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//===--- TypeCheckEffects.h - Effects checking ------------------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file provides type checking support for Swift's effect checking, which
// includes error handling (throws) and asynchronous (async) effects.
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_SEMA_TYPECHECKEFFECTS_H
#define SWIFT_SEMA_TYPECHECKEFFECTS_H
#include "swift/AST/Type.h"
namespace swift {
/// Classifies the result of a subtyping comparison between two thrown error
/// types.
enum class ThrownErrorSubtyping {
/// There is no subtyping relationship, and we're trying to convert from a
/// throwning type to a non-throwing type.
DropsThrows,
/// There is no subtyping relationship because the types mismatch.
Mismatch,
/// The thrown error types exactly match; there is a subtype relationship.
ExactMatch,
/// The thrown error types are different, but there is an obvious subtype
/// relationship.
Subtype,
/// The thrown error types are different, and the presence of type variables
/// or type parameters prevents us from determining now whether there is a
/// subtype relationship.
Dependent,
};
/// Compare the thrown error types for the purposes of subtyping.
ThrownErrorSubtyping compareThrownErrorsForSubtyping(
Type subThrownError, Type superThrownError, DeclContext *dc);
/// Determine whether the given function uses typed throws in a manner
/// that is structurally similar to 'rethrows', e.g.,
///
/// \code
/// func map<T, E>(_ body: (Element) throws(E) -> T) throws(E) -> [T]
/// \endcode
bool isRethrowLikeTypedThrows(AbstractFunctionDecl *func);
}
#endif // SWIFT_SEMA_TYPECHECKEFFECTS_H
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