diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 3e0840caaa6..518c59dba53 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -3,21 +3,15 @@
     CodeSuggestion, DiagnosticBuilder, DiagnosticMessage, EmissionGuarantee, Level, MultiSpan,
     SubdiagnosticMessage, Substitution, SubstitutionPart, SuggestionStyle,
 };
-use rustc_ast as ast;
-use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_error_messages::FluentValue;
-use rustc_hir as hir;
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_span::edition::LATEST_STABLE_EDITION;
-use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
-use rustc_span::{edition::Edition, Span, DUMMY_SP};
-use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
+use rustc_span::symbol::Symbol;
+use rustc_span::{Span, DUMMY_SP};
 use std::borrow::Cow;
 use std::fmt;
 use std::hash::{Hash, Hasher};
-use std::num::ParseIntError;
-use std::path::{Path, PathBuf};
 
 /// Error type for `Diagnostic`'s `suggestions` field, indicating that
 /// `.disable_suggestions()` was called on the `Diagnostic`.
@@ -49,119 +43,6 @@ pub trait IntoDiagnosticArg {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static>;
 }
 
-pub struct DiagnosticArgFromDisplay<'a>(pub &'a dyn fmt::Display);
-
-impl IntoDiagnosticArg for DiagnosticArgFromDisplay<'_> {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.0.to_string().into_diagnostic_arg()
-    }
-}
-
-impl<'a> From<&'a dyn fmt::Display> for DiagnosticArgFromDisplay<'a> {
-    fn from(t: &'a dyn fmt::Display) -> Self {
-        DiagnosticArgFromDisplay(t)
-    }
-}
-
-impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
-    fn from(t: &'a T) -> Self {
-        DiagnosticArgFromDisplay(t)
-    }
-}
-
-macro_rules! into_diagnostic_arg_using_display {
-    ($( $ty:ty ),+ $(,)?) => {
-        $(
-            impl IntoDiagnosticArg for $ty {
-                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-                    self.to_string().into_diagnostic_arg()
-                }
-            }
-        )+
-    }
-}
-
-into_diagnostic_arg_using_display!(
-    i8,
-    u8,
-    i16,
-    u16,
-    i32,
-    u32,
-    i64,
-    u64,
-    i128,
-    u128,
-    std::io::Error,
-    std::num::NonZeroU32,
-    hir::Target,
-    Edition,
-    Ident,
-    MacroRulesNormalizedIdent,
-    ParseIntError,
-    StackProtector,
-    &TargetTriple,
-    SplitDebuginfo
-);
-
-impl IntoDiagnosticArg for bool {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        if self {
-            DiagnosticArgValue::Str(Cow::Borrowed("true"))
-        } else {
-            DiagnosticArgValue::Str(Cow::Borrowed("false"))
-        }
-    }
-}
-
-impl IntoDiagnosticArg for char {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self)))
-    }
-}
-
-impl IntoDiagnosticArg for Symbol {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.to_ident_string().into_diagnostic_arg()
-    }
-}
-
-impl<'a> IntoDiagnosticArg for &'a str {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        self.to_string().into_diagnostic_arg()
-    }
-}
-
-impl IntoDiagnosticArg for String {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self))
-    }
-}
-
-impl<'a> IntoDiagnosticArg for &'a Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
-    }
-}
-
-impl IntoDiagnosticArg for PathBuf {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
-    }
-}
-
-impl IntoDiagnosticArg for usize {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Number(self)
-    }
-}
-
-impl IntoDiagnosticArg for PanicStrategy {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
-    }
-}
-
 impl<'source> Into<FluentValue<'source>> for DiagnosticArgValue<'source> {
     fn into(self) -> FluentValue<'source> {
         match self {
@@ -171,34 +52,6 @@ fn into(self) -> FluentValue<'source> {
     }
 }
 
-impl IntoDiagnosticArg for hir::ConstContext {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Borrowed(match self {
-            hir::ConstContext::ConstFn => "constant function",
-            hir::ConstContext::Static(_) => "static",
-            hir::ConstContext::Const => "constant",
-        }))
-    }
-}
-
-impl IntoDiagnosticArg for ast::Path {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(Cow::Owned(pprust::path_to_string(&self)))
-    }
-}
-
-impl IntoDiagnosticArg for ast::token::Token {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(pprust::token_to_string(&self))
-    }
-}
-
-impl IntoDiagnosticArg for ast::token::TokenKind {
-    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        DiagnosticArgValue::Str(pprust::token_kind_to_string(&self))
-    }
-}
-
 /// Trait implemented by error types. This should not be implemented manually. Instead, use
 /// `#[derive(Subdiagnostic)]` -- see [rustc_macros::Subdiagnostic].
 #[cfg_attr(bootstrap, rustc_diagnostic_item = "AddSubdiagnostic")]
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index 2a1a5d5afb0..860f24871bc 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -1,5 +1,159 @@
-use crate::{fluent, DiagnosticBuilder, Handler, IntoDiagnostic};
+use crate::{
+    fluent, DiagnosticArgValue, DiagnosticBuilder, Handler, IntoDiagnostic, IntoDiagnosticArg,
+};
 use rustc_target::abi::TargetDataLayoutErrors;
+use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
+
+use rustc_ast as ast;
+use rustc_ast_pretty::pprust;
+use rustc_hir as hir;
+use rustc_span::edition::Edition;
+use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
+use std::borrow::Cow;
+use std::fmt;
+use std::num::ParseIntError;
+use std::path::{Path, PathBuf};
+
+pub struct DiagnosticArgFromDisplay<'a>(pub &'a dyn fmt::Display);
+
+impl IntoDiagnosticArg for DiagnosticArgFromDisplay<'_> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.0.to_string().into_diagnostic_arg()
+    }
+}
+
+impl<'a> From<&'a dyn fmt::Display> for DiagnosticArgFromDisplay<'a> {
+    fn from(t: &'a dyn fmt::Display) -> Self {
+        DiagnosticArgFromDisplay(t)
+    }
+}
+
+impl<'a, T: fmt::Display> From<&'a T> for DiagnosticArgFromDisplay<'a> {
+    fn from(t: &'a T) -> Self {
+        DiagnosticArgFromDisplay(t)
+    }
+}
+
+macro_rules! into_diagnostic_arg_using_display {
+    ($( $ty:ty ),+ $(,)?) => {
+        $(
+            impl IntoDiagnosticArg for $ty {
+                fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+                    self.to_string().into_diagnostic_arg()
+                }
+            }
+        )+
+    }
+}
+
+into_diagnostic_arg_using_display!(
+    i8,
+    u8,
+    i16,
+    u16,
+    i32,
+    u32,
+    i64,
+    u64,
+    i128,
+    u128,
+    std::io::Error,
+    std::num::NonZeroU32,
+    hir::Target,
+    Edition,
+    Ident,
+    MacroRulesNormalizedIdent,
+    ParseIntError,
+    StackProtector,
+    &TargetTriple,
+    SplitDebuginfo
+);
+
+impl IntoDiagnosticArg for bool {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        if self {
+            DiagnosticArgValue::Str(Cow::Borrowed("true"))
+        } else {
+            DiagnosticArgValue::Str(Cow::Borrowed("false"))
+        }
+    }
+}
+
+impl IntoDiagnosticArg for char {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(format!("{:?}", self)))
+    }
+}
+
+impl IntoDiagnosticArg for Symbol {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.to_ident_string().into_diagnostic_arg()
+    }
+}
+
+impl<'a> IntoDiagnosticArg for &'a str {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.to_string().into_diagnostic_arg()
+    }
+}
+
+impl IntoDiagnosticArg for String {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self))
+    }
+}
+
+impl<'a> IntoDiagnosticArg for &'a Path {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for PathBuf {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.display().to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for usize {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Number(self)
+    }
+}
+
+impl IntoDiagnosticArg for PanicStrategy {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(self.desc().to_string()))
+    }
+}
+
+impl IntoDiagnosticArg for hir::ConstContext {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Borrowed(match self {
+            hir::ConstContext::ConstFn => "constant function",
+            hir::ConstContext::Static(_) => "static",
+            hir::ConstContext::Const => "constant",
+        }))
+    }
+}
+
+impl IntoDiagnosticArg for ast::Path {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Owned(pprust::path_to_string(&self)))
+    }
+}
+
+impl IntoDiagnosticArg for ast::token::Token {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(pprust::token_to_string(&self))
+    }
+}
+
+impl IntoDiagnosticArg for ast::token::TokenKind {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(pprust::token_kind_to_string(&self))
+    }
+}
 
 impl IntoDiagnostic<'_, !> for TargetDataLayoutErrors<'_> {
     fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, !> {
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 955e85c3616..9fafbe4bd40 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -372,10 +372,11 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 impl error::Error for ExplicitBug {}
 
 pub use diagnostic::{
-    AddToDiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgFromDisplay,
-    DiagnosticArgValue, DiagnosticId, DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
+    AddToDiagnostic, DecorateLint, Diagnostic, DiagnosticArg, DiagnosticArgValue, DiagnosticId,
+    DiagnosticStyledString, IntoDiagnosticArg, SubDiagnostic,
 };
 pub use diagnostic_builder::{DiagnosticBuilder, EmissionGuarantee, Noted};
+pub use diagnostic_impls::DiagnosticArgFromDisplay;
 use std::backtrace::Backtrace;
 
 /// A handler deals with errors and other compiler output.