Remove SubdiagMessage in favour of the identical DiagMessage

Author: JonathanBrouwer

compiler/rustc_error_messages/src/lib.rs

@@ -230,38 +230,6 @@ pub fn fallback_fluent_bundle(
     })))
 }
 
-/// 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 `DiagMessage` (using
-/// `DiagMessage::with_subdiagnostic_message`) before rendering. However, subdiagnostics from
-/// the `Subdiagnostic` derive refer to Fluent identifiers directly.
-#[rustc_diagnostic_item = "SubdiagMessage"]
-pub enum SubdiagMessage {
-    /// Non-translatable diagnostic message.
-    Str(Cow<'static, str>),
-    /// An inline Fluent message. Instances of this variant are generated by the
-    /// `Subdiagnostic` derive.
-    Inline(Cow<'static, str>),
-}
-
-impl From<String> for SubdiagMessage {
-    fn from(s: String) -> Self {
-        SubdiagMessage::Str(Cow::Owned(s))
-    }
-}
-impl From<&'static str> for SubdiagMessage {
-    fn from(s: &'static str) -> Self {
-        SubdiagMessage::Str(Cow::Borrowed(s))
-    }
-}
-impl From<Cow<'static, str>> for SubdiagMessage {
-    fn from(s: Cow<'static, str>) -> Self {
-        SubdiagMessage::Str(s)
-    }
-}
-
 /// Abstraction over a message in a diagnostic to support both translatable and non-translatable
 /// diagnostic messages.
 ///
@@ -281,18 +249,6 @@ pub enum DiagMessage {
 }
 
 impl DiagMessage {
-    /// Given a `SubdiagMessage` which may contain a Fluent attribute, create a new
-    /// `DiagMessage` that combines that attribute with the Fluent identifier of `self`.
-    ///
-    /// - If the `SubdiagMessage` is non-translatable then return the message as a `DiagMessage`.
-    /// - If `self` is non-translatable then return `self`'s message.
-    pub fn with_subdiagnostic_message(&self, sub: SubdiagMessage) -> Self {
-        match sub {
-            SubdiagMessage::Str(s) => DiagMessage::Str(s),
-            SubdiagMessage::Inline(s) => DiagMessage::Inline(s),
-        }
-    }
-
     pub fn as_str(&self) -> Option<&str> {
         match self {
             DiagMessage::Str(s) => Some(s),
@@ -317,20 +273,6 @@ impl From<Cow<'static, str>> for DiagMessage {
     }
 }
 
-/// Translating *into* a subdiagnostic message from a diagnostic message is a little strange - but
-/// the subdiagnostic functions (e.g. `span_label`) take a `SubdiagMessage` and the
-/// subdiagnostic derive refers to typed identifiers that are `DiagMessage`s, so need to be
-/// able to convert between these, as much as they'll be converted back into `DiagMessage`
-/// using `with_subdiagnostic_message` eventually. Don't use this other than for the derive.
-impl From<DiagMessage> for SubdiagMessage {
-    fn from(val: DiagMessage) -> Self {
-        match val {
-            DiagMessage::Str(s) => SubdiagMessage::Str(s),
-            DiagMessage::Inline(s) => SubdiagMessage::Inline(s),
-        }
-    }
-}
-
 /// A span together with some additional data.
 #[derive(Clone, Debug)]
 pub struct SpanLabel {