diff --git a/src/cmd/compile/internal/types/pkg.go b/src/cmd/compile/internal/types/pkg.go
index 8223d801359..c6ce7889afb 100644
--- a/src/cmd/compile/internal/types/pkg.go
+++ b/src/cmd/compile/internal/types/pkg.go
@@ -129,12 +129,3 @@ func InternString(b []byte) string {
 	internedStringsmu.Unlock()
 	return s
 }
-
-// CleanroomDo invokes f in an environment with no preexisting packages.
-// For testing of import/export only.
-func CleanroomDo(f func()) {
-	saved := pkgMap
-	pkgMap = make(map[string]*Pkg)
-	f()
-	pkgMap = saved
-}