Rollup of 6 pull requests

.github/ISSUE_TEMPLATE/tracking_issue.md

@@ -1,26 +1,34 @@
 ---
 name: Tracking Issue
-about: A tracking issue for an accepted feature or RFC in Rust.
+about: A tracking issue for an unstable feature in Rust.
 title: Tracking Issue for XXX
 labels: C-tracking-issue
 ---
 <!--
 NOTE: For library features, please use the "Library Tracking Issue" template instead.
 
 Thank you for creating a tracking issue! 📜 Tracking issues are for tracking a
-feature from implementation to stabilisation. Make sure to include the relevant
-RFC for the feature if it has one. Otherwise provide a short summary of the
-feature and link any relevant PRs or issues, and remove any sections that are
-not relevant to the feature.
+feature from implementation to stabilisation.
 
 Remember to add team labels to the tracking issue.
-For a language team feature, this would e.g., be `T-lang`.
+For a language team feature, this would e.g., be `T-lang`:
+
+> @rustbot label T-lang
+
 Such a feature should also be labeled with e.g., `F-my_feature`.
 This label is used to associate issues (e.g., bugs and design questions) to the feature.
 -->
 
-This is a tracking issue for the RFC "XXX" (rust-lang/rfcs#NNN).
-The feature gate for the issue is `#![feature(FFF)]`.
+This is a tracking issue for `#![feature(FFF)]`.
+The RFC for this feature is rust-lang/rfcs#NNN.
+
+<!-- 
+Make sure to include the relevant RFC for the feature if it has one.
+
+Otherwise, provide a short summary and motivation of the
+feature and link any relevant PRs or issues.
+Remove any sections that are not relevant to the feature.
+-->
 
 ### About tracking issues
 
@@ -38,8 +46,8 @@ implementing a feature, followed by a PR that stabilises the feature. However
 for larger features an implementation could be broken up into multiple PRs.
 -->
 
-- [ ] Implement the RFC (cc @rust-lang/XXX -- can anyone write up mentoring
-      instructions?)
+- [ ] Create the feature gate
+- [ ] Implement the feature
 - [ ] Adjust documentation ([see instructions on rustc-dev-guide][doc-guide])
 - [ ] Style updates for any new syntax ([nightly-style-procedure])
   - [ ] Style team decision on new formatting
@@ -59,8 +67,8 @@ stabilised. It is useful to link related discussions and conculsions as they
 develop.
 -->
 
-- [ ] list all the "unresolved questions" found in the RFC to ensure they are
-  not forgotten.
+- [ ] List any unresolved questions, including those listed in the RFC if there is one,
+      to ensure they are not forgotten.
 
 ### Implementation history
 

compiler/rustc_const_eval/src/const_eval/type_info.rs

@@ -91,9 +91,7 @@ impl<'tcx> InterpCx<'tcx, CompileTimeMachine<'tcx>> {
                                 self.project_downcast_named(&field_dest, sym::Slice)?;
                             variant
                         }
-                        ty::Adt(adt_def, generics) => {
-                            self.write_adt_type_info(&field_dest, (ty, *adt_def), generics)?
-                        }
+                        ty::Adt(adt_def, _) => self.write_adt_type_info(&field_dest, *adt_def)?,
                         ty::Bool => {
                             let (variant, _variant_place) =
                                 self.project_downcast_named(&field_dest, sym::Bool)?;

compiler/rustc_const_eval/src/const_eval/type_info/adt.rs

@@ -1,204 +1,38 @@
 use rustc_abi::{FieldIdx, VariantIdx};
-use rustc_middle::ty::layout::TyAndLayout;
 use rustc_middle::ty::{
-    AdtDef, AdtKind, Const, ConstKind, GenericArgKind, GenericArgs, Region, Ty, VariantDef,
+    AdtDef, AdtKind, Const, ConstKind, GenericArgKind, GenericArgs, Region, Ty,
 };
 use rustc_span::{bug, span_bug, sym};
 
 use crate::const_eval::CompileTimeMachine;
 use crate::interpret::{
-    CtfeProvenance, InterpCx, InterpResult, MPlaceTy, Projectable, Scalar, Writeable, interp_ok,
+    CtfeProvenance, InterpCx, InterpResult, MPlaceTy, Projectable, Writeable, interp_ok,
 };
 
 impl<'tcx> InterpCx<'tcx, CompileTimeMachine<'tcx>> {
     // FIXME(type_info): No semver considerations for now
     pub(crate) fn write_adt_type_info(
         &mut self,
         place: &impl Writeable<'tcx, CtfeProvenance>,
-        adt: (Ty<'tcx>, AdtDef<'tcx>),
-        generics: &'tcx GenericArgs<'tcx>,
+        adt_def: AdtDef<'tcx>,
     ) -> InterpResult<'tcx, VariantIdx> {
-        let (adt_ty, adt_def) = adt;
         let variant_idx = match adt_def.adt_kind() {
             AdtKind::Struct => {
-                let (variant, variant_place) = self.project_downcast_named(place, sym::Struct)?;
-                let place = self.project_field(&variant_place, FieldIdx::ZERO)?;
-                self.write_struct_type_info(
-                    place,
-                    (adt_ty, adt_def.variant(VariantIdx::ZERO)),
-                    generics,
-                )?;
+                let (variant, _) = self.project_downcast_named(place, sym::Struct)?;
                 variant
             }
             AdtKind::Union => {
-                let (variant, variant_place) = self.project_downcast_named(place, sym::Union)?;
-                let place = self.project_field(&variant_place, FieldIdx::ZERO)?;
-                self.write_union_type_info(
-                    place,
-                    (adt_ty, adt_def.variant(VariantIdx::ZERO)),
-                    generics,
-                )?;
+                let (variant, _) = self.project_downcast_named(place, sym::Union)?;
                 variant
             }
             AdtKind::Enum => {
-                let (variant, variant_place) = self.project_downcast_named(place, sym::Enum)?;
-                let place = self.project_field(&variant_place, FieldIdx::ZERO)?;
-                self.write_enum_type_info(place, adt, generics)?;
+                let (variant, _) = self.project_downcast_named(place, sym::Enum)?;
                 variant
             }
         };
         interp_ok(variant_idx)
     }
 
-    pub(crate) fn write_struct_type_info(
-        &mut self,
-        place: impl Writeable<'tcx, CtfeProvenance>,
-        struct_: (Ty<'tcx>, &'tcx VariantDef),
-        generics: &'tcx GenericArgs<'tcx>,
-    ) -> InterpResult<'tcx> {
-        let (struct_ty, struct_def) = struct_;
-        let struct_layout = self.layout_of(struct_ty)?;
-
-        for (field_idx, field) in
-            place.layout().ty.ty_adt_def().unwrap().non_enum_variant().fields.iter_enumerated()
-        {
-            let field_place = self.project_field(&place, field_idx)?;
-
-            match field.name {
-                sym::generics => self.write_generics(&field_place, generics)?,
-                sym::fields => {
-                    self.write_variant_fields(field_place, struct_def, struct_layout, generics)?
-                }
-                sym::non_exhaustive => {
-                    let is_non_exhaustive = struct_def.is_field_list_non_exhaustive();
-                    self.write_scalar(Scalar::from_bool(is_non_exhaustive), &field_place)?
-                }
-                other => span_bug!(self.tcx.def_span(field.did), "unimplemented field {other}"),
-            }
-        }
-
-        interp_ok(())
-    }
-
-    pub(crate) fn write_union_type_info(
-        &mut self,
-        place: impl Writeable<'tcx, CtfeProvenance>,
-        union_: (Ty<'tcx>, &'tcx VariantDef),
-        generics: &'tcx GenericArgs<'tcx>,
-    ) -> InterpResult<'tcx> {
-        let (union_ty, union_def) = union_;
-        let union_layout = self.layout_of(union_ty)?;
-
-        for (field_idx, field) in
-            place.layout().ty.ty_adt_def().unwrap().non_enum_variant().fields.iter_enumerated()
-        {
-            let field_place = self.project_field(&place, field_idx)?;
-
-            match field.name {
-                sym::generics => self.write_generics(&field_place, generics)?,
-                sym::fields => {
-                    self.write_variant_fields(field_place, union_def, union_layout, generics)?
-                }
-                sym::non_exhaustive => {
-                    let is_non_exhaustive = union_def.is_field_list_non_exhaustive();
-                    self.write_scalar(Scalar::from_bool(is_non_exhaustive), &field_place)?
-                }
-                other => span_bug!(self.tcx.def_span(field.did), "unimplemented field {other}"),
-            }
-        }
-
-        interp_ok(())
-    }
-
-    pub(crate) fn write_enum_type_info(
-        &mut self,
-        place: impl Writeable<'tcx, CtfeProvenance>,
-        enum_: (Ty<'tcx>, AdtDef<'tcx>),
-        generics: &'tcx GenericArgs<'tcx>,
-    ) -> InterpResult<'tcx> {
-        let (enum_ty, enum_def) = enum_;
-        let enum_layout = self.layout_of(enum_ty)?;
-
-        for (field_idx, field) in
-            place.layout().ty.ty_adt_def().unwrap().non_enum_variant().fields.iter_enumerated()
-        {
-            let field_place = self.project_field(&place, field_idx)?;
-
-            match field.name {
-                sym::generics => self.write_generics(&field_place, generics)?,
-                sym::type_id_variants => {
-                    self.allocate_fill_and_write_slice_ptr(
-                        &field_place,
-                        enum_def.variants().len() as u64,
-                        |this, i, place| {
-                            let variant_idx = VariantIdx::from_usize(i as usize);
-                            let variant_def = &enum_def.variants()[variant_idx];
-                            let variant_layout = enum_layout.for_variant(this, variant_idx);
-                            this.write_enum_variant(place, (variant_layout, &variant_def), generics)
-                        },
-                    )?;
-                }
-                sym::non_exhaustive => {
-                    let is_non_exhaustive = enum_def.is_variant_list_non_exhaustive();
-                    self.write_scalar(Scalar::from_bool(is_non_exhaustive), &field_place)?
-                }
-                other => span_bug!(self.tcx.def_span(field.did), "unimplemented field {other}"),
-            }
-        }
-
-        interp_ok(())
-    }
-
-    fn write_enum_variant(
-        &mut self,
-        place: impl Writeable<'tcx, CtfeProvenance>,
-        variant: (TyAndLayout<'tcx>, &'tcx VariantDef),
-        generics: &'tcx GenericArgs<'tcx>,
-    ) -> InterpResult<'tcx> {
-        let (variant_layout, variant_def) = variant;
-
-        for (field_idx, field_def) in
-            place.layout().ty.ty_adt_def().unwrap().non_enum_variant().fields.iter_enumerated()
-        {
-            let field_place = self.project_field(&place, field_idx)?;
-            match field_def.name {
-                sym::name => {
-                    let name_place = self.allocate_str_dedup(variant_def.name.as_str())?;
-                    let ptr = self.mplace_to_imm_ptr(&name_place, None)?;
-                    self.write_immediate(*ptr, &field_place)?
-                }
-                sym::fields => {
-                    self.write_variant_fields(field_place, &variant_def, variant_layout, generics)?
-                }
-                sym::non_exhaustive => {
-                    let is_non_exhaustive = variant_def.is_field_list_non_exhaustive();
-                    self.write_scalar(Scalar::from_bool(is_non_exhaustive), &field_place)?
-                }
-                other => span_bug!(self.tcx.def_span(field_def.did), "unimplemented field {other}"),
-            }
-        }
-        interp_ok(())
-    }
-
-    // Write fields for struct, enum variants
-    fn write_variant_fields(
-        &mut self,
-        place: impl Writeable<'tcx, CtfeProvenance>,
-        variant_def: &'tcx VariantDef,
-        variant_layout: TyAndLayout<'tcx>,
-        generics: &'tcx GenericArgs<'tcx>,
-    ) -> InterpResult<'tcx> {
-        self.allocate_fill_and_write_slice_ptr(
-            &place,
-            variant_def.fields.len() as u64,
-            |this, i, place| {
-                let field_def = &variant_def.fields[FieldIdx::from_usize(i as usize)];
-                let field_ty = field_def.ty(*this.tcx, generics).skip_norm_wip();
-                this.write_field(field_ty, place, variant_layout, Some(field_def.name), i)
-            },
-        )
-    }
-
     pub(super) fn write_generics(
         &mut self,
         place: &impl Writeable<'tcx, CtfeProvenance>,

compiler/rustc_target/src/target_features.rs

@@ -1062,26 +1062,28 @@ const XTENSA_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
 ///
 /// IMPORTANT: If you're adding another feature list above, make sure to add it to this iterator!
 pub fn all_rust_features() -> impl Iterator<Item = (&'static str, Stability)> {
-    std::iter::empty()
-        .chain(ARM_FEATURES)
-        .chain(AARCH64_FEATURES)
-        .chain(X86_FEATURES)
-        .chain(HEXAGON_FEATURES)
-        .chain(POWERPC_FEATURES)
-        .chain(MIPS_FEATURES)
-        .chain(NVPTX_FEATURES)
-        .chain(RISCV_FEATURES)
-        .chain(WASM_FEATURES)
-        .chain(BPF_FEATURES)
-        .chain(XTENSA_FEATURES)
-        .chain(CSKY_FEATURES)
-        .chain(LOONGARCH_FEATURES)
-        .chain(IBMZ_FEATURES)
-        .chain(SPARC_FEATURES)
-        .chain(M68K_FEATURES)
-        .chain(AVR_FEATURES)
-        .cloned()
-        .map(|(f, s, _)| (f, s))
+    [
+        ARM_FEATURES,
+        AARCH64_FEATURES,
+        X86_FEATURES,
+        HEXAGON_FEATURES,
+        POWERPC_FEATURES,
+        MIPS_FEATURES,
+        NVPTX_FEATURES,
+        RISCV_FEATURES,
+        WASM_FEATURES,
+        BPF_FEATURES,
+        XTENSA_FEATURES,
+        CSKY_FEATURES,
+        LOONGARCH_FEATURES,
+        IBMZ_FEATURES,
+        SPARC_FEATURES,
+        M68K_FEATURES,
+        AVR_FEATURES,
+    ]
+    .into_iter()
+    .flatten()
+    .map(|(f, s, _)| (*f, *s))
 }
 
 /// Find which target architectures a feature belongs to.