Make E0401 translatable

Author: fmease

compiler/rustc_resolve/messages.ftl

@@ -64,9 +64,6 @@ resolve_cannot_find_ident_in_this_scope =
 resolve_cannot_glob_import_possible_crates =
     cannot glob-import all possible crates
 
-resolve_cannot_use_self_type_here =
-    can't use `Self` here
-
 resolve_change_import_binding =
     you can use `as` to change the binding name of the import
 
@@ -86,9 +83,6 @@ resolve_const_not_member_of_trait =
     const `{$const_}` is not a member of trait `{$trait_}`
     .label = not a member of trait `{$trait_}`
 
-resolve_const_param_from_outer_fn =
-    const parameter from outer function
-
 resolve_const_param_in_enum_discriminant =
     const parameters may not be used in enum discriminant values
 
@@ -115,10 +109,19 @@ resolve_forward_declared_generic_param =
     generic parameters with a default cannot use forward declared identifiers
     .label = defaulted generic parameters cannot be forward declared
 
-resolve_generic_params_from_outer_function =
-    can't use generic parameters from outer function
-    .label = use of generic parameter from outer function
-    .suggestion = try using a local generic parameter instead
+resolve_generic_params_from_outer_item =
+    can't use generic parameters from outer item
+    .label = use of generic parameter from outer item
+    .refer_to_type_directly = refer to the type directly here instead
+    .suggestion = try introducing a local generic parameter here
+
+resolve_generic_params_from_outer_item_const_param = const parameter from outer item
+
+resolve_generic_params_from_outer_item_self_ty_alias = `Self` type implicitly declared here, by this `impl`
+
+resolve_generic_params_from_outer_item_self_ty_param = can't use `Self` here
+
+resolve_generic_params_from_outer_item_ty_param = type parameter from outer item
 
 resolve_glob_import_doesnt_reexport =
     glob import doesn't reexport anything because no candidate is public enough
@@ -273,9 +276,6 @@ resolve_type_not_member_of_trait =
     type `{$type_}` is not a member of trait `{$trait_}`
     .label = not a member of trait `{$trait_}`
 
-resolve_type_param_from_outer_fn =
-    type parameter from outer function
-
 resolve_type_param_in_enum_discriminant =
     type parameters may not be used in enum discriminant values
 
@@ -311,9 +311,6 @@ 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_use_a_type_here_instead =
-    use a type here instead
-
 resolve_variable_bound_with_different_mode =
     variable `{$variable_name}` is bound inconsistently across alternatives separated by `|`
     .label = bound in different ways

compiler/rustc_resolve/src/diagnostics.rs

@@ -554,34 +554,34 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
     ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
         match resolution_error {
             ResolutionError::GenericParamsFromOuterItem(outer_res, has_generic_params) => {
-                let mut err = struct_span_err!(
-                    self.tcx.sess,
+                use errs::GenericParamsFromOuterItemLabel as Label;
+                let mut err = errs::GenericParamsFromOuterItem {
                     span,
-                    E0401,
-                    "can't use generic parameters from outer item",
-                );
-                err.span_label(span, "use of generic parameter from outer item");
+                    label: None,
+                    refer_to_type_directly: None,
+                    sugg: None,
+                };
 
                 let sm = self.tcx.sess.source_map();
                 let def_id = match outer_res {
                     Res::SelfTyParam { .. } => {
-                        err.span_label(span, "can't use `Self` here");
-                        return err;
+                        err.label = Some(Label::SelfTyParam(span));
+                        return self.tcx.sess.create_err(err);
                     }
                     Res::SelfTyAlias { alias_to: def_id, .. } => {
-                        err.span_label(
-                            reduce_impl_span_to_impl_keyword(sm, self.def_span(def_id)),
-                            "`Self` type implicitly declared here, by this `impl`",
-                        );
-                        err.span_label(span, "refer to the type directly here instead");
-                        return err;
+                        err.label = Some(Label::SelfTyAlias(reduce_impl_span_to_impl_keyword(
+                            sm,
+                            self.def_span(def_id),
+                        )));
+                        err.refer_to_type_directly = Some(span);
+                        return self.tcx.sess.create_err(err);
                     }
                     Res::Def(DefKind::TyParam, def_id) => {
-                        err.span_label(self.def_span(def_id), "type parameter from outer item");
+                        err.label = Some(Label::TyParam(self.def_span(def_id)));
                         def_id
                     }
                     Res::Def(DefKind::ConstParam, def_id) => {
-                        err.span_label(self.def_span(def_id), "const parameter from outer item");
+                        err.label = Some(Label::ConstParam(self.def_span(def_id)));
                         def_id
                     }
                     _ => {
@@ -594,7 +594,6 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 };
 
                 if let HasGenericParams::Yes(span) = has_generic_params {
-                    let sugg_msg = "try introducing a local generic parameter here";
                     let name = self.tcx.item_name(def_id);
                     let (span, snippet) = if span.is_empty() {
                         let snippet = format!("<{name}>");
@@ -604,10 +603,10 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                         let snippet = format!("{name}, ");
                         (span, snippet)
                     };
-                    err.span_suggestion(span, sugg_msg, snippet, Applicability::MaybeIncorrect);
+                    err.sugg = Some(errs::GenericParamsFromOuterItemSugg { span, snippet });
                 }
 
-                err
+                self.tcx.sess.create_err(err)
             }
             ResolutionError::NameAlreadyUsedInParameterList(name, first_use_span) => self
                 .tcx

compiler/rustc_resolve/src/errors.rs

@@ -32,6 +32,40 @@ pub(crate) struct CrateRootNamesMustBeNamedExplicitly(#[primary_span] pub(crate)
 #[diag(resolve_crate_root_imports_must_be_named_explicitly)]
 pub(crate) struct ResolutionError(#[primary_span] pub(crate) Span);
 
+#[derive(Diagnostic)]
+#[diag(resolve_generic_params_from_outer_item, code = "E0401")]
+pub(crate) struct GenericParamsFromOuterItem {
+    #[primary_span]
+    #[label]
+    pub(crate) span: Span,
+    #[subdiagnostic]
+    pub(crate) label: Option<GenericParamsFromOuterItemLabel>,
+    #[label(resolve_refer_to_type_directly)]
+    pub(crate) refer_to_type_directly: Option<Span>,
+    #[subdiagnostic]
+    pub(crate) sugg: Option<GenericParamsFromOuterItemSugg>,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum GenericParamsFromOuterItemLabel {
+    #[label(resolve_generic_params_from_outer_item_self_ty_param)]
+    SelfTyParam(#[primary_span] Span),
+    #[label(resolve_generic_params_from_outer_item_self_ty_alias)]
+    SelfTyAlias(#[primary_span] Span),
+    #[label(resolve_generic_params_from_outer_item_ty_param)]
+    TyParam(#[primary_span] Span),
+    #[label(resolve_generic_params_from_outer_item_const_param)]
+    ConstParam(#[primary_span] Span),
+}
+
+#[derive(Subdiagnostic)]
+#[suggestion(resolve_suggestion, code = "{snippet}", applicability = "maybe-incorrect")]
+pub(crate) struct GenericParamsFromOuterItemSugg {
+    #[primary_span]
+    pub(crate) span: Span,
+    pub(crate) snippet: String,
+}
+
 #[derive(Diagnostic)]
 #[diag(resolve_name_is_already_used_as_generic_parameter, code = "E0403")]
 pub(crate) struct NameAlreadyUsedInParameterList {