lint: use derive more

Signed-off-by: David Wood <david.wood@huawei.com>

Author: davidtwco

compiler/rustc_errors/src/diagnostic_impls.rs

@@ -1,14 +1,14 @@
 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_lint_defs::Level;
 use rustc_span::edition::Edition;
 use rustc_span::symbol::{Ident, MacroRulesNormalizedIdent, Symbol};
+use rustc_target::abi::TargetDataLayoutErrors;
+use rustc_target::spec::{PanicStrategy, SplitDebuginfo, StackProtector, TargetTriple};
 use std::borrow::Cow;
 use std::fmt;
 use std::num::ParseIntError;
@@ -155,6 +155,21 @@ impl IntoDiagnosticArg for ast::token::TokenKind {
     }
 }
 
+impl IntoDiagnosticArg for Level {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        DiagnosticArgValue::Str(Cow::Borrowed(match self {
+            Level::Allow => "-A",
+            Level::Warn => "-W",
+            Level::ForceWarn(_) => "--force-warn",
+            Level::Deny => "-D",
+            Level::Forbid => "-F",
+            Level::Expect(_) => {
+                unreachable!("lints with the level of `expect` should not run this code");
+            }
+        }))
+    }
+}
+
 impl IntoDiagnostic<'_, !> for TargetDataLayoutErrors<'_> {
     fn into_diagnostic(self, handler: &Handler) -> DiagnosticBuilder<'_, !> {
         let mut diag;

compiler/rustc_lint/src/errors.rs

@@ -88,34 +88,13 @@ pub struct BuiltinEllpisisInclusiveRangePatterns {
     pub replace: String,
 }
 
+#[derive(Subdiagnostic)]
+#[note(lint::requested_level)]
 pub struct RequestedLevel {
     pub level: Level,
     pub lint_name: String,
 }
 
-impl AddToDiagnostic for RequestedLevel {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        diag.note(fluent::lint::requested_level);
-        diag.set_arg(
-            "level",
-            match self.level {
-                Level::Allow => "-A",
-                Level::Warn => "-W",
-                Level::ForceWarn(_) => "--force-warn",
-                Level::Deny => "-D",
-                Level::Forbid => "-F",
-                Level::Expect(_) => {
-                    unreachable!("lints with the level of `expect` should not run this code");
-                }
-            },
-        );
-        diag.set_arg("lint_name", self.lint_name);
-    }
-}
-
 #[derive(Diagnostic)]
 #[diag(lint::unsupported_group, code = "E0602")]
 pub struct UnsupportedGroup {