Add `SubdiagnosticMessageOp` as a trait alias.

It avoids a lot of repetition.

1 files changed, 3 insertions, 6 deletions

diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 86a64d90deb..3c3a8d6fbb9 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -3,8 +3,8 @@ use std::borrow::Cow;
 use rustc_ast::token::Token;
 use rustc_ast::{Path, Visibility};
 use rustc_errors::{
-    codes::*, AddToDiagnostic, Applicability, DiagCtxt, DiagnosticBuilder, IntoDiagnostic, Level,
-    SubdiagnosticMessage,
+    codes::*, AddToDiagnostic, Applicability, DiagCtxt, Diagnostic, DiagnosticBuilder,
+    IntoDiagnostic, Level, SubdiagnosticMessageOp,
 };
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_session::errors::ExprParenthesesNeeded;
@@ -1475,10 +1475,7 @@ pub(crate) struct FnTraitMissingParen {
 }
 
 impl AddToDiagnostic for FnTraitMissingParen {
-    fn add_to_diagnostic_with<F>(self, diag: &mut rustc_errors::Diagnostic, _: F)
-    where
-        F: Fn(&mut rustc_errors::Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
+    fn add_to_diagnostic_with<F: SubdiagnosticMessageOp>(self, diag: &mut Diagnostic, _: F) {
         diag.span_label(self.span, crate::fluent_generated::parse_fn_trait_missing_paren);
         let applicability = if self.machine_applicable {
             Applicability::MachineApplicable