RequirementMachine: Implement InferredGenericSignatureRequest

include/swift/AST/Decl.h

@@ -4225,6 +4225,7 @@ class ProtocolDecl final : public NominalTypeDecl {
   friend class SuperclassDeclRequest;
   friend class SuperclassTypeRequest;
   friend class StructuralRequirementsRequest;
+  friend class TypeAliasRequirementsRequest;
   friend class ProtocolDependenciesRequest;
   friend class RequirementSignatureRequest;
   friend class RequirementSignatureRequestRQM;
@@ -4421,6 +4422,11 @@ class ProtocolDecl final : public NominalTypeDecl {
   /// instead.
   ArrayRef<StructuralRequirement> getStructuralRequirements() const;
 
+  /// Retrieve same-type requirements implied by protocol typealiases with the
+  /// same name as associated types, and diagnose cases that are better expressed
+  /// via a 'where' clause.
+  ArrayRef<Requirement> getTypeAliasRequirements() const;
+
   /// Get the list of protocols appearing on the right hand side of conformance
   /// requirements. Computed from the structural requirements, above.
   ArrayRef<ProtocolDecl *> getProtocolDependencies() const;

include/swift/AST/TypeCheckRequests.h

@@ -387,6 +387,25 @@ class StructuralRequirementsRequest :
   bool isCached() const { return true; }
 };
 
+class TypeAliasRequirementsRequest :
+    public SimpleRequest<TypeAliasRequirementsRequest,
+                         ArrayRef<Requirement>(ProtocolDecl *),
+                         RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  ArrayRef<Requirement>
+  evaluate(Evaluator &evaluator, ProtocolDecl *proto) const;
+
+public:
+  // Caching.
+  bool isCached() const { return true; }
+};
+
 class ProtocolDependenciesRequest :
     public SimpleRequest<ProtocolDependenciesRequest,
                          ArrayRef<ProtocolDecl *>(ProtocolDecl *),
@@ -1534,7 +1553,50 @@ class InferredGenericSignatureRequest :
   SourceLoc getNearestLoc() const {
     return SourceLoc();
   }
-
+
+  // Cycle handling.
+  void noteCycleStep(DiagnosticEngine &diags) const;
+};
+
+/// Build a generic signature using the RequirementMachine. This is temporary;
+/// once the GenericSignatureBuilder goes away this will be folded into
+/// InferredGenericSignatureRequest.
+class InferredGenericSignatureRequestRQM :
+    public SimpleRequest<InferredGenericSignatureRequestRQM,
+                         GenericSignatureWithError (ModuleDecl *,
+                                                    const GenericSignatureImpl *,
+                                                    GenericParamList *,
+                                                    WhereClauseOwner,
+                                                    SmallVector<Requirement, 2>,
+                                                    SmallVector<TypeLoc, 2>,
+                                                    bool),
+                         RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  GenericSignatureWithError
+  evaluate(Evaluator &evaluator,
+           ModuleDecl *parentModule,
+           const GenericSignatureImpl *baseSignature,
+           GenericParamList *genericParams,
+           WhereClauseOwner whereClause,
+           SmallVector<Requirement, 2> addedRequirements,
+           SmallVector<TypeLoc, 2> inferenceSources,
+           bool allowConcreteGenericParams) const;
+
+public:
+  // Separate caching.
+  bool isCached() const { return true; }
+
+  /// Inferred generic signature requests don't have source-location info.
+  SourceLoc getNearestLoc() const {
+    return SourceLoc();
+  }
+
   // Cycle handling.
   void noteCycleStep(DiagnosticEngine &diags) const;
 };

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -143,6 +143,14 @@ SWIFT_REQUEST(TypeChecker, InferredGenericSignatureRequest,
                                          SmallVector<Requirement, 2>,
                                          SmallVector<TypeLoc, 2>, bool),
               Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, InferredGenericSignatureRequestRQM,
+              GenericSignatureWithError (ModuleDecl *,
+                                         const GenericSignatureImpl *,
+                                         GenericParamList *,
+                                         WhereClauseOwner,
+                                         SmallVector<Requirement, 2>,
+                                         SmallVector<TypeLoc, 2>, bool),
+              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, DistributedModuleIsAvailableRequest,
               bool(ModuleDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InheritedTypeRequest,
@@ -227,6 +235,9 @@ SWIFT_REQUEST(TypeChecker, RequirementRequest,
 SWIFT_REQUEST(TypeChecker, StructuralRequirementsRequest,
               ArrayRef<StructuralRequirement>(ProtocolDecl *), Cached,
               HasNearestLocation)
+SWIFT_REQUEST(TypeChecker, TypeAliasRequirementsRequest,
+              ArrayRef<Requirement>(ProtocolDecl *), Cached,
+              HasNearestLocation)
 SWIFT_REQUEST(TypeChecker, ProtocolDependenciesRequest,
               ArrayRef<ProtocolDecl *>(ProtocolDecl *), Cached,
               HasNearestLocation)

include/swift/Basic/LangOptions.h

@@ -489,8 +489,14 @@ namespace swift {
     RequirementMachineMode RequirementMachineProtocolSignatures =
         RequirementMachineMode::Disabled;
 
-    /// Enable the new experimental generic signature minimization algorithm.
-    RequirementMachineMode RequirementMachineGenericSignatures =
+    /// Enable the new experimental generic signature minimization algorithm
+    /// for abstract generic signatures.
+    RequirementMachineMode RequirementMachineAbstractSignatures =
+        RequirementMachineMode::Disabled;
+
+    /// Enable the new experimental generic signature minimization algorithm
+    /// for user-written generic signatures.
+    RequirementMachineMode RequirementMachineInferredSignatures =
         RequirementMachineMode::Disabled;
 
     /// Sets the target we are building for and updates platform conditions

include/swift/Option/Options.td

@@ -624,7 +624,11 @@ def requirement_machine_protocol_signatures_EQ : Joined<["-"], "requirement-mach
   Flags<[FrontendOption]>,
   HelpText<"Control usage of experimental protocol requirement signature minimization: 'on', 'off', or 'verify'">;
 
-def requirement_machine_generic_signatures_EQ : Joined<["-"], "requirement-machine-generic-signatures=">,
+def requirement_machine_abstract_signatures_EQ : Joined<["-"], "requirement-machine-abstract-signatures=">,
+  Flags<[FrontendOption]>,
+  HelpText<"Control usage of experimental generic signature minimization: 'on', 'off', or 'verify'">;
+
+def requirement_machine_inferred_signatures_EQ : Joined<["-"], "requirement-machine-inferred-signatures=">,
   Flags<[FrontendOption]>,
   HelpText<"Control usage of experimental generic signature minimization: 'on', 'off', or 'verify'">;
 

lib/AST/Decl.cpp

@@ -5260,6 +5260,13 @@ ProtocolDecl::getStructuralRequirements() const {
                None);
 }
 
+ArrayRef<Requirement>
+ProtocolDecl::getTypeAliasRequirements() const {
+  return evaluateOrDefault(getASTContext().evaluator,
+               TypeAliasRequirementsRequest { const_cast<ProtocolDecl *>(this) },
+               None);
+}
+
 ArrayRef<ProtocolDecl *>
 ProtocolDecl::getProtocolDependencies() const {
   return evaluateOrDefault(getASTContext().evaluator,