Implement display on all error types (#5969)

Fixes #5930


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components/calendar/src/ixdtf.rs

@@ -10,12 +10,14 @@ use ixdtf::parsers::IxdtfParser;
 use ixdtf::ParseError as IxdtfError;
 
 /// An error returned from parsing an IXDTF string to an `icu_calendar` type.
-#[derive(Debug)]
+#[derive(Debug, displaydoc::Display)]
 #[non_exhaustive]
 pub enum ParseError {
     /// Syntax error in the IXDTF string.
+    #[displaydoc("Syntax error in the IXDTF string: {0}")]
     Syntax(IxdtfError),
     /// Value is out of range.
+    #[displaydoc("Value out of range: {0}")]
     Range(RangeError),
     /// The IXDTF is missing fields required for parsing into the chosen type.
     MissingFields,

components/experimental/src/duration/validated_options.rs

@@ -61,19 +61,23 @@ pub struct ValidatedDurationFormatterOptions {
 
 /// Error type for [`DurationFormatterOptions`] validation.
 #[non_exhaustive]
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, displaydoc::Display)]
 pub enum DurationFormatterOptionsError {
     /// Returned when a unit field is set to [`FieldDisplay::Always`] and the style is set to [`FieldStyle::Fractional`].
+    #[displaydoc("Returned when a unit field is set to Always and the style is set to Fractional")]
     DisplayAlwaysFractional,
 
     /// Returned when a previous unit's style is [`FieldStyle::Fractional`], but the following unit's style is not [`FieldStyle::Fractional`].
+    #[displaydoc("Returned when a previous unit's style is Fractional, but the following unit's style is not Fractional")]
     PreviousFractional,
 
     /// Returned when a previous unit's style is set to [`FieldStyle::Numeric`] or [`FieldStyle::TwoDigit`] and the following unit's style is not
     /// [`FieldStyle::Fractional`], [`FieldStyle::Numeric`], or [`FieldStyle::TwoDigit`].
+    #[displaydoc("Returned when a previous unit's style is set to Numeric or TwoDigit and the following unit's style is not Fractional, Numeric, or TwoDigit")]
     PreviousNumeric,
 
     /// Returned when the number of fractional digits is out of acceptable range. See [`FractionalDigits::Fixed`].
+    #[displaydoc("Returned when the number of fractional digits is out of acceptable range")]
     FractionalDigitsOutOfRange,
 }
 

components/experimental/src/unicodeset_parse/parse.rs

@@ -30,14 +30,20 @@ use icu_properties::{provider::*, PropertyParser};
 use icu_provider::prelude::*;
 
 /// The kind of error that occurred.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, displaydoc::Display)]
 #[non_exhaustive]
 pub enum ParseErrorKind {
-    /// An unexpected character was encountered. This variant implies the other variants
+    /// An unexpected character was encountered.
+    ///
+    /// This variant implies the other variants
     /// (notably `UnknownProperty` and `Unimplemented`) do not apply.
+    #[displaydoc("An unexpected character was encountered")]
     UnexpectedChar(char),
-    /// The property name or value is unknown. For property names, make sure you use the spelling
+    /// The property name or value is unknown.
+    ///
+    /// For property names, make sure you use the spelling
     /// defined in [ECMA-262](https://tc39.es/ecma262/#table-nonbinary-unicode-properties).
+    #[displaydoc("The property name or value is unknown")]
     UnknownProperty,
     /// A reference to an unknown variable.
     UnknownVariable,
@@ -47,11 +53,13 @@ pub enum ParseErrorKind {
     Eof,
     /// Something unexpected went wrong with our code. Please file a bug report on GitHub.
     Internal,
-    /// The provided syntax is not supported by us. Note that unknown properties will return the
+    /// The provided syntax is not supported by us.
+    ///
+    /// Note that unknown properties will return the
     /// `UnknownProperty` variant, not this one.
+    #[displaydoc("The provided syntax is not supported by us.")]
     Unimplemented,
-    /// The provided escape sequence is not a valid Unicode code point or represents too many
-    /// code points.
+    /// The provided escape sequence is not a valid Unicode code point or represents too many code points.
     InvalidEscape,
 }
 use zerovec::VarZeroVec;

components/experimental/src/units/ratio.rs

@@ -22,29 +22,45 @@ use crate::measure::provider::si_prefix::{Base, SiPrefix};
 pub struct IcuRatio(Ratio<BigInt>);
 
 /// Represents an error when the ratio string is invalid and cannot be parsed.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, displaydoc::Display)]
 pub enum RatioFromStrError {
     /// Represents an error when the ratio string is divided by zero.
     DivisionByZero,
 
     /// Represents an error when the ratio string contains multiple slashes.
+    ///
     /// For example, "1/2/3".
+    #[displaydoc("Represents an error when the ratio string contains multiple slashes")]
     MultipleSlashes,
 
     /// Represents an error when the ratio string contains non-numeric characters in fractions.
+    ///
     /// For example, "1/2A".
+    #[displaydoc(
+        "Represents an error when the ratio string contains non-numeric characters in fractions"
+    )]
     NonNumericCharactersInFractions,
 
     /// Represents an error when the ratio string contains multiple scientific notations.
+    ///
     /// For example, "1.5E6E6".
+    #[displaydoc(
+        "Represents an error when the ratio string contains multiple scientific notations"
+    )]
     MultipleScientificNotations,
 
     /// Represents an error when the ratio string contains multiple decimal points.
+    ///
     /// For example, "1.5.6".
+    #[displaydoc("Represents an error when the ratio string contains multiple decimal points")]
     MultipleDecimalPoints,
 
     /// Represents an error when the exponent part of the ratio string is not an integer.
+    ///
     /// For example, "1.5E6.5".
+    #[displaydoc(
+        "Represents an error when the exponent part of the ratio string is not an integer"
+    )]
     ExponentPartIsNotAnInteger,
 
     /// Represents an error when the ratio string is dificient in some other way.

components/locale_core/src/preferences/extensions/unicode/errors.rs

@@ -6,7 +6,7 @@
 
 /// Error returned by parsers of unicode extensions as preferences.
 #[non_exhaustive]
-#[derive(Debug)]
+#[derive(Debug, displaydoc::Display)]
 pub enum PreferencesParseError {
     /// The given keyword value is not a valid preference variant.
     InvalidKeywordValue,

components/timezone/src/ixdtf.rs

@@ -22,14 +22,17 @@ use ixdtf::{
 };
 
 /// The error type for parsing IXDTF syntax strings in `icu_timezone`.
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, displaydoc::Display)]
 #[non_exhaustive]
 pub enum ParseError {
     /// Syntax error for IXDTF string.
+    #[displaydoc("Syntax error in the IXDTF string: {0}")]
     Syntax(IxdtfParseError),
     /// Parsed record is out of valid date range.
+    #[displaydoc("Value out of range: {0}")]
     Range(RangeError),
     /// Parsed date and time records were not a valid ISO date.
+    #[displaydoc("Parsed date and time records were not a valid ISO date: {0}")]
     Date(DateError),
     /// There were missing fields required to parse component.
     MissingFields,
@@ -40,6 +43,7 @@ pub enum ParseError {
     /// The set of time zone fields was not expected for the given type.
     /// For example, if a named time zone was present with offset-only parsing,
     /// or an offset was present with named-time-zone-only parsing.
+    #[displaydoc("The set of time zone fields was not expected for the given type")]
     MismatchedTimeZoneFields,
     /// An unknown calendar was provided.
     UnknownCalendar,
@@ -59,6 +63,9 @@ pub enum ParseError {
     /// IxdtfParser::new().try_loose_iso_from_str("2024-08-12T14:32:00+02:00[Europe/Zurich]").unwrap();
     /// IxdtfParser::new().try_loose_iso_from_str("2024-08-12T14:32:00[Europe/Zurich]").unwrap();
     /// ```
+    #[displaydoc(
+        "A timezone calculation is required to interpret this string, which is not supported"
+    )]
     RequiresCalculation,
 }