6 files changed, 17 insertions, 15 deletions
diff --git a/compiler/rustc_middle/src/error.rs b/compiler/rustc_middle/src/error.rs
index 211da800202..3ebbcd65030 100644
--- a/compiler/rustc_middle/src/error.rs
+++ b/compiler/rustc_middle/src/error.rs
@@ -1,7 +1,6 @@
-use std::borrow::Cow;
 use std::fmt;
 
-use rustc_errors::{codes::*, DiagnosticArgValue, DiagnosticMessage};
+use rustc_errors::{codes::*, DiagnosticArgName, DiagnosticArgValue, DiagnosticMessage};
 use rustc_macros::Diagnostic;
 use rustc_span::{Span, Symbol};
 
@@ -95,14 +94,14 @@ pub(super) struct ConstNotUsedTraitAlias {
 
 pub struct CustomSubdiagnostic<'a> {
     pub msg: fn() -> DiagnosticMessage,
-    pub add_args: Box<dyn FnOnce(&mut dyn FnMut(Cow<'static, str>, DiagnosticArgValue)) + 'a>,
+    pub add_args: Box<dyn FnOnce(&mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue)) + 'a>,
 }
 
 impl<'a> CustomSubdiagnostic<'a> {
     pub fn label(x: fn() -> DiagnosticMessage) -> Self {
         Self::label_and_then(x, |_| {})
     }
-    pub fn label_and_then<F: FnOnce(&mut dyn FnMut(Cow<'static, str>, DiagnosticArgValue)) + 'a>(
+    pub fn label_and_then<F: FnOnce(&mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue)) + 'a>(
         msg: fn() -> DiagnosticMessage,
         f: F,
     ) -> Self {
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
index b54e438f614..94191df30a5 100644
--- a/compiler/rustc_middle/src/hir/mod.rs
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -127,12 +127,11 @@ pub fn provide(providers: &mut Providers) {
     providers.hir_crate_items = map::hir_crate_items;
     providers.crate_hash = map::crate_hash;
     providers.hir_module_items = map::hir_module_items;
-    providers.opt_local_def_id_to_hir_id = |tcx, id| {
-        let owner = tcx.hir_crate(()).owners[id].map(|_| ());
-        Some(match owner {
-            MaybeOwner::Owner(_) => HirId::make_owner(id),
-            MaybeOwner::Phantom => bug!("No HirId for {:?}", id),
+    providers.opt_local_def_id_to_hir_id = |tcx, def_id| {
+        Some(match tcx.hir_crate(()).owners[def_id] {
+            MaybeOwner::Owner(_) => HirId::make_owner(def_id),
             MaybeOwner::NonOwner(hir_id) => hir_id,
+            MaybeOwner::Phantom => bug!("No HirId for {:?}", def_id),
         })
     };
     providers.opt_hir_owner_nodes =
diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs
index 95574aee499..0f69ab93452 100644
--- a/compiler/rustc_middle/src/mir/interpret/error.rs
+++ b/compiler/rustc_middle/src/mir/interpret/error.rs
@@ -5,7 +5,9 @@ use crate::mir::{ConstAlloc, ConstValue};
 use crate::ty::{layout, tls, Ty, TyCtxt, ValTree};
 
 use rustc_data_structures::sync::Lock;
-use rustc_errors::{DiagnosticArgValue, DiagnosticMessage, ErrorGuaranteed, IntoDiagnosticArg};
+use rustc_errors::{
+    DiagnosticArgName, DiagnosticArgValue, DiagnosticMessage, ErrorGuaranteed, IntoDiagnosticArg,
+};
 use rustc_macros::HashStable;
 use rustc_session::CtfeBacktrace;
 use rustc_span::{def_id::DefId, Span, DUMMY_SP};
@@ -485,7 +487,7 @@ pub trait MachineStopType: Any + fmt::Debug + Send {
     fn diagnostic_message(&self) -> DiagnosticMessage;
     /// Add diagnostic arguments by passing name and value pairs to `adder`, which are passed to
     /// fluent for formatting the translated diagnostic message.
-    fn add_args(self: Box<Self>, adder: &mut dyn FnMut(Cow<'static, str>, DiagnosticArgValue));
+    fn add_args(self: Box<Self>, adder: &mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue));
 }
 
 impl dyn MachineStopType {
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 37c5bba46a7..c9e69253701 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -14,7 +14,9 @@ use crate::ty::{AdtDef, InstanceDef, UserTypeAnnotationIndex};
 use crate::ty::{GenericArg, GenericArgsRef};
 
 use rustc_data_structures::captures::Captures;
-use rustc_errors::{DiagnosticArgValue, DiagnosticMessage, ErrorGuaranteed, IntoDiagnosticArg};
+use rustc_errors::{
+    DiagnosticArgName, DiagnosticArgValue, DiagnosticMessage, ErrorGuaranteed, IntoDiagnosticArg,
+};
 use rustc_hir::def::{CtorKind, Namespace};
 use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
 use rustc_hir::{self, CoroutineDesugaring, CoroutineKind, ImplicitSelfKind};
diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs
index 0fe33e441f4..91b7952bec5 100644
--- a/compiler/rustc_middle/src/mir/terminator.rs
+++ b/compiler/rustc_middle/src/mir/terminator.rs
@@ -292,7 +292,7 @@ impl<O> AssertKind<O> {
         }
     }
 
-    pub fn add_args(self, adder: &mut dyn FnMut(Cow<'static, str>, DiagnosticArgValue))
+    pub fn add_args(self, adder: &mut dyn FnMut(DiagnosticArgName, DiagnosticArgValue))
     where
         O: fmt::Debug,
     {
diff --git a/compiler/rustc_middle/src/query/erase.rs b/compiler/rustc_middle/src/query/erase.rs
index 1b01df6a187..a272a51f327 100644
--- a/compiler/rustc_middle/src/query/erase.rs
+++ b/compiler/rustc_middle/src/query/erase.rs
@@ -185,8 +185,8 @@ impl EraseType for Option<ty::EarlyBinder<Ty<'_>>> {
     type Result = [u8; size_of::<Option<ty::EarlyBinder<Ty<'static>>>>()];
 }
 
-impl<T> EraseType for rustc_hir::MaybeOwner<&'_ T> {
-    type Result = [u8; size_of::<rustc_hir::MaybeOwner<&'static ()>>()];
+impl EraseType for rustc_hir::MaybeOwner<'_> {
+    type Result = [u8; size_of::<rustc_hir::MaybeOwner<'static>>()];
 }
 
 impl<T: EraseType> EraseType for ty::EarlyBinder<T> {