migrate: OverruledAttribute

compiler/rustc_error_messages/locales/en-US/lint.ftl

@@ -394,6 +394,16 @@ lint_builtin_deref_nullptr = dereferencing a null pointer
 
 lint_builtin_asm_labels = avoid using named labels in inline assembly
 
+lint_overruled_attribute = {$lint_level}({$lint_source}) incompatible with previous forbid
+    .label = overruled by previous forbid
+
+lint_default_source = `forbid` lint level is the default for {$id}
+
+lint_node_source = `forbid` level set here
+    .note = {$reason}
+
+lint_command_line_source = `forbid` lint level was set on command line
+
 lint_malformed_attribute = malformed lint attribute input
 
 lint_bad_attribute_argument = bad attribute argument

compiler/rustc_lint/src/errors.rs

@@ -1,6 +1,46 @@
+use rustc_errors::{fluent, AddSubdiagnostic};
 use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
 use rustc_span::{Span, Symbol};
 
+#[derive(SessionDiagnostic)]
+#[error(lint::overruled_attribute, code = "E0453")]
+pub struct OverruledAttribute {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub overruled: Span,
+    pub lint_level: String,
+    pub lint_source: Symbol,
+    #[subdiagnostic]
+    pub sub: OverruledAttributeSub,
+}
+//
+pub enum OverruledAttributeSub {
+    DefaultSource { id: String },
+    NodeSource { span: Span, reason: Option<Symbol> },
+    CommandLineSource,
+}
+
+impl AddSubdiagnostic for OverruledAttributeSub {
+    fn add_to_diagnostic(self, diag: &mut rustc_errors::Diagnostic) {
+        match self {
+            OverruledAttributeSub::DefaultSource { id } => {
+                diag.note(fluent::lint::default_source);
+                diag.set_arg("id", id);
+            }
+            OverruledAttributeSub::NodeSource { span, reason } => {
+                diag.span_label(span, fluent::lint::node_source);
+                if let Some(rationale) = reason {
+                    diag.note(rationale.as_str());
+                }
+            }
+            OverruledAttributeSub::CommandLineSource => {
+                diag.note(fluent::lint::command_line_source);
+            }
+        }
+    }
+}
+
 #[derive(SessionDiagnostic)]
 #[error(lint::malformed_attribute, code = "E0452")]
 pub struct MalformedAttribute {

compiler/rustc_lint/src/levels.rs

@@ -6,7 +6,7 @@ use crate::late::unerased_lint_store;
 use rustc_ast as ast;
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::{struct_span_err, Applicability, Diagnostic, LintDiagnosticBuilder, MultiSpan};
+use rustc_errors::{Applicability, Diagnostic, LintDiagnosticBuilder, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::{intravisit, HirId};
 use rustc_middle::hir::nested_filter;
@@ -26,7 +26,10 @@ use rustc_span::symbol::{sym, Symbol};
 use rustc_span::{Span, DUMMY_SP};
 use tracing::debug;
 
-use crate::errors::{MalformedAttribute, MalformedAttributeSub, UnknownTool};
+use crate::errors::{
+    MalformedAttribute, MalformedAttributeSub, OverruledAttribute, OverruledAttributeSub,
+    UnknownTool,
+};
 
 fn lint_levels(tcx: TyCtxt<'_>, (): ()) -> LintLevelMap {
     let store = unerased_lint_store(tcx);
@@ -191,16 +194,26 @@ impl<'s> LintLevelsBuilder<'s> {
                     }
                 };
                 if !fcw_warning {
-                    let mut diag_builder = struct_span_err!(
-                        self.sess,
-                        src.span(),
-                        E0453,
-                        "{}({}) incompatible with previous forbid",
-                        level.as_str(),
-                        src.name(),
-                    );
-                    decorate_diag(&mut diag_builder);
-                    diag_builder.emit();
+                    self.sess.emit_err(OverruledAttribute {
+                        span: src.span(),
+                        overruled: src.span(),
+                        lint_level: level.as_str().to_string(),
+                        lint_source: src.name(),
+                        sub: match old_src {
+                            LintLevelSource::Default => {
+                                OverruledAttributeSub::DefaultSource { id: id.to_string() }
+                            }
+                            LintLevelSource::Node(_, forbid_source_span, reason) => {
+                                OverruledAttributeSub::NodeSource {
+                                    span: forbid_source_span,
+                                    reason,
+                                }
+                            }
+                            LintLevelSource::CommandLine(_, _) => {
+                                OverruledAttributeSub::CommandLineSource
+                            }
+                        },
+                    });
                 } else {
                     self.struct_lint(
                         FORBIDDEN_LINT_GROUPS,