Auto merge of #124289 - matthiaskrgr:rollup-oxw52jy, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #123050 (panic_str only exists for the migration to 2021 panic macros)
 - #124067 (weak lang items are not allowed to be #[track_caller])
 - #124099 (Disallow ambiguous attributes on expressions)
 - #124284 (parser: remove unused(no reads) max_angle_bracket_count field)
 - #124288 (remove `push_trait_bound_inner`)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_error_codes/src/error_codes/E0522.md

@@ -6,7 +6,7 @@ Erroneous code example:
 #![feature(lang_items)]
 
 #[lang = "cookie"]
-fn cookie() -> ! { // error: definition of an unknown language item: `cookie`
+fn cookie() -> ! { // error: definition of an unknown lang item: `cookie`
     loop {}
 }
 ```

compiler/rustc_feature/src/builtin_attrs.rs

@@ -798,7 +798,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     // ==========================================================================
     gated!(
         lang, Normal, template!(NameValueStr: "name"), DuplicatesOk, EncodeCrossCrate::No, lang_items,
-        "language items are subject to change",
+        "lang items are subject to change",
     ),
     rustc_attr!(
         rustc_pass_by_value, Normal, template!(Word), ErrorFollowing,

compiler/rustc_hir/src/lang_items.rs

@@ -1,4 +1,4 @@
-//! Defines language items.
+//! Defines lang items.
 //!
 //! Language items are items that represent concepts intrinsic to the language
 //! itself. Examples are:
@@ -16,7 +16,7 @@ use rustc_macros::HashStable_Generic;
 use rustc_span::symbol::{kw, sym, Symbol};
 use rustc_span::Span;
 
-/// All of the language items, defined or not.
+/// All of the lang items, defined or not.
 /// Defined lang items can come from the current crate or its dependencies.
 #[derive(HashStable_Generic, Debug)]
 pub struct LanguageItems {
@@ -57,7 +57,7 @@ macro_rules! language_item_table {
     ) => {
 
         enum_from_u32! {
-            /// A representation of all the valid language items in Rust.
+            /// A representation of all the valid lang items in Rust.
             #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable)]
             pub enum LangItem {
                 $(
@@ -177,7 +177,7 @@ language_item_table! {
     CoerceUnsized,           sym::coerce_unsized,      coerce_unsized_trait,       Target::Trait,          GenericRequirement::Minimum(1);
     DispatchFromDyn,         sym::dispatch_from_dyn,   dispatch_from_dyn_trait,    Target::Trait,          GenericRequirement::Minimum(1);
 
-    // language items relating to transmutability
+    // lang items relating to transmutability
     TransmuteOpts,           sym::transmute_opts,      transmute_opts,             Target::Struct,         GenericRequirement::Exact(0);
     TransmuteTrait,          sym::transmute_trait,     transmute_trait,            Target::Trait,          GenericRequirement::Exact(2);
 
@@ -304,7 +304,7 @@ language_item_table! {
     OwnedBox,                sym::owned_box,           owned_box,                  Target::Struct,         GenericRequirement::Minimum(1);
     GlobalAlloc,             sym::global_alloc_ty,     global_alloc_ty,            Target::Struct,         GenericRequirement::None;
 
-    // Experimental language item for Miri
+    // Experimental lang item for Miri
     PtrUnique,               sym::ptr_unique,          ptr_unique,                 Target::Struct,         GenericRequirement::Exact(1);
 
     PhantomData,             sym::phantom_data,        phantom_data,               Target::Struct,         GenericRequirement::Exact(1);

compiler/rustc_hir_analysis/src/bounds.rs

@@ -43,16 +43,6 @@ impl<'tcx> Bounds<'tcx> {
         trait_ref: ty::PolyTraitRef<'tcx>,
         span: Span,
         polarity: ty::PredicatePolarity,
-    ) {
-        self.push_trait_bound_inner(tcx, trait_ref, span, polarity);
-    }
-
-    fn push_trait_bound_inner(
-        &mut self,
-        tcx: TyCtxt<'tcx>,
-        trait_ref: ty::PolyTraitRef<'tcx>,
-        span: Span,
-        polarity: ty::PredicatePolarity,
     ) {
         let clause = (
             trait_ref

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -535,20 +535,20 @@ pub fn check_intrinsic_type(
 
             sym::va_start | sym::va_end => match mk_va_list_ty(hir::Mutability::Mut) {
                 Some((va_list_ref_ty, _)) => (0, 0, vec![va_list_ref_ty], Ty::new_unit(tcx)),
-                None => bug!("`va_list` language item needed for C-variadic intrinsics"),
+                None => bug!("`va_list` lang item needed for C-variadic intrinsics"),
             },
 
             sym::va_copy => match mk_va_list_ty(hir::Mutability::Not) {
                 Some((va_list_ref_ty, va_list_ty)) => {
                     let va_list_ptr_ty = Ty::new_mut_ptr(tcx, va_list_ty);
                     (0, 0, vec![va_list_ptr_ty, va_list_ref_ty], Ty::new_unit(tcx))
                 }
-                None => bug!("`va_list` language item needed for C-variadic intrinsics"),
+                None => bug!("`va_list` lang item needed for C-variadic intrinsics"),
             },
 
             sym::va_arg => match mk_va_list_ty(hir::Mutability::Mut) {
                 Some((va_list_ref_ty, _)) => (1, 0, vec![va_list_ref_ty], param(0)),
-                None => bug!("`va_list` language item needed for C-variadic intrinsics"),
+                None => bug!("`va_list` lang item needed for C-variadic intrinsics"),
             },
 
             sym::nontemporal_store => {

compiler/rustc_lint/src/non_fmt_panic.rs

@@ -53,7 +53,7 @@ impl<'tcx> LateLintPass<'tcx> for NonPanicFmt {
 
                 if Some(def_id) == cx.tcx.lang_items().begin_panic_fn()
                     || Some(def_id) == cx.tcx.lang_items().panic_fn()
-                    || f_diagnostic_name == Some(sym::panic_str)
+                    || f_diagnostic_name == Some(sym::panic_str_2015)
                 {
                     if let Some(id) = f.span.ctxt().outer_expn_data().macro_def_id {
                         if matches!(

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -1208,7 +1208,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         tcx.arena.alloc_from_iter(self.root.stability_implications.decode(self))
     }
 
-    /// Iterates over the language items in the given crate.
+    /// Iterates over the lang items in the given crate.
     fn get_lang_items(self, tcx: TyCtxt<'tcx>) -> &'tcx [(DefId, LangItem)] {
         tcx.arena.alloc_from_iter(
             self.root

compiler/rustc_middle/src/middle/lang_items.rs

@@ -1,4 +1,4 @@
-//! Detecting language items.
+//! Detecting lang items.
 //!
 //! Language items are items that represent concepts intrinsic to the language
 //! itself. Examples are:

compiler/rustc_mir_transform/src/deduce_param_attrs.rs

@@ -160,7 +160,7 @@ pub fn deduced_param_attrs<'tcx>(
         return &[];
     }
 
-    // If the Freeze language item isn't present, then don't bother.
+    // If the Freeze lang item isn't present, then don't bother.
     if tcx.lang_items().freeze_trait().is_none() {
         return &[];
     }

compiler/rustc_mir_transform/src/lower_slice_len.rs

@@ -21,7 +21,7 @@ impl<'tcx> MirPass<'tcx> for LowerSliceLenCalls {
 pub fn lower_slice_len_calls<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let language_items = tcx.lang_items();
     let Some(slice_len_fn_item_def_id) = language_items.slice_len_fn() else {
-        // there is no language item to compare to :)
+        // there is no lang item to compare to :)
         return;
     };
 

compiler/rustc_parse/messages.ftl

@@ -624,6 +624,8 @@ parse_or_pattern_not_allowed_in_let_binding = top-level or-patterns are not allo
 parse_out_of_range_hex_escape = out of range hex escape
     .label = must be a character in the range [\x00-\x7f]
 
+parse_outer_attr_ambiguous = ambiguous outer attributes
+
 parse_outer_attr_explanation = outer attributes, like `#[test]`, annotate the item following them
 
 parse_outer_attribute_not_allowed_on_if_else = outer attributes are not allowed on `if` and `else` branches

compiler/rustc_parse/src/errors.rs

@@ -495,6 +495,15 @@ pub(crate) struct OuterAttributeNotAllowedOnIfElse {
     pub attributes: Span,
 }
 
+#[derive(Diagnostic)]
+#[diag(parse_outer_attr_ambiguous)]
+pub(crate) struct AmbiguousOuterAttributes {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub sugg: WrapInParentheses,
+}
+
 #[derive(Diagnostic)]
 #[diag(parse_missing_in_in_for_loop)]
 pub(crate) struct MissingInInForLoop {

compiler/rustc_parse/src/parser/expr.rs

@@ -327,7 +327,9 @@ impl<'a> Parser<'a> {
                 this.parse_expr_assoc_with(prec + prec_adjustment, LhsExpr::NotYetParsed)
             })?;
 
-            let span = self.mk_expr_sp(&lhs, lhs_span, rhs.span);
+            self.error_ambiguous_outer_attrs(&lhs, lhs_span, rhs.span);
+            let span = lhs_span.to(rhs.span);
+
             lhs = match op {
                 AssocOp::Add
                 | AssocOp::Subtract
@@ -426,6 +428,18 @@ impl<'a> Parser<'a> {
         });
     }
 
+    fn error_ambiguous_outer_attrs(&self, lhs: &P<Expr>, lhs_span: Span, rhs_span: Span) {
+        if let Some(attr) = lhs.attrs.iter().find(|a| a.style == AttrStyle::Outer) {
+            self.dcx().emit_err(errors::AmbiguousOuterAttributes {
+                span: attr.span.to(rhs_span),
+                sugg: errors::WrapInParentheses::Expression {
+                    left: attr.span.shrink_to_lo(),
+                    right: lhs_span.shrink_to_hi(),
+                },
+            });
+        }
+    }
+
     /// Possibly translate the current token to an associative operator.
     /// The method does not advance the current token.
     ///
@@ -506,7 +520,8 @@ impl<'a> Parser<'a> {
             None
         };
         let rhs_span = rhs.as_ref().map_or(cur_op_span, |x| x.span);
-        let span = self.mk_expr_sp(&lhs, lhs.span, rhs_span);
+        self.error_ambiguous_outer_attrs(&lhs, lhs.span, rhs_span);
+        let span = lhs.span.to(rhs_span);
         let limits =
             if op == AssocOp::DotDot { RangeLimits::HalfOpen } else { RangeLimits::Closed };
         let range = self.mk_range(Some(lhs), rhs, limits);
@@ -722,7 +737,8 @@ impl<'a> Parser<'a> {
         expr_kind: fn(P<Expr>, P<Ty>) -> ExprKind,
     ) -> PResult<'a, P<Expr>> {
         let mk_expr = |this: &mut Self, lhs: P<Expr>, rhs: P<Ty>| {
-            this.mk_expr(this.mk_expr_sp(&lhs, lhs_span, rhs.span), expr_kind(lhs, rhs))
+            this.error_ambiguous_outer_attrs(&lhs, lhs_span, rhs.span);
+            this.mk_expr(lhs_span.to(rhs.span), expr_kind(lhs, rhs))
         };
 
         // Save the state of the parser before parsing type normally, in case there is a
@@ -3813,16 +3829,6 @@ impl<'a> Parser<'a> {
         self.mk_expr(span, ExprKind::Err(guar))
     }
 
-    /// Create expression span ensuring the span of the parent node
-    /// is larger than the span of lhs and rhs, including the attributes.
-    fn mk_expr_sp(&self, lhs: &P<Expr>, lhs_span: Span, rhs_span: Span) -> Span {
-        lhs.attrs
-            .iter()
-            .find(|a| a.style == AttrStyle::Outer)
-            .map_or(lhs_span, |a| a.span)
-            .to(rhs_span)
-    }
-
     fn collect_tokens_for_expr(
         &mut self,
         attrs: AttrWrapper,

compiler/rustc_parse/src/parser/mod.rs

@@ -162,7 +162,6 @@ pub struct Parser<'a> {
     ///
     /// See the comments in the `parse_path_segment` function for more details.
     unmatched_angle_bracket_count: u16,
-    max_angle_bracket_count: u16,
     angle_bracket_nesting: u16,
 
     last_unexpected_token_span: Option<Span>,
@@ -430,7 +429,6 @@ impl<'a> Parser<'a> {
             num_bump_calls: 0,
             break_last_token: false,
             unmatched_angle_bracket_count: 0,
-            max_angle_bracket_count: 0,
             angle_bracket_nesting: 0,
             last_unexpected_token_span: None,
             subparser_name,
@@ -778,7 +776,6 @@ impl<'a> Parser<'a> {
         if ate {
             // See doc comment for `unmatched_angle_bracket_count`.
             self.unmatched_angle_bracket_count += 1;
-            self.max_angle_bracket_count += 1;
             debug!("eat_lt: (increment) count={:?}", self.unmatched_angle_bracket_count);
         }
         ate

compiler/rustc_parse/src/parser/path.rs

@@ -299,7 +299,6 @@ impl<'a> Parser<'a> {
                 // parsing a new path.
                 if style == PathStyle::Expr {
                     self.unmatched_angle_bracket_count = 0;
-                    self.max_angle_bracket_count = 0;
                 }
 
                 // Generic arguments are found - `<`, `(`, `::<` or `::(`.

compiler/rustc_passes/messages.ftl

@@ -353,7 +353,7 @@ passes_incorrect_meta_item = expected a quoted string literal
 passes_incorrect_meta_item_suggestion = consider surrounding this with quotes
 
 passes_incorrect_target =
-    `{$name}` language item must be applied to a {$kind} with {$at_least ->
+    `{$name}` lang item must be applied to a {$kind} with {$at_least ->
         [true] at least {$num}
         *[false] {$num}
     } generic {$num ->
@@ -394,12 +394,21 @@ passes_invalid_macro_export_arguments = `{$name}` isn't a valid `#[macro_export]
 
 passes_invalid_macro_export_arguments_too_many_items = `#[macro_export]` can only take 1 or 0 arguments
 
+passes_lang_item_fn = {$name ->
+    [panic_impl] `#[panic_handler]`
+    *[other] `{$name}` lang item
+} function
+
 passes_lang_item_fn_with_target_feature =
-    `{$name}` language item function is not allowed to have `#[target_feature]`
-    .label = `{$name}` language item function is not allowed to have `#[target_feature]`
+    {passes_lang_item_fn} is not allowed to have `#[target_feature]`
+    .label = {passes_lang_item_fn} is not allowed to have `#[target_feature]`
+
+passes_lang_item_fn_with_track_caller =
+    {passes_lang_item_fn} is not allowed to have `#[track_caller]`
+    .label = {passes_lang_item_fn} is not allowed to have `#[target_feature]`
 
 passes_lang_item_on_incorrect_target =
-    `{$name}` language item must be applied to a {$expected_target}
+    `{$name}` lang item must be applied to a {$expected_target}
     .label = attribute should be applied to a {$expected_target}, not a {$actual_target}
 
 passes_layout_abi =
@@ -455,7 +464,7 @@ passes_missing_const_stab_attr =
     {$descr} has missing const stability attribute
 
 passes_missing_lang_item =
-    language item required, but not found: `{$name}`
+    lang item required, but not found: `{$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`
 
@@ -696,8 +705,8 @@ passes_unknown_feature =
     unknown feature `{$feature}`
 
 passes_unknown_lang_item =
-    definition of an unknown language item: `{$name}`
-    .label = definition of unknown language item `{$name}`
+    definition of an unknown lang item: `{$name}`
+    .label = definition of unknown lang item `{$name}`
 
 passes_unlabeled_cf_in_while_condition =
     `break` or `continue` with no label in the condition of a `while` loop

compiler/rustc_passes/src/check_attr.rs

@@ -11,9 +11,9 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::StashKey;
 use rustc_errors::{Applicability, DiagCtxt, IntoDiagArg, MultiSpan};
 use rustc_feature::{AttributeDuplicates, AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
-use rustc_hir as hir;
 use rustc_hir::def_id::LocalModDefId;
 use rustc_hir::intravisit::{self, Visitor};
+use rustc_hir::{self as hir};
 use rustc_hir::{
     self, FnSig, ForeignItem, HirId, Item, ItemKind, TraitItem, CRATE_HIR_ID, CRATE_OWNER_ID,
 };
@@ -519,7 +519,26 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 self.dcx().emit_err(errors::NakedTrackedCaller { attr_span });
                 false
             }
-            Target::Fn | Target::Method(..) | Target::ForeignFn | Target::Closure => true,
+            Target::Fn => {
+                // `#[track_caller]` is not valid on weak lang items because they are called via
+                // `extern` declarations and `#[track_caller]` would alter their ABI.
+                if let Some((lang_item, _)) = hir::lang_items::extract(attrs)
+                    && let Some(item) = hir::LangItem::from_name(lang_item)
+                    && item.is_weak()
+                {
+                    let sig = self.tcx.hir_node(hir_id).fn_sig().unwrap();
+
+                    self.dcx().emit_err(errors::LangItemWithTrackCaller {
+                        attr_span,
+                        name: lang_item,
+                        sig_span: sig.span,
+                    });
+                    false
+                } else {
+                    true
+                }
+            }
+            Target::Method(..) | Target::ForeignFn | Target::Closure => true,
             // FIXME(#80564): We permit struct fields, match arms and macro defs to have an
             // `#[track_caller]` attribute with just a lint, because we previously
             // erroneously allowed it and some crates used it accidentally, to be compatible
@@ -602,7 +621,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     ) -> bool {
         match target {
             Target::Fn => {
-                // `#[target_feature]` is not allowed in language items.
+                // `#[target_feature]` is not allowed in lang items.
                 if let Some((lang_item, _)) = hir::lang_items::extract(attrs)
                     // Calling functions with `#[target_feature]` is
                     // not unsafe on WASM, see #84988

compiler/rustc_passes/src/errors.rs

@@ -819,6 +819,16 @@ pub struct MissingLangItem {
     pub name: Symbol,
 }
 
+#[derive(Diagnostic)]
+#[diag(passes_lang_item_fn_with_track_caller)]
+pub struct LangItemWithTrackCaller {
+    #[primary_span]
+    pub attr_span: Span,
+    pub name: Symbol,
+    #[label]
+    pub sig_span: Span,
+}
+
 #[derive(Diagnostic)]
 #[diag(passes_lang_item_fn_with_target_feature)]
 pub struct LangItemWithTargetFeature {

compiler/rustc_passes/src/lang_items.rs

@@ -1,4 +1,4 @@
-//! Detecting language items.
+//! Detecting lang items.
 //!
 //! Language items are items that represent concepts intrinsic to the language
 //! itself. Examples are: