Enum rustc_errors::SubdiagnosticMessage

pub enum SubdiagnosticMessage {
    Str(String),
    Eager(String),
    FluentIdentifier(Cow<'static, str>),
    FluentAttr(Cow<'static, str>),
}

Abstraction over a message in a subdiagnostic (i.e. label, note, help, etc) to support both translatable and non-translatable diagnostic messages.

Translatable messages for subdiagnostics are typically attributes attached to a larger Fluent message so messages of this type must be combined with a DiagnosticMessage (using DiagnosticMessage::with_subdiagnostic_message) before rendering. However, subdiagnostics from the Subdiagnostic derive refer to Fluent identifiers directly.

Variants

Str(String)

Non-translatable diagnostic message.

Eager(String)

Translatable message which has already been translated eagerly.

Some diagnostics have repeated subdiagnostics where the same interpolated variables would be instantiated multiple times with different values. As translation normally happens immediately prior to emission, after the diagnostic and subdiagnostic derive logic has run, the setting of diagnostic arguments in the derived code will overwrite previous variable values and only the final value will be set when translation occurs - resulting in incorrect diagnostics. Eager translation results in translation for a subdiagnostic happening immediately after the subdiagnostic derive’s logic has been run. This variant stores messages which have been translated eagerly.

FluentIdentifier(Cow<'static, str>)

Identifier of a Fluent message. Instances of this variant are generated by the Subdiagnostic derive.

FluentAttr(Cow<'static, str>)

Attribute of a Fluent message. Needs to be combined with a Fluent identifier to produce an actual translated message. Instances of this variant are generated by the fluent_messages macro.

https://projectfluent.org/fluent/guide/attributes.html

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 40 bytes

Size for each variant:

• Str: 24 bytes
• Eager: 24 bytes
• FluentIdentifier: 32 bytes
• FluentAttr: 32 bytes