migrate the rest of weak_lang_items.rs to translateable diagnostics

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

@@ -358,6 +358,9 @@ passes_deprecated_annotation_has_no_effect =
     this `#[deprecated]` annotation has no effect
     .suggestion = remove the unnecessary deprecation attribute
     
+passes_unknown_external_lang_item =
+    unknown external lang item: `{$lang_item}`
+
 passes_missing_panic_handler =
     `#[panic_handler]` function required, but not found
 
@@ -384,6 +387,3 @@ passes_local_duplicate_lang_item =
 passes_invalid_attr_at_crate_level =
     `{$name}` attribute cannot be used at crate level
     .suggestion = perhaps you meant to use an outer attribute
-
-passes_deprecated_annotation_has_no_effect = this `#[deprecated]` annotation has no effect
-    .suggestion = remove the unnecessary deprecation attribute

compiler/rustc_passes/src/errors.rs

@@ -678,6 +678,14 @@ pub struct DeprecatedAnnotationHasNoEffect {
     pub span: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes::unknown_external_lang_item, code = "E0264")]
+pub struct UnknownExternLangItem {
+    #[primary_span]
+    pub span: Span,
+    pub lang_item: Symbol,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes::missing_panic_handler)]
 pub struct MissingPanicHandler;
@@ -744,10 +752,3 @@ impl IntoDiagnostic<'_> for InvalidAttrAtCrateLevel {
         diag
     }
 }
-
-#[derive(LintDiagnostic)]
-#[diag(passes::deprecated_annotation_has_no_effect)]
-pub struct DeprecatedAnnotationHasNoEffect {
-    #[suggestion(applicability = "machine-applicable", code = "")]
-    pub span: Span,
-}

compiler/rustc_passes/src/weak_lang_items.rs

@@ -1,14 +1,15 @@
 //! Validity checking for weak lang items
 
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::struct_span_err;
 use rustc_hir::lang_items::{self, LangItem};
 use rustc_hir::weak_lang_items::WEAK_ITEMS_REFS;
 use rustc_middle::middle::lang_items::required;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::CrateType;
 
-use crate::errors::{MissingAllocErrorHandler, MissingLangItem, MissingPanicHandler};
+use crate::errors::{
+    MissingAllocErrorHandler, MissingLangItem, MissingPanicHandler, UnknownExternLangItem,
+};
 
 /// Checks the crate for usage of weak lang items, returning a vector of all the
 /// language items required by this crate, but not defined yet.
@@ -33,14 +34,7 @@ pub fn check_crate<'tcx>(tcx: TyCtxt<'tcx>, items: &mut lang_items::LanguageItem
                 }
             } else {
                 let span = tcx.def_span(id.def_id);
-                struct_span_err!(
-                    tcx.sess,
-                    span,
-                    E0264,
-                    "unknown external lang item: `{}`",
-                    lang_item
-                )
-                .emit();
+                tcx.sess.emit_err(UnknownExternLangItem { span, lang_item });
             }
         }
     }