Auto merge of #94148 - matthiaskrgr:rollup-jgea68f, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #92902 (Improve the documentation of drain members)
 - #93658 (Stabilize `#[cfg(panic = "...")]`)
 - #93954 (rustdoc-json: buffer output)
 - #93979 (Add debug assertions to validate NUL terminator in c strings)
 - #93990 (pre #89862 cleanup)
 - #94006 (Use a `Field` in `ConstraintCategory::ClosureUpvar`)
 - #94086 (Fix ScalarInt to char conversion)

Failed merges:

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

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -5,6 +5,7 @@ use rustc_infer::infer::{
     error_reporting::nice_region_error::NiceRegionError,
     error_reporting::unexpected_hidden_region_diagnostic, NllRegionVariableOrigin,
 };
+use rustc_middle::hir::place::PlaceBase;
 use rustc_middle::mir::{ConstraintCategory, ReturnConstraint};
 use rustc_middle::ty::subst::{InternalSubsts, Subst};
 use rustc_middle::ty::{self, RegionVid, Ty};
@@ -421,17 +422,26 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
 
         diag.span_label(*span, message);
 
-        // FIXME(project-rfc-2229#48): This should store a captured_place not a hir id
-        if let ReturnConstraint::ClosureUpvar(upvar) = kind {
+        if let ReturnConstraint::ClosureUpvar(upvar_field) = kind {
             let def_id = match self.regioncx.universal_regions().defining_ty {
                 DefiningTy::Closure(def_id, _) => def_id,
                 ty => bug!("unexpected DefiningTy {:?}", ty),
             };
 
-            let upvar_def_span = self.infcx.tcx.hir().span(upvar);
-            let upvar_span = self.infcx.tcx.upvars_mentioned(def_id).unwrap()[&upvar].span;
-            diag.span_label(upvar_def_span, "variable defined here");
-            diag.span_label(upvar_span, "variable captured here");
+            let captured_place = &self.upvars[upvar_field.index()].place;
+            let defined_hir = match captured_place.place.base {
+                PlaceBase::Local(hirid) => Some(hirid),
+                PlaceBase::Upvar(upvar) => Some(upvar.var_path.hir_id),
+                _ => None,
+            };
+
+            if defined_hir.is_some() {
+                let upvars_map = self.infcx.tcx.upvars_mentioned(def_id).unwrap();
+                let upvar_def_span = self.infcx.tcx.hir().span(defined_hir.unwrap());
+                let upvar_span = upvars_map.get(&defined_hir.unwrap()).unwrap().span;
+                diag.span_label(upvar_def_span, "variable defined here");
+                diag.span_label(upvar_span, "variable captured here");
+            }
         }
 
         if let Some(fr_span) = self.give_region_a_name(*outlived_fr).unwrap().span() {

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2530,9 +2530,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             body,
         );
         let category = if let Some(field) = field {
-            let var_hir_id = self.borrowck_context.upvars[field.index()].place.get_root_variable();
-            // FIXME(project-rfc-2229#8): Use Place for better diagnostics
-            ConstraintCategory::ClosureUpvar(var_hir_id)
+            ConstraintCategory::ClosureUpvar(field)
         } else {
             ConstraintCategory::Boring
         };

compiler/rustc_feature/src/accepted.rs

@@ -70,6 +70,8 @@ declare_features! (
     (accepted, cfg_attr_multi, "1.33.0", Some(54881), None),
     /// Allows the use of `#[cfg(doctest)]`, set when rustdoc is collecting doctests.
     (accepted, cfg_doctest, "1.40.0", Some(62210), None),
+    /// Enables `#[cfg(panic = "...")]` config key.
+    (accepted, cfg_panic, "1.60.0", Some(77443), None),
     /// Allows `cfg(target_feature = "...")`.
     (accepted, cfg_target_feature, "1.27.0", Some(29717), None),
     /// Allows `cfg(target_vendor = "...")`.

compiler/rustc_feature/src/active.rs

@@ -306,8 +306,6 @@ declare_features! (
     (active, c_variadic, "1.34.0", Some(44930), None),
     /// Allows capturing disjoint fields in a closure/generator (RFC 2229).
     (incomplete, capture_disjoint_fields, "1.49.0", Some(53488), None),
-    /// Enables `#[cfg(panic = "...")]` config key.
-    (active, cfg_panic, "1.49.0", Some(77443), None),
     /// Allows the use of `#[cfg(sanitize = "option")]`; set when -Zsanitizer is used.
     (active, cfg_sanitize, "1.41.0", Some(39699), None),
     /// Allows `cfg(target_abi = "...")`.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -34,7 +34,6 @@ const GATED_CFGS: &[GatedCfg] = &[
     (sym::target_has_atomic_load_store, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
     (sym::sanitize, sym::cfg_sanitize, cfg_fn!(cfg_sanitize)),
     (sym::version, sym::cfg_version, cfg_fn!(cfg_version)),
-    (sym::panic, sym::cfg_panic, cfg_fn!(cfg_panic)),
 ];
 
 /// Find a gated cfg determined by the `pred`icate which is given the cfg's name.

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -497,16 +497,32 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let ty_to_string = |ty: Ty<'tcx>| -> String {
             let mut s = String::new();
             let mut printer = ty::print::FmtPrinter::new(self.tcx, &mut s, Namespace::TypeNS);
-            let mut inner = self.inner.borrow_mut();
-            let ty_vars = inner.type_variables();
-            let getter = move |ty_vid| {
-                let var_origin = ty_vars.var_origin(ty_vid);
-                if let TypeVariableOriginKind::TypeParameterDefinition(name, _) = var_origin.kind {
+            let ty_getter = move |ty_vid| {
+                if let TypeVariableOriginKind::TypeParameterDefinition(name, _) =
+                    self.inner.borrow_mut().type_variables().var_origin(ty_vid).kind
+                {
+                    Some(name.to_string())
+                } else {
+                    None
+                }
+            };
+            printer.ty_infer_name_resolver = Some(Box::new(ty_getter));
+            let const_getter = move |ct_vid| {
+                if let ConstVariableOriginKind::ConstParameterDefinition(name, _) = self
+                    .inner
+                    .borrow_mut()
+                    .const_unification_table()
+                    .probe_value(ct_vid)
+                    .origin
+                    .kind
+                {
                     return Some(name.to_string());
+                } else {
+                    None
                 }
-                None
             };
-            printer.name_resolver = Some(Box::new(&getter));
+            printer.const_infer_name_resolver = Some(Box::new(const_getter));
+
             let _ = if let ty::FnDef(..) = ty.kind() {
                 // We don't want the regular output for `fn`s because it includes its path in
                 // invalid pseudo-syntax, we want the `fn`-pointer output instead.

compiler/rustc_middle/src/mir/query.rs

@@ -341,7 +341,7 @@ pub enum ConstraintCategory {
     /// like `Foo { field: my_val }`)
     Usage,
     OpaqueType,
-    ClosureUpvar(hir::HirId),
+    ClosureUpvar(Field),
 
     /// A constraint from a user-written predicate
     /// with the provided span, written on the item
@@ -363,7 +363,7 @@ pub enum ConstraintCategory {
 #[derive(TyEncodable, TyDecodable, HashStable)]
 pub enum ReturnConstraint {
     Normal,
-    ClosureUpvar(hir::HirId),
+    ClosureUpvar(Field),
 }
 
 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing

compiler/rustc_middle/src/ty/consts/int.rs

@@ -294,12 +294,22 @@ impl From<char> for ScalarInt {
     }
 }
 
+/// Error returned when a conversion from ScalarInt to char fails.
+#[derive(Debug)]
+pub struct CharTryFromScalarInt;
+
 impl TryFrom<ScalarInt> for char {
-    type Error = Size;
+    type Error = CharTryFromScalarInt;
+
     #[inline]
-    fn try_from(int: ScalarInt) -> Result<Self, Size> {
-        int.to_bits(Size::from_bytes(std::mem::size_of::<char>()))
-            .map(|u| char::from_u32(u.try_into().unwrap()).unwrap())
+    fn try_from(int: ScalarInt) -> Result<Self, Self::Error> {
+        let Ok(bits) = int.to_bits(Size::from_bytes(std::mem::size_of::<char>())) else  {
+            return Err(CharTryFromScalarInt);
+        };
+        match char::from_u32(bits.try_into().unwrap()) {
+            Some(c) => Ok(c),
+            None => Err(CharTryFromScalarInt),
+        }
     }
 }
 

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -606,7 +606,7 @@ pub trait PrettyPrinter<'tcx>:
             ty::Infer(infer_ty) => {
                 let verbose = self.tcx().sess.verbose();
                 if let ty::TyVar(ty_vid) = infer_ty {
-                    if let Some(name) = self.infer_ty_name(ty_vid) {
+                    if let Some(name) = self.ty_infer_name(ty_vid) {
                         p!(write("{}", name))
                     } else {
                         if verbose {
@@ -1015,7 +1015,11 @@ pub trait PrettyPrinter<'tcx>:
         }
     }
 
-    fn infer_ty_name(&self, _: ty::TyVid) -> Option<String> {
+    fn ty_infer_name(&self, _: ty::TyVid) -> Option<String> {
+        None
+    }
+
+    fn const_infer_name(&self, _: ty::ConstVid<'tcx>) -> Option<String> {
         None
     }
 
@@ -1203,7 +1207,14 @@ pub trait PrettyPrinter<'tcx>:
                     }
                 }
             }
-            ty::ConstKind::Infer(..) => print_underscore!(),
+            ty::ConstKind::Infer(infer_ct) => {
+                match infer_ct {
+                    ty::InferConst::Var(ct_vid)
+                        if let Some(name) = self.const_infer_name(ct_vid) =>
+                            p!(write("{}", name)),
+                    _ => print_underscore!(),
+                }
+            }
             ty::ConstKind::Param(ParamConst { name, .. }) => p!(write("{}", name)),
             ty::ConstKind::Value(value) => {
                 return self.pretty_print_const_value(value, ct.ty(), print_ty);
@@ -1559,7 +1570,8 @@ pub struct FmtPrinterData<'a, 'tcx, F> {
 
     pub region_highlight_mode: RegionHighlightMode<'tcx>,
 
-    pub name_resolver: Option<Box<&'a dyn Fn(ty::TyVid) -> Option<String>>>,
+    pub ty_infer_name_resolver: Option<Box<dyn Fn(ty::TyVid) -> Option<String> + 'a>>,
+    pub const_infer_name_resolver: Option<Box<dyn Fn(ty::ConstVid<'tcx>) -> Option<String> + 'a>>,
 }
 
 impl<'a, 'tcx, F> Deref for FmtPrinter<'a, 'tcx, F> {
@@ -1588,7 +1600,8 @@ impl<'a, 'tcx, F> FmtPrinter<'a, 'tcx, F> {
             binder_depth: 0,
             printed_type_count: 0,
             region_highlight_mode: RegionHighlightMode::new(tcx),
-            name_resolver: None,
+            ty_infer_name_resolver: None,
+            const_infer_name_resolver: None,
         }))
     }
 }
@@ -1843,8 +1856,12 @@ impl<'tcx, F: fmt::Write> Printer<'tcx> for FmtPrinter<'_, 'tcx, F> {
 }
 
 impl<'tcx, F: fmt::Write> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx, F> {
-    fn infer_ty_name(&self, id: ty::TyVid) -> Option<String> {
-        self.0.name_resolver.as_ref().and_then(|func| func(id))
+    fn ty_infer_name(&self, id: ty::TyVid) -> Option<String> {
+        self.0.ty_infer_name_resolver.as_ref().and_then(|func| func(id))
+    }
+
+    fn const_infer_name(&self, id: ty::ConstVid<'tcx>) -> Option<String> {
+        self.0.const_infer_name_resolver.as_ref().and_then(|func| func(id))
     }
 
     fn print_value_path(

compiler/rustc_middle/src/ty/util.rs

@@ -17,7 +17,7 @@ use rustc_data_structures::intern::Interned;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_errors::ErrorReported;
 use rustc_hir as hir;
-use rustc_hir::def::DefKind;
+use rustc_hir::def::{CtorOf, DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 use rustc_query_system::ich::NodeIdHashingMode;
@@ -146,6 +146,37 @@ impl<'tcx> TyCtxt<'tcx> {
         hasher.finish()
     }
 
+    pub fn res_generics_def_id(self, res: Res) -> Option<DefId> {
+        match res {
+            Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => {
+                Some(self.parent(def_id).and_then(|def_id| self.parent(def_id)).unwrap())
+            }
+            Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Struct, _), def_id) => {
+                Some(self.parent(def_id).unwrap())
+            }
+            // Other `DefKind`s don't have generics and would ICE when calling
+            // `generics_of`.
+            Res::Def(
+                DefKind::Struct
+                | DefKind::Union
+                | DefKind::Enum
+                | DefKind::Trait
+                | DefKind::OpaqueTy
+                | DefKind::TyAlias
+                | DefKind::ForeignTy
+                | DefKind::TraitAlias
+                | DefKind::AssocTy
+                | DefKind::Fn
+                | DefKind::AssocFn
+                | DefKind::AssocConst
+                | DefKind::Impl,
+                def_id,
+            ) => Some(def_id),
+            Res::Err => None,
+            _ => None,
+        }
+    }
+
     pub fn has_error_field(self, ty: Ty<'tcx>) -> bool {
         if let ty::Adt(def, substs) = *ty.kind() {
             for field in def.all_fields() {

compiler/rustc_typeck/src/collect/type_of.rs

@@ -1,15 +1,14 @@
 use rustc_errors::{Applicability, ErrorReported, StashKey};
 use rustc_hir as hir;
-use rustc_hir::def::CtorOf;
-use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def::Res;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit;
 use rustc_hir::intravisit::Visitor;
 use rustc_hir::{HirId, Node};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::util::IntTypeExt;
-use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt, TypeFoldable, TypeFolder};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder};
 use rustc_span::symbol::Ident;
 use rustc_span::{Span, DUMMY_SP};
 
@@ -198,38 +197,9 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
             // Try to use the segment resolution if it is valid, otherwise we
             // default to the path resolution.
             let res = segment.res.filter(|&r| r != Res::Err).unwrap_or(path.res);
-            let generics = match res {
-                Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => tcx
-                    .generics_of(tcx.parent(def_id).and_then(|def_id| tcx.parent(def_id)).unwrap()),
-                Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Struct, _), def_id) => {
-                    tcx.generics_of(tcx.parent(def_id).unwrap())
-                }
-                // Other `DefKind`s don't have generics and would ICE when calling
-                // `generics_of`.
-                Res::Def(
-                    DefKind::Struct
-                    | DefKind::Union
-                    | DefKind::Enum
-                    | DefKind::Trait
-                    | DefKind::OpaqueTy
-                    | DefKind::TyAlias
-                    | DefKind::ForeignTy
-                    | DefKind::TraitAlias
-                    | DefKind::AssocTy
-                    | DefKind::Fn
-                    | DefKind::AssocFn
-                    | DefKind::AssocConst
-                    | DefKind::Impl,
-                    def_id,
-                ) => tcx.generics_of(def_id),
-                Res::Err => {
-                    tcx.sess.delay_span_bug(tcx.def_span(def_id), "anon const with Res::Err");
-                    return None;
-                }
-                _ => {
-                    // If the user tries to specify generics on a type that does not take them,
-                    // e.g. `usize<T>`, we may hit this branch, in which case we treat it as if
-                    // no arguments have been passed. An error should already have been emitted.
+            let generics = match tcx.res_generics_def_id(res) {
+                Some(def_id) => tcx.generics_of(def_id),
+                None => {
                     tcx.sess.delay_span_bug(
                         tcx.def_span(def_id),
                         &format!("unexpected anon const res {:?} in path: {:?}", res, path),

library/alloc/src/collections/binary_heap.rs

@@ -746,9 +746,12 @@ impl<T: Ord> BinaryHeap<T> {
         self.rebuild_tail(start);
     }
 
-    /// Returns an iterator which retrieves elements in heap order.
-    /// The retrieved elements are removed from the original heap.
-    /// The remaining elements will be removed on drop in heap order.
+    /// Clears the binary heap, returning an iterator over the removed elements
+    /// in heap order. If the iterator is dropped before being fully consumed,
+    /// it drops the remaining elements in heap order.
+    ///
+    /// The returned iterator keeps a mutable borrow on the heap to optimize
+    /// its implementation.
     ///
     /// Note:
     /// * `.drain_sorted()` is *O*(*n* \* log(*n*)); much slower than `.drain()`.
@@ -1158,9 +1161,12 @@ impl<T> BinaryHeap<T> {
         self.len() == 0
     }
 
-    /// Clears the binary heap, returning an iterator over the removed elements.
+    /// Clears the binary heap, returning an iterator over the removed elements
+    /// in arbitrary order. If the iterator is dropped before being fully
+    /// consumed, it drops the remaining elements in arbitrary order.
     ///
-    /// The elements are removed in arbitrary order.
+    /// The returned iterator keeps a mutable borrow on the heap to optimize
+    /// its implementation.
     ///
     /// # Examples
     ///