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Kavon Farvardin
d46a86e5b1
A requirement defines the maximal effects that a witness can have. In some cases, we'd fail to properly reject such a witness with more effects, when that witness is valid for another requirement within that protocol. Thus, we'd hit an assertion failure in that case rather than permitting the valid program to compile. In a non-asserts compiler, we could end up failing to diagnose an invalid chosen witness and crash in IRGen. https://github.com/apple/swift/issues/73479 rdar://127669069
121 lines
3.4 KiB
C++
121 lines
3.4 KiB
C++
//===--- Decl.h - Swift Language Declaration ASTs ---------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines some data types used for 'rethrows' and `reasync` checking.
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//
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// We refer to 'throws' and 'async' as "effects". A function might have either or
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// both effects.
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//
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// A function is _effect polymorphic_ if its effect depends on the call site.
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// This can either be unconditional (the usual 'throws' or 'async' case), or it
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// can depend on either its arguments or conformances (these are 'rethrows' and
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// 'reasync' functions).
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_EFFECTS_H
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#define SWIFT_EFFECTS_H
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#include "swift/AST/Type.h"
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#include "swift/Basic/OptionSet.h"
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#include <utility>
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namespace llvm {
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class raw_ostream;
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}
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namespace swift {
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class AbstractFunctionDecl;
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class ProtocolDecl;
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enum class EffectKind : uint8_t {
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Throws = 1 << 0,
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Async = 1 << 1,
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Unsafe = 1 << 2,
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LAST_EFFECT = Unsafe,
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};
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namespace EffectKinds {
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constexpr std::array<EffectKind, 3> all() {
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return {
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EffectKind::Throws,
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EffectKind::Async,
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EffectKind::Unsafe,
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};
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}
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static_assert(EffectKinds::all().back() == EffectKind::LAST_EFFECT);
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} // namespace EffectKinds
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using PossibleEffects = OptionSet<EffectKind>;
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void simple_display(llvm::raw_ostream &out, const EffectKind kind);
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class ValueDecl;
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class PolymorphicEffectRequirementList {
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using Requirements = ArrayRef<AbstractFunctionDecl *>;
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using Conformances = ArrayRef<std::pair<Type, ProtocolDecl *>>;
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private:
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Requirements requirements;
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Conformances conformances;
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public:
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PolymorphicEffectRequirementList(Requirements requirements,
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Conformances conformances)
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: requirements(requirements), conformances(conformances) {}
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PolymorphicEffectRequirementList() {}
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Requirements getRequirements() const {
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return requirements;
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}
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Conformances getConformances() const {
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return conformances;
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}
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};
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void simple_display(llvm::raw_ostream &out,
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const PolymorphicEffectRequirementList reqs);
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enum class PolymorphicEffectKind : uint8_t {
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/// The function does not have this effect at all.
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None,
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/// The function has this effect if at least one closure argument has it.
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///
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/// This is the ordinary 'rethrows' /'reasync' case.
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ByClosure,
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/// The function has this effect if at least one of its conformances has it.
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///
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/// This is the conformance-based 'rethrows' /'reasync' case.
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ByConformance,
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/// The function is only permitted to be `rethrows` because it depends
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/// on a conformance to `AsyncSequence` or `AsyncIteratorProtocol`,
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/// which historically were "@rethrows" protocols.
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AsyncSequenceRethrows,
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/// The function has this effect unconditionally.
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///
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/// This is a plain old 'throws' / 'async' function.
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Always,
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/// The function declaration was invalid.
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Invalid
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};
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void simple_display(llvm::raw_ostream &out, PolymorphicEffectKind value);
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} // end namespace swift
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#endif
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