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Merged
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Jun 21, 2025
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Use gen blocks in the compiler instead of from_coroutine #142801

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132 changes: 64 additions & 68 deletions compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2177,84 +2177,80 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
/// Walk the generics of the item for a trait bound whose self type
/// corresponds to the expected res, and return the trait def id.
fn for_each_trait_bound_on_res(&self, expected_res: Res) -> impl Iterator<Item = DefId> {
std::iter::from_coroutine(
#[coroutine]
move || {
let mut scope = self.scope;
loop {
let hir_id = match *scope {
Scope::Binder { hir_id, .. } => Some(hir_id),
Scope::Root { opt_parent_item: Some(parent_def_id) } => {
Some(self.tcx.local_def_id_to_hir_id(parent_def_id))
}
Scope::Body { .. }
| Scope::ObjectLifetimeDefault { .. }
| Scope::Supertrait { .. }
| Scope::TraitRefBoundary { .. }
| Scope::LateBoundary { .. }
| Scope::Opaque { .. }
| Scope::Root { opt_parent_item: None } => None,
};
gen move {
let mut scope = self.scope;
loop {
let hir_id = match *scope {
Scope::Binder { hir_id, .. } => Some(hir_id),
Scope::Root { opt_parent_item: Some(parent_def_id) } => {
Some(self.tcx.local_def_id_to_hir_id(parent_def_id))
}
Scope::Body { .. }
| Scope::ObjectLifetimeDefault { .. }
| Scope::Supertrait { .. }
| Scope::TraitRefBoundary { .. }
| Scope::LateBoundary { .. }
| Scope::Opaque { .. }
| Scope::Root { opt_parent_item: None } => None,
};

if let Some(hir_id) = hir_id {
let node = self.tcx.hir_node(hir_id);
// If this is a `Self` bound in a trait, yield the trait itself.
// Specifically, we don't need to look at any supertraits since
// we already do that in `BoundVarContext::supertrait_hrtb_vars`.
if let Res::SelfTyParam { trait_: _ } = expected_res
&& let hir::Node::Item(item) = node
&& let hir::ItemKind::Trait(..) = item.kind
{
// Yield the trait's def id. Supertraits will be
// elaborated from that.
yield item.owner_id.def_id.to_def_id();
} else if let Some(generics) = node.generics() {
for pred in generics.predicates {
let hir::WherePredicateKind::BoundPredicate(pred) = pred.kind
else {
continue;
};
let hir::TyKind::Path(hir::QPath::Resolved(None, bounded_path)) =
pred.bounded_ty.kind
else {
continue;
};
// Match the expected res.
if bounded_path.res != expected_res {
continue;
}
for pred in pred.bounds {
match pred {
hir::GenericBound::Trait(poly_trait_ref) => {
if let Some(def_id) =
poly_trait_ref.trait_ref.trait_def_id()
{
yield def_id;
}
if let Some(hir_id) = hir_id {
let node = self.tcx.hir_node(hir_id);
// If this is a `Self` bound in a trait, yield the trait itself.
// Specifically, we don't need to look at any supertraits since
// we already do that in `BoundVarContext::supertrait_hrtb_vars`.
if let Res::SelfTyParam { trait_: _ } = expected_res
&& let hir::Node::Item(item) = node
&& let hir::ItemKind::Trait(..) = item.kind
{
// Yield the trait's def id. Supertraits will be
// elaborated from that.
yield item.owner_id.def_id.to_def_id();
} else if let Some(generics) = node.generics() {
for pred in generics.predicates {
let hir::WherePredicateKind::BoundPredicate(pred) = pred.kind else {
continue;
};
let hir::TyKind::Path(hir::QPath::Resolved(None, bounded_path)) =
pred.bounded_ty.kind
else {
continue;
};
// Match the expected res.
if bounded_path.res != expected_res {
continue;
}
for pred in pred.bounds {
match pred {
hir::GenericBound::Trait(poly_trait_ref) => {
if let Some(def_id) =
poly_trait_ref.trait_ref.trait_def_id()
{
yield def_id;
}
hir::GenericBound::Outlives(_)
| hir::GenericBound::Use(_, _) => {}
}
hir::GenericBound::Outlives(_)
| hir::GenericBound::Use(_, _) => {}
}
}
}
}
}

match *scope {
Scope::Binder { s, .. }
| Scope::Body { s, .. }
| Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s }
| Scope::LateBoundary { s, .. }
| Scope::Opaque { s, .. } => {
scope = s;
}
Scope::Root { .. } => break,
match *scope {
Scope::Binder { s, .. }
| Scope::Body { s, .. }
| Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s }
| Scope::LateBoundary { s, .. }
| Scope::Opaque { s, .. } => {
scope = s;
}
Scope::Root { .. } => break,
}
},
)
}
}
}
}

Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_hir_analysis/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -62,8 +62,8 @@ This API is completely unstable and subject to change.
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![doc(rust_logo)]
#![feature(assert_matches)]
#![feature(coroutines)]
#![feature(debug_closure_helpers)]
#![feature(gen_blocks)]
#![feature(if_let_guard)]
#![feature(iter_from_coroutine)]
#![feature(iter_intersperse)]
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_metadata/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,10 +2,10 @@
#![allow(internal_features)]
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![doc(rust_logo)]
#![feature(coroutines)]
#![feature(decl_macro)]
#![feature(error_iter)]
#![feature(file_buffered)]
#![feature(gen_blocks)]
#![feature(if_let_guard)]
#![feature(iter_from_coroutine)]
#![feature(macro_metavar_expr)]
Expand Down
44 changes: 20 additions & 24 deletions compiler/rustc_metadata/src/rmeta/decoder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@
use std::iter::TrustedLen;
use std::path::{Path, PathBuf};
use std::sync::{Arc, OnceLock};
use std::{io, iter, mem};
use std::{io, mem};

pub(super) use cstore_impl::provide;
use rustc_ast as ast;
Expand Down Expand Up @@ -1272,34 +1272,30 @@ impl<'a> CrateMetadataRef<'a> {
id: DefIndex,
sess: &'a Session,
) -> impl Iterator<Item = ModChild> {
iter::from_coroutine(
#[coroutine]
move || {
if let Some(data) = &self.root.proc_macro_data {
// If we are loading as a proc macro, we want to return
// the view of this crate as a proc macro crate.
if id == CRATE_DEF_INDEX {
for child_index in data.macros.decode(self) {
yield self.get_mod_child(child_index, sess);
}
}
} else {
// Iterate over all children.
let non_reexports =
self.root.tables.module_children_non_reexports.get(self, id);
for child_index in non_reexports.unwrap().decode(self) {
gen move {
if let Some(data) = &self.root.proc_macro_data {
// If we are loading as a proc macro, we want to return
// the view of this crate as a proc macro crate.
if id == CRATE_DEF_INDEX {
for child_index in data.macros.decode(self) {
yield self.get_mod_child(child_index, sess);
}
}
} else {
// Iterate over all children.
let non_reexports = self.root.tables.module_children_non_reexports.get(self, id);
for child_index in non_reexports.unwrap().decode(self) {
yield self.get_mod_child(child_index, sess);
}

let reexports = self.root.tables.module_children_reexports.get(self, id);
if !reexports.is_default() {
for reexport in reexports.decode((self, sess)) {
yield reexport;
}
let reexports = self.root.tables.module_children_reexports.get(self, id);
if !reexports.is_default() {
for reexport in reexports.decode((self, sess)) {
yield reexport;
}
}
},
)
}
}
}

fn is_ctfe_mir_available(self, id: DefIndex) -> bool {
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -40,12 +40,12 @@
#![feature(box_patterns)]
#![feature(closure_track_caller)]
#![feature(core_intrinsics)]
#![feature(coroutines)]
#![feature(debug_closure_helpers)]
#![feature(decl_macro)]
#![feature(discriminant_kind)]
#![feature(extern_types)]
#![feature(file_buffered)]
#![feature(gen_blocks)]
#![feature(if_let_guard)]
#![feature(intra_doc_pointers)]
#![feature(iter_from_coroutine)]
Expand Down
82 changes: 39 additions & 43 deletions compiler/rustc_middle/src/ty/closure.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -422,53 +422,49 @@ pub fn analyze_coroutine_closure_captures<'a, 'tcx: 'a, T>(
child_captures: impl IntoIterator<Item = &'a CapturedPlace<'tcx>>,
mut for_each: impl FnMut((usize, &'a CapturedPlace<'tcx>), (usize, &'a CapturedPlace<'tcx>)) -> T,
) -> impl Iterator<Item = T> {
std::iter::from_coroutine(
#[coroutine]
move || {
let mut child_captures = child_captures.into_iter().enumerate().peekable();

// One parent capture may correspond to several child captures if we end up
// refining the set of captures via edition-2021 precise captures. We want to
// match up any number of child captures with one parent capture, so we keep
// peeking off this `Peekable` until the child doesn't match anymore.
for (parent_field_idx, parent_capture) in parent_captures.into_iter().enumerate() {
// Make sure we use every field at least once, b/c why are we capturing something
// if it's not used in the inner coroutine.
let mut field_used_at_least_once = false;

// A parent matches a child if they share the same prefix of projections.
// The child may have more, if it is capturing sub-fields out of
// something that is captured by-move in the parent closure.
while child_captures.peek().is_some_and(|(_, child_capture)| {
child_prefix_matches_parent_projections(parent_capture, child_capture)
}) {
let (child_field_idx, child_capture) = child_captures.next().unwrap();
// This analysis only makes sense if the parent capture is a
// prefix of the child capture.
assert!(
child_capture.place.projections.len()
>= parent_capture.place.projections.len(),
"parent capture ({parent_capture:#?}) expected to be prefix of \
gen move {
let mut child_captures = child_captures.into_iter().enumerate().peekable();

// One parent capture may correspond to several child captures if we end up
// refining the set of captures via edition-2021 precise captures. We want to
// match up any number of child captures with one parent capture, so we keep
// peeking off this `Peekable` until the child doesn't match anymore.
for (parent_field_idx, parent_capture) in parent_captures.into_iter().enumerate() {
// Make sure we use every field at least once, b/c why are we capturing something
// if it's not used in the inner coroutine.
let mut field_used_at_least_once = false;

// A parent matches a child if they share the same prefix of projections.
// The child may have more, if it is capturing sub-fields out of
// something that is captured by-move in the parent closure.
while child_captures.peek().is_some_and(|(_, child_capture)| {
child_prefix_matches_parent_projections(parent_capture, child_capture)
}) {
let (child_field_idx, child_capture) = child_captures.next().unwrap();
// This analysis only makes sense if the parent capture is a
// prefix of the child capture.
assert!(
child_capture.place.projections.len() >= parent_capture.place.projections.len(),
"parent capture ({parent_capture:#?}) expected to be prefix of \
child capture ({child_capture:#?})"
);

yield for_each(
(parent_field_idx, parent_capture),
(child_field_idx, child_capture),
);

field_used_at_least_once = true;
}
);

// Make sure the field was used at least once.
assert!(
field_used_at_least_once,
"we captured {parent_capture:#?} but it was not used in the child coroutine?"
yield for_each(
(parent_field_idx, parent_capture),
(child_field_idx, child_capture),
);

field_used_at_least_once = true;
}
assert_eq!(child_captures.next(), None, "leftover child captures?");
},
)

// Make sure the field was used at least once.
assert!(
field_used_at_least_once,
"we captured {parent_capture:#?} but it was not used in the child coroutine?"
);
}
assert_eq!(child_captures.next(), None, "leftover child captures?");
}
}

fn child_prefix_matches_parent_projections(
Expand Down
29 changes: 13 additions & 16 deletions compiler/rustc_middle/src/ty/context.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2087,23 +2087,20 @@ impl<'tcx> TyCtxt<'tcx> {
self.dep_graph.read_index(DepNodeIndex::FOREVER_RED_NODE);

let definitions = &self.untracked.definitions;
std::iter::from_coroutine(
#[coroutine]
|| {
let mut i = 0;

// Recompute the number of definitions each time, because our caller may be creating
// new ones.
while i < { definitions.read().num_definitions() } {
let local_def_index = rustc_span::def_id::DefIndex::from_usize(i);
yield LocalDefId { local_def_index };
i += 1;
}
gen {
let mut i = 0;

// Recompute the number of definitions each time, because our caller may be creating
// new ones.
while i < { definitions.read().num_definitions() } {
let local_def_index = rustc_span::def_id::DefIndex::from_usize(i);
yield LocalDefId { local_def_index };
i += 1;
}

// Freeze definitions once we finish iterating on them, to prevent adding new ones.
definitions.freeze();
},
)
// Freeze definitions once we finish iterating on them, to prevent adding new ones.
definitions.freeze();
}
}

pub fn def_path_table(self) -> &'tcx rustc_hir::definitions::DefPathTable {
Expand Down
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