Remove more BuiltinLintDiag variants - part 4

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }
 

compiler/rustc_errors/src/decorate_diag.rs

@@ -1,3 +1,5 @@
+use std::any::Any;
+
 /// This module provides types and traits for buffering lints until later in compilation.
 use rustc_ast::node_id::NodeId;
 use rustc_data_structures::fx::FxIndexMap;
@@ -10,9 +12,11 @@ use crate::{Diag, DiagCtxtHandle, Diagnostic, Level};
 /// We can't implement `Diagnostic` for `BuiltinLintDiag`, because decorating some of its
 /// variants requires types we don't have yet. So, handle that case separately.
 pub enum DecorateDiagCompat {
+ /// The third argument of the closure is a `Session`. However, due to the dependency tree,
+ /// we don't have access to `rustc_session` here, so we downcast it when needed.
  Dynamic(
  Box<
- dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level) -> Diag<'a, ()>
+ dyn for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
  + DynSync
  + DynSend
  + 'static,
@@ -30,7 +34,7 @@ impl std::fmt::Debug for DecorateDiagCompat {
 impl<D: for<'a> Diagnostic<'a, ()> + DynSync + DynSend + 'static> From<D> for DecorateDiagCompat {
  #[inline]
  fn from(d: D) -> Self {
- Self::Dynamic(Box::new(|dcx, level| d.into_diag(dcx, level)))
+ Self::Dynamic(Box::new(|dcx, level, _| d.into_diag(dcx, level)))
  }
 }
 
@@ -97,6 +101,26 @@ impl LintBuffer {
  node_id: NodeId,
  span: impl Into<MultiSpan>,
  callback: F,
+ ) {
+ self.add_early_lint(BufferedEarlyLint {
+ lint_id: LintId::of(lint),
+ node_id,
+ span: Some(span.into()),
+ diagnostic: DecorateDiagCompat::Dynamic(Box::new(|dcx, level, _| callback(dcx, level))),
+ });
+ }
+
+ pub fn dyn_buffer_lint_any<
+ F: for<'a> FnOnce(DiagCtxtHandle<'a>, Level, &dyn Any) -> Diag<'a, ()>
+ + DynSend
+ + DynSync
+ + 'static,
+ >(
+ &mut self,
+ lint: &'static Lint,
+ node_id: NodeId,
+ span: impl Into<MultiSpan>,
+ callback: F,
  ) {
  self.add_early_lint(BufferedEarlyLint {
  lint_id: LintId::of(lint),

compiler/rustc_errors/src/diagnostic.rs

@@ -7,7 +7,6 @@ use std::panic;
 use std::path::PathBuf;
 use std::thread::panicking;
 
-use rustc_data_structures::sync::{DynSend, DynSync};
 use rustc_error_messages::{DiagArgMap, DiagArgName, DiagArgValue, IntoDiagArg};
 use rustc_lint_defs::{Applicability, LintExpectationId};
 use rustc_macros::{Decodable, Encodable};
@@ -119,16 +118,6 @@ where
  }
 }
 
-impl<'a> Diagnostic<'a, ()>
- for Box<
- dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level) -> Diag<'b, ()> + DynSync + DynSend + 'static,
- >
-{
- fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
- self(dcx, level)
- }
-}
-
 /// Type used to emit diagnostic through a closure instead of implementing the `Diagnostic` trait.
 pub struct DiagDecorator<F: FnOnce(&mut Diag<'_, ()>)>(pub F);
 

compiler/rustc_lint/src/early.rs

@@ -15,9 +15,9 @@ use rustc_session::lint::LintPass;
 use rustc_span::{DUMMY_SP, Ident, Span};
 use tracing::debug;
 
-use crate::DecorateBuiltinLint;
 use crate::context::{EarlyContext, LintContext, LintStore};
 use crate::passes::{EarlyLintPass, EarlyLintPassObject};
+use crate::{DecorateBuiltinLint, DiagAndSess};
 
 pub(super) mod diagnostics;
 
@@ -49,8 +49,12 @@ impl<'ecx, 'tcx, T: EarlyLintPass> EarlyContextAndPass<'ecx, 'tcx, T> {
  },
  );
  }
- DecorateDiagCompat::Dynamic(d) => {
- self.context.opt_span_lint(lint_id.lint, span, d);
+ DecorateDiagCompat::Dynamic(callback) => {
+ self.context.opt_span_lint(
+ lint_id.lint,
+ span,
+ DiagAndSess { callback, sess: self.context.sess() },
+ );
  }
  }
  }

compiler/rustc_lint/src/early/diagnostics.rs

@@ -1,5 +1,7 @@
+use std::any::Any;
 use std::borrow::Cow;
 
+use rustc_data_structures::sync::DynSend;
 use rustc_errors::{
  Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, Level,
  elided_lifetime_in_path_suggestion,
@@ -8,12 +10,24 @@ use rustc_hir::lints::{AttributeLintKind, FormatWarning};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_session::lint::BuiltinLintDiag;
-use tracing::debug;
 
 use crate::lints;
 
 mod check_cfg;
 
+pub struct DiagAndSess<'sess> {
+ pub callback: Box<
+ dyn for<'b> FnOnce(DiagCtxtHandle<'b>, Level, &dyn Any) -> Diag<'b, ()> + DynSend + 'static,
+ >,
+ pub sess: &'sess Session,
+}
+
+impl<'a> Diagnostic<'a, ()> for DiagAndSess<'_> {
+ fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
+ (self.callback)(dcx, level, self.sess)
+ }
+}
+
 /// This is a diagnostic struct that will decorate a `BuiltinLintDiag`
 /// Directly creating the lint structs is expensive, using this will only decorate the lint structs when needed.
 pub struct DecorateBuiltinLint<'sess, 'tcx> {
@@ -25,28 +39,6 @@ pub struct DecorateBuiltinLint<'sess, 'tcx> {
 impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  fn into_diag(self, dcx: DiagCtxtHandle<'a>, level: Level) -> Diag<'a, ()> {
  match self.diagnostic {
- BuiltinLintDiag::AbsPathWithModule(mod_span) => {
- let (replacement, applicability) =
- match self.sess.source_map().span_to_snippet(mod_span) {
- Ok(ref s) => {
- // FIXME(Manishearth) ideally the emitting code
- // can tell us whether or not this is global
- let opt_colon =
- if s.trim_start().starts_with("::") { "" } else { "::" };
-
- (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
- }
- Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
- };
- lints::AbsPathWithModule {
- sugg: lints::AbsPathWithModuleSugg {
- span: mod_span,
- applicability,
- replacement,
- },
- }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::ElidedLifetimesInPaths(
  n,
  path_span,
@@ -87,36 +79,6 @@ impl<'a> Diagnostic<'a, ()> for DecorateBuiltinLint<'_, '_> {
  }
  .into_diag(dcx, level)
  }
- BuiltinLintDiag::SingleUseLifetime {
- param_span,
- use_span,
- elidable,
- deletion_span,
- ident,
- } => {
- debug!(?param_span, ?use_span, ?deletion_span);
- let suggestion = if let Some(deletion_span) = deletion_span {
- let (use_span, replace_lt) = if elidable {
- let use_span =
- self.sess.source_map().span_extend_while_whitespace(use_span);
- (use_span, String::new())
- } else {
- (use_span, "'_".to_owned())
- };
- debug!(?deletion_span, ?use_span);
-
- // issue 107998 for the case such as a wrong function pointer type
- // `deletion_span` is empty and there is no need to report lifetime uses here
- let deletion_span =
- if deletion_span.is_empty() { None } else { Some(deletion_span) };
- Some(lints::SingleUseLifetimeSugg { deletion_span, use_span, replace_lt })
- } else {
- None
- };
-
- lints::SingleUseLifetime { suggestion, param_span, use_span, ident }
- .into_diag(dcx, level)
- }
  BuiltinLintDiag::NamedArgumentUsedPositionally {
  position_sp_to_replace,
  position_sp_for_msg,

compiler/rustc_lint/src/lib.rs

@@ -129,7 +129,7 @@ use unused::*;
 #[rustfmt::skip]
 pub use builtin::{MissingDoc, SoftLints};
 pub use context::{EarlyContext, LateContext, LintContext, LintStore};
-pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint};
+pub use early::diagnostics::{DecorateAttrLint, DecorateBuiltinLint, DiagAndSess};
 pub use early::{EarlyCheckNode, check_ast_node};
 pub use late::{check_crate, late_lint_mod, unerased_lint_store};
 pub use levels::LintLevelsBuilder;

compiler/rustc_lint/src/lints.rs

@@ -3011,25 +3011,6 @@ pub(crate) struct IllFormedAttributeInput {
  pub docs: &'static str,
 }
 
-#[derive(Diagnostic)]
-#[diag(
- "absolute paths must start with `self`, `super`, `crate`, or an external crate name in the 2018 edition"
-)]
-pub(crate) struct AbsPathWithModule {
- #[subdiagnostic]
- pub sugg: AbsPathWithModuleSugg,
-}
-
-#[derive(Subdiagnostic)]
-#[suggestion("use `crate`", code = "{replacement}")]
-pub(crate) struct AbsPathWithModuleSugg {
- #[primary_span]
- pub span: Span,
- #[applicability]
- pub applicability: Applicability,
- pub replacement: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("hidden lifetime parameters in types are deprecated")]
 pub(crate) struct ElidedLifetimesInPaths {
@@ -3081,30 +3062,6 @@ pub(crate) enum UnusedImportsSugg {
  },
 }
 
-#[derive(Diagnostic)]
-#[diag("lifetime parameter `{$ident}` only used once")]
-pub(crate) struct SingleUseLifetime {
- #[label("this lifetime...")]
- pub param_span: Span,
- #[label("...is used only here")]
- pub use_span: Span,
- #[subdiagnostic]
- pub suggestion: Option<SingleUseLifetimeSugg>,
-
- pub ident: Ident,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion("elide the single-use lifetime", applicability = "machine-applicable")]
-pub(crate) struct SingleUseLifetimeSugg {
- #[suggestion_part(code = "")]
- pub deletion_span: Option<Span>,
- #[suggestion_part(code = "{replace_lt}")]
- pub use_span: Span,
-
- pub replace_lt: String,
-}
-
 #[derive(Diagnostic)]
 #[diag("named argument `{$named_arg_name}` is not used by name")]
 pub(crate) struct NamedArgumentUsedPositionally {

compiler/rustc_lint_defs/src/lib.rs

@@ -656,7 +656,6 @@ pub enum DeprecatedSinceKind {
 // becomes hacky (and it gets allocated).
 #[derive(Debug)]
 pub enum BuiltinLintDiag {
- AbsPathWithModule(Span),
  ElidedLifetimesInPaths(usize, Span, bool, Span),
  UnusedImports {
  remove_whole_use: bool,
@@ -665,18 +664,6 @@ pub enum BuiltinLintDiag {
  test_module_span: Option<Span>,
  span_snippets: Vec<String>,
  },
- SingleUseLifetime {
- /// Span of the parameter which declares this lifetime.
- param_span: Span,
- /// Span of the code that should be removed when eliding this lifetime.
- /// This span should include leading or trailing comma.
- deletion_span: Option<Span>,
- /// Span of the single use, or None if the lifetime is never used.
- /// If true, the lifetime will be fully elided.
- use_span: Span,
- elidable: bool,
- ident: Ident,
- },
  NamedArgumentUsedPositionally {
  /// Span where the named argument is used by position and will be replaced with the named
  /// argument name

compiler/rustc_resolve/src/diagnostics.rs

@@ -11,7 +11,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::codes::*;
 use rustc_errors::{
- Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, MultiSpan, SuggestionStyle,
+ Applicability, Diag, DiagCtxtHandle, Diagnostic, ErrorGuaranteed, MultiSpan, SuggestionStyle,
  struct_span_code_err,
 };
 use rustc_feature::BUILTIN_ATTRIBUTES;
@@ -23,7 +23,6 @@ use rustc_hir::{PrimTy, Stability, StabilityLevel, find_attr};
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::{
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE, AMBIGUOUS_GLOB_IMPORTS, AMBIGUOUS_IMPORT_VISIBILITIES,
  AMBIGUOUS_PANIC_IMPORTS, MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
@@ -510,12 +509,35 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
  return;
  }
 
- let diag = BuiltinLintDiag::AbsPathWithModule(root_span);
- self.lint_buffer.buffer_lint(
+ self.lint_buffer.dyn_buffer_lint_any(
  ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
  node_id,
  root_span,
- diag,
+ move |dcx, level, sess| {
+ let (replacement, applicability) = match sess
+ .downcast_ref::<Session>()
+ .expect("expected a `Session`")
+ .source_map()
+ .span_to_snippet(root_span)
+ {
+ Ok(ref s) => {
+ // FIXME(Manishearth) ideally the emitting code
+ // can tell us whether or not this is global
+ let opt_colon = if s.trim_start().starts_with("::") { "" } else { "::" };
+
+ (format!("crate{opt_colon}{s}"), Applicability::MachineApplicable)
+ }
+ Err(_) => ("crate::<path>".to_string(), Applicability::HasPlaceholders),
+ };
+ errors::AbsPathWithModule {
+ sugg: errors::AbsPathWithModuleSugg {
+ span: root_span,
+ applicability,
+ replacement,
+ },
+ }
+ .into_diag(dcx, level)
+ },
  );
  }