1 /// Violation of [`ArgMatches`][crate::ArgMatches] assumptions
2 #[derive(Clone, Debug)]
3 #[allow(missing_copy_implementations)] // We might add non-Copy types in the future
4 #[non_exhaustive]
5 pub enum MatchesError {
6 /// Failed to downcast `AnyValue` to the specified type
7 #[non_exhaustive]
8 Downcast {
9 /// Type for value stored in [`ArgMatches`][crate::ArgMatches]
10 actual: super::AnyValueId,
11 /// The target type to downcast to
12 expected: super::AnyValueId,
13 },
14 /// Argument not defined in [`Command`][crate::Command]
15 #[non_exhaustive]
16 UnknownArgument {
17 // Missing `id` but blocked on a public id type which will hopefully come with `unstable-v4`
18 },
19 }
20
21 impl MatchesError {
22 #[cfg_attr(debug_assertions, track_caller)]
unwrap<T>(id: &str, r: Result<T, MatchesError>) -> T23 pub(crate) fn unwrap<T>(id: &str, r: Result<T, MatchesError>) -> T {
24 let err = match r {
25 Ok(t) => {
26 return t;
27 }
28 Err(err) => err,
29 };
30 panic!(
31 "Mismatch between definition and access of `{}`. {}",
32 id, err
33 )
34 }
35 }
36
37 impl std::error::Error for MatchesError {}
38
39 impl std::fmt::Display for MatchesError {
fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result40 fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
41 match self {
42 Self::Downcast { actual, expected } => {
43 writeln!(
44 f,
45 "Could not downcast to {:?}, need to downcast to {:?}",
46 expected, actual
47 )
48 }
49 Self::UnknownArgument {} => {
50 writeln!(f, "Unknown argument or group id. Make sure you are using the argument id and not the short or long flags")
51 }
52 }
53 }
54 }
55
56 #[test]
check_auto_traits()57 fn check_auto_traits() {
58 static_assertions::assert_impl_all!(
59 MatchesError: Send,
60 Sync,
61 std::panic::RefUnwindSafe,
62 std::panic::UnwindSafe,
63 Unpin
64 );
65 }
66