diff --git a/mockgen/generic_go118.go b/mockgen/generic.go
similarity index 98%
rename from mockgen/generic_go118.go
rename to mockgen/generic.go
index b7b4494..d425e77 100644
--- a/mockgen/generic_go118.go
+++ b/mockgen/generic.go
@@ -5,9 +5,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build go1.18
-// +build go1.18
-
 package main
 
 import (
diff --git a/mockgen/generic_notgo118.go b/mockgen/generic_notgo118.go
deleted file mode 100644
index 8a779c8..0000000
--- a/mockgen/generic_notgo118.go
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright 2022 Google LLC
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build !go1.18
-// +build !go1.18
-
-package main
-
-import (
-	"fmt"
-	"go/ast"
-
-	"go.uber.org/mock/mockgen/model"
-)
-
-func getTypeSpecTypeParams(ts *ast.TypeSpec) []*ast.Field {
-	return nil
-}
-
-func (p *fileParser) parseGenericType(pkg string, typ ast.Expr, tps map[string]model.Type) (model.Type, error) {
-	return nil, nil
-}
-
-func getIdentTypeParams(decl any) string {
-	return ""
-}
-
-func (p *fileParser) parseGenericMethod(field *ast.Field, it *namedInterface, iface *model.Interface, pkg string, tps map[string]model.Type) ([]*model.Method, error) {
-	return nil, fmt.Errorf("don't know how to mock method of type %T", field.Type)
-}