elided_named_lifetimes: manually implement LintDiagnostic

Author: GrigorenkoPV

compiler/rustc_lint/messages.ftl

@@ -255,8 +255,7 @@ lint_duplicate_matcher_binding = duplicate matcher binding
 lint_elided_named_lifetime = elided lifetime has a name
     .label_elided = this elided lifetime gets resolved as `{$name}`
     .label_named = lifetime `{$name}` declared here
-
-lint_elided_named_lifetime_suggestion = consider specifying it explicitly
+    .suggestion = consider specifying it explicitly
 
 lint_enum_intrinsics_mem_discriminant =
     the return value of `mem::discriminant` is unspecified when called with a non-enum type

compiler/rustc_lint/src/context/diagnostics.rs

@@ -7,15 +7,13 @@ use rustc_ast::util::unicode::TEXT_FLOW_CONTROL_CHARS;
 use rustc_errors::{
     elided_lifetime_in_path_suggestion, Applicability, Diag, DiagArgValue, LintDiagnostic,
 };
-use rustc_hir::MissingLifetimeKind;
 use rustc_middle::middle::stability;
 use rustc_session::lint::{BuiltinLintDiag, ElidedLifetimeResolution};
 use rustc_session::Session;
 use rustc_span::symbol::kw;
 use rustc_span::BytePos;
 use tracing::debug;
 
-use crate::fluent_generated;
 use crate::lints::{self, ElidedNamedLifetime};
 
 mod check_cfg;
@@ -445,31 +443,15 @@ pub(super) fn decorate_lint(sess: &Session, diagnostic: BuiltinLintDiag, diag: &
             lints::UnexpectedBuiltinCfg { cfg, cfg_name, controlled_by }.decorate_lint(diag)
         }
         BuiltinLintDiag::ElidedNamedLifetimes { elided: (span, kind), resolution } => {
-            let (name, named_declaration) = match resolution {
-                ElidedLifetimeResolution::Static => (kw::StaticLifetime, None),
-                ElidedLifetimeResolution::Param(name, declaration) => (name, Some(declaration)),
-            };
-            ElidedNamedLifetime { span, name, named_declaration }.decorate_lint(diag);
-
-            let (applicability, suggestion) = match kind {
-                MissingLifetimeKind::Underscore => {
-                    (Applicability::MachineApplicable, format!("{name}"))
+            match resolution {
+                ElidedLifetimeResolution::Static => {
+                    ElidedNamedLifetime { span, kind, name: kw::StaticLifetime, declaration: None }
                 }
-                MissingLifetimeKind::Ampersand => {
-                    (Applicability::MachineApplicable, format!("&{name} "))
+                ElidedLifetimeResolution::Param(name, declaration) => {
+                    ElidedNamedLifetime { span, kind, name, declaration: Some(declaration) }
                 }
-                MissingLifetimeKind::Comma => (Applicability::Unspecified, format!("<{name}, ")),
-                MissingLifetimeKind::Brackets => (
-                    Applicability::Unspecified,
-                    format!("{}<{name}>", sess.source_map().span_to_snippet(span).unwrap()),
-                ),
-            };
-            diag.span_suggestion_verbose(
-                span,
-                fluent_generated::lint_elided_named_lifetime_suggestion,
-                suggestion,
-                applicability,
-            );
+            }
+            .decorate_lint(diag)
         }
     }
 }

compiler/rustc_lint/src/lints.rs

@@ -9,7 +9,7 @@ use rustc_errors::{
 };
 use rustc_hir::def::Namespace;
 use rustc_hir::def_id::DefId;
-use rustc_hir::{self as hir};
+use rustc_hir::{self as hir, MissingLifetimeKind};
 use rustc_macros::{LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::inhabitedness::InhabitedPredicate;
 use rustc_middle::ty::{Clause, PolyExistentialTraitRef, Ty, TyCtxt};
@@ -2623,14 +2623,49 @@ pub(crate) struct ElidedLifetimesInPaths {
     pub subdiag: ElidedLifetimeInPathSubdiag,
 }
 
-#[derive(LintDiagnostic)]
-#[diag(lint_elided_named_lifetime)]
 pub(crate) struct ElidedNamedLifetime {
-    #[label(lint_label_elided)]
     pub span: Span,
+    pub kind: MissingLifetimeKind,
     pub name: Symbol,
-    #[label(lint_label_named)]
-    pub named_declaration: Option<Span>,
+    pub declaration: Option<Span>,
+}
+
+impl<G: EmissionGuarantee> LintDiagnostic<'_, G> for ElidedNamedLifetime {
+    fn decorate_lint(self, diag: &mut rustc_errors::Diag<'_, G>) {
+        let Self { span, kind, name, declaration } = self;
+        diag.primary_message(fluent::lint_elided_named_lifetime);
+        diag.arg("name", name);
+        diag.span_label(span, fluent::lint_label_elided);
+        if let Some(declaration) = declaration {
+            diag.span_label(declaration, fluent::lint_label_named);
+        }
+        match kind {
+            MissingLifetimeKind::Underscore => diag.span_suggestion_verbose(
+                span,
+                fluent::lint_suggestion,
+                format!("{name}"),
+                Applicability::MachineApplicable,
+            ),
+            MissingLifetimeKind::Ampersand => diag.span_suggestion_verbose(
+                span.shrink_to_hi(),
+                fluent::lint_suggestion,
+                format!("{name} "),
+                Applicability::MachineApplicable,
+            ),
+            MissingLifetimeKind::Comma => diag.span_suggestion_verbose(
+                span.shrink_to_hi(),
+                fluent::lint_suggestion,
+                format!("{name}, "),
+                Applicability::MachineApplicable,
+            ),
+            MissingLifetimeKind::Brackets => diag.span_suggestion_verbose(
+                span.shrink_to_hi(),
+                fluent::lint_suggestion,
+                format!("<{name}>"),
+                Applicability::MachineApplicable,
+            ),
+        };
+    }
 }
 
 #[derive(LintDiagnostic)]

tests/ui/async-await/issues/issue-63388-1.stderr

@@ -11,7 +11,7 @@ LL |     ) -> &dyn Foo
 help: consider specifying it explicitly
    |
 LL |     ) -> &'a dyn Foo
-   |          ~~~
+   |           ++
 
 error[E0621]: explicit lifetime required in the type of `foo`
   --> $DIR/issue-63388-1.rs:13:5

tests/ui/const-generics/type-dependent/issue-71348.full.stderr

@@ -8,7 +8,7 @@ LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<N>>::Ta
 help: consider specifying it explicitly
    |
 LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<'a, N>>::Target
-   |                                                                    ~~~~
+   |                                                                     +++
 
 warning: 1 warning emitted
 

tests/ui/const-generics/type-dependent/issue-71348.min.stderr

@@ -8,7 +8,7 @@ LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<N>>::Ta
 help: consider specifying it explicitly
    |
 LL |     fn ask<'a, const N: &'static str>(&'a self) -> &'a <Self as Get<'a, N>>::Target
-   |                                                                    ~~~~
+   |                                                                     +++
 
 error: `&'static str` is forbidden as the type of a const generic parameter
   --> $DIR/issue-71348.rs:10:24

tests/ui/consts/min_const_fn/min_const_fn.stderr

@@ -11,7 +11,7 @@ LL |     const fn get_lt(&'a self) -> &T { &self.0 }
 help: consider specifying it explicitly
    |
 LL |     const fn get_lt(&'a self) -> &'a T { &self.0 }
-   |                                  ~~~
+   |                                   ++
 
 warning: elided lifetime has a name
   --> $DIR/min_const_fn.rs:48:42
@@ -25,7 +25,7 @@ LL |     const fn get_mut_lt(&'a mut self) -> &mut T { &mut self.0 }
 help: consider specifying it explicitly
    |
 LL |     const fn get_mut_lt(&'a mut self) -> &'a mut T { &mut self.0 }
-   |                                          ~~~
+   |                                           ++
 
 error[E0493]: destructor of `Foo<T>` cannot be evaluated at compile-time
   --> $DIR/min_const_fn.rs:37:25

tests/ui/impl-trait/rpit-assoc-pair-with-lifetime.stderr

@@ -8,7 +8,7 @@ LL | pub fn iter<'a>(v: Vec<(u32, &'a u32)>) -> impl DoubleEndedIterator<Item =
 help: consider specifying it explicitly
    |
 LL | pub fn iter<'a>(v: Vec<(u32, &'a u32)>) -> impl DoubleEndedIterator<Item = (u32, &'a u32)> {
-   |                                                                                  ~~~
+   |                                                                                   ++
 
 warning: 1 warning emitted
 

tests/ui/lifetimes/lifetime-elision-return-type-requires-explicit-lifetime.stderr

@@ -117,7 +117,7 @@ LL | fn m<'a>(_: &'a Foo<'a>) -> &str { "" }
 help: consider specifying it explicitly
    |
 LL | fn m<'a>(_: &'a Foo<'a>) -> &'a str { "" }
-   |                             ~~~
+   |                              ++
 
 error: aborting due to 7 previous errors; 1 warning emitted
 

tests/ui/lifetimes/lifetime-errors/ex1-return-one-existing-name-if-else-using-impl-3.stderr

@@ -10,7 +10,7 @@ LL |   fn foo<'a>(&'a self, x: &i32) -> &i32 {
 help: consider specifying it explicitly
    |
 LL |   fn foo<'a>(&'a self, x: &i32) -> &'a i32 {
-   |                                    ~~~
+   |                                     ++
 
 error[E0621]: explicit lifetime required in the type of `x`
   --> $DIR/ex1-return-one-existing-name-if-else-using-impl-3.rs:9:36