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!("Mismatch between definition and access of `{id}`. {err}",)
31 }
32 }
33
34 impl std::error::Error for MatchesError {}
35
36 impl std::fmt::Display for MatchesError {
fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result37 fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
38 match self {
39 Self::Downcast { actual, expected } => {
40 writeln!(
41 f,
42 "Could not downcast to {expected:?}, need to downcast to {actual:?}"
43 )
44 }
45 Self::UnknownArgument {} => {
46 writeln!(f, "Unknown argument or group id. Make sure you are using the argument id and not the short or long flags")
47 }
48 }
49 }
50 }
51
52 #[test]
check_auto_traits()53 fn check_auto_traits() {
54 static_assertions::assert_impl_all!(
55 MatchesError: Send,
56 Sync,
57 std::panic::RefUnwindSafe,
58 std::panic::UnwindSafe,
59 Unpin
60 );
61 }
62