Remove MutableFlagValue

We can just have an ad hoc interface and not clutter the API.

1 files changed, 1 insertions, 8 deletions

diff --git a/flag.go b/flag.go
index 4ef45d1..018540a 100644
--- a/flag.go
+++ b/flag.go
@@ -83,7 +83,7 @@ func InitFlagSet(fs *flag.FlagSet, env []string, cfg map[string]string, args []s
 		}
 
 		if f.DefValue != f.Value.String() {
-			if _, ok := f.Value.(MutableFlagValue); !ok {
+			if _, ok := f.Value.(interface{ MutableFlag() }); !ok {
 				return
 			}
 		}
@@ -108,13 +108,6 @@ func InitFlagSet(fs *flag.FlagSet, env []string, cfg map[string]string, args []s
 	return err
 }
 
-// MutableFlagValue is used to signal whether it is safe to set a flag
-// to another value if it has already been set before, i.e. if its
-// current value (as a string) is the same as its default value.
-type MutableFlagValue interface {
-	MutableFlagValue()
-}
-
 // ParseString returns the string passed with no error set.
 func ParseString(s string) (string, error) {
 	return s, nil