elided_named_lifetimes: LintDiagnostic

Author: GrigorenkoPV

compiler/rustc_lint/messages.ftl

@@ -252,8 +252,10 @@ lint_duplicate_macro_attribute =
 
 lint_duplicate_matcher_binding = duplicate matcher binding
 
-lint_elided_lifetime_static =
-    this lifetime is static, lol
+lint_elided_named_lifetime = elided lifetime has a name
+    .label_static = this elided lifetime gets resolved as `'static`
+    .label_this = this elided lifetime
+    .label_that = gets resolved as this named lifetime
 
 lint_enum_intrinsics_mem_discriminant =
     the return value of `mem::discriminant` is unspecified when called with a non-enum type

compiler/rustc_lint/src/context/diagnostics.rs

@@ -441,6 +441,11 @@ pub(super) fn decorate_lint(sess: &Session, diagnostic: BuiltinLintDiag, diag: &
         BuiltinLintDiag::UnexpectedBuiltinCfg { cfg, cfg_name, controlled_by } => {
             lints::UnexpectedBuiltinCfg { cfg, cfg_name, controlled_by }.decorate_lint(diag)
         }
-        BuiltinLintDiag::ElidedIsStatic => lints::ElidedIsStatic {}.decorate_lint(diag),
+        BuiltinLintDiag::ElidedIsStatic { elided } => {
+            lints::ElidedNamedLifetime::Static { elided }.decorate_lint(diag)
+        }
+        BuiltinLintDiag::ElidedIsParam { elided, param } => {
+            lints::ElidedNamedLifetime::Param { elided, param }.decorate_lint(diag)
+        }
     }
 }

compiler/rustc_lint/src/lints.rs

@@ -2612,8 +2612,20 @@ pub struct ElidedLifetimesInPaths {
 }
 
 #[derive(LintDiagnostic)]
-#[diag(lint_elided_lifetime_static)]
-pub struct ElidedIsStatic {}
+pub enum ElidedNamedLifetime {
+    #[diag(lint_elided_named_lifetime)]
+    Static {
+        #[label(lint_label_static)]
+        elided: Span,
+    },
+    #[diag(lint_elided_named_lifetime)]
+    Param {
+        #[label(lint_label_this)]
+        elided: Span,
+        #[label(lint_label_that)]
+        param: Span,
+    },
+}
 
 #[derive(LintDiagnostic)]
 #[diag(lint_invalid_crate_type_value)]

compiler/rustc_lint_defs/src/lib.rs

@@ -585,7 +585,13 @@ pub enum BuiltinLintDiag {
     },
     MacroExpandedMacroExportsAccessedByAbsolutePaths(Span),
     ElidedLifetimesInPaths(usize, Span, bool, Span),
-    ElidedIsStatic,
+    ElidedIsStatic {
+        elided: Span,
+    },
+    ElidedIsParam {
+        elided: Span,
+        param: Span,
+    },
     UnknownCrateTypes {
         span: Span,
         candidate: Option<Symbol>,

compiler/rustc_resolve/src/late.rs

@@ -2039,25 +2039,38 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
         if let Some(prev_res) = self.r.lifetimes_res_map.insert(id, res) {
             panic!("lifetime {id:?} resolved multiple times ({prev_res:?} before, {res:?} now)")
         }
+
         match candidate {
-            LifetimeElisionCandidate::Missing(missing) => match res {
-                LifetimeRes::Static => {
-                    self.r.lint_buffer.buffer_lint(
-                        lint::builtin::ELIDED_NAMED_LIFETIMES,
-                        missing.id,
-                        missing.span,
-                        BuiltinLintDiag::ElidedIsStatic {},
-                    );
-                    tracing::warn!(?missing, "static")
-                }
-                LifetimeRes::Param { param, binder } => {
-                    tracing::warn!(?missing, ?param, ?binder, "named")
+            LifetimeElisionCandidate::Missing(missing) => {
+                // FIXME: ICEs otherwise
+                if missing.kind != MissingLifetimeKind::Ampersand {
+                    match res {
+                        LifetimeRes::Static => {
+                            self.r.lint_buffer.buffer_lint(
+                                lint::builtin::ELIDED_NAMED_LIFETIMES,
+                                missing.id,
+                                missing.span,
+                                BuiltinLintDiag::ElidedIsStatic { elided: missing.span },
+                            );
+                        }
+                        LifetimeRes::Param { param, binder: _ } => {
+                            self.r.lint_buffer.buffer_lint(
+                                lint::builtin::ELIDED_NAMED_LIFETIMES,
+                                missing.id,
+                                missing.span,
+                                BuiltinLintDiag::ElidedIsParam {
+                                    elided: missing.span,
+                                    param: self.r.tcx().source_span(param),
+                                },
+                            );
+                        }
+                        LifetimeRes::Fresh { .. }
+                        | LifetimeRes::Infer
+                        | LifetimeRes::Error
+                        | LifetimeRes::ElidedAnchor { .. } => {}
+                    }
                 }
-                LifetimeRes::Fresh { .. }
-                | LifetimeRes::Infer
-                | LifetimeRes::Error
-                | LifetimeRes::ElidedAnchor { .. } => {}
-            },
+            }
             LifetimeElisionCandidate::Ignore | LifetimeElisionCandidate::Named => {}
         }