Auto merge of #114089 - Urgau:allow-with-implied-by, r=petrochenkov

Add an allow attribute suggestion along with the implied by suggestion

This PR adds an `#[allow(...)]` attribute hep suggestion along with the implied by suggestion:
```diff
  note: `-W dead-code` implied by `-W unused`
+ help: to override `-W unused` add `#[allow(dead_code)]`
```

This PR also adds the `OnceHelp` lint level (similar to `OnceNote`) to only put the help message one time, like the implied note.

Related to #114030

Author: bors

compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs

@@ -91,7 +91,7 @@ fn annotation_type_for_level(level: Level) -> AnnotationType {
         }
         Level::Warning(_) => AnnotationType::Warning,
         Level::Note | Level::OnceNote => AnnotationType::Note,
-        Level::Help => AnnotationType::Help,
+        Level::Help | Level::OnceHelp => AnnotationType::Help,
         // FIXME(#59346): Not sure how to map this level
         Level::FailureNote => AnnotationType::Error,
         Level::Allow => panic!("Should not call with Allow"),

compiler/rustc_errors/src/diagnostic.rs

@@ -270,6 +270,7 @@ impl Diagnostic {
             | Level::Note
             | Level::OnceNote
             | Level::Help
+            | Level::OnceHelp
             | Level::Allow
             | Level::Expect(_) => false,
         }
@@ -532,6 +533,13 @@ impl Diagnostic {
         self
     }
 
+    /// Prints the span with a help above it.
+    /// This is like [`Diagnostic::help()`], but it gets its own span.
+    pub fn help_once(&mut self, msg: impl Into<SubdiagnosticMessage>) -> &mut Self {
+        self.sub(Level::OnceHelp, msg, MultiSpan::new(), None);
+        self
+    }
+
     /// Add a help message attached to this diagnostic with a customizable highlighted message.
     pub fn highlighted_help(&mut self, msg: Vec<(String, Style)>) -> &mut Self {
         self.sub_with_highlights(Level::Help, msg, MultiSpan::new(), None);

compiler/rustc_errors/src/lib.rs

@@ -1390,7 +1390,7 @@ impl HandlerInner {
                 debug!(?self.emitted_diagnostics);
                 let already_emitted_sub = |sub: &mut SubDiagnostic| {
                     debug!(?sub);
-                    if sub.level != Level::OnceNote {
+                    if sub.level != Level::OnceNote && sub.level != Level::OnceHelp {
                         return false;
                     }
                     let mut hasher = StableHasher::new();
@@ -1792,6 +1792,8 @@ pub enum Level {
     /// A note that is only emitted once.
     OnceNote,
     Help,
+    /// A help that is only emitted once.
+    OnceHelp,
     FailureNote,
     Allow,
     Expect(LintExpectationId),
@@ -1816,7 +1818,7 @@ impl Level {
             Note | OnceNote => {
                 spec.set_fg(Some(Color::Green)).set_intense(true);
             }
-            Help => {
+            Help | OnceHelp => {
                 spec.set_fg(Some(Color::Cyan)).set_intense(true);
             }
             FailureNote => {}
@@ -1831,7 +1833,7 @@ impl Level {
             Fatal | Error { .. } => "error",
             Warning(_) => "warning",
             Note | OnceNote => "note",
-            Help => "help",
+            Help | OnceHelp => "help",
             FailureNote => "failure-note",
             Allow => panic!("Shouldn't call on allowed error"),
             Expect(_) => panic!("Shouldn't call on expected error"),

compiler/rustc_middle/src/lint.rs

@@ -225,6 +225,9 @@ pub fn explain_lint_level_source(
                 err.note_once(format!(
                     "`{flag} {hyphen_case_lint_name}` implied by `{flag} {hyphen_case_flag_val}`"
                 ));
+                err.help_once(format!(
+                    "to override `{flag} {hyphen_case_flag_val}` add `#[allow({name})]`"
+                ));
             }
         }
         LintLevelSource::Node { name: lint_attr_name, span, reason, .. } => {

src/tools/clippy/tests/ui-toml/absolute_paths/absolute_paths.allow_crates.stderr

@@ -5,6 +5,7 @@ LL |     std::f32::MAX;
    |     ^^^^^^^^^^^^^
    |
    = note: `-D clippy::absolute-paths` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::absolute_paths)]`
 
 error: consider bringing this path into scope with the `use` keyword
   --> $DIR/absolute_paths.rs:41:5

src/tools/clippy/tests/ui-toml/absolute_paths/absolute_paths.disallow_crates.stderr

@@ -5,6 +5,7 @@ LL |     std::f32::MAX;
    |     ^^^^^^^^^^^^^
    |
    = note: `-D clippy::absolute-paths` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::absolute_paths)]`
 
 error: consider bringing this path into scope with the `use` keyword
   --> $DIR/absolute_paths.rs:41:5

src/tools/clippy/tests/ui-toml/allow_mixed_uninlined_format_args/uninlined_format_args.stderr

@@ -5,6 +5,7 @@ LL |     println!("val='{}'", local_i32);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::uninlined-format-args` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::uninlined_format_args)]`
 help: change this to
    |
 LL -     println!("val='{}'", local_i32);
@@ -30,6 +31,7 @@ LL |     println!("Hello {} is {:.*}", "x", local_i32, local_f64);
    |                                   ^^^
    |
    = note: `-D clippy::print-literal` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::print_literal)]`
 help: try
    |
 LL -     println!("Hello {} is {:.*}", "x", local_i32, local_f64);

src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/arithmetic_side_effects_allowed.stderr

@@ -5,6 +5,7 @@ LL |     let _ = Baz + Baz;
    |             ^^^^^^^^^
    |
    = note: `-D clippy::arithmetic-side-effects` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::arithmetic_side_effects)]`
 
 error: arithmetic operation that can potentially result in unexpected side-effects
   --> $DIR/arithmetic_side_effects_allowed.rs:80:13

src/tools/clippy/tests/ui-toml/array_size_threshold/array_size_threshold.stderr

@@ -7,6 +7,7 @@ LL | const ABOVE: [u8; 11] = [0; 11];
    | help: make this a static item: `static`
    |
    = note: `-D clippy::large-const-arrays` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_const_arrays)]`
 
 error: allocating a local array larger than 10 bytes
   --> $DIR/array_size_threshold.rs:4:25
@@ -16,6 +17,7 @@ LL | const ABOVE: [u8; 11] = [0; 11];
    |
    = help: consider allocating on the heap with `vec![0; 11].into_boxed_slice()`
    = note: `-D clippy::large-stack-arrays` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_stack_arrays)]`
 
 error: allocating a local array larger than 10 bytes
   --> $DIR/array_size_threshold.rs:8:17

src/tools/clippy/tests/ui-toml/await_holding_invalid_type/await_holding_invalid_type.stderr

@@ -6,6 +6,7 @@ LL |     let _x = String::from("hello");
    |
    = note: strings are bad (from clippy.toml)
    = note: `-D clippy::await-holding-invalid-type` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::await_holding_invalid_type)]`
 
 error: `std::net::Ipv4Addr` may not be held across an `await` point per `clippy.toml`
   --> $DIR/await_holding_invalid_type.rs:10:9