Sema: Refactor InferredGenericSignatureRequest to take a WhereClauseOwner

slavapestov · slavapestov · commit d847bc1a55d4 · 2021-10-20T14:39:25.000-04:00
diff --git a/include/swift/AST/GenericParamList.h b/include/swift/AST/GenericParamList.h
@@ -203,8 +203,6 @@ class RequirementRepr {
   void print(ASTPrinter &Printer) const;
 };
 
-using GenericParamSource = PointerUnion<GenericContext *, GenericParamList *>;
-
 /// GenericParamList - A list of generic parameters that is part of a generic
 /// function or type, along with extra requirements placed on those generic
 /// parameters and types derived from them.
diff --git a/include/swift/AST/TypeCheckRequests.h b/include/swift/AST/TypeCheckRequests.h
@@ -459,6 +459,8 @@ struct WhereClauseOwner {
                      SpecializeAttr *, DifferentiableAttr *>
       source;
 
+  WhereClauseOwner() : dc(nullptr) {}
+
   WhereClauseOwner(GenericContext *genCtx);
   WhereClauseOwner(AssociatedTypeDecl *atd);
 
@@ -480,6 +482,10 @@ struct WhereClauseOwner {
     return llvm::hash_value(owner.source.getOpaqueValue());
   }
 
+  operator bool() const {
+    return dc != nullptr;
+  }
+
   friend bool operator==(const WhereClauseOwner &lhs,
                          const WhereClauseOwner &rhs) {
     return lhs.source.getOpaqueValue() == rhs.source.getOpaqueValue();
@@ -1437,11 +1443,12 @@ class AbstractGenericSignatureRequest :
 class InferredGenericSignatureRequest :
     public SimpleRequest<InferredGenericSignatureRequest,
                          GenericSignature (ModuleDecl *,
-                                            const GenericSignatureImpl *,
-                                            GenericParamSource,
-                                            SmallVector<Requirement, 2>,
-                                            SmallVector<TypeLoc, 2>,
-                                            bool),
+                                           const GenericSignatureImpl *,
+                                           GenericParamList *,
+                                           WhereClauseOwner,
+                                           SmallVector<Requirement, 2>,
+                                           SmallVector<TypeLoc, 2>,
+                                           bool),
                          RequestFlags::Cached> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -1452,9 +1459,10 @@ class InferredGenericSignatureRequest :
   // Evaluation.
   GenericSignature
   evaluate(Evaluator &evaluator,
-           ModuleDecl *module,
+           ModuleDecl *parentModule,
            const GenericSignatureImpl *baseSignature,
-           GenericParamSource paramSource,
+           GenericParamList *genericParams,
+           WhereClauseOwner whereClause,
            SmallVector<Requirement, 2> addedRequirements,
            SmallVector<TypeLoc, 2> inferenceSources,
            bool allowConcreteGenericParams) const;
diff --git a/include/swift/AST/TypeCheckerTypeIDZone.def b/include/swift/AST/TypeCheckerTypeIDZone.def
@@ -131,10 +131,12 @@ SWIFT_REQUEST(TypeChecker, HasImplementationOnlyImportsRequest,
 SWIFT_REQUEST(TypeChecker, ModuleLibraryLevelRequest,
               LibraryLevel(ModuleDecl *), Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InferredGenericSignatureRequest,
-              GenericSignature (ModuleDecl *, const GenericSignatureImpl *,
-                                 GenericParamSource,
-                                 SmallVector<Requirement, 2>,
-                                 SmallVector<TypeLoc, 2>, bool),
+              GenericSignature (ModuleDecl *,
+                                const GenericSignatureImpl *,
+                                GenericParamList *,
+                                WhereClauseOwner,
+                                SmallVector<Requirement, 2>,
+                                SmallVector<TypeLoc, 2>, bool),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, DistributedModuleIsAvailableRequest,
               bool(ModuleDecl *), Cached, NoLocationInfo)
diff --git a/lib/AST/GenericSignatureBuilder.cpp b/lib/AST/GenericSignatureBuilder.cpp
@@ -8679,9 +8679,11 @@ AbstractGenericSignatureRequest::evaluate(
 
 GenericSignature
 InferredGenericSignatureRequest::evaluate(
-        Evaluator &evaluator, ModuleDecl *parentModule,
+        Evaluator &evaluator,
+        ModuleDecl *parentModule,
         const GenericSignatureImpl *parentSig,
-        GenericParamSource paramSource,
+        GenericParamList *genericParams,
+        WhereClauseOwner whereClause,
         SmallVector<Requirement, 2> addedRequirements,
         SmallVector<TypeLoc, 2> inferenceSources,
         bool allowConcreteGenericParams) const {
@@ -8729,12 +8731,6 @@ InferredGenericSignatureRequest::evaluate(
     return false;
   };
 
-  GenericParamList *genericParams = nullptr;
-  if (auto params = paramSource.dyn_cast<GenericParamList *>())
-      genericParams = params;
-  else
-      genericParams = paramSource.get<GenericContext *>()->getGenericParams();
-
   if (genericParams) {
     // Extensions never have a parent signature.
     if (genericParams->getOuterParameters())
@@ -8777,15 +8773,10 @@ InferredGenericSignatureRequest::evaluate(
     }
   }
 
-  if (auto *ctx = paramSource.dyn_cast<GenericContext *>()) {
-    // The declaration might have a trailing where clause.
-    if (auto *where = ctx->getTrailingWhereClause()) {
-      // Determine where and how to perform name lookup.
-      lookupDC = ctx;
-
-      WhereClauseOwner(lookupDC, where).visitRequirements(
+  if (whereClause) {
+    lookupDC = whereClause.dc;
+    std::move(whereClause).visitRequirements(
         TypeResolutionStage::Structural, visitRequirement);
-    }
   }
       
   /// Perform any remaining requirement inference.
diff --git a/lib/Sema/TypeCheckGeneric.cpp b/lib/Sema/TypeCheckGeneric.cpp
@@ -517,44 +517,6 @@ void TypeChecker::checkReferencedGenericParams(GenericContext *dc) {
 /// Generic types
 ///
 
-GenericSignature TypeChecker::checkGenericSignature(
-                      GenericParamSource paramSource,
-                      DeclContext *dc,
-                      GenericSignature parentSig,
-                      bool allowConcreteGenericParams,
-                      SmallVector<Requirement, 2> additionalRequirements,
-                      SmallVector<TypeLoc, 2> inferenceSources) {
-  if (auto genericParamList = paramSource.dyn_cast<GenericParamList *>())
-    assert(genericParamList && "Missing generic parameters?");
-
-  auto request = InferredGenericSignatureRequest{
-    dc->getParentModule(), parentSig.getPointer(), paramSource,
-    additionalRequirements, inferenceSources,
-    allowConcreteGenericParams};
-  auto sig = evaluateOrDefault(dc->getASTContext().evaluator,
-                               request, nullptr);
-
-  // Debugging of the generic signature builder and generic signature
-  // generation.
-  if (dc->getASTContext().TypeCheckerOpts.DebugGenericSignatures) {
-    llvm::errs() << "\n";
-    if (auto *VD = dyn_cast_or_null<ValueDecl>(dc->getAsDecl())) {
-      VD->dumpRef(llvm::errs());
-      llvm::errs() << "\n";
-    } else {
-      dc->printContext(llvm::errs());
-    }
-    llvm::errs() << "Generic signature: ";
-    sig->print(llvm::errs());
-    llvm::errs() << "\n";
-    llvm::errs() << "Canonical generic signature: ";
-    sig.getCanonicalSignature()->print(llvm::errs());
-    llvm::errs() << "\n";
-  }
-
-  return sig;
-}
-
 /// Form the interface type of an extension from the raw type and the
 /// extension's list of generic parameters.
 static Type formExtensionInterfaceType(
@@ -649,6 +611,8 @@ static unsigned getExtendedTypeGenericDepth(ExtensionDecl *ext) {
 GenericSignature
 GenericSignatureRequest::evaluate(Evaluator &evaluator,
                                   GenericContext *GC) const {
+  auto &ctx = GC->getASTContext();
+
   // The signature of a Protocol is trivial (Self: TheProtocol) so let's compute
   // it.
   if (auto PD = dyn_cast<ProtocolDecl>(GC)) {
@@ -660,7 +624,7 @@ GenericSignatureRequest::evaluate(Evaluator &evaluator,
 
     // Debugging of the generic signature builder and generic signature
     // generation.
-    if (GC->getASTContext().TypeCheckerOpts.DebugGenericSignatures) {
+    if (ctx.TypeCheckerOpts.DebugGenericSignatures) {
       llvm::errs() << "\n";
       PD->printContext(llvm::errs());
       llvm::errs() << "Generic signature: ";
@@ -698,10 +662,10 @@ GenericSignatureRequest::evaluate(Evaluator &evaluator,
     // If there is no generic context for the where clause to
     // rely on, diagnose that now and bail out.
     if (!GC->isGenericContext()) {
-      GC->getASTContext().Diags.diagnose(where->getWhereLoc(),
-                                         GC->getParent()->isModuleScopeContext()
-                                             ? diag::where_nongeneric_toplevel
-                                             : diag::where_nongeneric_ctx);
+      ctx.Diags.diagnose(where->getWhereLoc(),
+                         GC->getParent()->isModuleScopeContext()
+                             ? diag::where_nongeneric_toplevel
+                             : diag::where_nongeneric_ctx);
       return nullptr;
     }
   }
@@ -806,10 +770,33 @@ GenericSignatureRequest::evaluate(Evaluator &evaluator,
     inferenceSources.emplace_back(nullptr, extInterfaceType);
   }
 
-  return TypeChecker::checkGenericSignature(
-      GC, GC, parentSig,
-      allowConcreteGenericParams,
-      sameTypeReqs, inferenceSources);
+  auto request = InferredGenericSignatureRequest{
+      GC->getParentModule(), parentSig.getPointer(),
+      GC->getGenericParams(), WhereClauseOwner(GC),
+      sameTypeReqs, inferenceSources,
+      allowConcreteGenericParams};
+  auto sig = evaluateOrDefault(ctx.evaluator,
+                               request, nullptr);
+
+  // Debugging of the generic signature builder and generic signature
+  // generation.
+  if (ctx.TypeCheckerOpts.DebugGenericSignatures) {
+    llvm::errs() << "\n";
+    if (auto *VD = dyn_cast_or_null<ValueDecl>(GC->getAsDecl())) {
+      VD->dumpRef(llvm::errs());
+      llvm::errs() << "\n";
+    } else {
+      GC->printContext(llvm::errs());
+    }
+    llvm::errs() << "Generic signature: ";
+    sig->print(llvm::errs());
+    llvm::errs() << "\n";
+    llvm::errs() << "Canonical generic signature: ";
+    sig.getCanonicalSignature()->print(llvm::errs());
+    llvm::errs() << "\n";
+  }
+
+  return sig;
 }
 
 ///
diff --git a/lib/Sema/TypeChecker.cpp b/lib/Sema/TypeChecker.cpp
@@ -437,10 +437,14 @@ swift::handleSILGenericParams(GenericParamList *genericParams,
     genericParams->walk(walker);
   }
 
-  return TypeChecker::checkGenericSignature(nestedList.back(), DC,
-                                         /*parentSig=*/nullptr,
-                                         /*allowConcreteGenericParams=*/true)
-    .getGenericEnvironment();
+  auto request = InferredGenericSignatureRequest{
+      DC->getParentModule(), /*parentSig=*/nullptr,
+      nestedList.back(), WhereClauseOwner(),
+      {}, {}, /*allowConcreteGenericParams=*/true};
+  auto sig = evaluateOrDefault(DC->getASTContext().evaluator,
+                               request, GenericSignature());
+
+  return sig.getGenericEnvironment();
 }
 
 void swift::typeCheckPatternBinding(PatternBindingDecl *PBD,
diff --git a/lib/Sema/TypeChecker.h b/lib/Sema/TypeChecker.h
@@ -422,34 +422,6 @@ void checkProtocolSelfRequirements(ValueDecl *decl);
 /// declaration's type, otherwise we have no way to infer them.
 void checkReferencedGenericParams(GenericContext *dc);
 
-/// Construct a new generic environment for the given declaration context.
-///
-/// \param paramSource The source of generic info: either a generic parameter
-/// list or a generic context with a \c where clause dependent on outer
-/// generic parameters.
-///
-/// \param dc The declaration context in which to perform the validation.
-///
-/// \param outerSignature The generic signature of the outer
-/// context, if not available as part of the \c dc argument (used
-/// for SIL parsing).
-///
-/// \param allowConcreteGenericParams Whether or not to allow
-/// same-type constraints between generic parameters and concrete types.
-///
-/// \param additionalRequirements Additional requirements to add
-/// directly to the GSB.
-///
-/// \param inferenceSources Additional types to infer requirements from.
-///
-/// \returns the resulting generic signature.
-GenericSignature
-checkGenericSignature(GenericParamSource paramSource, DeclContext *dc,
-                      GenericSignature outerSignature,
-                      bool allowConcreteGenericParams,
-                      SmallVector<Requirement, 2> additionalRequirements = {},
-                      SmallVector<TypeLoc, 2> inferenceSources = {});
-
 /// Create a text string that describes the bindings of generic parameters
 /// that are relevant to the given set of types, e.g.,
 /// "[with T = Bar, U = Wibble]".
