diff --git a/draw/go1_8.go b/draw/go1_8.go
index 95db46f..ec192b7 100644
--- a/draw/go1_8.go
+++ b/draw/go1_8.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !go1.9
+// +build !go1.9,!go1.8.typealias
 
 package draw
 
diff --git a/draw/go1_9.go b/draw/go1_9.go
index 1e878e1..fc548e9 100644
--- a/draw/go1_9.go
+++ b/draw/go1_9.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.9
+// +build go1.9 go1.8.typealias
 
 package draw