const github.com/google/go-cmp/cmp/internal/function.ValueFilter

2 uses

	github.com/google/go-cmp/cmp/internal/function (current package)
		func.go#L29: 	ValueFilter       = ttbFunc // func(T, T) bool

	github.com/google/go-cmp/cmp
		options.go#L161: 	if !function.IsType(v.Type(), function.ValueFilter) || v.IsNil() {