mirror of
https://github.com/carbon-language/carbon-lang.git
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Dana Jansens
917a6ea971
Currently each interface has a `Self` facet internally that becomes a binding to every entity inside the interface: associated constants, functions, and require decls. Each of these has to be independently generic as a result. This makes is challenging in extended name lookup to move into an extended scope of an interface, as we have a specific for the interface, but the names within require a different specific that includes a `Self` facet value. We generalize this relationship by adding a second generic to Interface, called `generic_with_self`. When we want to work with entities inside the interface, we move from the interface-without-specific to the interface-with-self specific by adding a Self to the specific. This is done independently of any particular entity inside the Interface, as those entities are now all members of the interface-with-self generic. Associated constants no longer need a generic of their own, as they do not have separate generic bindings. Functions retain a generic, but if the function has no generic arguments, it will have no bindings of its own now. Require decls retain a generic so that their specific can be instantiated separately from the interface. Requiring the interface to be complete does not require the types in a require decl to be complete unless it is modified by `extend`. So we allow them to be completed later by keeping them in a separate generic. Named constraints look like interfaces and gain the additional inner generic-with-self, with the same relationship to require decls. This removes the need for name lookup to perform Substitution of a Self facet into the extended scope instruction. Instead, the `SpecificConstant` instruction inserted by a `require` decl is part of the interface-with-self generic. When looking through a FacetType for extended scopes, for each interface, we push the scope with the specific for the interface-with-self. Then the constant value of the `SpecificConstant` is correctly modified by the provided self automatically through applying that specific.
33 lines
1.3 KiB
C++
33 lines
1.3 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_DEDUCE_H_
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#define CARBON_TOOLCHAIN_CHECK_DEDUCE_H_
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#include "toolchain/check/context.h"
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#include "toolchain/sem_ir/ids.h"
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namespace Carbon::Check {
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// Deduces the generic arguments to use in a call to a generic.
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auto DeduceGenericCallArguments(Context& context, SemIR::LocId loc_id,
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SemIR::GenericId generic_id,
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SemIR::SpecificId enclosing_specific_id,
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SemIR::InstBlockId implicit_param_patterns_id,
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SemIR::InstBlockId param_patterns_id,
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SemIR::InstId self_id,
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llvm::ArrayRef<SemIR::InstId> arg_ids)
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-> SemIR::SpecificId;
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// Deduces the impl arguments to use in a use of a parameterized impl. Returns
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// `None` if deduction fails.
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auto DeduceImplArguments(Context& context, SemIR::LocId loc_id,
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const SemIR::Impl& impl, SemIR::ConstantId self_id,
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SemIR::SpecificId constraint_specific_id)
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-> SemIR::SpecificId;
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} // namespace Carbon::Check
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#endif // CARBON_TOOLCHAIN_CHECK_DEDUCE_H_
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