4 files changed, 25 insertions, 2 deletions
diff --git a/compiler/rustc_resolve/messages.ftl b/compiler/rustc_resolve/messages.ftl
index 1c0e5ad65b3..32833f5e8d9 100644
--- a/compiler/rustc_resolve/messages.ftl
+++ b/compiler/rustc_resolve/messages.ftl
@@ -231,6 +231,9 @@ resolve_item_was_cfg_out = the item is gated here
 resolve_label_with_similar_name_reachable =
     a label with a similar name is reachable
 
+resolve_legacy_derive_helpers = derive helper attribute is used before it is introduced
+    .label = the attribute is introduced here
+
 resolve_lending_iterator_report_error =
     associated type `Iterator::Item` is declared without lifetime parameters, so using a borrowed type for them requires that lifetime to come from the implemented type
     .note = you can't create an `Iterator` that borrows each `Item` from itself, but you can instead create a new type that borrows your existing type and implement `Iterator` for that new type
@@ -471,6 +474,10 @@ resolve_unreachable_label_suggestion_use_similarly_named =
 resolve_unreachable_label_with_similar_name_exists =
     a label with a similar name exists but is unreachable
 
+resolve_unused_extern_crate = unused extern crate
+    .label = unused
+    .suggestion = remove the unused `extern crate`
+
 resolve_variable_bound_with_different_mode =
     variable `{$variable_name}` is bound inconsistently across alternatives separated by `|`
     .label = bound in different ways
diff --git a/compiler/rustc_resolve/src/check_unused.rs b/compiler/rustc_resolve/src/check_unused.rs
index 50a1ad23a54..a80cd7540af 100644
--- a/compiler/rustc_resolve/src/check_unused.rs
+++ b/compiler/rustc_resolve/src/check_unused.rs
@@ -169,7 +169,7 @@ impl<'a, 'ra, 'tcx> UnusedImportCheckVisitor<'a, 'ra, 'tcx> {
                         UNUSED_EXTERN_CRATES,
                         extern_crate.id,
                         span,
-                        BuiltinLintDiag::UnusedExternCrate {
+                        crate::errors::UnusedExternCrate {
                             span: extern_crate.span,
                             removal_span: extern_crate.span_with_attributes,
                         },
diff --git a/compiler/rustc_resolve/src/errors.rs b/compiler/rustc_resolve/src/errors.rs
index fb77b9ca1d3..6b36906c865 100644
--- a/compiler/rustc_resolve/src/errors.rs
+++ b/compiler/rustc_resolve/src/errors.rs
@@ -1292,3 +1292,19 @@ pub(crate) struct TraitImplMismatch {
     #[label(resolve_trait_impl_mismatch_label_item)]
     pub(crate) trait_item_span: Span,
 }
+
+#[derive(LintDiagnostic)]
+#[diag(resolve_legacy_derive_helpers)]
+pub(crate) struct LegacyDeriveHelpers {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(resolve_unused_extern_crate)]
+pub(crate) struct UnusedExternCrate {
+    #[label]
+    pub span: Span,
+    #[suggestion(code = "", applicability = "machine-applicable", style = "verbose")]
+    pub removal_span: Span,
+}
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 5fa87b4cd9b..d3e98ef839b 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -979,7 +979,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             LEGACY_DERIVE_HELPERS,
                             node_id,
                             ident.span,
-                            BuiltinLintDiag::LegacyDeriveHelpers(binding.span),
+                            errors::LegacyDeriveHelpers { span: binding.span },
                         );
                     }
                 }