AST: Fix bad merge

Author: slavapestov

lib/AST/GenericSignature.cpp

@@ -1019,21 +1019,6 @@ GenericSignatureImpl::lookupNestedType(Type type, Identifier name) const {
   }
 }
 
-TypeDecl *
-GenericSignatureImpl::lookupNestedType(Type type, Identifier name) const {
-  assert(type->isTypeParameter());
-
-  auto *builder = getGenericSignatureBuilder();
-  auto equivClass =
-    builder->resolveEquivalenceClass(
-                                type,
-                                ArchetypeResolutionKind::CompleteWellFormed);
-  if (!equivClass)
-    return nullptr;
-
-  return equivClass->lookupNestedType(*builder, name);
-}
-
 unsigned GenericParamKey::findIndexIn(
                       TypeArrayView<GenericTypeParamType> genericParams) const {
   // For depth 0, we have random access. We perform the extra checking so that