simplify error variant

src/assign.rs

@@ -773,7 +773,7 @@ mod tests {
  assign: json!("foo"),
  expected: Err(AssignError::FailedToParseIndex {
  offset: 0,
- source: ParseIndexError::InvalidCharacters("+".into()),
+ source: ParseIndexError::InvalidCharacter,
  }),
  expected_data: json!([]),
  },

src/index.rs

@@ -36,7 +36,7 @@
 //! ```
 
 use crate::Token;
-use alloc::{string::String, vec::Vec};
+use alloc::string::String;
 use core::{fmt, num::ParseIntError, str::FromStr};
 
 /// Represents an abstract index into an array.
@@ -173,13 +173,7 @@ impl FromStr for Index {
  // this comes up with the `+` sign which is valid for
  // representing a `usize` but not allowed in RFC 6901 array
  // indices
- let mut invalid: Vec<_> = s.chars().filter(|c| !c.is_ascii_digit()).collect();
- // remove duplicate characters
- invalid.sort_unstable();
- invalid.dedup();
- Err(ParseIndexError::InvalidCharacters(
- invalid.into_iter().collect(),
- ))
+ Err(ParseIndexError::InvalidCharacter)
  }
  }
  }
@@ -281,8 +275,8 @@ pub enum ParseIndexError {
  InvalidInteger(ParseIntError),
  /// The Token contains leading zeros.
  LeadingZeros,
- /// The Token contains non-digit characters.
- InvalidCharacters(String),
+ /// The Token contains a non-digit character.
+ InvalidCharacter,
 }
 
 impl From<ParseIntError> for ParseIndexError {
@@ -301,10 +295,10 @@ impl fmt::Display for ParseIndexError {
  f,
  "token contained leading zeros, which are disallowed by RFC 6901"
  ),
- ParseIndexError::InvalidCharacters(chars) => write!(
+ ParseIndexError::InvalidCharacter => write!(
  f,
- "token contains non-digit character(s) '{chars}', \
- which are disallowed by RFC 6901",
+ "token contains the non-digit character '+', \
+ which is disallowed by RFC 6901",
  ),
  }
  }
@@ -315,7 +309,7 @@ impl std::error::Error for ParseIndexError {
  fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
  match self {
  ParseIndexError::InvalidInteger(source) => Some(source),
- ParseIndexError::LeadingZeros | ParseIndexError::InvalidCharacters(_) => None,
+ ParseIndexError::LeadingZeros | ParseIndexError::InvalidCharacter => None,
  }
  }
 }
@@ -435,9 +429,9 @@ mod tests {
  "token contained leading zeros, which are disallowed by RFC 6901"
  );
  assert_eq!(
- ParseIndexError::InvalidCharacters("+@".into()).to_string(),
- "token contains non-digit character(s) '+@', \
- which are disallowed by RFC 6901"
+ ParseIndexError::InvalidCharacter.to_string(),
+ "token contains the non-digit character '+', \
+ which is disallowed by RFC 6901"
  );
  }