diff --git a/README.md b/README.md
index 149cbe70..2de4e002 100644
--- a/README.md
+++ b/README.md
@@ -207,6 +207,7 @@ Here are the Go packages that can be imported correctly:
 * [unicode](https://pkg.go.dev/unicode)
 * [unicode/utf8](https://pkg.go.dev/unicode/utf8)
 * [unicode/utf16](https://pkg.go.dev/unicode/utf16)
+* [math/bits](https://pkg.go.dev/math/bits)
 
 
 ## How to install
diff --git a/cl/_testlibgo/math/in.go b/cl/_testlibgo/math/in.go
index 2b07ec66..92d94ca5 100644
--- a/cl/_testlibgo/math/in.go
+++ b/cl/_testlibgo/math/in.go
@@ -6,4 +6,5 @@ import (
 
 func main() {
 	println(bits.Len8(20))
+	println(bits.OnesCount(20))
 }
diff --git a/cl/builtin_test.go b/cl/builtin_test.go
index abdbb8e4..5f5a49dd 100644
--- a/cl/builtin_test.go
+++ b/cl/builtin_test.go
@@ -27,6 +27,12 @@ import (
 	"golang.org/x/tools/go/ssa"
 )
 
+func TestReplaceGoName(t *testing.T) {
+	if ret := replaceGoName("foo", 0); ret != "foo" {
+		t.Fatal("replaceGoName:", ret)
+	}
+}
+
 func TestIsAllocVargs(t *testing.T) {
 	if isAllocVargs(nil, ssaAlloc(&ssa.Return{})) {
 		t.Fatal("isVargs?")