Lift requirementsNotSatisfiedBy Into GenericSignature

Author: CodaFi

include/swift/AST/GenericSignature.h

@@ -201,6 +201,14 @@ class GenericSignature {
   /// signature.
   GenericEnvironment *getGenericEnvironment() const;
 
+  /// Return the requirements of this generic signature that are not also
+  /// satisfied by \c otherSig.
+  ///
+  /// \param otherSig Another generic signature whose generic parameters are
+  /// equivalent to or a subset of the generic parameters in this signature.
+  SmallVector<Requirement, 4>
+  requirementsNotSatisfiedBy(GenericSignature otherSig) const;
+
   /// Check invariants.
   void verify() const;
 };
@@ -373,14 +381,6 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   bool isRequirementSatisfied(
       Requirement requirement, bool allowMissing = false) const;
 
-  /// Return the requirements of this generic signature that are not also
-  /// satisfied by \c otherSig.
-  ///
-  /// \param otherSig Another generic signature whose generic parameters are
-  /// equivalent to or a subset of the generic parameters in this signature.
-  SmallVector<Requirement, 4> requirementsNotSatisfiedBy(
-                                  GenericSignature otherSig) const;
-
   /// Return the canonical version of the given type under this generic
   /// signature.
   CanType getCanonicalTypeInContext(Type type) const;
@@ -462,6 +462,14 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   /// (archetypes) that correspond to the interface types in this generic
   /// signature.
   GenericEnvironment *getGenericEnvironment() const;
+
+  /// Return the requirements of this generic signature that are not also
+  /// satisfied by \c otherSig.
+  ///
+  /// \param otherSig Another generic signature whose generic parameters are
+  /// equivalent to or a subset of the generic parameters in this signature.
+  SmallVector<Requirement, 4>
+  requirementsNotSatisfiedBy(GenericSignature otherSig) const;
 };
 
 void simple_display(raw_ostream &out, GenericSignature sig);

lib/AST/ASTContext.cpp

@@ -5159,9 +5159,9 @@ bool ASTContext::overrideGenericSignatureReqsSatisfied(
 
   switch (direction) {
   case OverrideGenericSignatureReqCheck::BaseReqSatisfiedByDerived:
-    return sig->requirementsNotSatisfiedBy(derivedSig).empty();
+    return sig.requirementsNotSatisfiedBy(derivedSig).empty();
   case OverrideGenericSignatureReqCheck::DerivedReqSatisfiedByBase:
-    return derivedSig->requirementsNotSatisfiedBy(sig).empty();
+    return derivedSig.requirementsNotSatisfiedBy(sig).empty();
   }
   llvm_unreachable("Unhandled OverrideGenericSignatureReqCheck in switch");
 }

lib/AST/ASTMangler.cpp

@@ -2645,7 +2645,7 @@ bool ASTMangler::appendGenericSignature(GenericSignature sig,
       genericParams = canSig.getGenericParams();
       requirements = canSig.getRequirements();
     } else {
-      requirementsBuffer = canSig->requirementsNotSatisfiedBy(contextSig);
+      requirementsBuffer = canSig.requirementsNotSatisfiedBy(contextSig);
       requirements = requirementsBuffer;
     }
   } else {

lib/AST/Attr.cpp

@@ -991,8 +991,7 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
       auto genericSig = FnDecl->getGenericSignature();
 
       if (auto sig = attr->getSpecializedSignature()) {
-        requirementsScratch = sig->requirementsNotSatisfiedBy(
-            genericSig);
+        requirementsScratch = sig.requirementsNotSatisfiedBy(genericSig);
         requirements = requirementsScratch;
       }
     }

lib/AST/GenericSignature.cpp

@@ -967,6 +967,16 @@ bool GenericSignatureImpl::isRequirementSatisfied(
   return requirement.isSatisfied(conditionalRequirements, allowMissing);
 }
 
+SmallVector<Requirement, 4>
+GenericSignature::requirementsNotSatisfiedBy(GenericSignature otherSig) const {
+  // The null generic signature has no requirements, therefore all requirements
+  // are satisfied by any signature.
+  if (isNull()) {
+    return {};
+  }
+  return getPointer()->requirementsNotSatisfiedBy(otherSig);
+}
+
 SmallVector<Requirement, 4> GenericSignatureImpl::requirementsNotSatisfiedBy(
                                             GenericSignature otherSig) const {
   SmallVector<Requirement, 4> result;

lib/AST/ProtocolConformance.cpp

@@ -543,7 +543,7 @@ ConditionalRequirementsRequest::evaluate(Evaluator &evaluator,
 
   // Find the requirements in the extension that aren't proved by the original
   // type, these are the ones that make the conformance conditional.
-  const auto unsatReqs = extensionSig->requirementsNotSatisfiedBy(typeSig);
+  const auto unsatReqs = extensionSig.requirementsNotSatisfiedBy(typeSig);
   if (unsatReqs.empty())
     return {};
 

lib/SIL/IR/SILFunctionType.cpp

@@ -3542,21 +3542,18 @@ TypeConverter::getConstantOverrideInfo(TypeExpansionContext context,
 
   assert(base.requiresNewVTableEntry() && "base must not be an override");
 
-  // Figure out the generic signature for the class method call. This is the
-  // signature of the derived class, with requirements transplanted from
-  // the base method. The derived method is allowed to have fewer
-  // requirements, in which case the thunk will translate the calling
-  // convention appropriately before calling the derived method.
-  bool hasGenericRequirementDifference = false;
 
   auto derivedSig = derived.getDecl()->getAsGenericContext()
                                      ->getGenericSignature();
   auto genericSig = Context.getOverrideGenericSignature(base.getDecl(),
                                                         derived.getDecl());
-  if (genericSig) {
-    hasGenericRequirementDifference =
-      !genericSig->requirementsNotSatisfiedBy(derivedSig).empty();
-  }
+  // Figure out the generic signature for the class method call. This is the
+  // signature of the derived class, with requirements transplanted from
+  // the base method. The derived method is allowed to have fewer
+  // requirements, in which case the thunk will translate the calling
+  // convention appropriately before calling the derived method.
+  bool hasGenericRequirementDifference =
+      !genericSig.requirementsNotSatisfiedBy(derivedSig).empty();
 
   auto baseInfo = getConstantInfo(context, base);
   auto derivedInfo = getConstantInfo(context, derived);

lib/SIL/IR/SILPrinter.cpp

@@ -3706,17 +3706,8 @@ void SILSpecializeAttr::print(llvm::raw_ostream &OS) const {
   if (genericEnv)
     genericSig = genericEnv->getGenericSignature();
 
-  ArrayRef<Requirement> requirements;
-  SmallVector<Requirement, 4> requirementsScratch;
-  if (auto specializedSig = getSpecializedSignature()) {
-    if (genericSig) {
-      requirementsScratch = specializedSig->requirementsNotSatisfiedBy(
-          genericSig);
-      requirements = requirementsScratch;
-    } else {
-      requirements = specializedSig.getRequirements();
-    }
-  }
+  auto requirements =
+      getSpecializedSignature().requirementsNotSatisfiedBy(genericSig);
   if (targetFunction) {
     OS << "target: \"" << targetFunction->getName() << "\", ";
   }

lib/Sema/TypeCheckAttr.cpp

@@ -2148,7 +2148,7 @@ static void checkSpecializeAttrRequirements(SpecializeAttr *attr,
                                             ASTContext &ctx) {
   bool hadError = false;
 
-  auto specializedReqs = specializedSig->requirementsNotSatisfiedBy(originalSig);
+  auto specializedReqs = specializedSig.requirementsNotSatisfiedBy(originalSig);
   for (auto specializedReq : specializedReqs) {
     if (!specializedReq.getFirstType()->is<GenericTypeParamType>()) {
       ctx.Diags.diagnose(attr->getLocation(),
@@ -4687,18 +4687,10 @@ static bool typeCheckDerivativeAttr(ASTContext &Ctx, Decl *D,
   // Returns true if the generic parameters in `source` satisfy the generic
   // requirements in `target`.
   std::function<bool(GenericSignature, GenericSignature)>
-      checkGenericSignatureSatisfied = [&](GenericSignature source,
-                                           GenericSignature target) {
-        // If target is null, then its requirements are satisfied.
-        if (!target)
-          return true;
-        // If source is null but target is not null, then target's
-        // requirements are not satisfied.
-        if (!source)
-          return false;
-
-        return target->requirementsNotSatisfiedBy(source).empty();
-      };
+      checkGenericSignatureSatisfied =
+          [&](GenericSignature source, GenericSignature target) {
+            return target.requirementsNotSatisfiedBy(source).empty();
+          };
 
   // Returns true if the derivative function and original function candidate are
   // defined in compatible type contexts. If the derivative function and the
@@ -5326,18 +5318,10 @@ void AttributeChecker::visitTransposeAttr(TransposeAttr *attr) {
   // Returns true if the generic parameters in `source` satisfy the generic
   // requirements in `target`.
   std::function<bool(GenericSignature, GenericSignature)>
-      checkGenericSignatureSatisfied = [&](GenericSignature source,
-                                           GenericSignature target) {
-        // If target is null, then its requirements are satisfied.
-        if (!target)
-          return true;
-        // If source is null but target is not null, then target's
-        // requirements are not satisfied.
-        if (!source)
-          return false;
-
-        return target->requirementsNotSatisfiedBy(source).empty();
-      };
+      checkGenericSignatureSatisfied =
+          [&](GenericSignature source, GenericSignature target) {
+            return target.requirementsNotSatisfiedBy(source).empty();
+          };
 
   auto isValidOriginalCandidate = [&](AbstractFunctionDecl *originalCandidate)
       -> Optional<AbstractFunctionDeclLookupErrorKind> {

lib/Sema/TypeCheckProtocolInference.cpp

@@ -215,13 +215,10 @@ AssociatedTypeInference::inferTypeWitnessesViaValueWitnesses(
     if (!proto) {
       // Retrieve the generic signature of the extension.
       const auto extensionSig = extension->getGenericSignature();
-
-      // Extensions of non-generic nominals are always viable for inference.
-      if (!extensionSig)
-        return true;
-
-      return extensionSig->requirementsNotSatisfiedBy(
-          conformanceCtx->getGenericSignatureOfContext()).empty();
+      return extensionSig
+          .requirementsNotSatisfiedBy(
+              conformanceCtx->getGenericSignatureOfContext())
+          .empty();
     }
 
     // The condition here is a bit more fickle than