include/swift/AST/TypeCheckRequests.h

//===--- TypeCheckRequests.h - Type Checking Requests -----------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 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 defines type checking requests.
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_TYPE_CHECK_REQUESTS_H
#define SWIFT_TYPE_CHECK_REQUESTS_H

#include "swift/AST/ASTTypeIDs.h"
#include "swift/AST/GenericSignature.h"
#include "swift/AST/Type.h"
#include "swift/AST/Evaluator.h"
#include "swift/AST/SimpleRequest.h"
#include "swift/AST/TypeResolutionStage.h"
#include "swift/Basic/AnyValue.h"
#include "swift/Basic/Statistic.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/TinyPtrVector.h"

namespace swift {

class AbstractStorageDecl;
class AccessorDecl;
enum class AccessorKind;
class GenericParamList;
class PrecedenceGroupDecl;
struct PropertyWrapperBackingPropertyInfo;
struct PropertyWrapperMutability;
class RequirementRepr;
class SpecializeAttr;
class TypeAliasDecl;
struct TypeLoc;
class ValueDecl;
enum class OpaqueReadOwnership: uint8_t;
class StorageImplInfo;

/// Display a nominal type or extension thereof.
void simple_display(
       llvm::raw_ostream &out,
       const llvm::PointerUnion<TypeDecl *, ExtensionDecl *> &value);

/// Request the type from the ith entry in the inheritance clause for the
/// given declaration.
class InheritedTypeRequest :
    public SimpleRequest<InheritedTypeRequest,
                         Type(llvm::PointerUnion<TypeDecl *, ExtensionDecl *>,
                              unsigned,
                              TypeResolutionStage),
                         CacheKind::SeparatelyCached>
{
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type>
  evaluate(Evaluator &evaluator,
           llvm::PointerUnion<TypeDecl *, ExtensionDecl *> decl,
           unsigned index,
           TypeResolutionStage stage) const;

public:
  // Source location
  SourceLoc getNearestLoc() const;

  // Caching
  bool isCached() const;
  Optional<Type> getCachedResult() const;
  void cacheResult(Type value) const;
};

/// Request the superclass type for the given class.
class SuperclassTypeRequest :
    public SimpleRequest<SuperclassTypeRequest,
                         Type(NominalTypeDecl *, TypeResolutionStage),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type>
  evaluate(Evaluator &evaluator, NominalTypeDecl *classDecl,
           TypeResolutionStage stage) const;

public:
  // Cycle handling
  void diagnoseCycle(DiagnosticEngine &diags) const;

  // Separate caching.
  bool isCached() const;
  Optional<Type> getCachedResult() const;
  void cacheResult(Type value) const;
};

/// Request the raw type of the given enum.
class EnumRawTypeRequest :
    public SimpleRequest<EnumRawTypeRequest,
                         Type(EnumDecl *, TypeResolutionStage),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type>
  evaluate(Evaluator &evaluator, EnumDecl *enumDecl,
           TypeResolutionStage stage) const;

public:
  // Cycle handling
  void diagnoseCycle(DiagnosticEngine &diags) const;

  // Separate caching.
  bool isCached() const;
  Optional<Type> getCachedResult() const;
  void cacheResult(Type value) const;
};

/// Request to determine the set of declarations that were are overridden
/// by the given declaration.
class OverriddenDeclsRequest :
  public SimpleRequest<OverriddenDeclsRequest,
                       llvm::TinyPtrVector<ValueDecl *>(ValueDecl *),
                       CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<llvm::TinyPtrVector<ValueDecl *>>
  evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<llvm::TinyPtrVector<ValueDecl *>> getCachedResult() const;
  void cacheResult(llvm::TinyPtrVector<ValueDecl *> value) const;
};

/// Determine whether the given declaration is exposed to Objective-C.
class IsObjCRequest :
    public SimpleRequest<IsObjCRequest,
                         bool(ValueDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

void simple_display(llvm::raw_ostream &out, CtorInitializerKind initKind);

/// Computes the kind of initializer for a given \c ConstructorDecl
class InitKindRequest :
    public SimpleRequest<InitKindRequest,
                         CtorInitializerKind(ConstructorDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<CtorInitializerKind>
      evaluate(Evaluator &evaluator, ConstructorDecl *decl) const;

public:
  // Caching.
  bool isCached() const { return true; }
};

/// Determine whether the given protocol declaration is class-bounded.
class ProtocolRequiresClassRequest :
    public SimpleRequest<ProtocolRequiresClassRequest,
                         bool(ProtocolDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ProtocolDecl *decl) const;

public:
  // Cycle handling.
  void diagnoseCycle(DiagnosticEngine &diags) const;
  void noteCycleStep(DiagnosticEngine &diags) const;

  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Determine whether an existential conforming to a protocol can be matched
/// with a generic type parameter constrained to that protocol.
class ExistentialConformsToSelfRequest :
    public SimpleRequest<ExistentialConformsToSelfRequest,
                         bool(ProtocolDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ProtocolDecl *decl) const;

public:
  // Cycle handling.
  void diagnoseCycle(DiagnosticEngine &diags) const;
  void noteCycleStep(DiagnosticEngine &diags) const;

  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Determine whether we are allowed to refer to an existential type conforming
/// to this protocol.
class ExistentialTypeSupportedRequest :
    public SimpleRequest<ExistentialTypeSupportedRequest,
                         bool(ProtocolDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ProtocolDecl *decl) const;

public:
  // Cycle handling.
  void diagnoseCycle(DiagnosticEngine &diags) const;
  void noteCycleStep(DiagnosticEngine &diags) const;

  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Determine whether the given declaration is 'final'.
class IsFinalRequest :
    public SimpleRequest<IsFinalRequest,
                         bool(ValueDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Determine whether the given declaration is 'dynamic''.
class IsDynamicRequest :
    public SimpleRequest<IsDynamicRequest,
                         bool(ValueDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Compute the requirements that describe a protocol.
class RequirementSignatureRequest :
    public SimpleRequest<RequirementSignatureRequest,
                         ArrayRef<Requirement>(ProtocolDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<ArrayRef<Requirement>> evaluate(Evaluator &evaluator, ProtocolDecl *proto) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<ArrayRef<Requirement>> getCachedResult() const;
  void cacheResult(ArrayRef<Requirement> value) const;
};

/// Compute the default definition type of an associated type.
class DefaultDefinitionTypeRequest :
    public SimpleRequest<DefaultDefinitionTypeRequest,
                         Type(AssociatedTypeDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type> evaluate(Evaluator &evaluator, AssociatedTypeDecl *decl) const;

public:
  // Caching.
  bool isCached() const { return true; }
};

/// Describes the owner of a where clause, from which we can extract
/// requirements.
struct WhereClauseOwner {
  /// The declaration context in which the where clause will be evaluated.
  DeclContext *dc;

  /// The source of the where clause, which can be a generic parameter list
  /// or a declaration that can have a where clause.
  llvm::PointerUnion<GenericParamList *, Decl *, SpecializeAttr *,
                     // SWIFT_ENABLE_TENSORFLOW
                     DifferentiableAttr *>
      source;

  WhereClauseOwner(Decl *decl);

  WhereClauseOwner(DeclContext *dc, GenericParamList *genericParams)
      : dc(dc), source(genericParams) {}

  WhereClauseOwner(DeclContext *dc, SpecializeAttr *attr)
      : dc(dc), source(attr) {}

  // SWIFT_ENABLE_TENSORFLOW
  WhereClauseOwner(DeclContext *dc, DifferentiableAttr *attr)
    : dc(dc), source(attr) {}

  SourceLoc getLoc() const;

  friend hash_code hash_value(const WhereClauseOwner &owner) {
    return llvm::hash_combine(owner.dc, owner.source.getOpaqueValue());
  }

  friend bool operator==(const WhereClauseOwner &lhs,
                         const WhereClauseOwner &rhs) {
    return lhs.dc == rhs.dc &&
           lhs.source.getOpaqueValue() == rhs.source.getOpaqueValue();
  }

  friend bool operator!=(const WhereClauseOwner &lhs,
                         const WhereClauseOwner &rhs) {
    return !(lhs == rhs);
  }

public:
  /// Retrieve the array of requirements.
  MutableArrayRef<RequirementRepr> getRequirements() const;

  /// Visit each of the requirements,
  ///
  /// \returns true after short-circuiting if the callback returned \c true
  /// for any of the requirements.
  bool
  visitRequirements(TypeResolutionStage stage,
                    llvm::function_ref<bool(Requirement, RequirementRepr *)>
                        callback) const &&;
};

void simple_display(llvm::raw_ostream &out, const WhereClauseOwner &owner);

/// Retrieve a requirement from the where clause of the given declaration.
class RequirementRequest :
    public SimpleRequest<RequirementRequest,
                         Requirement(WhereClauseOwner, unsigned,
                                     TypeResolutionStage),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  /// Retrieve the requirement this request operates on.
  RequirementRepr &getRequirement() const;

  // Evaluation.
  llvm::Expected<Requirement> evaluate(Evaluator &evaluator,
                                       WhereClauseOwner,
                                       unsigned index,
                                       TypeResolutionStage stage) const;

public:
  // Source location
  SourceLoc getNearestLoc() const;

  // Cycle handling.
  void noteCycleStep(DiagnosticEngine &diags) const;
                           
  // Separate caching.
  bool isCached() const;
  Optional<Requirement> getCachedResult() const;
  void cacheResult(Requirement value) const;
};

/// Generate the USR for the given declaration.
class USRGenerationRequest :
    public SimpleRequest<USRGenerationRequest,
                         std::string(const ValueDecl*),
                         CacheKind::Cached>
{
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<std::string> evaluate(Evaluator &eval, const ValueDecl *d) const;

public:
  // Caching
  bool isCached() const { return true; }
};

/// Generate the mangling for the given local type declaration.
class MangleLocalTypeDeclRequest :
    public SimpleRequest<MangleLocalTypeDeclRequest,
                         std::string(const TypeDecl*),
                         CacheKind::Cached>
{
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<std::string> evaluate(Evaluator &eval, const TypeDecl *d) const;

public:
  // Caching
  bool isCached() const { return true; }
};

void simple_display(llvm::raw_ostream &out, const KnownProtocolKind);
class TypeChecker;

// Find the type in the cache or look it up
class DefaultTypeRequest
    : public SimpleRequest<DefaultTypeRequest,
                           Type(KnownProtocolKind, const DeclContext *),
                           CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type> evaluate(Evaluator &eval, KnownProtocolKind,
                                const DeclContext *) const;

public:
  // Caching
  bool isCached() const { return true; }
  Optional<Type> getCachedResult() const;
  void cacheResult(Type value) const;
};

/// Retrieve information about a property wrapper type.
class PropertyWrapperTypeInfoRequest
  : public SimpleRequest<PropertyWrapperTypeInfoRequest,
                         PropertyWrapperTypeInfo(NominalTypeDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<PropertyWrapperTypeInfo>
      evaluate(Evaluator &eval, NominalTypeDecl *nominal) const;

public:
  // Caching
  bool isCached() const;
};

/// Request the nominal type declaration to which the given custom attribute
/// refers.
class AttachedPropertyWrappersRequest :
    public SimpleRequest<AttachedPropertyWrappersRequest,
                         llvm::TinyPtrVector<CustomAttr *>(VarDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<llvm::TinyPtrVector<CustomAttr *>>
  evaluate(Evaluator &evaluator, VarDecl *) const;

public:
  // Caching
  bool isCached() const;
};

/// Request the raw (possibly unbound generic) type of the property wrapper
/// that is attached to the given variable.
class AttachedPropertyWrapperTypeRequest :
    public SimpleRequest<AttachedPropertyWrapperTypeRequest,
                         Type(VarDecl *, unsigned),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type>
  evaluate(Evaluator &evaluator, VarDecl *var, unsigned i) const;

public:
  // Caching
  bool isCached() const;
};

/// Request the nominal type declaration to which the given custom attribute
/// refers.
class PropertyWrapperBackingPropertyTypeRequest :
    public SimpleRequest<PropertyWrapperBackingPropertyTypeRequest,
                         Type(VarDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type>
  evaluate(Evaluator &evaluator, VarDecl *var) const;

public:
  // Caching
  bool isCached() const;
};

/// Request information about the mutability of composed property wrappers.
class PropertyWrapperMutabilityRequest :
    public SimpleRequest<PropertyWrapperMutabilityRequest,
                         Optional<PropertyWrapperMutability> (VarDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Optional<PropertyWrapperMutability>>
  evaluate(Evaluator &evaluator, VarDecl *var) const;

public:
  // Caching
  bool isCached() const;
};

/// Request information about the backing property for properties that have
/// attached property wrappers.
class PropertyWrapperBackingPropertyInfoRequest :
    public SimpleRequest<PropertyWrapperBackingPropertyInfoRequest,
                         PropertyWrapperBackingPropertyInfo(VarDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<PropertyWrapperBackingPropertyInfo>
  evaluate(Evaluator &evaluator, VarDecl *var) const;

public:
  // Caching
  bool isCached() const;
};

/// Retrieve the structural type of an alias type.
class StructuralTypeRequest :
    public SimpleRequest<StructuralTypeRequest,
                         Type(TypeAliasDecl*),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type> evaluate(Evaluator &eval, TypeAliasDecl *d) const;

public:
  // Caching.
  bool isCached() const { return true; }
};

/// Request the most optimal resilience expansion for the code in the context.
class ResilienceExpansionRequest :
    public SimpleRequest<ResilienceExpansionRequest,
                         ResilienceExpansion(DeclContext*),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<ResilienceExpansion> evaluate(Evaluator &eval,
                                               DeclContext *context) const;

public:
  // Caching.
  bool isCached() const { return true; }
};

void simple_display(llvm::raw_ostream &out,
                    const ResilienceExpansion &value);

/// Request the custom attribute which attaches a function builder to the
/// given declaration.
class AttachedFunctionBuilderRequest :
    public SimpleRequest<AttachedFunctionBuilderRequest,
                         CustomAttr *(ValueDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<CustomAttr *>
  evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Caching
  bool isCached() const;
};

/// Request the function builder type attached to the given declaration,
/// if any.
class FunctionBuilderTypeRequest :
    public SimpleRequest<FunctionBuilderTypeRequest,
                         Type(ValueDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  llvm::Expected<Type>
  evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Caching
  bool isCached() const { return true; }
};

/// Request a function's self access kind.
class SelfAccessKindRequest :
    public SimpleRequest<SelfAccessKindRequest,
                         SelfAccessKind(FuncDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<SelfAccessKind>
  evaluate(Evaluator &evaluator, FuncDecl *func) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<SelfAccessKind> getCachedResult() const;
  void cacheResult(SelfAccessKind value) const;
};

/// Request whether the storage has a mutating getter.
class IsGetterMutatingRequest :
    public SimpleRequest<IsGetterMutatingRequest,
                         bool(AbstractStorageDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, AbstractStorageDecl *func) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Request whether the storage has a mutating getter.
class IsSetterMutatingRequest :
    public SimpleRequest<IsSetterMutatingRequest,
                         bool(AbstractStorageDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, AbstractStorageDecl *func) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

/// Request whether reading the storage yields a borrowed value.
class OpaqueReadOwnershipRequest :
    public SimpleRequest<OpaqueReadOwnershipRequest,
                         OpaqueReadOwnership(AbstractStorageDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<OpaqueReadOwnership>
  evaluate(Evaluator &evaluator, AbstractStorageDecl *storage) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<OpaqueReadOwnership> getCachedResult() const;
  void cacheResult(OpaqueReadOwnership value) const;
};

/// Request to build the underlying storage for a lazy property.
class LazyStoragePropertyRequest :
    public SimpleRequest<LazyStoragePropertyRequest,
                         VarDecl *(VarDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<VarDecl *>
  evaluate(Evaluator &evaluator, VarDecl *lazyVar) const;

public:
  bool isCached() const { return true; }
};

/// Request to type check the body of the given function up to the given
/// source location.
///
/// Produces true if an error occurred, false otherwise.
/// FIXME: it would be far better to return the type-checked body.
class TypeCheckFunctionBodyUntilRequest :
    public SimpleRequest<TypeCheckFunctionBodyUntilRequest,
                         bool(AbstractFunctionDecl *, SourceLoc),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, AbstractFunctionDecl *func,
           SourceLoc endTypeCheckLoc) const;

public:
  bool isCached() const { return true; }
};

/// Request to obtain a list of stored properties in a nominal type.
///
/// This will include backing storage for lazy properties and
/// property wrappers, synthesizing them if necessary.
class StoredPropertiesRequest :
    public SimpleRequest<StoredPropertiesRequest,
                         ArrayRef<VarDecl *>(NominalTypeDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<ArrayRef<VarDecl *>>
  evaluate(Evaluator &evaluator, NominalTypeDecl *decl) const;

public:
  bool isCached() const { return true; }
};

/// Request to obtain a list of stored properties in a nominal type,
/// together with any missing members corresponding to stored
/// properties that could not be deserialized.
///
/// This will include backing storage for lazy properties and
/// property wrappers, synthesizing them if necessary.
class StoredPropertiesAndMissingMembersRequest :
    public SimpleRequest<StoredPropertiesAndMissingMembersRequest,
                         ArrayRef<Decl *>(NominalTypeDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<ArrayRef<Decl *>>
  evaluate(Evaluator &evaluator, NominalTypeDecl *decl) const;

public:
  bool isCached() const { return true; }
};

class StorageImplInfoRequest :
    public SimpleRequest<StorageImplInfoRequest,
                         StorageImplInfo(AbstractStorageDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<StorageImplInfo>
  evaluate(Evaluator &evaluator, AbstractStorageDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<StorageImplInfo> getCachedResult() const;
  void cacheResult(StorageImplInfo value) const;
};

class RequiresOpaqueAccessorsRequest :
    public SimpleRequest<RequiresOpaqueAccessorsRequest,
                         bool(VarDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, VarDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

class RequiresOpaqueModifyCoroutineRequest :
    public SimpleRequest<RequiresOpaqueModifyCoroutineRequest,
                         bool(AbstractStorageDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, AbstractStorageDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

class IsAccessorTransparentRequest :
    public SimpleRequest<IsAccessorTransparentRequest,
                         bool(AccessorDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, AccessorDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

class SynthesizeAccessorRequest :
    public SimpleRequest<SynthesizeAccessorRequest,
                         AccessorDecl *(AbstractStorageDecl *,
                                        AccessorKind),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<AccessorDecl *>
  evaluate(Evaluator &evaluator, AbstractStorageDecl *decl,
           AccessorKind kind) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<AccessorDecl *> getCachedResult() const;
  void cacheResult(AccessorDecl *value) const;
};

class EmittedMembersRequest :
    public SimpleRequest<EmittedMembersRequest,
                         DeclRange(ClassDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<DeclRange>
  evaluate(Evaluator &evaluator, ClassDecl *classDecl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<DeclRange> getCachedResult() const;
  void cacheResult(DeclRange value) const;
};

class IsImplicitlyUnwrappedOptionalRequest :
    public SimpleRequest<IsImplicitlyUnwrappedOptionalRequest,
                         bool(ValueDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, ValueDecl *value) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

class ClassAncestryFlagsRequest :
    public SimpleRequest<ClassAncestryFlagsRequest,
                         AncestryFlags (ClassDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<AncestryFlags>
  evaluate(Evaluator &evaluator, ClassDecl *value) const;
public:
  // Caching.
  bool isCached() const { return true; }
};

void simple_display(llvm::raw_ostream &out, AncestryFlags value);

class AbstractGenericSignatureRequest :
    public SimpleRequest<AbstractGenericSignatureRequest,
                         GenericSignature (GenericSignatureImpl *,
                                           SmallVector<GenericTypeParamType *, 2>,
                                           SmallVector<Requirement, 2>),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<GenericSignature>
  evaluate(Evaluator &evaluator,
           GenericSignatureImpl *baseSignature,
           SmallVector<GenericTypeParamType *, 2> addedParameters,
           SmallVector<Requirement, 2> addedRequirements) const;

public:
  // Separate caching.
  bool isCached() const;

  /// Abstract generic signature requests never have source-location info.
  SourceLoc getNearestLoc() const {
    return SourceLoc();
  }
};

class InferredGenericSignatureRequest :
    public SimpleRequest<InferredGenericSignatureRequest,
                         GenericSignature (ModuleDecl *,
                                            GenericSignatureImpl *,
                                            GenericParamList *,
                                            SmallVector<Requirement, 2>,
                                            SmallVector<TypeLoc, 2>,
                                            bool),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<GenericSignature>
  evaluate(Evaluator &evaluator,
           ModuleDecl *module,
           GenericSignatureImpl *baseSignature,
           GenericParamList *gpl,
           SmallVector<Requirement, 2> addedRequirements,
           SmallVector<TypeLoc, 2> inferenceSources,
           bool allowConcreteGenericParams) const;

public:
  // Separate caching.
  bool isCached() const;

  /// Inferred generic signature requests don't have source-location info.
  SourceLoc getNearestLoc() const {
    return SourceLoc();
  }
                           
  // Cycle handling.
  void noteCycleStep(DiagnosticEngine &diags) const;
};

void simple_display(llvm::raw_ostream &out, const TypeLoc source);

class ExtendedTypeRequest
    : public SimpleRequest<ExtendedTypeRequest,
                           Type(ExtensionDecl *),
                           CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type> evaluate(Evaluator &eval, ExtensionDecl *) const;
public:
  // Caching.
  bool isCached() const { return true; }
};

class FunctionOperatorRequest :
    public SimpleRequest<FunctionOperatorRequest,
                         OperatorDecl *(FuncDecl *),
                         CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;
  
private:
  friend SimpleRequest;
  
  // Evaluation.
  llvm::Expected<OperatorDecl *>
  evaluate(Evaluator &evaluator, FuncDecl *value) const;
  
public:
  // Caching.
  bool isCached() const { return true; }
};

class GenericSignatureRequest :
    public SimpleRequest<GenericSignatureRequest,
                         GenericSignature (GenericContext *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;
  
private:
  friend SimpleRequest;
  
  // Evaluation.
  llvm::Expected<GenericSignature>
  evaluate(Evaluator &evaluator, GenericContext *value) const;
  
public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<GenericSignature> getCachedResult() const;
  void cacheResult(GenericSignature value) const;
};

/// Compute the underlying interface type of a typealias.
class UnderlyingTypeRequest :
    public SimpleRequest<UnderlyingTypeRequest,
                         Type(TypeAliasDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<Type> evaluate(Evaluator &evaluator,
                                TypeAliasDecl *decl) const;

public:
  // Caching.
  bool isCached() const { return true; }
  Optional<Type> getCachedResult() const;
  void cacheResult(Type value) const;
  void diagnoseCycle(DiagnosticEngine &diags) const;
};

/// Looks up the precedence group of an operator declaration.
class OperatorPrecedenceGroupRequest
    : public SimpleRequest<OperatorPrecedenceGroupRequest,
                           PrecedenceGroupDecl *(InfixOperatorDecl *),
                           CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<PrecedenceGroupDecl *>
  evaluate(Evaluator &evaluator, InfixOperatorDecl *PGD) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
};

class EnumRawValuesRequest :
    public SimpleRequest<EnumRawValuesRequest,
                         bool (EnumDecl *, TypeResolutionStage),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;
  
private:
  friend SimpleRequest;
  
  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, EnumDecl *ED, TypeResolutionStage stage) const;
  
public:
  // Cycle handling.
  void diagnoseCycle(DiagnosticEngine &diags) const;
  void noteCycleStep(DiagnosticEngine &diags) const;
                           
  // Separate caching.
  bool isCached() const;
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

class IsABICompatibleOverrideRequest
    : public SimpleRequest<IsABICompatibleOverrideRequest, bool(ValueDecl *),
                           CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator, ValueDecl *decl) const;

public:
  // Caching.
  bool isCached() const { return true; }
};

/// Builds an opaque result type for a declaration.
class OpaqueResultTypeRequest
    : public SimpleRequest<OpaqueResultTypeRequest,
                           OpaqueTypeDecl *(ValueDecl *),
                           CacheKind::Cached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  llvm::Expected<OpaqueTypeDecl *>
  evaluate(Evaluator &evaluator, ValueDecl *VD) const;

public:
  // Caching.
  bool isCached() const { return true; }
};

/// Determines if a function declaration is 'static'.
class IsStaticRequest :
    public SimpleRequest<IsStaticRequest,
                         bool(FuncDecl *),
                         CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool>
  evaluate(Evaluator &evaluator, FuncDecl *value) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

class NeedsNewVTableEntryRequest
    : public SimpleRequest<NeedsNewVTableEntryRequest,
                           bool(AbstractFunctionDecl *),
                           CacheKind::SeparatelyCached> {
public:
  using SimpleRequest::SimpleRequest;

private:
  friend SimpleRequest;

  // Evaluation.
  llvm::Expected<bool> evaluate(Evaluator &evaluator,
                                AbstractFunctionDecl *decl) const;

public:
  // Separate caching.
  bool isCached() const { return true; }
  Optional<bool> getCachedResult() const;
  void cacheResult(bool value) const;
};

// Allow AnyValue to compare two Type values, even though Type doesn't
// support ==.
template<>
inline bool AnyValue::Holder<Type>::equals(const HolderBase &other) const {
  assert(typeID == other.typeID && "Caller should match type IDs");
  return value.getPointer() ==
      static_cast<const Holder<Type> &>(other).value.getPointer();
}

// Allow AnyValue to compare two GenericSignature values.
template <>
inline bool
AnyValue::Holder<GenericSignature>::equals(const HolderBase &other) const {
  assert(typeID == other.typeID && "Caller should match type IDs");
  return value.getPointer() ==
         static_cast<const Holder<GenericSignature> &>(other)
             .value.getPointer();
}

void simple_display(llvm::raw_ostream &out, Type value);
void simple_display(llvm::raw_ostream &out, const TypeRepr *TyR);

#define SWIFT_TYPEID_ZONE TypeChecker
#define SWIFT_TYPEID_HEADER "swift/AST/TypeCheckerTypeIDZone.def"
#include "swift/Basic/DefineTypeIDZone.h"
#undef SWIFT_TYPEID_ZONE
#undef SWIFT_TYPEID_HEADER

// Set up reporting of evaluated requests.
#define SWIFT_REQUEST(Zone, RequestType, Sig, Caching, LocOptions)             \
  template<>                                                                   \
  inline void reportEvaluatedRequest(UnifiedStatsReporter &stats,              \
                              const RequestType &request) {                    \
    ++stats.getFrontendCounters().RequestType;                                 \
  }
#include "swift/AST/TypeCheckerTypeIDZone.def"
#undef SWIFT_REQUEST

} // end namespace swift

#endif // SWIFT_TYPE_CHECK_REQUESTS_H