bjoernager/rust
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Move opaque type cache into InferCtxt

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This commit is contained in:
Oli Scherer 2021-07-26 16:57:18 +00:00
parent 1f94abcda6
commit d99805982b
7 changed files with 102 additions and 107 deletions
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83
compiler/rustc_trait_selection/src/opaque_types.rs
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@ -2,11 +2,11 @@ use crate::infer::InferCtxtExt as _;
use crate::traits::{self, ObligationCause, PredicateObligation};
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::vec_map::VecMap;
use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_infer::infer::error_reporting::unexpected_hidden_region_diagnostic;
use rustc_infer::infer::free_regions::FreeRegionRelations;
use rustc_infer::infer::opaque_types::{OpaqueTypeDecl, OpaqueTypeMap};
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::{self, InferCtxt, InferOk};
use rustc_middle::ty::fold::{BottomUpFolder, TypeFoldable, TypeFolder, TypeVisitor};
@ -16,72 +16,6 @@ use rustc_span::Span;
use std::ops::ControlFlow;
pub type OpaqueTypeMap<'tcx> = VecMap<OpaqueTypeKey<'tcx>, OpaqueTypeDecl<'tcx>>;
/// Information about the opaque types whose values we
/// are inferring in this function (these are the `impl Trait` that
/// appear in the return type).
#[derive(Copy, Clone, Debug)]
pub struct OpaqueTypeDecl<'tcx> {
/// The opaque type (`ty::Opaque`) for this declaration.
pub opaque_type: Ty<'tcx>,
/// The span of this particular definition of the opaque type. So
/// for example:
///
/// ```ignore (incomplete snippet)
/// type Foo = impl Baz;
/// fn bar() -> Foo {
/// // ^^^ This is the span we are looking for!
/// }
/// ```
///
/// In cases where the fn returns `(impl Trait, impl Trait)` or
/// other such combinations, the result is currently
/// over-approximated, but better than nothing.
pub definition_span: Span,
/// The type variable that represents the value of the opaque type
/// that we require. In other words, after we compile this function,
/// we will be created a constraint like:
///
/// Foo<'a, T> = ?C
///
/// where `?C` is the value of this type variable. =) It may
/// naturally refer to the type and lifetime parameters in scope
/// in this function, though ultimately it should only reference
/// those that are arguments to `Foo` in the constraint above. (In
/// other words, `?C` should not include `'b`, even though it's a
/// lifetime parameter on `foo`.)
pub concrete_ty: Ty<'tcx>,
/// Returns `true` if the `impl Trait` bounds include region bounds.
/// For example, this would be true for:
///
/// fn foo<'a, 'b, 'c>() -> impl Trait<'c> + 'a + 'b
///
/// but false for:
///
/// fn foo<'c>() -> impl Trait<'c>
///
/// unless `Trait` was declared like:
///
/// trait Trait<'c>: 'c
///
/// in which case it would be true.
///
/// This is used during regionck to decide whether we need to
/// impose any additional constraints to ensure that region
/// variables in `concrete_ty` wind up being constrained to
/// something from `substs` (or, at minimum, things that outlive
/// the fn body). (Ultimately, writeback is responsible for this
/// check.)
pub has_required_region_bounds: bool,
/// The origin of the opaque type.
pub origin: hir::OpaqueTyOrigin,
}
/// Whether member constraints should be generated for all opaque types
#[derive(Debug)]
pub enum GenerateMemberConstraints {
@ -105,11 +39,7 @@ pub trait InferCtxtExt<'tcx> {
value_span: Span,
) -> InferOk<'tcx, (T, OpaqueTypeMap<'tcx>)>;
fn constrain_opaque_types<FRR: FreeRegionRelations<'tcx>>(
&self,
opaque_types: &OpaqueTypeMap<'tcx>,
free_region_relations: &FRR,
);
fn constrain_opaque_types<FRR: FreeRegionRelations<'tcx>>(&self, free_region_relations: &FRR);
fn constrain_opaque_type<FRR: FreeRegionRelations<'tcx>>(
&self,
@ -350,12 +280,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
/// - `opaque_types` -- the map produced by `instantiate_opaque_types`
/// - `free_region_relations` -- something that can be used to relate
/// the free regions (`'a`) that appear in the impl trait.
fn constrain_opaque_types<FRR: FreeRegionRelations<'tcx>>(
&self,
opaque_types: &OpaqueTypeMap<'tcx>,
free_region_relations: &FRR,
) {
for &(opaque_type_key, opaque_defn) in opaque_types {
fn constrain_opaque_types<FRR: FreeRegionRelations<'tcx>>(&self, free_region_relations: &FRR) {
let opaque_types = self.inner.borrow().opaque_types.clone();
for (opaque_type_key, opaque_defn) in opaque_types {
self.constrain_opaque_type(
opaque_type_key,
&opaque_defn,