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passes: check implied feature exists

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Add a check confirming that features referenced in `implied_by` meta
items actually exist.

Signed-off-by: David Wood <david.wood@huawei.com>
This commit is contained in:
David Wood 2022-07-20 14:52:23 +01:00
parent 6246d66c6d
commit e5872990d1
5 changed files with 60 additions and 30 deletions
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50
compiler/rustc_passes/src/stability.rs
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@ -3,7 +3,7 @@
use attr::StabilityLevel;
use rustc_attr::{self as attr, ConstStability, Stability, Unstable};
use rustc_data_structures::fx::{FxHashSet, FxIndexMap};
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
use rustc_errors::{struct_span_err, Applicability};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
@ -952,19 +952,45 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
remaining_lib_features.remove(&sym::libc);
remaining_lib_features.remove(&sym::test);
// We always collect the lib features declared in the current crate, even if there are
// no unknown features, because the collection also does feature attribute validation.
let local_defined_features = tcx.lib_features(());
let mut all_lib_features: FxHashMap<_, _> =
local_defined_features.to_vec().iter().map(|el| *el).collect();
let mut implications = tcx.stability_implications(rustc_hir::def_id::LOCAL_CRATE).clone();
for &cnum in tcx.crates(()) {
implications.extend(tcx.stability_implications(cnum));
all_lib_features.extend(tcx.defined_lib_features(cnum).iter().map(|el| *el));
}
let check_features = |remaining_lib_features: &mut FxIndexMap<_, _>, defined_features: &[_]| {
for &(feature, since) in defined_features {
// Check that every feature referenced by an `implied_by` exists (for features defined in the
// local crate).
for (implied_by, feature) in tcx.stability_implications(rustc_hir::def_id::LOCAL_CRATE) {
// Only `implied_by` needs to be checked, `feature` is guaranteed to exist.
if !all_lib_features.contains_key(implied_by) {
let span = local_defined_features
.stable
.get(feature)
.map(|(_, span)| span)
.or_else(|| local_defined_features.unstable.get(feature))
.expect("feature that implied another does not exist");
tcx.sess
.struct_span_err(
*span,
format!("feature `{implied_by}` implying `{feature}` does not exist"),
)
.emit();
}
}
if !remaining_lib_features.is_empty() {
for (feature, since) in all_lib_features.iter() {
if let Some(since) = since && let Some(span) = remaining_lib_features.get(&feature) {
// Warn if the user has enabled an already-stable lib feature.
if let Some(implies) = implications.get(&feature) {
unnecessary_partially_stable_feature_lint(tcx, *span, feature, *implies, since);
unnecessary_partially_stable_feature_lint(tcx, *span, *feature, *implies, *since);
} else {
unnecessary_stable_feature_lint(tcx, *span, feature, since);
unnecessary_stable_feature_lint(tcx, *span, *feature, *since);
}
}
remaining_lib_features.remove(&feature);
@ -972,20 +998,6 @@ pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
break;
}
}
};
// We always collect the lib features declared in the current crate, even if there are
// no unknown features, because the collection also does feature attribute validation.
let local_defined_features = tcx.lib_features(()).to_vec();
if !remaining_lib_features.is_empty() {
check_features(&mut remaining_lib_features, &local_defined_features);
for &cnum in tcx.crates(()) {
if remaining_lib_features.is_empty() {
break;
}
check_features(&mut remaining_lib_features, tcx.defined_lib_features(cnum));
}
}
for (feature, span) in remaining_lib_features {