mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-05 22:02:55 +01:00
Dana Jansens
4819e68dac
This avoids the need for a virtual method, and a class overriding it in eval.
100 lines
4.2 KiB
C++
100 lines
4.2 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef CARBON_TOOLCHAIN_CHECK_PERIOD_SELF_H_
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#define CARBON_TOOLCHAIN_CHECK_PERIOD_SELF_H_
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#include "toolchain/check/context.h"
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#include "toolchain/check/subst.h"
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#include "toolchain/sem_ir/ids.h"
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namespace Carbon::Check {
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// Introduce `.Self` as a symbolic binding into the current scope, and return
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// the `SymbolicBinding` instruction.
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//
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// The type of `.Self` must be a `FacetType`, so that it gets wrapped in
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// `FacetAccessType` when used in a type position, such as in `U:! I(.Self)`.
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// This allows substitution with other facet values without requiring an
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// additional `FacetAccessType` to be inserted.
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auto MakePeriodSelfFacetValue(Context& context, SemIR::LocId loc_id,
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SemIR::TypeId self_type_id) -> SemIR::InstId;
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class SubstPeriodSelfCallbacks : public SubstInstCallbacks {
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public:
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enum Behaviour {
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ImplicitOnly,
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All,
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};
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explicit SubstPeriodSelfCallbacks(
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Context* context, SemIR::LocId loc_id,
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SemIR::ConstantId period_self_replacement_id,
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Behaviour behaviour = Behaviour::All);
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auto Subst(SemIR::InstId& inst_id) -> SubstResult override;
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auto Rebuild(SemIR::InstId orig_inst_id, SemIR::Inst new_inst)
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-> SemIR::InstId override;
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auto loc_id() const -> SemIR::LocId { return loc_id_; }
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auto period_self_replacement_id() const -> SemIR::ConstantId {
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return period_self_replacement_id_;
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}
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private:
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auto GetReplacement(SemIR::InstId period_self) -> SemIR::InstId;
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auto ConvertReplacement(SemIR::InstId replacement_self_inst_id,
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SemIR::TypeId replacement_type_id,
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SemIR::TypeId period_self_type_id) -> SemIR::InstId;
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SemIR::LocId loc_id_;
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SemIR::ConstantId period_self_replacement_id_;
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Behaviour behaviour_;
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// The last output of GetReplacement().
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SemIR::InstId cached_replacement_id_ = SemIR::InstId::None;
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// The type of the last output of GetReplacement(). If the type of `.Self`
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// matches, we can reuse the `cached_replacement_id_`.
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SemIR::TypeId cached_replacement_type_id_ = SemIR::TypeId::None;
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};
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// Replace all `.Self` references in `const_id`. The `callbacks` specifies the
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// facet to replace them with.
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auto SubstPeriodSelf(Context& context, SubstPeriodSelfCallbacks& callbacks,
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SemIR::ConstantId const_id) -> SemIR::ConstantId;
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// Replace all `.Self` references in the specific of the interface or named
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// constraint. The `callbacks` specifies the facet to replace them with.
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auto SubstPeriodSelf(Context& context, SubstPeriodSelfCallbacks& callbacks,
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SemIR::SpecificInterface interface)
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-> SemIR::SpecificInterface;
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auto SubstPeriodSelf(Context& context, SubstPeriodSelfCallbacks& callbacks,
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SemIR::SpecificNamedConstraint constraint)
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-> SemIR::SpecificNamedConstraint;
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// Returns whether the constant value of `inst_id` is a reference to `.Self`.
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//
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// If `canonicalize` is true, look at the constant value of `inst_id` and get
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// the canonicalized facet or type to look through FacetAccessType.
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auto IsPeriodSelf(Context& context, SemIR::InstId inst_id,
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bool canonicalize = true) -> bool;
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// Look for ambiguous `.Self` in a `T impls X where ...` statement. The given
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// inst ids are the non-canonical insts for the LHS and RHS of the `impls`
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// inside a `where` expression.
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//
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// If the LHS is not `.Self` and RHS contains a nested `where` expression, the
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// value of `.Self` becomes ambiguous on the RHS of the `where` (it could mean
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// either the original value or new value given by the LHS of the `impls`). Note
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// that implicit `.Self` references are never ambiguous, they always refer to
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// the innermost value that `.Self` could refer to.
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//
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// Returns true if an error was diagnosed.
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auto FindAndDiagnoseAmbiguousPeriodSelf(Context& context,
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SemIR::InstId impls_lhs_id,
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SemIR::InstId impls_rhs_id) -> bool;
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} // namespace Carbon::Check
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#endif // CARBON_TOOLCHAIN_CHECK_PERIOD_SELF_H_
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