Rollup of 4 pull requests

compiler/rustc_hir_analysis/src/delegation.rs

@@ -572,17 +572,15 @@ fn get_delegation_user_specified_args<'tcx>(
         .opt_delegation_generics()
         .expect("Lowering delegation");
 
-    let get_segment = |hir_id: HirId| -> (&'tcx PathSegment<'tcx>, DefId) {
+    let get_segment = |hir_id: HirId| -> Option<(&'tcx PathSegment<'tcx>, DefId)> {
         let segment = tcx.hir_node(hir_id).expect_path_segment();
-        let def_id = segment.res.def_id();
-
-        (segment, def_id)
+        segment.res.opt_def_id().map(|def_id| (segment, def_id))
     };
 
     let ctx = ItemCtxt::new(tcx, delegation_id);
     let lowerer = ctx.lowerer();
 
-    let parent_args = info.parent_args_segment_id.map(get_segment).map(|(segment, def_id)| {
+    let parent_args = info.parent_args_segment_id.and_then(get_segment).map(|(segment, def_id)| {
         let self_ty = get_delegation_self_ty(tcx, delegation_id);
 
         lowerer
@@ -598,7 +596,7 @@ fn get_delegation_user_specified_args<'tcx>(
             .as_slice()
     });
 
-    let child_args = info.child_args_segment_id.map(get_segment).map(|(segment, def_id)| {
+    let child_args = info.child_args_segment_id.and_then(get_segment).map(|(segment, def_id)| {
         let parent_args = if let Some(parent_args) = parent_args {
             parent_args
         } else {

compiler/rustc_interface/src/passes.rs

@@ -964,6 +964,17 @@ pub fn create_and_enter_global_ctxt<T, F: for<'tcx> FnOnce(TyCtxt<'tcx>) -> T>(
 
     let incremental = dep_graph.is_fully_enabled();
 
+    // Note: this function body is the origin point of the widely-used 'tcx lifetime.
+    //
+    // `gcx_cell` is defined here and `&gcx_cell` is passed to `create_global_ctxt`, which then
+    // actually creates the `GlobalCtxt` with a `gcx_cell.get_or_init(...)` call. This is done so
+    // that the resulting reference has the type `&'tcx GlobalCtxt<'tcx>`, which is what `TyCtxt`
+    // needs. If we defined and created the `GlobalCtxt` within `create_global_ctxt` then its type
+    // would be `&'a GlobalCtxt<'tcx>`, with two lifetimes.
+    //
+    // Similarly, by creating `arena` here and passing in `&arena`, that reference has the type
+    // `&'tcx WorkerLocal<Arena<'tcx>>`, also with one lifetime. And likewise for `hir_arena`.
+
     let gcx_cell = OnceLock::new();
     let arena = WorkerLocal::new(|_| Arena::default());
     let hir_arena = WorkerLocal::new(|_| rustc_hir::Arena::default());

compiler/rustc_middle/src/dep_graph/graph.rs

@@ -1,6 +1,5 @@
 use std::fmt::Debug;
 use std::hash::Hash;
-use std::marker::PhantomData;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicU32, Ordering};
 
@@ -1377,8 +1376,6 @@ pub struct TaskDeps {
     /// scan. If the number is higher, a hashset has better perf. This field is that hashset. It's
     /// only used if the number of elements in `reads` exceeds `LINEAR_SCAN_MAX`.
     read_set: FxHashSet<DepNodeIndex>,
-
-    phantom_data: PhantomData<DepNode>,
 }
 
 impl TaskDeps {
@@ -1392,7 +1389,6 @@ impl TaskDeps {
             node,
             reads: EdgesVec::new(),
             read_set: FxHashSet::with_capacity_and_hasher(read_set_capacity, Default::default()),
-            phantom_data: PhantomData,
         }
     }
 }

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -4,7 +4,6 @@
 //! to help with the tedium.
 
 use std::fmt::{self, Debug};
-use std::marker::PhantomData;
 
 use rustc_abi::TyAndLayout;
 use rustc_hir::def::Namespace;
@@ -270,13 +269,6 @@ TrivialTypeTraversalAndLiftImpls! {
 ///////////////////////////////////////////////////////////////////////////
 // Lift implementations
 
-impl<'tcx> Lift<TyCtxt<'tcx>> for PhantomData<&()> {
-    type Lifted = PhantomData<&'tcx ()>;
-    fn lift_to_interner(self, _: TyCtxt<'tcx>) -> Option<Self::Lifted> {
-        Some(PhantomData)
-    }
-}
-
 impl<'tcx, T: Lift<TyCtxt<'tcx>>> Lift<TyCtxt<'tcx>> for Option<T> {
     type Lifted = Option<T::Lifted>;
     fn lift_to_interner(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {

src/bootstrap/src/core/build_steps/dist.rs

@@ -87,6 +87,12 @@ impl Step for Docs {
         // from a shared directory.
         builder.run_default_doc_steps();
 
+        // In case no default doc steps are run for host, it is possible that `<host>/doc` directory
+        // is never created.
+        if !builder.config.dry_run() {
+            t!(fs::create_dir_all(builder.doc_out(host)));
+        }
+
         let dest = "share/doc/rust/html";
 
         let mut tarball = Tarball::new(builder, "rust-docs", &host.triple);

tests/ui/delegation/generics/unresolved-segment-ice-153389.rs

@@ -0,0 +1,13 @@
+#![feature(fn_delegation)]
+#![allow(incomplete_features)]
+
+trait Trait{
+    fn bar();
+}
+
+impl Trait for () {
+    reuse missing::<> as bar;
+    //~^ ERROR: cannot find function `missing` in this scope
+}
+
+fn main() {}

tests/ui/delegation/generics/unresolved-segment-ice-153389.stderr

@@ -0,0 +1,9 @@
+error[E0425]: cannot find function `missing` in this scope
+  --> $DIR/unresolved-segment-ice-153389.rs:9:11
+   |
+LL |     reuse missing::<> as bar;
+   |           ^^^^^^^ not found in this scope
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0425`.