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//===--- Diagnostics.h - Requirement machine diagnostics --------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2021 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
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_REQUIREMENT_DIAGNOSTICS_H
#define SWIFT_REQUIREMENT_DIAGNOSTICS_H
#include "swift/AST/ASTContext.h"
#include "swift/AST/Requirement.h"
#include "swift/AST/Type.h"
namespace swift {
namespace rewriting {
/// Represents an invalid requirement, such as `T: Int`.
///
/// Invalid requirements are recorded while computing the
/// generic signature of a declaration, and diagnosed via
/// \c diagnoseRequirementErrors .
struct RequirementError {
/// The kind of requirement error.
enum class Kind {
/// A constraint to a non-protocol, non-class type, e.g. T: Int.
InvalidTypeRequirement,
/// A type requirement on a trivially invalid subject type,
/// e.g. Bool: Collection.
InvalidRequirementSubject,
/// An inverse constraint applied to an invalid subject type,
/// e.g., each T : ~Copyable
InvalidInverseSubject,
/// The inverse constraint requirement cannot applied to the subject because
/// it's an outer generic parameter, e.g.,
/// protocol P { func f() where Self: ~Copyable }
InvalidInverseOuterSubject,
/// An invalid shape requirement, e.g. T.shape == Int.shape
InvalidShapeRequirement,
/// A pair of conflicting requirements, T == Int, T == String
ConflictingRequirement,
/// An inverse requirement that conflicts with the computed requirements of
/// a generic parameter, e.g., T : Copyable, T : ~Copyable
ConflictingInverseRequirement,
/// A recursive requirement, e.g. T == G<T.A>.
RecursiveRequirement,
/// A not-yet-supported same-element requirement, e.g. each T == Int.
UnsupportedSameElement,
} kind;
private:
/// The invalid requirement.
union {
Requirement requirement;
InverseRequirement inverse;
};
public:
/// A requirement that conflicts with \c requirement. Both
/// requirements will have the same subject type.
std::optional<Requirement> conflictingRequirement;
SourceLoc loc;
private:
RequirementError(Kind kind, Requirement requirement, SourceLoc loc)
: kind(kind), requirement(requirement),
conflictingRequirement(std::nullopt), loc(loc) {}
RequirementError(Kind kind, InverseRequirement inverse, SourceLoc loc)
: kind(kind), inverse(inverse), conflictingRequirement(std::nullopt),
loc(loc) {}
RequirementError(Kind kind, Requirement requirement,
Requirement conflict,
SourceLoc loc)
: kind(kind), requirement(requirement), conflictingRequirement(conflict), loc(loc) {}
public:
Requirement getRequirement() const {
assert(kind != Kind::InvalidInverseOuterSubject &&
kind != Kind::InvalidInverseSubject &&
kind != Kind::ConflictingInverseRequirement);
return requirement;
}
InverseRequirement getInverse() const {
assert(kind == Kind::InvalidInverseOuterSubject ||
kind == Kind::InvalidInverseSubject ||
kind == Kind::ConflictingInverseRequirement);
return inverse;
}
static RequirementError forInvalidTypeRequirement(Type subjectType,
Type constraint,
SourceLoc loc) {
Requirement requirement(RequirementKind::Conformance, subjectType, constraint);
return {Kind::InvalidTypeRequirement, requirement, loc};
}
static RequirementError forInvalidRequirementSubject(Requirement req,
SourceLoc loc) {
return {Kind::InvalidRequirementSubject, req, loc};
}
static RequirementError forInvalidInverseSubject(InverseRequirement inv) {
return {Kind::InvalidInverseSubject, inv, inv.loc};
}
static
RequirementError forInvalidInverseOuterSubject(InverseRequirement inv) {
return {Kind::InvalidInverseOuterSubject, inv, inv.loc};
}
static RequirementError forConflictingInverseRequirement(
InverseRequirement req,
SourceLoc loc) {
return {Kind::ConflictingInverseRequirement, req, loc};
}
static RequirementError forInvalidShapeRequirement(Requirement req,
SourceLoc loc) {
return {Kind::InvalidShapeRequirement, req, loc};
}
static RequirementError forConflictingRequirement(Requirement req,
SourceLoc loc) {
return {Kind::ConflictingRequirement, req, loc};
}
static RequirementError forConflictingRequirement(Requirement first,
Requirement second,
SourceLoc loc) {
return {Kind::ConflictingRequirement, first, second, loc};
}
static RequirementError forRecursiveRequirement(Requirement req,
SourceLoc loc) {
return {Kind::RecursiveRequirement, req, loc};
}
static RequirementError forSameElement(Requirement req, SourceLoc loc) {
return {Kind::UnsupportedSameElement, req, loc};
}
};
/// Policy for the fixit that transforms 'T : S' where 'S' is not a protocol
/// or a class into 'T == S'.
enum AllowConcreteTypePolicy {
/// Any type parameter can be concrete.
All,
/// Only associated types can be concrete.
AssocTypes,
/// Only nested associated types can be concrete. This is for protocols,
/// where we don't want to suggest making an associated type member of
/// 'Self' concrete.
NestedAssocTypes
};
bool diagnoseRequirementErrors(ASTContext &ctx,
ArrayRef<RequirementError> errors,
AllowConcreteTypePolicy concreteTypePolicy);
} // end namespace rewriting
} // end namespace swift
#endif
|
