Rollup of 7 pull requests

.mailmap

@@ -205,6 +205,10 @@ Gareth Daniel Smith <garethdanielsmith@gmail.com> gareth <gareth@gareth-N56VM.(n
 Gareth Daniel Smith <garethdanielsmith@gmail.com> Gareth Smith <garethdanielsmith@gmail.com>
 Gauri Kholkar <f2013002@goa.bits-pilani.ac.in>
 Georges Dubus <georges.dubus@gmail.com> <georges.dubus@compiletoi.net>
+Ghost <ghost> <jonasschievink@gmail.com>
+Ghost <ghost> <jonas.schievink@ferrous-systems.com>
+Ghost <ghost> <jonas@schievink.net>
+Ghost <ghost> <Jonas.Schievink@sony.com>
 Giles Cope <gilescope@gmail.com>
 Glen De Cauwsemaecker <decauwsemaecker.glen@gmail.com>
 Graham Fawcett <graham.fawcett@gmail.com> Graham Fawcett <fawcett@uwindsor.ca>

compiler/rustc_error_codes/src/error_codes/E0401.md

@@ -1,4 +1,4 @@
-Inner items do not inherit type or const parameters from the functions
+Inner items do not inherit the generic parameters from the items
 they are embedded in.
 
 Erroneous code example:
@@ -32,8 +32,8 @@ fn foo<T>(x: T) {
 }
 ```
 
-Items inside functions are basically just like top-level items, except
-that they can only be used from the function they are in.
+Items nested inside other items are basically just like top-level items, except
+that they can only be used from the item they are in.
 
 There are a couple of solutions for this.
 

compiler/rustc_hir_typeck/src/generator_interior/mod.rs

@@ -643,17 +643,14 @@ fn check_must_not_suspend_ty<'tcx>(
         }
         ty::Array(ty, len) => {
             let descr_pre = &format!("{}array{} of ", data.descr_pre, plural_suffix);
+            let target_usize =
+                len.try_eval_target_usize(fcx.tcx, fcx.param_env).unwrap_or(0) as usize;
+            let plural_len = target_usize.saturating_add(1);
             check_must_not_suspend_ty(
                 fcx,
                 ty,
                 hir_id,
-                SuspendCheckData {
-                    descr_pre,
-                    plural_len: len.try_eval_target_usize(fcx.tcx, fcx.param_env).unwrap_or(0)
-                        as usize
-                        + 1,
-                    ..data
-                },
+                SuspendCheckData { descr_pre, plural_len, ..data },
             )
         }
         // If drop tracking is enabled, we want to look through references, since the referent

compiler/rustc_lint/src/late.rs

@@ -21,7 +21,6 @@ use rustc_data_structures::sync::join;
 use rustc_hir as hir;
 use rustc_hir::def_id::{LocalDefId, LocalModDefId};
 use rustc_hir::intravisit as hir_visit;
-use rustc_hir::intravisit::Visitor;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint::LintPass;
@@ -61,6 +60,9 @@ impl<'tcx, T: LateLintPass<'tcx>> LateContextAndPass<'tcx, T> {
         self.context.last_node_with_lint_attrs = id;
         debug!("late context: enter_attrs({:?})", attrs);
         lint_callback!(self, enter_lint_attrs, attrs);
+        for attr in attrs {
+            lint_callback!(self, check_attribute, attr);
+        }
         f(self);
         debug!("late context: exit_attrs({:?})", attrs);
         lint_callback!(self, exit_lint_attrs, attrs);
@@ -377,20 +379,18 @@ fn late_lint_mod_inner<'tcx, T: LateLintPass<'tcx>>(
 
     let (module, _span, hir_id) = tcx.hir().get_module(module_def_id);
 
-    // There is no module lint that will have the crate itself as an item, so check it here.
-    if hir_id == hir::CRATE_HIR_ID {
-        lint_callback!(cx, check_crate,);
-    }
+    cx.with_lint_attrs(hir_id, |cx| {
+        // There is no module lint that will have the crate itself as an item, so check it here.
+        if hir_id == hir::CRATE_HIR_ID {
+            lint_callback!(cx, check_crate,);
+        }
 
-    cx.process_mod(module, hir_id);
+        cx.process_mod(module, hir_id);
 
-    // Visit the crate attributes
-    if hir_id == hir::CRATE_HIR_ID {
-        for attr in tcx.hir().attrs(hir::CRATE_HIR_ID).iter() {
-            cx.visit_attribute(attr)
+        if hir_id == hir::CRATE_HIR_ID {
+            lint_callback!(cx, check_crate_post,);
         }
-        lint_callback!(cx, check_crate_post,);
-    }
+    });
 }
 
 fn late_lint_crate<'tcx>(tcx: TyCtxt<'tcx>) {
@@ -431,7 +431,6 @@ fn late_lint_crate_inner<'tcx, T: LateLintPass<'tcx>>(
         // item), warn for it here.
         lint_callback!(cx, check_crate,);
         tcx.hir().walk_toplevel_module(cx);
-        tcx.hir().walk_attributes(cx);
         lint_callback!(cx, check_crate_post,);
     })
 }

compiler/rustc_middle/src/ty/trait_def.rs

@@ -90,6 +90,10 @@ pub struct TraitImpls {
 }
 
 impl TraitImpls {
+    pub fn is_empty(&self) -> bool {
+        self.blanket_impls.is_empty() && self.non_blanket_impls.is_empty()
+    }
+
     pub fn blanket_impls(&self) -> &[DefId] {
         self.blanket_impls.as_slice()
     }

compiler/rustc_resolve/messages.ftl

@@ -68,9 +68,6 @@ 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
 
@@ -90,9 +87,6 @@ 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
 
@@ -119,10 +113,19 @@ 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
@@ -277,9 +280,6 @@ 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
 
@@ -315,9 +315,6 @@ 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

@@ -553,53 +553,47 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
         resolution_error: ResolutionError<'a>,
     ) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
         match resolution_error {
-            ResolutionError::GenericParamsFromOuterFunction(outer_res, has_generic_params) => {
-                let mut err = struct_span_err!(
-                    self.tcx.sess,
+            ResolutionError::GenericParamsFromOuterItem(outer_res, has_generic_params) => {
+                use errs::GenericParamsFromOuterItemLabel as Label;
+                let mut err = errs::GenericParamsFromOuterItem {
                     span,
-                    E0401,
-                    "can't use generic parameters from outer function",
-                );
-                err.span_label(span, "use of generic parameter from outer function");
+                    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, "use a type 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 function");
+                        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 function",
-                        );
+                        err.label = Some(Label::ConstParam(self.def_span(def_id)));
                         def_id
                     }
                     _ => {
                         bug!(
-                            "GenericParamsFromOuterFunction should only be used with \
+                            "GenericParamsFromOuterItem should only be used with \
                             Res::SelfTyParam, Res::SelfTyAlias, DefKind::TyParam or \
                             DefKind::ConstParam"
                         );
                     }
                 };
 
                 if let HasGenericParams::Yes(span) = has_generic_params {
-                    // Try to retrieve the span of the function signature and generate a new
-                    // message with a local type or const parameter.
-                    let sugg_msg = "try using a local generic parameter instead";
                     let name = self.tcx.item_name(def_id);
                     let (span, snippet) = if span.is_empty() {
                         let snippet = format!("<{name}>");
@@ -609,11 +603,10 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                         let snippet = format!("{name}, ");
                         (span, snippet)
                     };
-                    // Suggest the modification to the user
-                    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 {

compiler/rustc_resolve/src/ident.rs

@@ -1229,10 +1229,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                     if let Some(span) = finalize {
                         self.report_error(
                             span,
-                            ResolutionError::GenericParamsFromOuterFunction(
-                                res,
-                                has_generic_params,
-                            ),
+                            ResolutionError::GenericParamsFromOuterItem(res, has_generic_params),
                         );
                     }
                     return Res::Err;
@@ -1296,10 +1293,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                     if let Some(span) = finalize {
                         self.report_error(
                             span,
-                            ResolutionError::GenericParamsFromOuterFunction(
-                                res,
-                                has_generic_params,
-                            ),
+                            ResolutionError::GenericParamsFromOuterItem(res, has_generic_params),
                         );
                     }
                     return Res::Err;

compiler/rustc_resolve/src/late.rs

@@ -2450,7 +2450,11 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             ItemKind::Const(box ast::ConstItem { ref generics, ref ty, ref expr, .. }) => {
                 self.with_generic_param_rib(
                     &generics.params,
-                    RibKind::Item(HasGenericParams::Yes(generics.span)),
+                    RibKind::Item(if self.r.tcx.features().generic_const_items {
+                        HasGenericParams::Yes(generics.span)
+                    } else {
+                        HasGenericParams::No
+                    }),
                     LifetimeRibKind::Generics {
                         binder: item.id,
                         kind: LifetimeBinderKind::ConstItem,

compiler/rustc_resolve/src/lib.rs

@@ -186,8 +186,8 @@ struct BindingError {
 
 #[derive(Debug)]
 enum ResolutionError<'a> {
-    /// Error E0401: can't use type or const parameters from outer function.
-    GenericParamsFromOuterFunction(Res, HasGenericParams),
+    /// Error E0401: can't use type or const parameters from outer item.
+    GenericParamsFromOuterItem(Res, HasGenericParams),
     /// Error E0403: the name is already used for a type or const parameter in this generic
     /// parameter list.
     NameAlreadyUsedInParameterList(Symbol, Span),

compiler/rustc_trait_selection/messages.ftl

@@ -40,5 +40,7 @@ trait_selection_no_value_in_rustc_on_unimplemented = this attribute must have a
     .label = expected value here
     .note = eg `#[rustc_on_unimplemented(message="foo")]`
 
+trait_selection_trait_has_no_impls = this trait has no implementations, consider adding one
+
 trait_selection_ty_alias_overflow = in case this is a recursive type alias, consider using a struct, enum, or union instead
 trait_selection_unable_to_construct_constant_value = unable to construct a constant value for the unevaluated constant {$unevaluated}