Migrate derivable diagnostics in lang_items.rs

Author: naritanara

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

@@ -274,3 +274,11 @@ passes_missing_alloc_error_handler = `#[alloc_error_handler]` function required,
 passes_missing_lang_item = language item required, but not found: `{$name}`
     .note = this can occur when a binary crate with `#![no_std]` is compiled for a target where `{$name}` is defined in the standard library
     .help = you may be able to compile for a target that doesn't need `{$name}`, specify a target with `--target` or in `.cargo/config`
+
+passes_lang_item_on_incorrect_target = `{$name}` language item must be applied to a {$expected_target}
+    .label = attribute should be applied to a {$expected_target}, not a {$actual_target}
+
+passes_unknown_lang_item = definition of an unknown language item: `{$name}`
+    .label = definition of unknown language item `{$name}`
+
+passes_local_duplicate_lang_item = found duplicate lang item `{$name}`

compiler/rustc_passes/src/errors.rs

@@ -1,4 +1,5 @@
 use rustc_errors::{Applicability, MultiSpan};
+use rustc_hir::Target;
 use rustc_macros::{LintDiagnostic, SessionDiagnostic, SessionSubdiagnostic};
 use rustc_span::{Span, Symbol};
 
@@ -666,3 +667,23 @@ pub struct MissingAllocErrorHandler;
 pub struct MissingLangItem {
     pub name: Symbol,
 }
+
+#[derive(SessionDiagnostic)]
+#[diag(passes::lang_item_on_incorrect_target, code = "E0718")]
+pub struct LangItemOnIncorrectTarget {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub name: Symbol,
+    pub expected_target: Target,
+    pub actual_target: Target,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(passes::unknown_lang_item, code = "E0522")]
+pub struct UnknownLangItem {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub name: Symbol,
+}

compiler/rustc_passes/src/lang_items.rs

@@ -7,6 +7,7 @@
 //! * Traits that represent operators; e.g., `Add`, `Sub`, `Index`.
 //! * Functions called by the compiler itself.
 
+use crate::errors::{LangItemOnIncorrectTarget, UnknownLangItem};
 use crate::check_attr::target_from_impl_item;
 use crate::weak_lang_items;
 
@@ -42,34 +43,19 @@ impl<'tcx> LanguageItemCollector<'tcx> {
                 }
                 // Known lang item with attribute on incorrect target.
                 Some((_, expected_target)) => {
-                    struct_span_err!(
-                        self.tcx.sess,
+                    self.tcx.sess.emit_err(LangItemOnIncorrectTarget {
                         span,
-                        E0718,
-                        "`{}` language item must be applied to a {}",
-                        value,
+                        name: value,
                         expected_target,
-                    )
-                    .span_label(
-                        span,
-                        format!(
-                            "attribute should be applied to a {}, not a {}",
-                            expected_target, actual_target,
-                        ),
-                    )
-                    .emit();
+                        actual_target,
+                    });
                 }
                 // Unknown lang item.
                 _ => {
-                    struct_span_err!(
-                        self.tcx.sess,
+                    self.tcx.sess.emit_err(UnknownLangItem {
                         span,
-                        E0522,
-                        "definition of an unknown language item: `{}`",
-                        value
-                    )
-                    .span_label(span, format!("definition of unknown language item `{}`", value))
-                    .emit();
+                        name: value,
+                    });
                 }
             }
         }