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}
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#[derive(Clone)]
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pub struct Resolutions {
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pub freevars: FreevarMap,
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pub trait_map: TraitMap,
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pub maybe_unused_trait_imports: NodeSet,
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pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
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pub export_map: ExportMap,
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}
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#[derive(Clone, Copy, PartialEq, Eq, Debug)]
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pub enum AssociatedItemContainer {
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TraitContainer(DefId),
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ImplContainer(DefId),
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}
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impl AssociatedItemContainer {
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pub fn id(&self) -> DefId {
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match *self {
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TraitContainer(id) => id,
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ImplContainer(id) => id,
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}
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}
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}
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/// The "header" of an impl is everything outside the body: a Self type, a trait
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/// ref (in the case of a trait impl), and a set of predicates (from the
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/// bounds/where clauses).
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#[derive(Clone, PartialEq, Eq, Hash, Debug)]
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pub struct ImplHeader<'tcx> {
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pub impl_def_id: DefId,
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pub self_ty: Ty<'tcx>,
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pub trait_ref: Option<TraitRef<'tcx>>,
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pub predicates: Vec<Predicate<'tcx>>,
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}
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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pub struct AssociatedItem {
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pub def_id: DefId,
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pub name: Name,
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pub kind: AssociatedKind,
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pub vis: Visibility,
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pub defaultness: hir::Defaultness,
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pub container: AssociatedItemContainer,
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/// Whether this is a method with an explicit self
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/// as its first argument, allowing method calls.
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pub method_has_self_argument: bool,
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}
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#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
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pub enum AssociatedKind {
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Const,
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Method,
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Type
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}
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impl AssociatedItem {
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pub fn def(&self) -> Def {
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match self.kind {
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AssociatedKind::Const => Def::AssociatedConst(self.def_id),
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AssociatedKind::Method => Def::Method(self.def_id),
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AssociatedKind::Type => Def::AssociatedTy(self.def_id),
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}
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}
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/// Tests whether the associated item admits a non-trivial implementation
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/// for !
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pub fn relevant_for_never<'tcx>(&self) -> bool {
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match self.kind {
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AssociatedKind::Const => true,
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AssociatedKind::Type => true,
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// FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
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AssociatedKind::Method => !self.method_has_self_argument,
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}
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}
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pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
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match self.kind {
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ty::AssociatedKind::Method => {
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// We skip the binder here because the binder would deanonymize all
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// late-bound regions, and we don't want method signatures to show up
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// `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
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// regions just fine, showing `fn(&MyType)`.
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format!("{}", tcx.fn_sig(self.def_id).skip_binder())
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}
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ty::AssociatedKind::Type => format!("type {};", self.name.to_string()),
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ty::AssociatedKind::Const => {
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format!("const {}: {:?};", self.name.to_string(), tcx.type_of(self.def_id))
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}
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}
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}
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}
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#[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
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pub enum Visibility {
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/// Visible everywhere (including in other crates).
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Public,
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/// Visible only in the given crate-local module.
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Restricted(DefId),
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/// Not visible anywhere in the local crate. This is the visibility of private external items.
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Invisible,
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}
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pub trait DefIdTree: Copy {
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fn parent(self, id: DefId) -> Option<DefId>;
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fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
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if descendant.krate != ancestor.krate {
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return false;
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}
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while descendant != ancestor {
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match self.parent(descendant) {
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Some(parent) => descendant = parent,
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None => return false,
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}
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}
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true
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}
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}
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impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
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fn parent(self, id: DefId) -> Option<DefId> {
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self.def_key(id).parent.map(|index| DefId { index: index, ..id })
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}
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}
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impl Visibility {
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pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
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match *visibility {
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hir::Public => Visibility::Public,
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hir::Visibility::Crate => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
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hir::Visibility::Restricted { ref path, .. } => match path.def {
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// If there is no resolution, `resolve` will have already reported an error, so
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// assume that the visibility is public to avoid reporting more privacy errors.
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Def::Err => Visibility::Public,
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def => Visibility::Restricted(def.def_id()),
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},
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hir::Inherited => {
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Visibility::Restricted(tcx.hir.get_module_parent(id))
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}
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}
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}
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/// Returns true if an item with this visibility is accessible from the given block.
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pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
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let restriction = match self {
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// Public items are visible everywhere.
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Visibility::Public => return true,
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// Private items from other crates are visible nowhere.
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Visibility::Invisible => return false,
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// Restricted items are visible in an arbitrary local module.
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Visibility::Restricted(other) if other.krate != module.krate => return false,
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Visibility::Restricted(module) => module,
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};
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tree.is_descendant_of(module, restriction)
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}
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/// Returns true if this visibility is at least as accessible as the given visibility
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pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
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let vis_restriction = match vis {
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Visibility::Public => return self == Visibility::Public,
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Visibility::Invisible => return true,
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Visibility::Restricted(module) => module,
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};
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self.is_accessible_from(vis_restriction, tree)
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}
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}
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#[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
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pub enum Variance {
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Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
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Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
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Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
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Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
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}
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/// The crate variances map is computed during typeck and contains the
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/// variance of every item in the local crate. You should not use it
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/// directly, because to do so will make your pass dependent on the
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/// HIR of every item in the local crate. Instead, use
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/// `tcx.variances_of()` to get the variance for a *particular*
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/// item.
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pub struct CrateVariancesMap {
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/// This relation tracks the dependencies between the variance of
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/// various items. In particular, if `a < b`, then the variance of
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/// `a` depends on the sources of `b`.
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pub dependencies: TransitiveRelation<DefId>,
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/// For each item with generics, maps to a vector of the variance
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/// of its generics. If an item has no generics, it will have no
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/// entry.
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pub variances: FxHashMap<DefId, Rc<Vec<ty::Variance>>>,
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/// An empty vector, useful for cloning.
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pub empty_variance: Rc<Vec<ty::Variance>>,
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}
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impl Variance {
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/// `a.xform(b)` combines the variance of a context with the
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/// variance of a type with the following meaning. If we are in a
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/// context with variance `a`, and we encounter a type argument in
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/// a position with variance `b`, then `a.xform(b)` is the new
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/// variance with which the argument appears.
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///
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/// Example 1:
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///
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/// *mut Vec<i32>
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///
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/// Here, the "ambient" variance starts as covariant. `*mut T` is
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/// invariant with respect to `T`, so the variance in which the
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/// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
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/// yields `Invariant`. Now, the type `Vec<T>` is covariant with
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/// respect to its type argument `T`, and hence the variance of
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/// the `i32` here is `Invariant.xform(Covariant)`, which results
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/// (again) in `Invariant`.
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///
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/// Example 2:
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///
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/// fn(*const Vec<i32>, *mut Vec<i32)
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///
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/// The ambient variance is covariant. A `fn` type is
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/// contravariant with respect to its parameters, so the variance
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/// within which both pointer types appear is
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/// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
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/// T` is covariant with respect to `T`, so the variance within
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/// which the first `Vec<i32>` appears is
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/// `Contravariant.xform(Covariant)` or `Contravariant`. The same
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/// is true for its `i32` argument. In the `*mut T` case, the
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/// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
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/// and hence the outermost type is `Invariant` with respect to
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/// `Vec<i32>` (and its `i32` argument).
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///
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/// Source: Figure 1 of "Taming the Wildcards:
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/// Combining Definition- and Use-Site Variance" published in PLDI'11.
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pub fn xform(self, v: ty::Variance) -> ty::Variance {
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match (self, v) {
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// Figure 1, column 1.
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(ty::Covariant, ty::Covariant) => ty::Covariant,
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(ty::Covariant, ty::Contravariant) => ty::Contravariant,
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(ty::Covariant, ty::Invariant) => ty::Invariant,
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(ty::Covariant, ty::Bivariant) => ty::Bivariant,
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// Figure 1, column 2.
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(ty::Contravariant, ty::Covariant) => ty::Contravariant,
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(ty::Contravariant, ty::Contravariant) => ty::Covariant,
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(ty::Contravariant, ty::Invariant) => ty::Invariant,
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(ty::Contravariant, ty::Bivariant) => ty::Bivariant,
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// Figure 1, column 3.
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(ty::Invariant, _) => ty::Invariant,
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// Figure 1, column 4.
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(ty::Bivariant, _) => ty::Bivariant,
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}
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}
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}
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// Contains information needed to resolve types and (in the future) look up
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// the types of AST nodes.
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#[derive(Copy, Clone, PartialEq, Eq, Hash)]
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pub struct CReaderCacheKey {
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pub cnum: CrateNum,
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pub pos: usize,
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}
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// Flags that we track on types. These flags are propagated upwards
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// through the type during type construction, so that we can quickly
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// check whether the type has various kinds of types in it without
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// recursing over the type itself.
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bitflags! {
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pub struct TypeFlags: u32 {
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const HAS_PARAMS = 1 << 0;
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const HAS_SELF = 1 << 1;
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const HAS_TY_INFER = 1 << 2;
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const HAS_RE_INFER = 1 << 3;
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const HAS_RE_SKOL = 1 << 4;
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const HAS_RE_EARLY_BOUND = 1 << 5;
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const HAS_FREE_REGIONS = 1 << 6;
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const HAS_TY_ERR = 1 << 7;
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const HAS_PROJECTION = 1 << 8;
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// FIXME: Rename this to the actual property since it's used for generators too
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const HAS_TY_CLOSURE = 1 << 9;
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// true if there are "names" of types and regions and so forth
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// that are local to a particular fn
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const HAS_LOCAL_NAMES = 1 << 10;
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// Present if the type belongs in a local type context.
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// Only set for TyInfer other than Fresh.
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const KEEP_IN_LOCAL_TCX = 1 << 11;
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// Is there a projection that does not involve a bound region?
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// Currently we can't normalize projections w/ bound regions.
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const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
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const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
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TypeFlags::HAS_SELF.bits |
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TypeFlags::HAS_RE_EARLY_BOUND.bits;
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// Flags representing the nominal content of a type,
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// computed by FlagsComputation. If you add a new nominal
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// flag, it should be added here too.
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const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
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TypeFlags::HAS_SELF.bits |
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TypeFlags::HAS_TY_INFER.bits |
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TypeFlags::HAS_RE_INFER.bits |
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TypeFlags::HAS_RE_SKOL.bits |
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TypeFlags::HAS_RE_EARLY_BOUND.bits |
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TypeFlags::HAS_FREE_REGIONS.bits |
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TypeFlags::HAS_TY_ERR.bits |
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TypeFlags::HAS_PROJECTION.bits |
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TypeFlags::HAS_TY_CLOSURE.bits |
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TypeFlags::HAS_LOCAL_NAMES.bits |
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TypeFlags::KEEP_IN_LOCAL_TCX.bits;
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}
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}
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pub struct TyS<'tcx> {
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pub sty: TypeVariants<'tcx>,
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pub flags: TypeFlags,
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// the maximal depth of any bound regions appearing in this type.
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region_depth: u32,
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}
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impl<'tcx> PartialEq for TyS<'tcx> {
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#[inline]
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fn eq(&self, other: &TyS<'tcx>) -> bool {
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// (self as *const _) == (other as *const _)
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(self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
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}
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}
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impl<'tcx> Eq for TyS<'tcx> {}
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impl<'tcx> Hash for TyS<'tcx> {
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fn hash<H: Hasher>(&self, s: &mut H) {
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(self as *const TyS).hash(s)
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}
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}
|
|
|
|
impl<'tcx> TyS<'tcx> {
|
|
pub fn is_primitive_ty(&self) -> bool {
|
|
match self.sty {
|
|
TypeVariants::TyBool |
|
|
TypeVariants::TyChar |
|
|
TypeVariants::TyInt(_) |
|
|
TypeVariants::TyUint(_) |
|
|
TypeVariants::TyFloat(_) |
|
|
TypeVariants::TyInfer(InferTy::IntVar(_)) |
|
|
TypeVariants::TyInfer(InferTy::FloatVar(_)) |
|
|
TypeVariants::TyInfer(InferTy::FreshIntTy(_)) |
|
|
TypeVariants::TyInfer(InferTy::FreshFloatTy(_)) => true,
|
|
TypeVariants::TyRef(_, x) => x.ty.is_primitive_ty(),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_suggestable(&self) -> bool {
|
|
match self.sty {
|
|
TypeVariants::TyAnon(..) |
|
|
TypeVariants::TyFnDef(..) |
|
|
TypeVariants::TyFnPtr(..) |
|
|
TypeVariants::TyDynamic(..) |
|
|
TypeVariants::TyClosure(..) |
|
|
TypeVariants::TyInfer(..) |
|
|
TypeVariants::TyProjection(..) => false,
|
|
_ => true,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for ty::TyS<'gcx> {
|
|
fn hash_stable<W: StableHasherResult>(&self,
|
|
hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
|
|
hasher: &mut StableHasher<W>) {
|
|
let ty::TyS {
|
|
ref sty,
|
|
|
|
// The other fields just provide fast access to information that is
|
|
// also contained in `sty`, so no need to hash them.
|
|
flags: _,
|
|
region_depth: _,
|
|
} = *self;
|
|
|
|
sty.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
pub type Ty<'tcx> = &'tcx TyS<'tcx>;
|
|
|
|
impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
|
|
impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
|
|
|
|
/// A wrapper for slices with the additional invariant
|
|
/// that the slice is interned and no other slice with
|
|
/// the same contents can exist in the same context.
|
|
/// This means we can use pointer + length for both
|
|
/// equality comparisons and hashing.
|
|
#[derive(Debug, RustcEncodable)]
|
|
pub struct Slice<T>([T]);
|
|
|
|
impl<T> PartialEq for Slice<T> {
|
|
#[inline]
|
|
fn eq(&self, other: &Slice<T>) -> bool {
|
|
(&self.0 as *const [T]) == (&other.0 as *const [T])
|
|
}
|
|
}
|
|
impl<T> Eq for Slice<T> {}
|
|
|
|
impl<T> Hash for Slice<T> {
|
|
fn hash<H: Hasher>(&self, s: &mut H) {
|
|
(self.as_ptr(), self.len()).hash(s)
|
|
}
|
|
}
|
|
|
|
impl<T> Deref for Slice<T> {
|
|
type Target = [T];
|
|
fn deref(&self) -> &[T] {
|
|
&self.0
|
|
}
|
|
}
|
|
|
|
impl<'a, T> IntoIterator for &'a Slice<T> {
|
|
type Item = &'a T;
|
|
type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
|
|
fn into_iter(self) -> Self::IntoIter {
|
|
self[..].iter()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<Ty<'tcx>> {}
|
|
|
|
impl<T> Slice<T> {
|
|
pub fn empty<'a>() -> &'a Slice<T> {
|
|
unsafe {
|
|
mem::transmute(slice::from_raw_parts(0x1 as *const T, 0))
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Upvars do not get their own node-id. Instead, we use the pair of
|
|
/// the original var id (that is, the root variable that is referenced
|
|
/// by the upvar) and the id of the closure expression.
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct UpvarId {
|
|
pub var_id: hir::HirId,
|
|
pub closure_expr_id: DefIndex,
|
|
}
|
|
|
|
#[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
|
|
pub enum BorrowKind {
|
|
/// Data must be immutable and is aliasable.
|
|
ImmBorrow,
|
|
|
|
/// Data must be immutable but not aliasable. This kind of borrow
|
|
/// cannot currently be expressed by the user and is used only in
|
|
/// implicit closure bindings. It is needed when the closure
|
|
/// is borrowing or mutating a mutable referent, e.g.:
|
|
///
|
|
/// let x: &mut isize = ...;
|
|
/// let y = || *x += 5;
|
|
///
|
|
/// If we were to try to translate this closure into a more explicit
|
|
/// form, we'd encounter an error with the code as written:
|
|
///
|
|
/// struct Env { x: & &mut isize }
|
|
/// let x: &mut isize = ...;
|
|
/// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
|
|
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
|
///
|
|
/// This is then illegal because you cannot mutate a `&mut` found
|
|
/// in an aliasable location. To solve, you'd have to translate with
|
|
/// an `&mut` borrow:
|
|
///
|
|
/// struct Env { x: & &mut isize }
|
|
/// let x: &mut isize = ...;
|
|
/// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
|
|
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
|
///
|
|
/// Now the assignment to `**env.x` is legal, but creating a
|
|
/// mutable pointer to `x` is not because `x` is not mutable. We
|
|
/// could fix this by declaring `x` as `let mut x`. This is ok in
|
|
/// user code, if awkward, but extra weird for closures, since the
|
|
/// borrow is hidden.
|
|
///
|
|
/// So we introduce a "unique imm" borrow -- the referent is
|
|
/// immutable, but not aliasable. This solves the problem. For
|
|
/// simplicity, we don't give users the way to express this
|
|
/// borrow, it's just used when translating closures.
|
|
UniqueImmBorrow,
|
|
|
|
/// Data is mutable and not aliasable.
|
|
MutBorrow
|
|
}
|
|
|
|
/// Information describing the capture of an upvar. This is computed
|
|
/// during `typeck`, specifically by `regionck`.
|
|
#[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
|
|
pub enum UpvarCapture<'tcx> {
|
|
/// Upvar is captured by value. This is always true when the
|
|
/// closure is labeled `move`, but can also be true in other cases
|
|
/// depending on inference.
|
|
ByValue,
|
|
|
|
/// Upvar is captured by reference.
|
|
ByRef(UpvarBorrow<'tcx>),
|
|
}
|
|
|
|
#[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
|
|
pub struct UpvarBorrow<'tcx> {
|
|
/// The kind of borrow: by-ref upvars have access to shared
|
|
/// immutable borrows, which are not part of the normal language
|
|
/// syntax.
|
|
pub kind: BorrowKind,
|
|
|
|
/// Region of the resulting reference.
|
|
pub region: ty::Region<'tcx>,
|
|
}
|
|
|
|
pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
|
|
|
|
#[derive(Copy, Clone)]
|
|
pub struct ClosureUpvar<'tcx> {
|
|
pub def: Def,
|
|
pub span: Span,
|
|
pub ty: Ty<'tcx>,
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq)]
|
|
pub enum IntVarValue {
|
|
IntType(ast::IntTy),
|
|
UintType(ast::UintTy),
|
|
}
|
|
|
|
#[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
|
|
pub struct TypeParameterDef {
|
|
pub name: Name,
|
|
pub def_id: DefId,
|
|
pub index: u32,
|
|
pub has_default: bool,
|
|
pub object_lifetime_default: ObjectLifetimeDefault,
|
|
|
|
/// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
|
|
/// on generic parameter `T`, asserts data behind the parameter
|
|
/// `T` won't be accessed during the parent type's `Drop` impl.
|
|
pub pure_wrt_drop: bool,
|
|
}
|
|
|
|
#[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
|
|
pub struct RegionParameterDef {
|
|
pub name: Name,
|
|
pub def_id: DefId,
|
|
pub index: u32,
|
|
|
|
/// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
|
|
/// on generic parameter `'a`, asserts data of lifetime `'a`
|
|
/// won't be accessed during the parent type's `Drop` impl.
|
|
pub pure_wrt_drop: bool,
|
|
}
|
|
|
|
impl RegionParameterDef {
|
|
pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
|
|
ty::EarlyBoundRegion {
|
|
def_id: self.def_id,
|
|
index: self.index,
|
|
name: self.name,
|
|
}
|
|
}
|
|
|
|
pub fn to_bound_region(&self) -> ty::BoundRegion {
|
|
self.to_early_bound_region_data().to_bound_region()
|
|
}
|
|
}
|
|
|
|
impl ty::EarlyBoundRegion {
|
|
pub fn to_bound_region(&self) -> ty::BoundRegion {
|
|
ty::BoundRegion::BrNamed(self.def_id, self.name)
|
|
}
|
|
}
|
|
|
|
/// Information about the formal type/lifetime parameters associated
|
|
/// with an item or method. Analogous to hir::Generics.
|
|
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
|
|
pub struct Generics {
|
|
pub parent: Option<DefId>,
|
|
pub parent_regions: u32,
|
|
pub parent_types: u32,
|
|
pub regions: Vec<RegionParameterDef>,
|
|
pub types: Vec<TypeParameterDef>,
|
|
|
|
/// Reverse map to each `TypeParameterDef`'s `index` field, from
|
|
/// `def_id.index` (`def_id.krate` is the same as the item's).
|
|
pub type_param_to_index: BTreeMap<DefIndex, u32>,
|
|
|
|
pub has_self: bool,
|
|
pub has_late_bound_regions: Option<Span>,
|
|
}
|
|
|
|
impl Generics {
|
|
pub fn parent_count(&self) -> usize {
|
|
self.parent_regions as usize + self.parent_types as usize
|
|
}
|
|
|
|
pub fn own_count(&self) -> usize {
|
|
self.regions.len() + self.types.len()
|
|
}
|
|
|
|
pub fn count(&self) -> usize {
|
|
self.parent_count() + self.own_count()
|
|
}
|
|
|
|
pub fn region_param(&self, param: &EarlyBoundRegion) -> &RegionParameterDef {
|
|
assert_eq!(self.parent_count(), 0);
|
|
&self.regions[param.index as usize - self.has_self as usize]
|
|
}
|
|
|
|
pub fn type_param(&self, param: &ParamTy) -> &TypeParameterDef {
|
|
assert_eq!(self.parent_count(), 0);
|
|
&self.types[param.idx as usize - self.has_self as usize - self.regions.len()]
|
|
}
|
|
}
|
|
|
|
/// Bounds on generics.
|
|
#[derive(Clone, Default)]
|
|
pub struct GenericPredicates<'tcx> {
|
|
pub parent: Option<DefId>,
|
|
pub predicates: Vec<Predicate<'tcx>>,
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
|
|
impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
|
|
|
|
impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
|
|
pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
|
|
-> InstantiatedPredicates<'tcx> {
|
|
let mut instantiated = InstantiatedPredicates::empty();
|
|
self.instantiate_into(tcx, &mut instantiated, substs);
|
|
instantiated
|
|
}
|
|
pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
|
|
-> InstantiatedPredicates<'tcx> {
|
|
InstantiatedPredicates {
|
|
predicates: self.predicates.subst(tcx, substs)
|
|
}
|
|
}
|
|
|
|
fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
|
instantiated: &mut InstantiatedPredicates<'tcx>,
|
|
substs: &Substs<'tcx>) {
|
|
if let Some(def_id) = self.parent {
|
|
tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
|
|
}
|
|
instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
|
|
}
|
|
|
|
pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
|
|
-> InstantiatedPredicates<'tcx> {
|
|
let mut instantiated = InstantiatedPredicates::empty();
|
|
self.instantiate_identity_into(tcx, &mut instantiated);
|
|
instantiated
|
|
}
|
|
|
|
fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
|
instantiated: &mut InstantiatedPredicates<'tcx>) {
|
|
if let Some(def_id) = self.parent {
|
|
tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
|
|
}
|
|
instantiated.predicates.extend(&self.predicates)
|
|
}
|
|
|
|
pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
|
poly_trait_ref: &ty::PolyTraitRef<'tcx>)
|
|
-> InstantiatedPredicates<'tcx>
|
|
{
|
|
assert_eq!(self.parent, None);
|
|
InstantiatedPredicates {
|
|
predicates: self.predicates.iter().map(|pred| {
|
|
pred.subst_supertrait(tcx, poly_trait_ref)
|
|
}).collect()
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub enum Predicate<'tcx> {
|
|
/// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
|
|
/// the `Self` type of the trait reference and `A`, `B`, and `C`
|
|
/// would be the type parameters.
|
|
Trait(PolyTraitPredicate<'tcx>),
|
|
|
|
/// where `T1 == T2`.
|
|
Equate(PolyEquatePredicate<'tcx>),
|
|
|
|
/// where 'a : 'b
|
|
RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
|
|
|
|
/// where T : 'a
|
|
TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
|
|
|
|
/// where <T as TraitRef>::Name == X, approximately.
|
|
/// See `ProjectionPredicate` struct for details.
|
|
Projection(PolyProjectionPredicate<'tcx>),
|
|
|
|
/// no syntax: T WF
|
|
WellFormed(Ty<'tcx>),
|
|
|
|
/// trait must be object-safe
|
|
ObjectSafe(DefId),
|
|
|
|
/// No direct syntax. May be thought of as `where T : FnFoo<...>`
|
|
/// for some substitutions `...` and T being a closure type.
|
|
/// Satisfied (or refuted) once we know the closure's kind.
|
|
ClosureKind(DefId, ClosureKind),
|
|
|
|
/// `T1 <: T2`
|
|
Subtype(PolySubtypePredicate<'tcx>),
|
|
|
|
/// Constant initializer must evaluate successfully.
|
|
ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
|
|
/// Performs a substitution suitable for going from a
|
|
/// poly-trait-ref to supertraits that must hold if that
|
|
/// poly-trait-ref holds. This is slightly different from a normal
|
|
/// substitution in terms of what happens with bound regions. See
|
|
/// lengthy comment below for details.
|
|
pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
|
trait_ref: &ty::PolyTraitRef<'tcx>)
|
|
-> ty::Predicate<'tcx>
|
|
{
|
|
// The interaction between HRTB and supertraits is not entirely
|
|
// obvious. Let me walk you (and myself) through an example.
|
|
//
|
|
// Let's start with an easy case. Consider two traits:
|
|
//
|
|
// trait Foo<'a> : Bar<'a,'a> { }
|
|
// trait Bar<'b,'c> { }
|
|
//
|
|
// Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
|
|
// we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
|
|
// knew that `Foo<'x>` (for any 'x) then we also know that
|
|
// `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
|
|
// normal substitution.
|
|
//
|
|
// In terms of why this is sound, the idea is that whenever there
|
|
// is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
|
|
// holds. So if there is an impl of `T:Foo<'a>` that applies to
|
|
// all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
|
|
// `'a`.
|
|
//
|
|
// Another example to be careful of is this:
|
|
//
|
|
// trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
|
|
// trait Bar1<'b,'c> { }
|
|
//
|
|
// Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
|
|
// The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
|
|
// reason is similar to the previous example: any impl of
|
|
// `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
|
|
// basically we would want to collapse the bound lifetimes from
|
|
// the input (`trait_ref`) and the supertraits.
|
|
//
|
|
// To achieve this in practice is fairly straightforward. Let's
|
|
// consider the more complicated scenario:
|
|
//
|
|
// - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
|
|
// has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
|
|
// where both `'x` and `'b` would have a DB index of 1.
|
|
// The substitution from the input trait-ref is therefore going to be
|
|
// `'a => 'x` (where `'x` has a DB index of 1).
|
|
// - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
|
|
// early-bound parameter and `'b' is a late-bound parameter with a
|
|
// DB index of 1.
|
|
// - If we replace `'a` with `'x` from the input, it too will have
|
|
// a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
|
|
// just as we wanted.
|
|
//
|
|
// There is only one catch. If we just apply the substitution `'a
|
|
// => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
|
|
// adjust the DB index because we substituting into a binder (it
|
|
// tries to be so smart...) resulting in `for<'x> for<'b>
|
|
// Bar1<'x,'b>` (we have no syntax for this, so use your
|
|
// imagination). Basically the 'x will have DB index of 2 and 'b
|
|
// will have DB index of 1. Not quite what we want. So we apply
|
|
// the substitution to the *contents* of the trait reference,
|
|
// rather than the trait reference itself (put another way, the
|
|
// substitution code expects equal binding levels in the values
|
|
// from the substitution and the value being substituted into, and
|
|
// this trick achieves that).
|
|
|
|
let substs = &trait_ref.0.substs;
|
|
match *self {
|
|
Predicate::Trait(ty::Binder(ref data)) =>
|
|
Predicate::Trait(ty::Binder(data.subst(tcx, substs))),
|
|
Predicate::Equate(ty::Binder(ref data)) =>
|
|
Predicate::Equate(ty::Binder(data.subst(tcx, substs))),
|
|
Predicate::Subtype(ty::Binder(ref data)) =>
|
|
Predicate::Subtype(ty::Binder(data.subst(tcx, substs))),
|
|
Predicate::RegionOutlives(ty::Binder(ref data)) =>
|
|
Predicate::RegionOutlives(ty::Binder(data.subst(tcx, substs))),
|
|
Predicate::TypeOutlives(ty::Binder(ref data)) =>
|
|
Predicate::TypeOutlives(ty::Binder(data.subst(tcx, substs))),
|
|
Predicate::Projection(ty::Binder(ref data)) =>
|
|
Predicate::Projection(ty::Binder(data.subst(tcx, substs))),
|
|
Predicate::WellFormed(data) =>
|
|
Predicate::WellFormed(data.subst(tcx, substs)),
|
|
Predicate::ObjectSafe(trait_def_id) =>
|
|
Predicate::ObjectSafe(trait_def_id),
|
|
Predicate::ClosureKind(closure_def_id, kind) =>
|
|
Predicate::ClosureKind(closure_def_id, kind),
|
|
Predicate::ConstEvaluatable(def_id, const_substs) =>
|
|
Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct TraitPredicate<'tcx> {
|
|
pub trait_ref: TraitRef<'tcx>
|
|
}
|
|
pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
|
|
|
|
impl<'tcx> TraitPredicate<'tcx> {
|
|
pub fn def_id(&self) -> DefId {
|
|
self.trait_ref.def_id
|
|
}
|
|
|
|
pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
|
|
self.trait_ref.input_types()
|
|
}
|
|
|
|
pub fn self_ty(&self) -> Ty<'tcx> {
|
|
self.trait_ref.self_ty()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PolyTraitPredicate<'tcx> {
|
|
pub fn def_id(&self) -> DefId {
|
|
// ok to skip binder since trait def-id does not care about regions
|
|
self.0.def_id()
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
pub struct EquatePredicate<'tcx>(pub Ty<'tcx>, pub Ty<'tcx>); // `0 == 1`
|
|
pub type PolyEquatePredicate<'tcx> = ty::Binder<EquatePredicate<'tcx>>;
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
|
|
pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
|
|
pub type PolyRegionOutlivesPredicate<'tcx> = PolyOutlivesPredicate<ty::Region<'tcx>,
|
|
ty::Region<'tcx>>;
|
|
pub type PolyTypeOutlivesPredicate<'tcx> = PolyOutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>;
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
pub struct SubtypePredicate<'tcx> {
|
|
pub a_is_expected: bool,
|
|
pub a: Ty<'tcx>,
|
|
pub b: Ty<'tcx>
|
|
}
|
|
pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
|
|
|
|
/// This kind of predicate has no *direct* correspondent in the
|
|
/// syntax, but it roughly corresponds to the syntactic forms:
|
|
///
|
|
/// 1. `T : TraitRef<..., Item=Type>`
|
|
/// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
|
|
///
|
|
/// In particular, form #1 is "desugared" to the combination of a
|
|
/// normal trait predicate (`T : TraitRef<...>`) and one of these
|
|
/// predicates. Form #2 is a broader form in that it also permits
|
|
/// equality between arbitrary types. Processing an instance of Form
|
|
/// #2 eventually yields one of these `ProjectionPredicate`
|
|
/// instances to normalize the LHS.
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct ProjectionPredicate<'tcx> {
|
|
pub projection_ty: ProjectionTy<'tcx>,
|
|
pub ty: Ty<'tcx>,
|
|
}
|
|
|
|
pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
|
|
|
|
impl<'tcx> PolyProjectionPredicate<'tcx> {
|
|
pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
|
|
// Note: unlike with TraitRef::to_poly_trait_ref(),
|
|
// self.0.trait_ref is permitted to have escaping regions.
|
|
// This is because here `self` has a `Binder` and so does our
|
|
// return value, so we are preserving the number of binding
|
|
// levels.
|
|
ty::Binder(self.0.projection_ty.trait_ref(tcx))
|
|
}
|
|
|
|
pub fn ty(&self) -> Binder<Ty<'tcx>> {
|
|
Binder(self.skip_binder().ty) // preserves binding levels
|
|
}
|
|
}
|
|
|
|
pub trait ToPolyTraitRef<'tcx> {
|
|
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
|
|
}
|
|
|
|
impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
|
|
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
|
|
assert!(!self.has_escaping_regions());
|
|
ty::Binder(self.clone())
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
|
|
fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
|
|
self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
|
|
}
|
|
}
|
|
|
|
pub trait ToPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx>;
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
// we're about to add a binder, so let's check that we don't
|
|
// accidentally capture anything, or else that might be some
|
|
// weird debruijn accounting.
|
|
assert!(!self.has_escaping_regions());
|
|
|
|
ty::Predicate::Trait(ty::Binder(ty::TraitPredicate {
|
|
trait_ref: self.clone()
|
|
}))
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
ty::Predicate::Trait(self.to_poly_trait_predicate())
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyEquatePredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::Equate(self.clone())
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::RegionOutlives(self.clone())
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::TypeOutlives(self.clone())
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
|
|
fn to_predicate(&self) -> Predicate<'tcx> {
|
|
Predicate::Projection(self.clone())
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Predicate<'tcx> {
|
|
/// Iterates over the types in this predicate. Note that in all
|
|
/// cases this is skipping over a binder, so late-bound regions
|
|
/// with depth 0 are bound by the predicate.
|
|
pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
|
|
let vec: Vec<_> = match *self {
|
|
ty::Predicate::Trait(ref data) => {
|
|
data.skip_binder().input_types().collect()
|
|
}
|
|
ty::Predicate::Equate(ty::Binder(ref data)) => {
|
|
vec![data.0, data.1]
|
|
}
|
|
ty::Predicate::Subtype(ty::Binder(SubtypePredicate { a, b, a_is_expected: _ })) => {
|
|
vec![a, b]
|
|
}
|
|
ty::Predicate::TypeOutlives(ty::Binder(ref data)) => {
|
|
vec![data.0]
|
|
}
|
|
ty::Predicate::RegionOutlives(..) => {
|
|
vec![]
|
|
}
|
|
ty::Predicate::Projection(ref data) => {
|
|
data.0.projection_ty.substs.types().chain(Some(data.0.ty)).collect()
|
|
}
|
|
ty::Predicate::WellFormed(data) => {
|
|
vec![data]
|
|
}
|
|
ty::Predicate::ObjectSafe(_trait_def_id) => {
|
|
vec![]
|
|
}
|
|
ty::Predicate::ClosureKind(_closure_def_id, _kind) => {
|
|
vec![]
|
|
}
|
|
ty::Predicate::ConstEvaluatable(_, substs) => {
|
|
substs.types().collect()
|
|
}
|
|
};
|
|
|
|
// The only reason to collect into a vector here is that I was
|
|
// too lazy to make the full (somewhat complicated) iterator
|
|
// type that would be needed here. But I wanted this fn to
|
|
// return an iterator conceptually, rather than a `Vec`, so as
|
|
// to be closer to `Ty::walk`.
|
|
vec.into_iter()
|
|
}
|
|
|
|
pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
|
|
match *self {
|
|
Predicate::Trait(ref t) => {
|
|
Some(t.to_poly_trait_ref())
|
|
}
|
|
Predicate::Projection(..) |
|
|
Predicate::Equate(..) |
|
|
Predicate::Subtype(..) |
|
|
Predicate::RegionOutlives(..) |
|
|
Predicate::WellFormed(..) |
|
|
Predicate::ObjectSafe(..) |
|
|
Predicate::ClosureKind(..) |
|
|
Predicate::TypeOutlives(..) |
|
|
Predicate::ConstEvaluatable(..) => {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Represents the bounds declared on a particular set of type
|
|
/// parameters. Should eventually be generalized into a flag list of
|
|
/// where clauses. You can obtain a `InstantiatedPredicates` list from a
|
|
/// `GenericPredicates` by using the `instantiate` method. Note that this method
|
|
/// reflects an important semantic invariant of `InstantiatedPredicates`: while
|
|
/// the `GenericPredicates` are expressed in terms of the bound type
|
|
/// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
|
|
/// represented a set of bounds for some particular instantiation,
|
|
/// meaning that the generic parameters have been substituted with
|
|
/// their values.
|
|
///
|
|
/// Example:
|
|
///
|
|
/// struct Foo<T,U:Bar<T>> { ... }
|
|
///
|
|
/// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
|
|
/// `[[], [U:Bar<T>]]`. Now if there were some particular reference
|
|
/// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
|
|
/// [usize:Bar<isize>]]`.
|
|
#[derive(Clone)]
|
|
pub struct InstantiatedPredicates<'tcx> {
|
|
pub predicates: Vec<Predicate<'tcx>>,
|
|
}
|
|
|
|
impl<'tcx> InstantiatedPredicates<'tcx> {
|
|
pub fn empty() -> InstantiatedPredicates<'tcx> {
|
|
InstantiatedPredicates { predicates: vec![] }
|
|
}
|
|
|
|
pub fn is_empty(&self) -> bool {
|
|
self.predicates.is_empty()
|
|
}
|
|
}
|
|
|
|
/// When type checking, we use the `ParamEnv` to track
|
|
/// details about the set of where-clauses that are in scope at this
|
|
/// particular point.
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
|
|
pub struct ParamEnv<'tcx> {
|
|
/// Obligations that the caller must satisfy. This is basically
|
|
/// the set of bounds on the in-scope type parameters, translated
|
|
/// into Obligations, and elaborated and normalized.
|
|
pub caller_bounds: &'tcx Slice<ty::Predicate<'tcx>>,
|
|
|
|
/// Typically, this is `Reveal::UserFacing`, but during trans we
|
|
/// want `Reveal::All` -- note that this is always paired with an
|
|
/// empty environment. To get that, use `ParamEnv::reveal()`.
|
|
pub reveal: traits::Reveal,
|
|
}
|
|
|
|
impl<'tcx> ParamEnv<'tcx> {
|
|
/// Creates a suitable environment in which to perform trait
|
|
/// queries on the given value. This will either be `self` *or*
|
|
/// the empty environment, depending on whether `value` references
|
|
/// type parameters that are in scope. (If it doesn't, then any
|
|
/// judgements should be completely independent of the context,
|
|
/// and hence we can safely use the empty environment so as to
|
|
/// enable more sharing across functions.)
|
|
///
|
|
/// NB: This is a mildly dubious thing to do, in that a function
|
|
/// (or other environment) might have wacky where-clauses like
|
|
/// `where Box<u32>: Copy`, which are clearly never
|
|
/// satisfiable. The code will at present ignore these,
|
|
/// effectively, when type-checking the body of said
|
|
/// function. This preserves existing behavior in any
|
|
/// case. --nmatsakis
|
|
pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
|
|
assert!(!value.needs_infer());
|
|
if value.has_param_types() || value.has_self_ty() {
|
|
ParamEnvAnd {
|
|
param_env: self,
|
|
value,
|
|
}
|
|
} else {
|
|
ParamEnvAnd {
|
|
param_env: ParamEnv::empty(self.reveal),
|
|
value,
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
|
|
pub struct ParamEnvAnd<'tcx, T> {
|
|
pub param_env: ParamEnv<'tcx>,
|
|
pub value: T,
|
|
}
|
|
|
|
impl<'tcx, T> ParamEnvAnd<'tcx, T> {
|
|
pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
|
|
(self.param_env, self.value)
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug)]
|
|
pub struct Destructor {
|
|
/// The def-id of the destructor method
|
|
pub did: DefId,
|
|
}
|
|
|
|
bitflags! {
|
|
pub struct AdtFlags: u32 {
|
|
const NO_ADT_FLAGS = 0;
|
|
const IS_ENUM = 1 << 0;
|
|
const IS_PHANTOM_DATA = 1 << 1;
|
|
const IS_FUNDAMENTAL = 1 << 2;
|
|
const IS_UNION = 1 << 3;
|
|
const IS_BOX = 1 << 4;
|
|
}
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct VariantDef {
|
|
/// The variant's DefId. If this is a tuple-like struct,
|
|
/// this is the DefId of the struct's ctor.
|
|
pub did: DefId,
|
|
pub name: Name, // struct's name if this is a struct
|
|
pub discr: VariantDiscr,
|
|
pub fields: Vec<FieldDef>,
|
|
pub ctor_kind: CtorKind,
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
|
|
pub enum VariantDiscr {
|
|
/// Explicit value for this variant, i.e. `X = 123`.
|
|
/// The `DefId` corresponds to the embedded constant.
|
|
Explicit(DefId),
|
|
|
|
/// The previous variant's discriminant plus one.
|
|
/// For efficiency reasons, the distance from the
|
|
/// last `Explicit` discriminant is being stored,
|
|
/// or `0` for the first variant, if it has none.
|
|
Relative(usize),
|
|
}
|
|
|
|
#[derive(Debug)]
|
|
pub struct FieldDef {
|
|
pub did: DefId,
|
|
pub name: Name,
|
|
pub vis: Visibility,
|
|
}
|
|
|
|
/// The definition of an abstract data type - a struct or enum.
|
|
///
|
|
/// These are all interned (by intern_adt_def) into the adt_defs
|
|
/// table.
|
|
pub struct AdtDef {
|
|
pub did: DefId,
|
|
pub variants: Vec<VariantDef>,
|
|
flags: AdtFlags,
|
|
pub repr: ReprOptions,
|
|
}
|
|
|
|
impl PartialEq for AdtDef {
|
|
// AdtDef are always interned and this is part of TyS equality
|
|
#[inline]
|
|
fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
|
|
}
|
|
|
|
impl Eq for AdtDef {}
|
|
|
|
impl Hash for AdtDef {
|
|
#[inline]
|
|
fn hash<H: Hasher>(&self, s: &mut H) {
|
|
(self as *const AdtDef).hash(s)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
|
|
fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
|
|
self.did.encode(s)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
|
|
|
|
|
|
impl<'a, 'gcx, 'tcx> HashStable<StableHashingContext<'a, 'gcx, 'tcx>> for AdtDef {
|
|
fn hash_stable<W: StableHasherResult>(&self,
|
|
hcx: &mut StableHashingContext<'a, 'gcx, 'tcx>,
|
|
hasher: &mut StableHasher<W>) {
|
|
let ty::AdtDef {
|
|
did,
|
|
ref variants,
|
|
ref flags,
|
|
ref repr,
|
|
} = *self;
|
|
|
|
did.hash_stable(hcx, hasher);
|
|
variants.hash_stable(hcx, hasher);
|
|
flags.hash_stable(hcx, hasher);
|
|
repr.hash_stable(hcx, hasher);
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
|
|
pub enum AdtKind { Struct, Union, Enum }
|
|
|
|
bitflags! {
|
|
#[derive(RustcEncodable, RustcDecodable, Default)]
|
|
pub struct ReprFlags: u8 {
|
|
const IS_C = 1 << 0;
|
|
const IS_PACKED = 1 << 1;
|
|
const IS_SIMD = 1 << 2;
|
|
// Internal only for now. If true, don't reorder fields.
|
|
const IS_LINEAR = 1 << 3;
|
|
|
|
// Any of these flags being set prevent field reordering optimisation.
|
|
const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
|
|
ReprFlags::IS_PACKED.bits |
|
|
ReprFlags::IS_SIMD.bits |
|
|
ReprFlags::IS_LINEAR.bits;
|
|
}
|
|
}
|
|
|
|
impl_stable_hash_for!(struct ReprFlags {
|
|
bits
|
|
});
|
|
|
|
|
|
|
|
/// Represents the repr options provided by the user,
|
|
#[derive(Copy, Clone, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
|
|
pub struct ReprOptions {
|
|
pub int: Option<attr::IntType>,
|
|
pub align: u32,
|
|
pub flags: ReprFlags,
|
|
}
|
|
|
|
impl_stable_hash_for!(struct ReprOptions {
|
|
align,
|
|
int,
|
|
flags
|
|
});
|
|
|
|
impl ReprOptions {
|
|
pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
|
|
let mut flags = ReprFlags::empty();
|
|
let mut size = None;
|
|
let mut max_align = 0;
|
|
for attr in tcx.get_attrs(did).iter() {
|
|
for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
|
|
flags.insert(match r {
|
|
attr::ReprExtern => ReprFlags::IS_C,
|
|
attr::ReprPacked => ReprFlags::IS_PACKED,
|
|
attr::ReprSimd => ReprFlags::IS_SIMD,
|
|
attr::ReprInt(i) => {
|
|
size = Some(i);
|
|
ReprFlags::empty()
|
|
},
|
|
attr::ReprAlign(align) => {
|
|
max_align = cmp::max(align, max_align);
|
|
ReprFlags::empty()
|
|
},
|
|
});
|
|
}
|
|
}
|
|
|
|
// FIXME(eddyb) This is deprecated and should be removed.
|
|
if tcx.has_attr(did, "simd") {
|
|
flags.insert(ReprFlags::IS_SIMD);
|
|
}
|
|
|
|
// This is here instead of layout because the choice must make it into metadata.
|
|
if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
|
|
flags.insert(ReprFlags::IS_LINEAR);
|
|
}
|
|
ReprOptions { int: size, align: max_align, flags: flags }
|
|
}
|
|
|
|
#[inline]
|
|
pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
|
|
#[inline]
|
|
pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
|
|
#[inline]
|
|
pub fn packed(&self) -> bool { self.flags.contains(ReprFlags::IS_PACKED) }
|
|
#[inline]
|
|
pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
|
|
|
|
pub fn discr_type(&self) -> attr::IntType {
|
|
self.int.unwrap_or(attr::SignedInt(ast::IntTy::Is))
|
|
}
|
|
|
|
/// Returns true if this `#[repr()]` should inhabit "smart enum
|
|
/// layout" optimizations, such as representing `Foo<&T>` as a
|
|
/// single pointer.
|
|
pub fn inhibit_enum_layout_opt(&self) -> bool {
|
|
self.c() || self.int.is_some()
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> AdtDef {
|
|
fn new(tcx: TyCtxt,
|
|
did: DefId,
|
|
kind: AdtKind,
|
|
variants: Vec<VariantDef>,
|
|
repr: ReprOptions) -> Self {
|
|
let mut flags = AdtFlags::NO_ADT_FLAGS;
|
|
let attrs = tcx.get_attrs(did);
|
|
if attr::contains_name(&attrs, "fundamental") {
|
|
flags = flags | AdtFlags::IS_FUNDAMENTAL;
|
|
}
|
|
if Some(did) == tcx.lang_items().phantom_data() {
|
|
flags = flags | AdtFlags::IS_PHANTOM_DATA;
|
|
}
|
|
if Some(did) == tcx.lang_items().owned_box() {
|
|
flags = flags | AdtFlags::IS_BOX;
|
|
}
|
|
match kind {
|
|
AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
|
|
AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
|
|
AdtKind::Struct => {}
|
|
}
|
|
AdtDef {
|
|
did,
|
|
variants,
|
|
flags,
|
|
repr,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn is_struct(&self) -> bool {
|
|
!self.is_union() && !self.is_enum()
|
|
}
|
|
|
|
#[inline]
|
|
pub fn is_union(&self) -> bool {
|
|
self.flags.intersects(AdtFlags::IS_UNION)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn is_enum(&self) -> bool {
|
|
self.flags.intersects(AdtFlags::IS_ENUM)
|
|
}
|
|
|
|
/// Returns the kind of the ADT - Struct or Enum.
|
|
#[inline]
|
|
pub fn adt_kind(&self) -> AdtKind {
|
|
if self.is_enum() {
|
|
AdtKind::Enum
|
|
} else if self.is_union() {
|
|
AdtKind::Union
|
|
} else {
|
|
AdtKind::Struct
|
|
}
|
|
}
|
|
|
|
pub fn descr(&self) -> &'static str {
|
|
match self.adt_kind() {
|
|
AdtKind::Struct => "struct",
|
|
AdtKind::Union => "union",
|
|
AdtKind::Enum => "enum",
|
|
}
|
|
}
|
|
|
|
pub fn variant_descr(&self) -> &'static str {
|
|
match self.adt_kind() {
|
|
AdtKind::Struct => "struct",
|
|
AdtKind::Union => "union",
|
|
AdtKind::Enum => "variant",
|
|
}
|
|
}
|
|
|
|
/// Returns whether this type is #[fundamental] for the purposes
|
|
/// of coherence checking.
|
|
#[inline]
|
|
pub fn is_fundamental(&self) -> bool {
|
|
self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
|
|
}
|
|
|
|
/// Returns true if this is PhantomData<T>.
|
|
#[inline]
|
|
pub fn is_phantom_data(&self) -> bool {
|
|
self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
|
|
}
|
|
|
|
/// Returns true if this is Box<T>.
|
|
#[inline]
|
|
pub fn is_box(&self) -> bool {
|
|
self.flags.intersects(AdtFlags::IS_BOX)
|
|
}
|
|
|
|
/// Returns whether this type has a destructor.
|
|
pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
|
|
self.destructor(tcx).is_some()
|
|
}
|
|
|
|
/// Asserts this is a struct and returns the struct's unique
|
|
/// variant.
|
|
pub fn struct_variant(&self) -> &VariantDef {
|
|
assert!(!self.is_enum());
|
|
&self.variants[0]
|
|
}
|
|
|
|
#[inline]
|
|
pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
|
|
tcx.predicates_of(self.did)
|
|
}
|
|
|
|
/// Returns an iterator over all fields contained
|
|
/// by this ADT.
|
|
#[inline]
|
|
pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
|
|
self.variants.iter().flat_map(|v| v.fields.iter())
|
|
}
|
|
|
|
#[inline]
|
|
pub fn is_univariant(&self) -> bool {
|
|
self.variants.len() == 1
|
|
}
|
|
|
|
pub fn is_payloadfree(&self) -> bool {
|
|
!self.variants.is_empty() &&
|
|
self.variants.iter().all(|v| v.fields.is_empty())
|
|
}
|
|
|
|
pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
|
|
self.variants
|
|
.iter()
|
|
.find(|v| v.did == vid)
|
|
.expect("variant_with_id: unknown variant")
|
|
}
|
|
|
|
pub fn variant_index_with_id(&self, vid: DefId) -> usize {
|
|
self.variants
|
|
.iter()
|
|
.position(|v| v.did == vid)
|
|
.expect("variant_index_with_id: unknown variant")
|
|
}
|
|
|
|
pub fn variant_of_def(&self, def: Def) -> &VariantDef {
|
|
match def {
|
|
Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
|
|
Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
|
|
Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => self.struct_variant(),
|
|
_ => bug!("unexpected def {:?} in variant_of_def", def)
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn discriminants(&'a self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
|
|
-> impl Iterator<Item=ConstInt> + 'a {
|
|
let param_env = ParamEnv::empty(traits::Reveal::UserFacing);
|
|
let repr_type = self.repr.discr_type();
|
|
let initial = repr_type.initial_discriminant(tcx.global_tcx());
|
|
let mut prev_discr = None::<ConstInt>;
|
|
self.variants.iter().map(move |v| {
|
|
let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr());
|
|
if let VariantDiscr::Explicit(expr_did) = v.discr {
|
|
let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
|
|
match tcx.const_eval(param_env.and((expr_did, substs))) {
|
|
Ok(&ty::Const { val: ConstVal::Integral(v), .. }) => {
|
|
discr = v;
|
|
}
|
|
err => {
|
|
if !expr_did.is_local() {
|
|
span_bug!(tcx.def_span(expr_did),
|
|
"variant discriminant evaluation succeeded \
|
|
in its crate but failed locally: {:?}", err);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
prev_discr = Some(discr);
|
|
|
|
discr
|
|
})
|
|
}
|
|
|
|
/// Compute the discriminant value used by a specific variant.
|
|
/// Unlike `discriminants`, this is (amortized) constant-time,
|
|
/// only doing at most one query for evaluating an explicit
|
|
/// discriminant (the last one before the requested variant),
|
|
/// assuming there are no constant-evaluation errors there.
|
|
pub fn discriminant_for_variant(&self,
|
|
tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
|
variant_index: usize)
|
|
-> ConstInt {
|
|
let param_env = ParamEnv::empty(traits::Reveal::UserFacing);
|
|
let repr_type = self.repr.discr_type();
|
|
let mut explicit_value = repr_type.initial_discriminant(tcx.global_tcx());
|
|
let mut explicit_index = variant_index;
|
|
loop {
|
|
match self.variants[explicit_index].discr {
|
|
ty::VariantDiscr::Relative(0) => break,
|
|
ty::VariantDiscr::Relative(distance) => {
|
|
explicit_index -= distance;
|
|
}
|
|
ty::VariantDiscr::Explicit(expr_did) => {
|
|
let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
|
|
match tcx.const_eval(param_env.and((expr_did, substs))) {
|
|
Ok(&ty::Const { val: ConstVal::Integral(v), .. }) => {
|
|
explicit_value = v;
|
|
break;
|
|
}
|
|
err => {
|
|
if !expr_did.is_local() {
|
|
span_bug!(tcx.def_span(expr_did),
|
|
"variant discriminant evaluation succeeded \
|
|
in its crate but failed locally: {:?}", err);
|
|
}
|
|
if explicit_index == 0 {
|
|
break;
|
|
}
|
|
explicit_index -= 1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
let discr = explicit_value.to_u128_unchecked()
|
|
.wrapping_add((variant_index - explicit_index) as u128);
|
|
match repr_type {
|
|
attr::UnsignedInt(ty) => {
|
|
ConstInt::new_unsigned_truncating(discr, ty,
|
|
tcx.sess.target.usize_ty)
|
|
}
|
|
attr::SignedInt(ty) => {
|
|
ConstInt::new_signed_truncating(discr as i128, ty,
|
|
tcx.sess.target.isize_ty)
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
|
|
tcx.adt_destructor(self.did)
|
|
}
|
|
|
|
/// Returns a list of types such that `Self: Sized` if and only
|
|
/// if that type is Sized, or `TyErr` if this type is recursive.
|
|
///
|
|
/// Oddly enough, checking that the sized-constraint is Sized is
|
|
/// actually more expressive than checking all members:
|
|
/// the Sized trait is inductive, so an associated type that references
|
|
/// Self would prevent its containing ADT from being Sized.
|
|
///
|
|
/// Due to normalization being eager, this applies even if
|
|
/// the associated type is behind a pointer, e.g. issue #31299.
|
|
pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
|
|
match queries::adt_sized_constraint::try_get(tcx, DUMMY_SP, self.did) {
|
|
Ok(tys) => tys,
|
|
Err(mut bug) => {
|
|
debug!("adt_sized_constraint: {:?} is recursive", self);
|
|
// This should be reported as an error by `check_representable`.
|
|
//
|
|
// Consider the type as Sized in the meanwhile to avoid
|
|
// further errors. Delay our `bug` diagnostic here to get
|
|
// emitted later as well in case we accidentally otherwise don't
|
|
// emit an error.
|
|
bug.delay_as_bug();
|
|
tcx.intern_type_list(&[tcx.types.err])
|
|
}
|
|
}
|
|
}
|
|
|
|
fn sized_constraint_for_ty(&self,
|
|
tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
ty: Ty<'tcx>)
|
|
-> Vec<Ty<'tcx>> {
|
|
let result = match ty.sty {
|
|
TyBool | TyChar | TyInt(..) | TyUint(..) | TyFloat(..) |
|
|
TyRawPtr(..) | TyRef(..) | TyFnDef(..) | TyFnPtr(_) |
|
|
TyArray(..) | TyClosure(..) | TyGenerator(..) | TyNever => {
|
|
vec![]
|
|
}
|
|
|
|
TyStr | TyDynamic(..) | TySlice(_) | TyError => {
|
|
// these are never sized - return the target type
|
|
vec![ty]
|
|
}
|
|
|
|
TyTuple(ref tys, _) => {
|
|
match tys.last() {
|
|
None => vec![],
|
|
Some(ty) => self.sized_constraint_for_ty(tcx, ty)
|
|
}
|
|
}
|
|
|
|
TyAdt(adt, substs) => {
|
|
// recursive case
|
|
let adt_tys = adt.sized_constraint(tcx);
|
|
debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
|
|
ty, adt_tys);
|
|
adt_tys.iter()
|
|
.map(|ty| ty.subst(tcx, substs))
|
|
.flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
|
|
.collect()
|
|
}
|
|
|
|
TyProjection(..) | TyAnon(..) => {
|
|
// must calculate explicitly.
|
|
// FIXME: consider special-casing always-Sized projections
|
|
vec![ty]
|
|
}
|
|
|
|
TyParam(..) => {
|
|
// perf hack: if there is a `T: Sized` bound, then
|
|
// we know that `T` is Sized and do not need to check
|
|
// it on the impl.
|
|
|
|
let sized_trait = match tcx.lang_items().sized_trait() {
|
|
Some(x) => x,
|
|
_ => return vec![ty]
|
|
};
|
|
let sized_predicate = Binder(TraitRef {
|
|
def_id: sized_trait,
|
|
substs: tcx.mk_substs_trait(ty, &[])
|
|
}).to_predicate();
|
|
let predicates = tcx.predicates_of(self.did).predicates;
|
|
if predicates.into_iter().any(|p| p == sized_predicate) {
|
|
vec![]
|
|
} else {
|
|
vec![ty]
|
|
}
|
|
}
|
|
|
|
TyInfer(..) => {
|
|
bug!("unexpected type `{:?}` in sized_constraint_for_ty",
|
|
ty)
|
|
}
|
|
};
|
|
debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
|
|
result
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> VariantDef {
|
|
#[inline]
|
|
pub fn find_field_named(&self, name: ast::Name) -> Option<&FieldDef> {
|
|
self.index_of_field_named(name).map(|index| &self.fields[index])
|
|
}
|
|
|
|
pub fn index_of_field_named(&self, name: ast::Name) -> Option<usize> {
|
|
if let Some(index) = self.fields.iter().position(|f| f.name == name) {
|
|
return Some(index);
|
|
}
|
|
let mut ident = name.to_ident();
|
|
while ident.ctxt != SyntaxContext::empty() {
|
|
ident.ctxt.remove_mark();
|
|
if let Some(field) = self.fields.iter().position(|f| f.name.to_ident() == ident) {
|
|
return Some(field);
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
#[inline]
|
|
pub fn field_named(&self, name: ast::Name) -> &FieldDef {
|
|
self.find_field_named(name).unwrap()
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> FieldDef {
|
|
pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
|
|
tcx.type_of(self.did).subst(tcx, subst)
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
pub enum ClosureKind {
|
|
// Warning: Ordering is significant here! The ordering is chosen
|
|
// because the trait Fn is a subtrait of FnMut and so in turn, and
|
|
// hence we order it so that Fn < FnMut < FnOnce.
|
|
Fn,
|
|
FnMut,
|
|
FnOnce,
|
|
}
|
|
|
|
impl<'a, 'tcx> ClosureKind {
|
|
pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
|
|
match *self {
|
|
ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
|
|
ClosureKind::FnMut => {
|
|
tcx.require_lang_item(FnMutTraitLangItem)
|
|
}
|
|
ClosureKind::FnOnce => {
|
|
tcx.require_lang_item(FnOnceTraitLangItem)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// True if this a type that impls this closure kind
|
|
/// must also implement `other`.
|
|
pub fn extends(self, other: ty::ClosureKind) -> bool {
|
|
match (self, other) {
|
|
(ClosureKind::Fn, ClosureKind::Fn) => true,
|
|
(ClosureKind::Fn, ClosureKind::FnMut) => true,
|
|
(ClosureKind::Fn, ClosureKind::FnOnce) => true,
|
|
(ClosureKind::FnMut, ClosureKind::FnMut) => true,
|
|
(ClosureKind::FnMut, ClosureKind::FnOnce) => true,
|
|
(ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> TyS<'tcx> {
|
|
/// Iterator that walks `self` and any types reachable from
|
|
/// `self`, in depth-first order. Note that just walks the types
|
|
/// that appear in `self`, it does not descend into the fields of
|
|
/// structs or variants. For example:
|
|
///
|
|
/// ```notrust
|
|
/// isize => { isize }
|
|
/// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
|
|
/// [isize] => { [isize], isize }
|
|
/// ```
|
|
pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
|
|
TypeWalker::new(self)
|
|
}
|
|
|
|
/// Iterator that walks the immediate children of `self`. Hence
|
|
/// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
|
|
/// (but not `i32`, like `walk`).
|
|
pub fn walk_shallow(&'tcx self) -> AccIntoIter<walk::TypeWalkerArray<'tcx>> {
|
|
walk::walk_shallow(self)
|
|
}
|
|
|
|
/// Walks `ty` and any types appearing within `ty`, invoking the
|
|
/// callback `f` on each type. If the callback returns false, then the
|
|
/// children of the current type are ignored.
|
|
///
|
|
/// Note: prefer `ty.walk()` where possible.
|
|
pub fn maybe_walk<F>(&'tcx self, mut f: F)
|
|
where F : FnMut(Ty<'tcx>) -> bool
|
|
{
|
|
let mut walker = self.walk();
|
|
while let Some(ty) = walker.next() {
|
|
if !f(ty) {
|
|
walker.skip_current_subtree();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
|
|
pub enum LvaluePreference {
|
|
PreferMutLvalue,
|
|
NoPreference
|
|
}
|
|
|
|
impl LvaluePreference {
|
|
pub fn from_mutbl(m: hir::Mutability) -> Self {
|
|
match m {
|
|
hir::MutMutable => PreferMutLvalue,
|
|
hir::MutImmutable => NoPreference,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl BorrowKind {
|
|
pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
|
|
match m {
|
|
hir::MutMutable => MutBorrow,
|
|
hir::MutImmutable => ImmBorrow,
|
|
}
|
|
}
|
|
|
|
/// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
|
|
/// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
|
|
/// mutability that is stronger than necessary so that it at least *would permit* the borrow in
|
|
/// question.
|
|
pub fn to_mutbl_lossy(self) -> hir::Mutability {
|
|
match self {
|
|
MutBorrow => hir::MutMutable,
|
|
ImmBorrow => hir::MutImmutable,
|
|
|
|
// We have no type corresponding to a unique imm borrow, so
|
|
// use `&mut`. It gives all the capabilities of an `&uniq`
|
|
// and hence is a safe "over approximation".
|
|
UniqueImmBorrow => hir::MutMutable,
|
|
}
|
|
}
|
|
|
|
pub fn to_user_str(&self) -> &'static str {
|
|
match *self {
|
|
MutBorrow => "mutable",
|
|
ImmBorrow => "immutable",
|
|
UniqueImmBorrow => "uniquely immutable",
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone)]
|
|
pub enum Attributes<'gcx> {
|
|
Owned(Rc<[ast::Attribute]>),
|
|
Borrowed(&'gcx [ast::Attribute])
|
|
}
|
|
|
|
impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
|
|
type Target = [ast::Attribute];
|
|
|
|
fn deref(&self) -> &[ast::Attribute] {
|
|
match self {
|
|
&Attributes::Owned(ref data) => &data,
|
|
&Attributes::Borrowed(data) => data
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
|
|
pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
|
|
self.typeck_tables_of(self.hir.body_owner_def_id(body))
|
|
}
|
|
|
|
/// Returns an iterator of the def-ids for all body-owners in this
|
|
/// crate. If you would prefer to iterate over the bodies
|
|
/// themselves, you can do `self.hir.krate().body_ids.iter()`.
|
|
pub fn body_owners(self) -> impl Iterator<Item = DefId> + 'a {
|
|
self.hir.krate()
|
|
.body_ids
|
|
.iter()
|
|
.map(move |&body_id| self.hir.body_owner_def_id(body_id))
|
|
}
|
|
|
|
pub fn expr_span(self, id: NodeId) -> Span {
|
|
match self.hir.find(id) {
|
|
Some(hir_map::NodeExpr(e)) => {
|
|
e.span
|
|
}
|
|
Some(f) => {
|
|
bug!("Node id {} is not an expr: {:?}", id, f);
|
|
}
|
|
None => {
|
|
bug!("Node id {} is not present in the node map", id);
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn expr_is_lval(self, expr: &hir::Expr) -> bool {
|
|
match expr.node {
|
|
hir::ExprPath(hir::QPath::Resolved(_, ref path)) => {
|
|
match path.def {
|
|
Def::Local(..) | Def::Upvar(..) | Def::Static(..) | Def::Err => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
hir::ExprType(ref e, _) => {
|
|
self.expr_is_lval(e)
|
|
}
|
|
|
|
hir::ExprUnary(hir::UnDeref, _) |
|
|
hir::ExprField(..) |
|
|
hir::ExprTupField(..) |
|
|
hir::ExprIndex(..) => {
|
|
true
|
|
}
|
|
|
|
// Partially qualified paths in expressions can only legally
|
|
// refer to associated items which are always rvalues.
|
|
hir::ExprPath(hir::QPath::TypeRelative(..)) |
|
|
|
|
hir::ExprCall(..) |
|
|
hir::ExprMethodCall(..) |
|
|
hir::ExprStruct(..) |
|
|
hir::ExprTup(..) |
|
|
hir::ExprIf(..) |
|
|
hir::ExprMatch(..) |
|
|
hir::ExprClosure(..) |
|
|
hir::ExprBlock(..) |
|
|
hir::ExprRepeat(..) |
|
|
hir::ExprArray(..) |
|
|
hir::ExprBreak(..) |
|
|
hir::ExprAgain(..) |
|
|
hir::ExprRet(..) |
|
|
hir::ExprWhile(..) |
|
|
hir::ExprLoop(..) |
|
|
hir::ExprAssign(..) |
|
|
hir::ExprInlineAsm(..) |
|
|
hir::ExprAssignOp(..) |
|
|
hir::ExprLit(_) |
|
|
hir::ExprUnary(..) |
|
|
hir::ExprBox(..) |
|
|
hir::ExprAddrOf(..) |
|
|
hir::ExprBinary(..) |
|
|
hir::ExprYield(..) |
|
|
hir::ExprCast(..) => {
|
|
false
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
|
|
self.associated_items(id)
|
|
.filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
|
|
.collect()
|
|
}
|
|
|
|
pub fn trait_relevant_for_never(self, did: DefId) -> bool {
|
|
self.associated_items(did).any(|item| {
|
|
item.relevant_for_never()
|
|
})
|
|
}
|
|
|
|
pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
|
|
let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
|
|
match self.hir.get(node_id) {
|
|
hir_map::NodeTraitItem(_) | hir_map::NodeImplItem(_) => true,
|
|
_ => false,
|
|
}
|
|
} else {
|
|
match self.describe_def(def_id).expect("no def for def-id") {
|
|
Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
|
|
_ => false,
|
|
}
|
|
};
|
|
|
|
if is_associated_item {
|
|
Some(self.associated_item(def_id))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
fn associated_item_from_trait_item_ref(self,
|
|
parent_def_id: DefId,
|
|
parent_vis: &hir::Visibility,
|
|
trait_item_ref: &hir::TraitItemRef)
|
|
-> AssociatedItem {
|
|
let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
|
|
let (kind, has_self) = match trait_item_ref.kind {
|
|
hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
|
|
hir::AssociatedItemKind::Method { has_self } => {
|
|
(ty::AssociatedKind::Method, has_self)
|
|
}
|
|
hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
|
|
};
|
|
|
|
AssociatedItem {
|
|
name: trait_item_ref.name,
|
|
kind,
|
|
// Visibility of trait items is inherited from their traits.
|
|
vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
|
|
defaultness: trait_item_ref.defaultness,
|
|
def_id,
|
|
container: TraitContainer(parent_def_id),
|
|
method_has_self_argument: has_self
|
|
}
|
|
}
|
|
|
|
fn associated_item_from_impl_item_ref(self,
|
|
parent_def_id: DefId,
|
|
impl_item_ref: &hir::ImplItemRef)
|
|
-> AssociatedItem {
|
|
let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
|
|
let (kind, has_self) = match impl_item_ref.kind {
|
|
hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
|
|
hir::AssociatedItemKind::Method { has_self } => {
|
|
(ty::AssociatedKind::Method, has_self)
|
|
}
|
|
hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
|
|
};
|
|
|
|
ty::AssociatedItem {
|
|
name: impl_item_ref.name,
|
|
kind,
|
|
// Visibility of trait impl items doesn't matter.
|
|
vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
|
|
defaultness: impl_item_ref.defaultness,
|
|
def_id,
|
|
container: ImplContainer(parent_def_id),
|
|
method_has_self_argument: has_self
|
|
}
|
|
}
|
|
|
|
#[inline] // FIXME(#35870) Avoid closures being unexported due to impl Trait.
|
|
pub fn associated_items(self, def_id: DefId)
|
|
-> impl Iterator<Item = ty::AssociatedItem> + 'a {
|
|
let def_ids = self.associated_item_def_ids(def_id);
|
|
(0..def_ids.len()).map(move |i| self.associated_item(def_ids[i]))
|
|
}
|
|
|
|
/// Returns true if the impls are the same polarity and are implementing
|
|
/// a trait which contains no items
|
|
pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
|
|
if !self.sess.features.borrow().overlapping_marker_traits {
|
|
return false;
|
|
}
|
|
let trait1_is_empty = self.impl_trait_ref(def_id1)
|
|
.map_or(false, |trait_ref| {
|
|
self.associated_item_def_ids(trait_ref.def_id).is_empty()
|
|
});
|
|
let trait2_is_empty = self.impl_trait_ref(def_id2)
|
|
.map_or(false, |trait_ref| {
|
|
self.associated_item_def_ids(trait_ref.def_id).is_empty()
|
|
});
|
|
self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
|
|
&& trait1_is_empty
|
|
&& trait2_is_empty
|
|
}
|
|
|
|
// Returns `ty::VariantDef` if `def` refers to a struct,
|
|
// or variant or their constructors, panics otherwise.
|
|
pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
|
|
match def {
|
|
Def::Variant(did) | Def::VariantCtor(did, ..) => {
|
|
let enum_did = self.parent_def_id(did).unwrap();
|
|
self.adt_def(enum_did).variant_with_id(did)
|
|
}
|
|
Def::Struct(did) | Def::Union(did) => {
|
|
self.adt_def(did).struct_variant()
|
|
}
|
|
Def::StructCtor(ctor_did, ..) => {
|
|
let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
|
|
self.adt_def(did).struct_variant()
|
|
}
|
|
_ => bug!("expect_variant_def used with unexpected def {:?}", def)
|
|
}
|
|
}
|
|
|
|
pub fn item_name(self, id: DefId) -> InternedString {
|
|
if let Some(id) = self.hir.as_local_node_id(id) {
|
|
self.hir.name(id).as_str()
|
|
} else if id.index == CRATE_DEF_INDEX {
|
|
self.original_crate_name(id.krate).as_str()
|
|
} else {
|
|
let def_key = self.def_key(id);
|
|
// The name of a StructCtor is that of its struct parent.
|
|
if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
|
|
self.item_name(DefId {
|
|
krate: id.krate,
|
|
index: def_key.parent.unwrap()
|
|
})
|
|
} else {
|
|
def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
|
|
bug!("item_name: no name for {:?}", self.def_path(id));
|
|
})
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
|
|
pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
|
|
-> &'gcx Mir<'gcx>
|
|
{
|
|
match instance {
|
|
ty::InstanceDef::Item(did) => {
|
|
self.optimized_mir(did)
|
|
}
|
|
ty::InstanceDef::Intrinsic(..) |
|
|
ty::InstanceDef::FnPtrShim(..) |
|
|
ty::InstanceDef::Virtual(..) |
|
|
ty::InstanceDef::ClosureOnceShim { .. } |
|
|
ty::InstanceDef::DropGlue(..) |
|
|
ty::InstanceDef::CloneShim(..) => {
|
|
self.mir_shims(instance)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Given the DefId of an item, returns its MIR, borrowed immutably.
|
|
/// Returns None if there is no MIR for the DefId
|
|
pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
|
|
if self.is_mir_available(did) {
|
|
Some(self.optimized_mir(did))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
/// Get the attributes of a definition.
|
|
pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
|
|
if let Some(id) = self.hir.as_local_node_id(did) {
|
|
Attributes::Borrowed(self.hir.attrs(id))
|
|
} else {
|
|
Attributes::Owned(self.item_attrs(did))
|
|
}
|
|
}
|
|
|
|
/// Determine whether an item is annotated with an attribute
|
|
pub fn has_attr(self, did: DefId, attr: &str) -> bool {
|
|
self.get_attrs(did).iter().any(|item| item.check_name(attr))
|
|
}
|
|
|
|
pub fn trait_has_default_impl(self, trait_def_id: DefId) -> bool {
|
|
self.trait_def(trait_def_id).has_default_impl
|
|
}
|
|
|
|
pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
|
|
self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
|
|
}
|
|
|
|
/// Given the def_id of an impl, return the def_id of the trait it implements.
|
|
/// If it implements no trait, return `None`.
|
|
pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
|
|
self.impl_trait_ref(def_id).map(|tr| tr.def_id)
|
|
}
|
|
|
|
/// If the given def ID describes a method belonging to an impl, return the
|
|
/// ID of the impl that the method belongs to. Otherwise, return `None`.
|
|
pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
|
|
let item = if def_id.krate != LOCAL_CRATE {
|
|
if let Some(Def::Method(_)) = self.describe_def(def_id) {
|
|
Some(self.associated_item(def_id))
|
|
} else {
|
|
None
|
|
}
|
|
} else {
|
|
self.opt_associated_item(def_id)
|
|
};
|
|
|
|
match item {
|
|
Some(trait_item) => {
|
|
match trait_item.container {
|
|
TraitContainer(_) => None,
|
|
ImplContainer(def_id) => Some(def_id),
|
|
}
|
|
}
|
|
None => None
|
|
}
|
|
}
|
|
|
|
/// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
|
|
/// with the name of the crate containing the impl.
|
|
pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
|
|
if impl_did.is_local() {
|
|
let node_id = self.hir.as_local_node_id(impl_did).unwrap();
|
|
Ok(self.hir.span(node_id))
|
|
} else {
|
|
Err(self.crate_name(impl_did.krate))
|
|
}
|
|
}
|
|
|
|
pub fn adjust(self, name: Name, scope: DefId, block: NodeId) -> (Ident, DefId) {
|
|
self.adjust_ident(name.to_ident(), scope, block)
|
|
}
|
|
|
|
pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
|
|
let expansion = match scope.krate {
|
|
LOCAL_CRATE => self.hir.definitions().expansion(scope.index),
|
|
_ => Mark::root(),
|
|
};
|
|
let scope = match ident.ctxt.adjust(expansion) {
|
|
Some(macro_def) => self.hir.definitions().macro_def_scope(macro_def),
|
|
None => self.hir.get_module_parent(block),
|
|
};
|
|
(ident, scope)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
|
|
pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
|
|
F: FnOnce(&[hir::Freevar]) -> T,
|
|
{
|
|
let def_id = self.hir.local_def_id(fid);
|
|
match self.freevars(def_id) {
|
|
None => f(&[]),
|
|
Some(d) => f(&d),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
|
|
-> AssociatedItem
|
|
{
|
|
let id = tcx.hir.as_local_node_id(def_id).unwrap();
|
|
let parent_id = tcx.hir.get_parent(id);
|
|
let parent_def_id = tcx.hir.local_def_id(parent_id);
|
|
let parent_item = tcx.hir.expect_item(parent_id);
|
|
match parent_item.node {
|
|
hir::ItemImpl(.., ref impl_item_refs) => {
|
|
if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
|
|
let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
|
|
impl_item_ref);
|
|
debug_assert_eq!(assoc_item.def_id, def_id);
|
|
return assoc_item;
|
|
}
|
|
}
|
|
|
|
hir::ItemTrait(.., ref trait_item_refs) => {
|
|
if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
|
|
let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
|
|
&parent_item.vis,
|
|
trait_item_ref);
|
|
debug_assert_eq!(assoc_item.def_id, def_id);
|
|
return assoc_item;
|
|
}
|
|
}
|
|
|
|
_ => { }
|
|
}
|
|
|
|
span_bug!(parent_item.span,
|
|
"unexpected parent of trait or impl item or item not found: {:?}",
|
|
parent_item.node)
|
|
}
|
|
|
|
/// Calculates the Sized-constraint.
|
|
///
|
|
/// In fact, there are only a few options for the types in the constraint:
|
|
/// - an obviously-unsized type
|
|
/// - a type parameter or projection whose Sizedness can't be known
|
|
/// - a tuple of type parameters or projections, if there are multiple
|
|
/// such.
|
|
/// - a TyError, if a type contained itself. The representability
|
|
/// check should catch this case.
|
|
fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId)
|
|
-> &'tcx [Ty<'tcx>] {
|
|
let def = tcx.adt_def(def_id);
|
|
|
|
let result = tcx.intern_type_list(&def.variants.iter().flat_map(|v| {
|
|
v.fields.last()
|
|
}).flat_map(|f| {
|
|
def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
|
|
}).collect::<Vec<_>>());
|
|
|
|
debug!("adt_sized_constraint: {:?} => {:?}", def, result);
|
|
|
|
result
|
|
}
|
|
|
|
/// Calculates the dtorck constraint for a type.
|
|
fn adt_dtorck_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId)
|
|
-> DtorckConstraint<'tcx> {
|
|
let def = tcx.adt_def(def_id);
|
|
let span = tcx.def_span(def_id);
|
|
debug!("dtorck_constraint: {:?}", def);
|
|
|
|
if def.is_phantom_data() {
|
|
let result = DtorckConstraint {
|
|
outlives: vec![],
|
|
dtorck_types: vec![
|
|
tcx.mk_param_from_def(&tcx.generics_of(def_id).types[0])
|
|
]
|
|
};
|
|
debug!("dtorck_constraint: {:?} => {:?}", def, result);
|
|
return result;
|
|
}
|
|
|
|
let mut result = def.all_fields()
|
|
.map(|field| tcx.type_of(field.did))
|
|
.map(|fty| tcx.dtorck_constraint_for_ty(span, fty, 0, fty))
|
|
.collect::<Result<DtorckConstraint, ErrorReported>>()
|
|
.unwrap_or(DtorckConstraint::empty());
|
|
result.outlives.extend(tcx.destructor_constraints(def));
|
|
result.dedup();
|
|
|
|
debug!("dtorck_constraint: {:?} => {:?}", def, result);
|
|
|
|
result
|
|
}
|
|
|
|
fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId)
|
|
-> Rc<Vec<DefId>> {
|
|
let id = tcx.hir.as_local_node_id(def_id).unwrap();
|
|
let item = tcx.hir.expect_item(id);
|
|
let vec: Vec<_> = match item.node {
|
|
hir::ItemTrait(.., ref trait_item_refs) => {
|
|
trait_item_refs.iter()
|
|
.map(|trait_item_ref| trait_item_ref.id)
|
|
.map(|id| tcx.hir.local_def_id(id.node_id))
|
|
.collect()
|
|
}
|
|
hir::ItemImpl(.., ref impl_item_refs) => {
|
|
impl_item_refs.iter()
|
|
.map(|impl_item_ref| impl_item_ref.id)
|
|
.map(|id| tcx.hir.local_def_id(id.node_id))
|
|
.collect()
|
|
}
|
|
_ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
|
|
};
|
|
Rc::new(vec)
|
|
}
|
|
|
|
fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
|
|
tcx.hir.span_if_local(def_id).unwrap()
|
|
}
|
|
|
|
/// If the given def ID describes an item belonging to a trait,
|
|
/// return the ID of the trait that the trait item belongs to.
|
|
/// Otherwise, return `None`.
|
|
fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
|
|
tcx.opt_associated_item(def_id)
|
|
.and_then(|associated_item| {
|
|
match associated_item.container {
|
|
TraitContainer(def_id) => Some(def_id),
|
|
ImplContainer(_) => None
|
|
}
|
|
})
|
|
}
|
|
|
|
/// See `ParamEnv` struct def'n for details.
|
|
fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
def_id: DefId)
|
|
-> ParamEnv<'tcx> {
|
|
// Compute the bounds on Self and the type parameters.
|
|
|
|
let bounds = tcx.predicates_of(def_id).instantiate_identity(tcx);
|
|
let predicates = bounds.predicates;
|
|
|
|
// Finally, we have to normalize the bounds in the environment, in
|
|
// case they contain any associated type projections. This process
|
|
// can yield errors if the put in illegal associated types, like
|
|
// `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
|
|
// report these errors right here; this doesn't actually feel
|
|
// right to me, because constructing the environment feels like a
|
|
// kind of a "idempotent" action, but I'm not sure where would be
|
|
// a better place. In practice, we construct environments for
|
|
// every fn once during type checking, and we'll abort if there
|
|
// are any errors at that point, so after type checking you can be
|
|
// sure that this will succeed without errors anyway.
|
|
|
|
let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
|
|
traits::Reveal::UserFacing);
|
|
|
|
let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
|
|
tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
|
|
});
|
|
let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
|
|
traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
|
|
}
|
|
|
|
fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
crate_num: CrateNum) -> Symbol {
|
|
assert_eq!(crate_num, LOCAL_CRATE);
|
|
tcx.sess.local_crate_disambiguator()
|
|
}
|
|
|
|
fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
crate_num: CrateNum) -> Symbol {
|
|
assert_eq!(crate_num, LOCAL_CRATE);
|
|
tcx.crate_name.clone()
|
|
}
|
|
|
|
pub fn provide(providers: &mut ty::maps::Providers) {
|
|
util::provide(providers);
|
|
context::provide(providers);
|
|
*providers = ty::maps::Providers {
|
|
associated_item,
|
|
associated_item_def_ids,
|
|
adt_sized_constraint,
|
|
adt_dtorck_constraint,
|
|
def_span,
|
|
param_env,
|
|
trait_of_item,
|
|
crate_disambiguator,
|
|
original_crate_name,
|
|
trait_impls_of: trait_def::trait_impls_of_provider,
|
|
..*providers
|
|
};
|
|
}
|
|
|
|
pub fn provide_extern(providers: &mut ty::maps::Providers) {
|
|
*providers = ty::maps::Providers {
|
|
adt_sized_constraint,
|
|
adt_dtorck_constraint,
|
|
trait_impls_of: trait_def::trait_impls_of_provider,
|
|
param_env,
|
|
..*providers
|
|
};
|
|
}
|
|
|
|
|
|
/// A map for the local crate mapping each type to a vector of its
|
|
/// inherent impls. This is not meant to be used outside of coherence;
|
|
/// rather, you should request the vector for a specific type via
|
|
/// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
|
|
/// (constructing this map requires touching the entire crate).
|
|
#[derive(Clone, Debug)]
|
|
pub struct CrateInherentImpls {
|
|
pub inherent_impls: DefIdMap<Rc<Vec<DefId>>>,
|
|
}
|
|
|
|
/// A set of constraints that need to be satisfied in order for
|
|
/// a type to be valid for destruction.
|
|
#[derive(Clone, Debug)]
|
|
pub struct DtorckConstraint<'tcx> {
|
|
/// Types that are required to be alive in order for this
|
|
/// type to be valid for destruction.
|
|
pub outlives: Vec<ty::subst::Kind<'tcx>>,
|
|
/// Types that could not be resolved: projections and params.
|
|
pub dtorck_types: Vec<Ty<'tcx>>,
|
|
}
|
|
|
|
impl<'tcx> FromIterator<DtorckConstraint<'tcx>> for DtorckConstraint<'tcx>
|
|
{
|
|
fn from_iter<I: IntoIterator<Item=DtorckConstraint<'tcx>>>(iter: I) -> Self {
|
|
let mut result = Self::empty();
|
|
|
|
for constraint in iter {
|
|
result.outlives.extend(constraint.outlives);
|
|
result.dtorck_types.extend(constraint.dtorck_types);
|
|
}
|
|
|
|
result
|
|
}
|
|
}
|
|
|
|
|
|
impl<'tcx> DtorckConstraint<'tcx> {
|
|
fn empty() -> DtorckConstraint<'tcx> {
|
|
DtorckConstraint {
|
|
outlives: vec![],
|
|
dtorck_types: vec![]
|
|
}
|
|
}
|
|
|
|
fn dedup<'a>(&mut self) {
|
|
let mut outlives = FxHashSet();
|
|
let mut dtorck_types = FxHashSet();
|
|
|
|
self.outlives.retain(|&val| outlives.replace(val).is_none());
|
|
self.dtorck_types.retain(|&val| dtorck_types.replace(val).is_none());
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
|
|
pub struct SymbolName {
|
|
// FIXME: we don't rely on interning or equality here - better have
|
|
// this be a `&'tcx str`.
|
|
pub name: InternedString
|
|
}
|
|
|
|
impl Deref for SymbolName {
|
|
type Target = str;
|
|
|
|
fn deref(&self) -> &str { &self.name }
|
|
}
|
|
|
|
impl fmt::Display for SymbolName {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
|
fmt::Display::fmt(&self.name, fmt)
|
|
}
|
|
}
|