vendor/clap/src/parser/error.rs

   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)]
  23     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 {
  40     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]
  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 }