diff --git a/src/pkg/path/filepath/path_plan9.go b/src/pkg/path/filepath/path_plan9.go
index 17b873f1a9..cf028a75c5 100644
--- a/src/pkg/path/filepath/path_plan9.go
+++ b/src/pkg/path/filepath/path_plan9.go
@@ -17,7 +17,7 @@ func VolumeName(path string) string {
 	return ""
 }
 
-// HasPrefix tests whether the path p begins with prefix.
+// HasPrefix exists for historical compatibility and should not be used.
 func HasPrefix(p, prefix string) bool {
 	return strings.HasPrefix(p, prefix)
 }
diff --git a/src/pkg/path/filepath/path_unix.go b/src/pkg/path/filepath/path_unix.go
index c5ac71efe2..305e307272 100644
--- a/src/pkg/path/filepath/path_unix.go
+++ b/src/pkg/path/filepath/path_unix.go
@@ -19,7 +19,7 @@ func VolumeName(path string) string {
 	return ""
 }
 
-// HasPrefix tests whether the path p begins with prefix.
+// HasPrefix exists for historical compatibility and should not be used.
 func HasPrefix(p, prefix string) bool {
 	return strings.HasPrefix(p, prefix)
 }
diff --git a/src/pkg/path/filepath/path_windows.go b/src/pkg/path/filepath/path_windows.go
index 9692fd978c..1d1d23bfe7 100644
--- a/src/pkg/path/filepath/path_windows.go
+++ b/src/pkg/path/filepath/path_windows.go
@@ -67,8 +67,7 @@ func VolumeName(path string) (v string) {
 	return ""
 }
 
-// HasPrefix tests whether the path p begins with prefix.
-// It ignores case while comparing.
+// HasPrefix exists for historical compatibility and should not be used.
 func HasPrefix(p, prefix string) bool {
 	if strings.HasPrefix(p, prefix) {
 		return true