Auto merge of #151852 - Zalathar:rollup-jdJCcDh, r=Zalathar

Rollup of 5 pull requests

Successful merges:

 - #151777 (    Reduce generics use in the query system.)
 - #151808 (Document a safety condition for `TypedArena::alloc_raw_slice`)
 - #151811 (Fix false positive in unused_parens caused by break)
 - #151817 (Fix missing syntax context in lifetime hygiene debug output)
 - #151844 (rustc-dev-guide subtree update)

Author: bors

compiler/rustc_arena/src/lib.rs

@@ -172,8 +172,22 @@ impl<T> TypedArena<T> {
         available_bytes >= additional_bytes
     }
 
+    /// Allocates storage for `len >= 1` values in this arena, and returns a
+    /// raw pointer to the first value's storage.
+    ///
+    /// # Safety
+    ///
+    /// Caller must initialize each of the `len` slots to a droppable value
+    /// before the arena is dropped.
+    ///
+    /// In practice, this typically means that the caller must be able to
+    /// raw-copy `len` already-initialized values into the slice without any
+    /// possibility of panicking.
+    ///
+    /// FIXME(Zalathar): This is *very* fragile; perhaps we need a different
+    /// approach to arena-allocating slices of droppable values.
     #[inline]
-    fn alloc_raw_slice(&self, len: usize) -> *mut T {
+    unsafe fn alloc_raw_slice(&self, len: usize) -> *mut T {
         assert!(size_of::<T>() != 0);
         assert!(len != 0);
 
@@ -208,7 +222,7 @@ impl<T> TypedArena<T> {
         &self,
         iter: impl IntoIterator<Item = Result<T, E>>,
     ) -> Result<&mut [T], E> {
-        // Despite the similarlty with `DroplessArena`, we cannot reuse their fast case. The reason
+        // Despite the similarity with `DroplessArena`, we cannot reuse their fast case. The reason
         // is subtle: these arenas are reentrant. In other words, `iter` may very well be holding a
         // reference to `self` and adding elements to the arena during iteration.
         //
@@ -229,9 +243,15 @@ impl<T> TypedArena<T> {
         }
         // Move the content to the arena by copying and then forgetting it.
         let len = vec.len();
-        let start_ptr = self.alloc_raw_slice(len);
+
+        // SAFETY: After allocating raw storage for exactly `len` values, we
+        // must fully initialize the storage without panicking, and we must
+        // also prevent the stale values in the vec from being dropped.
         Ok(unsafe {
+            let start_ptr = self.alloc_raw_slice(len);
+            // Initialize the newly-allocated storage without panicking.
             vec.as_ptr().copy_to_nonoverlapping(start_ptr, len);
+            // Prevent the stale values in the vec from being dropped.
             vec.set_len(0);
             slice::from_raw_parts_mut(start_ptr, len)
         })
@@ -584,7 +604,7 @@ impl DroplessArena {
         &self,
         iter: impl IntoIterator<Item = Result<T, E>>,
     ) -> Result<&mut [T], E> {
-        // Despite the similarlty with `alloc_from_iter`, we cannot reuse their fast case, as we
+        // Despite the similarity with `alloc_from_iter`, we cannot reuse their fast case, as we
         // cannot know the minimum length of the iterator in this case.
         assert!(size_of::<T>() != 0);
 

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1961,7 +1961,8 @@ impl<'a> State<'a> {
     }
 
     fn print_lifetime(&mut self, lifetime: ast::Lifetime) {
-        self.print_name(lifetime.ident.name)
+        self.word(lifetime.ident.name.to_string());
+        self.ann_post(lifetime.ident)
     }
 
     fn print_lifetime_bounds(&mut self, bounds: &ast::GenericBounds) {

compiler/rustc_lint/src/unused.rs

@@ -805,7 +805,10 @@ trait UnusedDelimLint {
 
                 ExprKind::Break(_label, None) => return false,
                 ExprKind::Break(_label, Some(break_expr)) => {
-                    return matches!(break_expr.kind, ExprKind::Block(..));
+                    // `if (break 'label i) { ... }` removing parens would make `i { ... }`
+                    // be parsed as a struct literal, so keep parentheses if the break value
+                    // ends with a path (which could be mistaken for a struct name).
+                    return matches!(break_expr.kind, ExprKind::Block(..) | ExprKind::Path(..));
                 }
 
                 ExprKind::Range(_lhs, Some(rhs), _limits) => {

compiler/rustc_middle/src/query/mod.rs

@@ -88,7 +88,7 @@ use rustc_index::IndexVec;
 use rustc_lint_defs::LintId;
 use rustc_macros::rustc_queries;
 use rustc_query_system::ich::StableHashingContext;
-use rustc_query_system::query::{QueryMode, QueryStackDeferred, QueryState};
+use rustc_query_system::query::{QueryMode, QueryState};
 use rustc_session::Limits;
 use rustc_session::config::{EntryFnType, OptLevel, OutputFilenames, SymbolManglingVersion};
 use rustc_session::cstore::{

compiler/rustc_middle/src/query/plumbing.rs

@@ -440,7 +440,7 @@ macro_rules! define_callbacks {
         #[derive(Default)]
         pub struct QueryStates<'tcx> {
             $(
-                pub $name: QueryState<$($K)*, QueryStackDeferred<'tcx>>,
+                pub $name: QueryState<'tcx, $($K)*>,
             )*
         }
 

compiler/rustc_query_impl/src/lib.rs

@@ -21,7 +21,7 @@ use rustc_query_system::dep_graph::SerializedDepNodeIndex;
 use rustc_query_system::ich::StableHashingContext;
 use rustc_query_system::query::{
     CycleError, CycleErrorHandling, HashResult, QueryCache, QueryDispatcher, QueryMap, QueryMode,
-    QueryStackDeferred, QueryState, get_query_incr, get_query_non_incr,
+    QueryState, get_query_incr, get_query_non_incr,
 };
 use rustc_span::{ErrorGuaranteed, Span};
 
@@ -66,7 +66,7 @@ impl<'tcx, C: QueryCache, const ANON: bool, const DEPTH_LIMIT: bool, const FEEDA
 
 // This is `impl QueryDispatcher for SemiDynamicQueryDispatcher`.
 impl<'tcx, C: QueryCache, const ANON: bool, const DEPTH_LIMIT: bool, const FEEDABLE: bool>
-    QueryDispatcher for SemiDynamicQueryDispatcher<'tcx, C, ANON, DEPTH_LIMIT, FEEDABLE>
+    QueryDispatcher<'tcx> for SemiDynamicQueryDispatcher<'tcx, C, ANON, DEPTH_LIMIT, FEEDABLE>
 where
     for<'a> C::Key: HashStable<StableHashingContext<'a>>,
 {
@@ -86,10 +86,7 @@ where
     }
 
     #[inline(always)]
-    fn query_state<'a>(
-        self,
-        qcx: QueryCtxt<'tcx>,
-    ) -> &'a QueryState<Self::Key, QueryStackDeferred<'tcx>>
+    fn query_state<'a>(self, qcx: QueryCtxt<'tcx>) -> &'a QueryState<'tcx, Self::Key>
     where
         QueryCtxt<'tcx>: 'a,
     {
@@ -98,7 +95,7 @@ where
         unsafe {
             &*(&qcx.tcx.query_system.states as *const QueryStates<'tcx>)
                 .byte_add(self.vtable.query_state)
-                .cast::<QueryState<Self::Key, QueryStackDeferred<'tcx>>>()
+                .cast::<QueryState<'tcx, Self::Key>>()
         }
     }
 
@@ -211,13 +208,15 @@ where
 /// on the type `rustc_query_impl::query_impl::$name::QueryType`.
 trait QueryDispatcherUnerased<'tcx> {
     type UnerasedValue;
-    type Dispatcher: QueryDispatcher<Qcx = QueryCtxt<'tcx>>;
+    type Dispatcher: QueryDispatcher<'tcx, Qcx = QueryCtxt<'tcx>>;
 
     const NAME: &'static &'static str;
 
     fn query_dispatcher(tcx: TyCtxt<'tcx>) -> Self::Dispatcher;
 
-    fn restore_val(value: <Self::Dispatcher as QueryDispatcher>::Value) -> Self::UnerasedValue;
+    fn restore_val(
+        value: <Self::Dispatcher as QueryDispatcher<'tcx>>::Value,
+    ) -> Self::UnerasedValue;
 }
 
 pub fn query_system<'a>(

compiler/rustc_query_impl/src/plumbing.rs

@@ -60,9 +60,7 @@ impl<'tcx> HasDepContext for QueryCtxt<'tcx> {
     }
 }
 
-impl<'tcx> QueryContext for QueryCtxt<'tcx> {
-    type QueryInfo = QueryStackDeferred<'tcx>;
-
+impl<'tcx> QueryContext<'tcx> for QueryCtxt<'tcx> {
     #[inline]
     fn jobserver_proxy(&self) -> &Proxy {
         &self.tcx.jobserver_proxy
@@ -93,10 +91,7 @@ impl<'tcx> QueryContext for QueryCtxt<'tcx> {
     /// Prefer passing `false` to `require_complete` to avoid potential deadlocks,
     /// especially when called from within a deadlock handler, unless a
     /// complete map is needed and no deadlock is possible at this call site.
-    fn collect_active_jobs(
-        self,
-        require_complete: bool,
-    ) -> Result<QueryMap<QueryStackDeferred<'tcx>>, QueryMap<QueryStackDeferred<'tcx>>> {
+    fn collect_active_jobs(self, require_complete: bool) -> Result<QueryMap<'tcx>, QueryMap<'tcx>> {
         let mut jobs = QueryMap::default();
         let mut complete = true;
 
@@ -322,7 +317,7 @@ macro_rules! should_ever_cache_on_disk {
     };
 }
 
-fn create_query_frame_extra<'tcx, K: Key + Copy + 'tcx>(
+fn mk_query_stack_frame_extra<'tcx, K: Key + Copy + 'tcx>(
     (tcx, key, kind, name, do_describe): (
         TyCtxt<'tcx>,
         K,
@@ -373,18 +368,16 @@ pub(crate) fn create_query_frame<
 ) -> QueryStackFrame<QueryStackDeferred<'tcx>> {
     let def_id = key.key_as_def_id();
 
-    let hash = || {
-        tcx.with_stable_hashing_context(|mut hcx| {
-            let mut hasher = StableHasher::new();
-            kind.as_usize().hash_stable(&mut hcx, &mut hasher);
-            key.hash_stable(&mut hcx, &mut hasher);
-            hasher.finish::<Hash64>()
-        })
-    };
+    let hash = tcx.with_stable_hashing_context(|mut hcx| {
+        let mut hasher = StableHasher::new();
+        kind.as_usize().hash_stable(&mut hcx, &mut hasher);
+        key.hash_stable(&mut hcx, &mut hasher);
+        hasher.finish::<Hash64>()
+    });
     let def_id_for_ty_in_cycle = key.def_id_for_ty_in_cycle();
 
     let info =
-        QueryStackDeferred::new((tcx, key, kind, name, do_describe), create_query_frame_extra);
+        QueryStackDeferred::new((tcx, key, kind, name, do_describe), mk_query_stack_frame_extra);
 
     QueryStackFrame::new(info, kind, hash, def_id, def_id_for_ty_in_cycle)
 }
@@ -417,7 +410,7 @@ pub(crate) fn encode_query_results<'a, 'tcx, Q>(
 }
 
 pub(crate) fn query_key_hash_verify<'tcx>(
-    query: impl QueryDispatcher<Qcx = QueryCtxt<'tcx>>,
+    query: impl QueryDispatcher<'tcx, Qcx = QueryCtxt<'tcx>>,
     qcx: QueryCtxt<'tcx>,
 ) {
     let _timer = qcx.tcx.prof.generic_activity_with_arg("query_key_hash_verify_for", query.name());
@@ -445,7 +438,7 @@ pub(crate) fn query_key_hash_verify<'tcx>(
 
 fn try_load_from_on_disk_cache<'tcx, Q>(query: Q, tcx: TyCtxt<'tcx>, dep_node: DepNode)
 where
-    Q: QueryDispatcher<Qcx = QueryCtxt<'tcx>>,
+    Q: QueryDispatcher<'tcx, Qcx = QueryCtxt<'tcx>>,
 {
     debug_assert!(tcx.dep_graph.is_green(&dep_node));
 
@@ -491,7 +484,7 @@ where
 
 fn force_from_dep_node<'tcx, Q>(query: Q, tcx: TyCtxt<'tcx>, dep_node: DepNode) -> bool
 where
-    Q: QueryDispatcher<Qcx = QueryCtxt<'tcx>>,
+    Q: QueryDispatcher<'tcx, Qcx = QueryCtxt<'tcx>>,
 {
     // We must avoid ever having to call `force_from_dep_node()` for a
     // `DepNode::codegen_unit`:
@@ -734,14 +727,14 @@ macro_rules! define_queries {
                 }
 
                 #[inline(always)]
-                fn restore_val(value: <Self::Dispatcher as QueryDispatcher>::Value) -> Self::UnerasedValue {
+                fn restore_val(value: <Self::Dispatcher as QueryDispatcher<'tcx>>::Value) -> Self::UnerasedValue {
                     erase::restore_val::<queries::$name::Value<'tcx>>(value)
                 }
             }
 
             pub(crate) fn collect_active_jobs<'tcx>(
                 tcx: TyCtxt<'tcx>,
-                qmap: &mut QueryMap<QueryStackDeferred<'tcx>>,
+                qmap: &mut QueryMap<'tcx>,
                 require_complete: bool,
             ) -> Option<()> {
                 let make_query = |tcx, key| {
@@ -825,7 +818,7 @@ macro_rules! define_queries {
         // These arrays are used for iteration and can't be indexed by `DepKind`.
 
         const COLLECT_ACTIVE_JOBS: &[
-            for<'tcx> fn(TyCtxt<'tcx>, &mut QueryMap<QueryStackDeferred<'tcx>>, bool) -> Option<()>
+            for<'tcx> fn(TyCtxt<'tcx>, &mut QueryMap<'tcx>, bool) -> Option<()>
         ] =
             &[$(query_impl::$name::collect_active_jobs),*];
 

compiler/rustc_query_system/src/dep_graph/graph.rs

@@ -519,7 +519,11 @@ impl<D: Deps> DepGraph<D> {
     /// This encodes a diagnostic by creating a node with an unique index and associating
     /// `diagnostic` with it, for use in the next session.
     #[inline]
-    pub fn record_diagnostic<Qcx: QueryContext>(&self, qcx: Qcx, diagnostic: &DiagInner) {
+    pub fn record_diagnostic<'tcx, Qcx: QueryContext<'tcx>>(
+        &self,
+        qcx: Qcx,
+        diagnostic: &DiagInner,
+    ) {
         if let Some(ref data) = self.data {
             D::read_deps(|task_deps| match task_deps {
                 TaskDepsRef::EvalAlways | TaskDepsRef::Ignore => return,
@@ -532,7 +536,7 @@ impl<D: Deps> DepGraph<D> {
     /// This forces a diagnostic node green by running its side effect. `prev_index` would
     /// refer to a node created used `encode_diagnostic` in the previous session.
     #[inline]
-    pub fn force_diagnostic_node<Qcx: QueryContext>(
+    pub fn force_diagnostic_node<'tcx, Qcx: QueryContext<'tcx>>(
         &self,
         qcx: Qcx,
         prev_index: SerializedDepNodeIndex,
@@ -669,7 +673,7 @@ impl<D: Deps> DepGraphData<D> {
     /// This encodes a diagnostic by creating a node with an unique index and associating
     /// `diagnostic` with it, for use in the next session.
     #[inline]
-    fn encode_diagnostic<Qcx: QueryContext>(
+    fn encode_diagnostic<'tcx, Qcx: QueryContext<'tcx>>(
         &self,
         qcx: Qcx,
         diagnostic: &DiagInner,
@@ -693,7 +697,7 @@ impl<D: Deps> DepGraphData<D> {
     /// This forces a diagnostic node green by running its side effect. `prev_index` would
     /// refer to a node created used `encode_diagnostic` in the previous session.
     #[inline]
-    fn force_diagnostic_node<Qcx: QueryContext>(
+    fn force_diagnostic_node<'tcx, Qcx: QueryContext<'tcx>>(
         &self,
         qcx: Qcx,
         prev_index: SerializedDepNodeIndex,
@@ -843,7 +847,7 @@ impl<D: Deps> DepGraph<D> {
         DepNodeColor::Unknown
     }
 
-    pub fn try_mark_green<Qcx: QueryContext<Deps = D>>(
+    pub fn try_mark_green<'tcx, Qcx: QueryContext<'tcx, Deps = D>>(
         &self,
         qcx: Qcx,
         dep_node: &DepNode,
@@ -858,7 +862,7 @@ impl<D: Deps> DepGraphData<D> {
     /// A node will have an index, when it's already been marked green, or when we can mark it
     /// green. This function will mark the current task as a reader of the specified node, when
     /// a node index can be found for that node.
-    pub(crate) fn try_mark_green<Qcx: QueryContext<Deps = D>>(
+    pub(crate) fn try_mark_green<'tcx, Qcx: QueryContext<'tcx, Deps = D>>(
         &self,
         qcx: Qcx,
         dep_node: &DepNode,
@@ -883,7 +887,7 @@ impl<D: Deps> DepGraphData<D> {
     }
 
     #[instrument(skip(self, qcx, parent_dep_node_index, frame), level = "debug")]
-    fn try_mark_parent_green<Qcx: QueryContext<Deps = D>>(
+    fn try_mark_parent_green<'tcx, Qcx: QueryContext<'tcx, Deps = D>>(
         &self,
         qcx: Qcx,
         parent_dep_node_index: SerializedDepNodeIndex,
@@ -973,7 +977,7 @@ impl<D: Deps> DepGraphData<D> {
 
     /// Try to mark a dep-node which existed in the previous compilation session as green.
     #[instrument(skip(self, qcx, prev_dep_node_index, frame), level = "debug")]
-    fn try_mark_previous_green<Qcx: QueryContext<Deps = D>>(
+    fn try_mark_previous_green<'tcx, Qcx: QueryContext<'tcx, Deps = D>>(
         &self,
         qcx: Qcx,
         prev_dep_node_index: SerializedDepNodeIndex,