AST: Remove DependentMemberType::substBaseType()

Author: slavapestov

include/swift/AST/Types.h

@@ -7158,17 +7158,6 @@ class DependentMemberType : public TypeBase {
   AssociatedTypeDecl *getAssocType() const {
     return NameOrAssocType.dyn_cast<AssociatedTypeDecl *>();
   }
-  
-  /// Substitute the base type, looking up our associated type in it if it is
-  /// non-dependent. Returns null if the member could not be found in the new
-  /// base.
-  Type substBaseType(Type base);
-
-  /// Substitute the base type, looking up our associated type in it if it is
-  /// non-dependent. Returns null if the member could not be found in the new
-  /// base.
-  Type substBaseType(Type base, LookupConformanceFn lookupConformance,
-                     SubstOptions options);
 
   // Implement isa/cast/dyncast/etc.
   static bool classof(const TypeBase *T) {

lib/AST/TypeSubstitution.cpp

@@ -264,24 +264,6 @@ operator()(CanType dependentType, Type conformingReplacementType,
   return ProtocolConformanceRef(conformedProtocol);
 }
 
-Type DependentMemberType::substBaseType(Type substBase) {
-  return substBaseType(substBase, LookUpConformanceInModule(),
-                       std::nullopt);
-}
-
-Type DependentMemberType::substBaseType(Type substBase,
-                                        LookupConformanceFn lookupConformance,
-                                        SubstOptions options) {
-  if (substBase.getPointer() == getBase().getPointer() &&
-      substBase->hasTypeParameter())
-    return this;
-
-  InFlightSubstitution IFS(nullptr, lookupConformance, options);
-  return getMemberForBaseType(IFS, getBase(), substBase,
-                              getAssocType(), getName(),
-                              /*level=*/0);
-}
-
 static Type substGenericFunctionType(GenericFunctionType *genericFnType,
                                      InFlightSubstitution &IFS) {
   // Substitute into the function type (without generic signature).