clean up some unused leftovers

Author: RalfJung

compiler/rustc_middle/src/error.rs

@@ -1,8 +1,7 @@
+use std::io;
 use std::path::Path;
-use std::{fmt, io};
 
 use rustc_errors::codes::*;
-use rustc_errors::{DiagArgName, DiagArgValue, DiagMessage};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
@@ -114,29 +113,6 @@ pub(super) struct ConstNotUsedTraitAlias {
     pub span: Span,
 }
 
-pub struct CustomSubdiagnostic<'a> {
-    pub msg: fn() -> DiagMessage,
-    pub add_args: Box<dyn FnOnce(&mut dyn FnMut(DiagArgName, DiagArgValue)) + 'a>,
-}
-
-impl<'a> CustomSubdiagnostic<'a> {
-    pub fn label(x: fn() -> DiagMessage) -> Self {
-        Self::label_and_then(x, |_| {})
-    }
-    pub fn label_and_then<F: FnOnce(&mut dyn FnMut(DiagArgName, DiagArgValue)) + 'a>(
-        msg: fn() -> DiagMessage,
-        f: F,
-    ) -> Self {
-        Self { msg, add_args: Box::new(move |x| f(x)) }
-    }
-}
-
-impl fmt::Debug for CustomSubdiagnostic<'_> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.debug_struct("CustomSubdiagnostic").finish_non_exhaustive()
-    }
-}
-
 #[derive(Diagnostic)]
 pub enum LayoutError<'tcx> {
     #[diag("the type `{$ty}` has an unknown layout")]

compiler/rustc_middle/src/ty/consts/int.rs

@@ -4,7 +4,6 @@ use std::num::NonZero;
 use rustc_abi::Size;
 use rustc_apfloat::Float;
 use rustc_apfloat::ieee::{Double, Half, Quad, Single};
-use rustc_errors::{DiagArgValue, IntoDiagArg};
 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
 use crate::ty::TyCtxt;
@@ -137,14 +136,6 @@ impl std::fmt::Debug for ConstInt {
     }
 }
 
-impl IntoDiagArg for ConstInt {
-    // FIXME this simply uses the Debug impl, but we could probably do better by converting both
-    // to an inherent method that returns `Cow`.
-    fn into_diag_arg(self, _: &mut Option<std::path::PathBuf>) -> DiagArgValue {
-        DiagArgValue::Str(format!("{self:?}").into())
-    }
-}
-
 /// The raw bytes of a simple value.
 ///
 /// This is a packed struct in order to allow this type to be optimally embedded in enums