AST: Remove OpaqueTypeArchetypeType::getCanonicalInterfaceType()

Author: slavapestov

include/swift/AST/Types.h

@@ -6679,10 +6679,6 @@ class OpaqueTypeArchetypeType final : public ArchetypeType,
   /// Retrieve the set of substitutions applied to the opaque type.
   SubstitutionMap getSubstitutions() const;
 
-  /// Compute the canonical interface type within the environment of this
-  /// opaque type archetype.
-  CanType getCanonicalInterfaceType(Type interfaceType);
-
   static bool classof(const TypeBase *T) {
     return T->getKind() == TypeKind::OpaqueTypeArchetype;
   }

lib/AST/Type.cpp

@@ -3556,14 +3556,6 @@ OpaqueTypeArchetypeType::OpaqueTypeArchetypeType(
   assert(!interfaceType->isParameterPack());
 }
 
-CanType OpaqueTypeArchetypeType::getCanonicalInterfaceType(Type interfaceType) {
-  auto sig = Environment->getOpaqueTypeDecl()
-      ->getOpaqueInterfaceGenericSignature();
-  CanType canonicalType = interfaceType->getReducedType(sig);
-  return Environment->maybeApplyOuterContextSubstitutions(canonicalType)
-      ->getCanonicalType();
-}
-
 OpaqueTypeDecl *OpaqueTypeArchetypeType::getDecl() const {
   return Environment->getOpaqueTypeDecl();
 }

lib/Sema/CSSimplify.cpp

@@ -3784,9 +3784,7 @@ ConstraintSystem::matchDeepEqualityTypes(Type type1, Type type2,
 
     // It's possible to declare a generic requirement like Self == Self.Iterator
     // where both types are going to be opaque.
-    if (!opaque1->getCanonicalInterfaceType(arch1->getInterfaceType())
-             ->isEqual(
-                 opaque2->getCanonicalInterfaceType(arch2->getInterfaceType())))
+    if (!opaque1->getInterfaceType()->isEqual(opaque2->getInterfaceType()))
       return getTypeMatchFailure(locator);
 
     auto args1 = opaque1->getSubstitutions().getReplacementTypes();