Rollup of 11 pull requests

.editorconfig

@@ -12,6 +12,9 @@ trim_trailing_whitespace = true
 indent_style = space
 indent_size = 4
 
+[*.css]
+indent_style = tab
+
 # some tests need trailing whitespace in output snapshots
 [tests/**]
 trim_trailing_whitespace = false

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -702,7 +702,9 @@ pub(crate) fn global_llvm_features(sess: &Session, only_base_features: bool) ->
 
                 features_string
             };
-            features.extend(features_string.split(',').map(String::from));
+            if !features_string.is_empty() {
+                features.extend(features_string.split(',').map(String::from));
+            }
         }
         Some(_) | None => {}
     };

compiler/rustc_feature/src/unstable.rs

@@ -257,6 +257,8 @@ declare_features! (
     (internal, rustc_attrs, "1.0.0", None),
     /// Allows using the `#[stable]` and `#[unstable]` attributes.
     (internal, staged_api, "1.0.0", None),
+    /// Perma-unstable, only used to test the `incomplete_features` lint.
+    (incomplete, test_incomplete_feature, "CURRENT_RUSTC_VERSION", None),
     /// Added for testing unstable lints; perma-unstable.
     (internal, test_unstable_lint, "1.60.0", None),
     /// Use for stable + negative coherence and strict coherence depending on trait's

compiler/rustc_lint_defs/src/builtin.rs

@@ -1033,8 +1033,8 @@ declare_lint! {
     /// ```rust
     /// #[warn(unused_macro_rules)]
     /// macro_rules! unused_empty {
-    ///     (hello) => { println!("Hello, world!") }; // This rule is unused
-    ///     () => { println!("empty") }; // This rule is used
+    ///     (hello) => { println!("Hello, world!") }; // This rule is used
+    ///     () => { println!("empty") }; // This rule is unused
     /// }
     ///
     /// fn main() {

compiler/rustc_middle/src/mir/basic_blocks.rs

@@ -65,7 +65,7 @@ impl<'tcx> BasicBlocks<'tcx> {
 
     /// Returns basic blocks in a reverse postorder.
     ///
-    /// See [`traversal::reverse_postorder`]'s docs to learn what is preorder traversal.
+    /// See [`traversal::reverse_postorder`]'s docs to learn what is postorder traversal.
     ///
     /// [`traversal::reverse_postorder`]: crate::mir::traversal::reverse_postorder
     #[inline]

compiler/rustc_middle/src/query/plumbing.rs

@@ -136,8 +136,12 @@ pub struct QueryVTable<'tcx, C: QueryCache> {
     /// For `no_hash` queries, this function pointer is None.
     pub hash_value_fn: Option<fn(&mut StableHashingContext<'_>, &C::Value) -> Fingerprint>,
 
-    pub value_from_cycle_error:
-        fn(tcx: TyCtxt<'tcx>, cycle_error: CycleError, guar: ErrorGuaranteed) -> C::Value,
+    pub value_from_cycle_error: fn(
+        tcx: TyCtxt<'tcx>,
+        key: C::Key,
+        cycle_error: CycleError,
+        guar: ErrorGuaranteed,
+    ) -> C::Value,
     pub format_value: fn(&C::Value) -> String,
 
     /// Formats a human-readable description of this query and its key, as

compiler/rustc_mir_dataflow/src/impls/initialized.rs

@@ -109,21 +109,21 @@ impl<'tcx> MaybePlacesSwitchIntData<'tcx> {
 /// ```rust
 /// struct S;
 /// #[rustfmt::skip]
-/// fn foo(pred: bool) {                        // maybe-init:
-///                                             // {}
-///     let a = S; let mut b = S; let c; let d; // {a, b}
+/// fn foo(p: bool) {                           // maybe-init:
+///                                             // {p}
+///     let a = S; let mut b = S; let c; let d; // {p, a, b}
 ///
-///     if pred {
-///         drop(a);                            // {   b}
-///         b = S;                              // {   b}
+///     if p {
+///         drop(a);                            // {p,    b}
+///         b = S;                              // {p,    b}
 ///
 ///     } else {
-///         drop(b);                            // {a}
-///         d = S;                              // {a,       d}
+///         drop(b);                            // {p, a}
+///         d = S;                              // {p, a,       d}
 ///
-///     }                                       // {a, b,    d}
+///     }                                       // {p, a, b,    d}
 ///
-///     c = S;                                  // {a, b, c, d}
+///     c = S;                                  // {p, a, b, c, d}
 /// }
 /// ```
 ///
@@ -199,11 +199,11 @@ impl<'a, 'tcx> HasMoveData<'tcx> for MaybeInitializedPlaces<'a, 'tcx> {
 /// ```rust
 /// struct S;
 /// #[rustfmt::skip]
-/// fn foo(pred: bool) {                        // maybe-uninit:
+/// fn foo(p: bool) {                           // maybe-uninit:
 ///                                             // {a, b, c, d}
 ///     let a = S; let mut b = S; let c; let d; // {      c, d}
 ///
-///     if pred {
+///     if p {
 ///         drop(a);                            // {a,    c, d}
 ///         b = S;                              // {a,    c, d}
 ///
@@ -279,34 +279,36 @@ impl<'tcx> HasMoveData<'tcx> for MaybeUninitializedPlaces<'_, 'tcx> {
     }
 }
 
-/// `EverInitializedPlaces` tracks all places that might have ever been
-/// initialized upon reaching a particular point in the control flow
-/// for a function, without an intervening `StorageDead`.
+/// `EverInitializedPlaces` tracks all initializations that may have occurred
+/// upon reaching a particular point in the control flow for a function,
+/// without an intervening `StorageDead`.
 ///
 /// This dataflow is used to determine if an immutable local variable may
 /// be assigned to.
 ///
 /// For example, in code like the following, we have corresponding
-/// dataflow information shown in the right-hand comments.
+/// dataflow information shown in the right-hand comments. Underscored indices
+/// are used to distinguish between multiple initializations of the same local
+/// variable, e.g. `b_0` and `b_1`.
 ///
 /// ```rust
 /// struct S;
 /// #[rustfmt::skip]
-/// fn foo(pred: bool) {                        // ever-init:
-///                                             // {          }
-///     let a = S; let mut b = S; let c; let d; // {a, b      }
+/// fn foo(p: bool) {                           // ever-init:
+///                                             // {p,                  }
+///     let a = S; let mut b = S; let c; let d; // {p, a, b_0,          }
 ///
-///     if pred {
-///         drop(a);                            // {a, b,     }
-///         b = S;                              // {a, b,     }
+///     if p {
+///         drop(a);                            // {p, a, b_0,          }
+///         b = S;                              // {p, a, b_0, b_1,     }
 ///
 ///     } else {
-///         drop(b);                            // {a, b,      }
-///         d = S;                              // {a, b,    d }
+///         drop(b);                            // {p, a, b_0, b_1,     }
+///         d = S;                              // {p, a, b_0, b_1,    d}
 ///
-///     }                                       // {a, b,    d }
+///     }                                       // {p, a, b_0, b_1,    d}
 ///
-///     c = S;                                  // {a, b, c, d }
+///     c = S;                                  // {p, a, b_0, b_1, c, d}
 /// }
 /// ```
 pub struct EverInitializedPlaces<'a, 'tcx> {

compiler/rustc_query_impl/src/execution.rs

@@ -125,17 +125,18 @@ where
 fn mk_cycle<'tcx, C: QueryCache>(
     query: &'tcx QueryVTable<'tcx, C>,
     tcx: TyCtxt<'tcx>,
+    key: C::Key,
     cycle_error: CycleError,
 ) -> C::Value {
     let error = report_cycle(tcx.sess, &cycle_error);
     match query.cycle_error_handling {
         CycleErrorHandling::Error => {
             let guar = error.emit();
-            (query.value_from_cycle_error)(tcx, cycle_error, guar)
+            (query.value_from_cycle_error)(tcx, key, cycle_error, guar)
         }
         CycleErrorHandling::DelayBug => {
             let guar = error.delay_as_bug();
-            (query.value_from_cycle_error)(tcx, cycle_error, guar)
+            (query.value_from_cycle_error)(tcx, key, cycle_error, guar)
         }
     }
 }
@@ -219,6 +220,7 @@ where
 fn cycle_error<'tcx, C: QueryCache>(
     query: &'tcx QueryVTable<'tcx, C>,
     tcx: TyCtxt<'tcx>,
+    key: C::Key,
     try_execute: QueryJobId,
     span: Span,
 ) -> (C::Value, Option<DepNodeIndex>) {
@@ -229,7 +231,7 @@ fn cycle_error<'tcx, C: QueryCache>(
         .expect("failed to collect active queries");
 
     let error = find_cycle_in_stack(try_execute, job_map, &current_query_job(), span);
-    (mk_cycle(query, tcx, error.lift()), None)
+    (mk_cycle(query, tcx, key, error.lift()), None)
 }
 
 #[inline(always)]
@@ -274,7 +276,7 @@ fn wait_for_query<'tcx, C: QueryCache>(
 
             (v, Some(index))
         }
-        Err(cycle) => (mk_cycle(query, tcx, cycle.lift()), None),
+        Err(cycle) => (mk_cycle(query, tcx, key, cycle.lift()), None),
     }
 }
 
@@ -337,7 +339,7 @@ fn try_execute_query<'tcx, C: QueryCache, const INCR: bool>(
 
                         // If we are single-threaded we know that we have cycle error,
                         // so we just return the error.
-                        cycle_error(query, tcx, id, span)
+                        cycle_error(query, tcx, key, id, span)
                     }
                 }
                 ActiveKeyStatus::Poisoned => FatalError.raise(),

compiler/rustc_query_impl/src/from_cycle_error.rs

@@ -15,34 +15,34 @@ use rustc_middle::query::erase::erase_val;
 use rustc_middle::ty::layout::{LayoutError, TyAndLayout};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
-use rustc_span::def_id::LocalDefId;
+use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::{ErrorGuaranteed, Span};
 
 use crate::job::report_cycle;
 
 pub(crate) fn specialize_query_vtables<'tcx>(vtables: &mut QueryVTables<'tcx>) {
     vtables.type_of.value_from_cycle_error =
-        |tcx, _, guar| erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)));
+        |tcx, _, _, guar| erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)));
 
     vtables.type_of_opaque_hir_typeck.value_from_cycle_error =
-        |tcx, _, guar| erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)));
+        |tcx, _, _, guar| erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)));
 
     vtables.erase_and_anonymize_regions_ty.value_from_cycle_error =
-        |tcx, _, guar| erase_val(Ty::new_error(tcx, guar));
+        |tcx, _, _, guar| erase_val(Ty::new_error(tcx, guar));
 
-    vtables.fn_sig.value_from_cycle_error = |tcx, cycle, guar| erase_val(fn_sig(tcx, cycle, guar));
+    vtables.fn_sig.value_from_cycle_error = |tcx, key, _, guar| erase_val(fn_sig(tcx, key, guar));
 
     vtables.check_representability.value_from_cycle_error =
-        |tcx, cycle, guar| check_representability(tcx, cycle, guar);
+        |tcx, _, cycle, guar| check_representability(tcx, cycle, guar);
 
     vtables.check_representability_adt_ty.value_from_cycle_error =
-        |tcx, cycle, guar| check_representability(tcx, cycle, guar);
+        |tcx, _, cycle, guar| check_representability(tcx, cycle, guar);
 
     vtables.variances_of.value_from_cycle_error =
-        |tcx, cycle, guar| erase_val(variances_of(tcx, cycle, guar));
+        |tcx, _, cycle, guar| erase_val(variances_of(tcx, cycle, guar));
 
     vtables.layout_of.value_from_cycle_error =
-        |tcx, cycle, guar| erase_val(layout_of(tcx, cycle, guar));
+        |tcx, _, cycle, guar| erase_val(layout_of(tcx, cycle, guar));
 }
 
 pub(crate) fn default<'tcx>(tcx: TyCtxt<'tcx>, cycle_error: CycleError, query_name: &str) -> ! {
@@ -57,15 +57,12 @@ pub(crate) fn default<'tcx>(tcx: TyCtxt<'tcx>, cycle_error: CycleError, query_na
 
 fn fn_sig<'tcx>(
     tcx: TyCtxt<'tcx>,
-    cycle_error: CycleError,
+    def_id: DefId,
     guar: ErrorGuaranteed,
 ) -> ty::EarlyBinder<'tcx, ty::PolyFnSig<'tcx>> {
     let err = Ty::new_error(tcx, guar);
 
-    let arity = if let Some(info) = cycle_error.cycle.get(0)
-        && info.frame.dep_kind == DepKind::fn_sig
-        && let Some(def_id) = info.frame.def_id
-        && let Some(node) = tcx.hir_get_if_local(def_id)
+    let arity = if let Some(node) = tcx.hir_get_if_local(def_id)
         && let Some(sig) = node.fn_sig()
     {
         sig.decl.inputs.len()

compiler/rustc_query_impl/src/plumbing.rs

@@ -487,7 +487,7 @@ macro_rules! define_queries {
                     #[cfg(not($cache_on_disk))]
                     is_loadable_from_disk_fn: |_tcx, _key, _index| false,
 
-                    value_from_cycle_error: |tcx, cycle, _| {
+                    value_from_cycle_error: |tcx, _, cycle, _| {
                         $crate::from_cycle_error::default(tcx, cycle, stringify!($name))
                     },
 

compiler/rustc_span/src/symbol.rs

@@ -2006,6 +2006,7 @@ symbols! {
         test_2018_feature,
         test_accepted_feature,
         test_case,
+        test_incomplete_feature,
         test_removed_feature,
         test_runner,
         test_unstable_lint,

library/core/src/array/mod.rs

@@ -1003,9 +1003,10 @@ impl<T: [const] Destruct> const Drop for Guard<'_, T> {
 /// dropped.
 ///
 /// Used for [`Iterator::next_chunk`].
+#[rustc_const_unstable(feature = "const_iter", issue = "92476")]
 #[inline]
-pub(crate) fn iter_next_chunk<T, const N: usize>(
-    iter: &mut impl Iterator<Item = T>,
+pub(crate) const fn iter_next_chunk<T, const N: usize>(
+    iter: &mut impl [const] Iterator<Item = T>,
 ) -> Result<[T; N], IntoIter<T, N>> {
     let mut array = [const { MaybeUninit::uninit() }; N];
     let r = iter_next_chunk_erased(&mut array, iter);
@@ -1026,10 +1027,11 @@ pub(crate) fn iter_next_chunk<T, const N: usize>(
 ///
 /// Unfortunately this loop has two exit conditions, the buffer filling up
 /// or the iterator running out of items, making it tend to optimize poorly.
+#[rustc_const_unstable(feature = "const_iter", issue = "92476")]
 #[inline]
-fn iter_next_chunk_erased<T>(
+const fn iter_next_chunk_erased<T>(
     buffer: &mut [MaybeUninit<T>],
-    iter: &mut impl Iterator<Item = T>,
+    iter: &mut impl [const] Iterator<Item = T>,
 ) -> Result<(), usize> {
     // if `Iterator::next` panics, this guard will drop already initialized items
     let mut guard = Guard { array_mut: buffer, initialized: 0 };

library/core/src/iter/adapters/array_chunks.rs

@@ -26,7 +26,7 @@ where
     I: Iterator,
 {
     #[track_caller]
-    pub(in crate::iter) fn new(iter: I) -> Self {
+    pub(in crate::iter) const fn new(iter: I) -> Self {
         assert!(N != 0, "chunk size must be non-zero");
         Self { iter, remainder: None }
     }

library/core/src/iter/adapters/chain.rs

@@ -33,7 +33,7 @@ pub struct Chain<A, B> {
     b: Option<B>,
 }
 impl<A, B> Chain<A, B> {
-    pub(in super::super) fn new(a: A, b: B) -> Chain<A, B> {
+    pub(in super::super) const fn new(a: A, b: B) -> Chain<A, B> {
         Chain { a: Some(a), b: Some(b) }
     }
 }

library/core/src/iter/adapters/cloned.rs

@@ -20,7 +20,7 @@ pub struct Cloned<I> {
 }
 
 impl<I> Cloned<I> {
-    pub(in crate::iter) fn new(it: I) -> Cloned<I> {
+    pub(in crate::iter) const fn new(it: I) -> Cloned<I> {
         Cloned { it }
     }
 }

library/core/src/iter/adapters/copied.rs

@@ -21,7 +21,7 @@ pub struct Copied<I> {
 }
 
 impl<I> Copied<I> {
-    pub(in crate::iter) fn new(it: I) -> Copied<I> {
+    pub(in crate::iter) const fn new(it: I) -> Copied<I> {
         Copied { it }
     }
 

library/core/src/iter/adapters/cycle.rs

@@ -18,7 +18,11 @@ pub struct Cycle<I> {
 }
 
 impl<I: Clone> Cycle<I> {
-    pub(in crate::iter) fn new(iter: I) -> Cycle<I> {
+    #[rustc_const_unstable(feature = "const_iter", issue = "92476")]
+    pub(in crate::iter) const fn new(iter: I) -> Cycle<I>
+    where
+        I: [const] Clone,
+    {
         Cycle { orig: iter.clone(), iter }
     }
 }

library/core/src/iter/adapters/enumerate.rs

@@ -20,7 +20,7 @@ pub struct Enumerate<I> {
     count: usize,
 }
 impl<I> Enumerate<I> {
-    pub(in crate::iter) fn new(iter: I) -> Enumerate<I> {
+    pub(in crate::iter) const fn new(iter: I) -> Enumerate<I> {
         Enumerate { iter, count: 0 }
     }
 

library/core/src/iter/adapters/filter.rs

@@ -24,7 +24,7 @@ pub struct Filter<I, P> {
     predicate: P,
 }
 impl<I, P> Filter<I, P> {
-    pub(in crate::iter) fn new(iter: I, predicate: P) -> Filter<I, P> {
+    pub(in crate::iter) const fn new(iter: I, predicate: P) -> Filter<I, P> {
         Filter { iter, predicate }
     }
 }

library/core/src/iter/adapters/filter_map.rs

@@ -20,7 +20,7 @@ pub struct FilterMap<I, F> {
     f: F,
 }
 impl<I, F> FilterMap<I, F> {
-    pub(in crate::iter) fn new(iter: I, f: F) -> FilterMap<I, F> {
+    pub(in crate::iter) const fn new(iter: I, f: F) -> FilterMap<I, F> {
         FilterMap { iter, f }
     }
 }