--- /dev/null
+package main
+
+// Regression test for https://golang.org/issue/23925
+
+type stringFlagImpl string
+
+func (*stringFlagImpl) Set(s string) error { return nil }
+
+type boolFlagImpl bool
+
+func (*boolFlagImpl) Set(s string) error { return nil }
+func (*boolFlagImpl) extra() {}
+
+// A copy of flag.boolFlag interface, without a dependency.
+// Must appear first, so that it becomes the owner of the Set methods.
+type boolFlag interface {
+ flagValue
+ extra()
+}
+
+// A copy of flag.Value, without adding a dependency.
+type flagValue interface {
+ Set(string) error
+}
+
+func main() {
+ var x flagValue = new(stringFlagImpl)
+ x.Set("")
+
+ var y boolFlag = new(boolFlagImpl)
+ y.Set("")
+}
+
+// WANT:
+// Dynamic calls
+// main --> (*boolFlagImpl).Set
+// main --> (*boolFlagImpl).Set
+// main --> (*stringFlagImpl).Set