698 lines
27 KiB
Rust
698 lines
27 KiB
Rust
//! A pass that annotates every item and method with its stability level,
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//! propagating default levels lexically from parent to children ast nodes.
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use rustc_ast::Attribute;
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use rustc_attr::{self as attr, ConstStability, Stability};
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_errors::struct_span_err;
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, Res};
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use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
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use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
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use rustc_hir::{Generics, HirId, Item, StructField, Variant};
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use rustc_middle::hir::map::Map;
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use rustc_middle::middle::privacy::AccessLevels;
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use rustc_middle::middle::stability::{DeprecationEntry, Index};
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use rustc_middle::ty::query::Providers;
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use rustc_middle::ty::TyCtxt;
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use rustc_session::lint;
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use rustc_session::parse::feature_err;
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use rustc_session::Session;
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use rustc_span::symbol::{sym, Symbol};
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use rustc_span::Span;
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use rustc_trait_selection::traits::misc::can_type_implement_copy;
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use std::cmp::Ordering;
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use std::mem::replace;
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use std::num::NonZeroU32;
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#[derive(PartialEq)]
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enum AnnotationKind {
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// Annotation is required if not inherited from unstable parents
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Required,
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// Annotation is useless, reject it
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Prohibited,
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// Annotation itself is useless, but it can be propagated to children
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Container,
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}
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// A private tree-walker for producing an Index.
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struct Annotator<'a, 'tcx> {
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tcx: TyCtxt<'tcx>,
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index: &'a mut Index<'tcx>,
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parent_stab: Option<&'tcx Stability>,
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parent_const_stab: Option<&'tcx ConstStability>,
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parent_depr: Option<DeprecationEntry>,
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in_trait_impl: bool,
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}
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impl<'a, 'tcx> Annotator<'a, 'tcx> {
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// Determine the stability for a node based on its attributes and inherited
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// stability. The stability is recorded in the index and used as the parent.
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fn annotate<F>(
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&mut self,
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hir_id: HirId,
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attrs: &[Attribute],
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item_sp: Span,
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kind: AnnotationKind,
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visit_children: F,
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) where
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F: FnOnce(&mut Self),
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{
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debug!("annotate(id = {:?}, attrs = {:?})", hir_id, attrs);
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let mut did_error = false;
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if !self.tcx.features().staged_api {
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did_error = self.forbid_staged_api_attrs(hir_id, attrs);
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}
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let depr =
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if did_error { None } else { attr::find_deprecation(&self.tcx.sess, attrs, item_sp) };
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let mut is_deprecated = false;
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if let Some(depr) = &depr {
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is_deprecated = true;
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if kind == AnnotationKind::Prohibited {
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self.tcx.sess.span_err(item_sp, "This deprecation annotation is useless");
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}
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// `Deprecation` is just two pointers, no need to intern it
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let depr_entry = DeprecationEntry::local(depr.clone(), hir_id);
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self.index.depr_map.insert(hir_id, depr_entry);
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} else if let Some(parent_depr) = self.parent_depr.clone() {
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is_deprecated = true;
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info!("tagging child {:?} as deprecated from parent", hir_id);
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self.index.depr_map.insert(hir_id, parent_depr);
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}
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if self.tcx.features().staged_api {
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if let Some(..) = attrs.iter().find(|a| self.tcx.sess.check_name(a, sym::deprecated)) {
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self.tcx.sess.span_err(
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item_sp,
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"`#[deprecated]` cannot be used in staged API; \
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use `#[rustc_deprecated]` instead",
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);
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}
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} else {
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self.recurse_with_stability_attrs(
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depr.map(|d| DeprecationEntry::local(d, hir_id)),
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None,
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None,
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visit_children,
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);
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return;
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}
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let (stab, const_stab) = attr::find_stability(&self.tcx.sess, attrs, item_sp);
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let const_stab = const_stab.map(|const_stab| {
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let const_stab = self.tcx.intern_const_stability(const_stab);
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self.index.const_stab_map.insert(hir_id, const_stab);
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const_stab
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});
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if const_stab.is_none() {
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debug!("annotate: const_stab not found, parent = {:?}", self.parent_const_stab);
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if let Some(parent) = self.parent_const_stab {
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if parent.level.is_unstable() {
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self.index.const_stab_map.insert(hir_id, parent);
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}
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}
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}
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if depr.as_ref().map_or(false, |d| d.is_since_rustc_version) {
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if stab.is_none() {
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struct_span_err!(
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self.tcx.sess,
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item_sp,
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E0549,
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"rustc_deprecated attribute must be paired with \
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either stable or unstable attribute"
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)
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.emit();
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}
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}
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let stab = stab.map(|stab| {
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// Error if prohibited, or can't inherit anything from a container.
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if kind == AnnotationKind::Prohibited
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|| (kind == AnnotationKind::Container && stab.level.is_stable() && is_deprecated)
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{
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self.tcx.sess.span_err(item_sp, "This stability annotation is useless");
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}
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debug!("annotate: found {:?}", stab);
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let stab = self.tcx.intern_stability(stab);
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// Check if deprecated_since < stable_since. If it is,
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// this is *almost surely* an accident.
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if let (&Some(dep_since), &attr::Stable { since: stab_since }) =
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(&depr.as_ref().and_then(|d| d.since), &stab.level)
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{
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// Explicit version of iter::order::lt to handle parse errors properly
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for (dep_v, stab_v) in
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dep_since.as_str().split('.').zip(stab_since.as_str().split('.'))
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{
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if let (Ok(dep_v), Ok(stab_v)) = (dep_v.parse::<u64>(), stab_v.parse()) {
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match dep_v.cmp(&stab_v) {
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Ordering::Less => {
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self.tcx.sess.span_err(
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item_sp,
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"An API can't be stabilized \
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after it is deprecated",
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);
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break;
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}
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Ordering::Equal => continue,
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Ordering::Greater => break,
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}
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} else {
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// Act like it isn't less because the question is now nonsensical,
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// and this makes us not do anything else interesting.
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self.tcx.sess.span_err(
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item_sp,
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"Invalid stability or deprecation \
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version found",
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);
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break;
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}
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}
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}
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self.index.stab_map.insert(hir_id, stab);
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stab
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});
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if stab.is_none() {
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debug!("annotate: stab not found, parent = {:?}", self.parent_stab);
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if let Some(stab) = self.parent_stab {
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if stab.level.is_unstable() {
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self.index.stab_map.insert(hir_id, stab);
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}
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}
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}
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self.recurse_with_stability_attrs(
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depr.map(|d| DeprecationEntry::local(d, hir_id)),
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stab,
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const_stab,
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visit_children,
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);
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}
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fn recurse_with_stability_attrs(
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&mut self,
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depr: Option<DeprecationEntry>,
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stab: Option<&'tcx Stability>,
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const_stab: Option<&'tcx ConstStability>,
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f: impl FnOnce(&mut Self),
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) {
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// These will be `Some` if this item changes the corresponding stability attribute.
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let mut replaced_parent_depr = None;
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let mut replaced_parent_stab = None;
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let mut replaced_parent_const_stab = None;
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if let Some(depr) = depr {
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replaced_parent_depr = Some(replace(&mut self.parent_depr, Some(depr)));
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}
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if let Some(stab) = stab {
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replaced_parent_stab = Some(replace(&mut self.parent_stab, Some(stab)));
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}
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if let Some(const_stab) = const_stab {
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replaced_parent_const_stab =
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Some(replace(&mut self.parent_const_stab, Some(const_stab)));
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}
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f(self);
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if let Some(orig_parent_depr) = replaced_parent_depr {
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self.parent_depr = orig_parent_depr;
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}
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if let Some(orig_parent_stab) = replaced_parent_stab {
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self.parent_stab = orig_parent_stab;
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}
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if let Some(orig_parent_const_stab) = replaced_parent_const_stab {
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self.parent_const_stab = orig_parent_const_stab;
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}
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}
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// returns true if an error occurred, used to suppress some spurious errors
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fn forbid_staged_api_attrs(&mut self, hir_id: HirId, attrs: &[Attribute]) -> bool {
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// Emit errors for non-staged-api crates.
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let unstable_attrs = [
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sym::unstable,
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sym::stable,
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sym::rustc_deprecated,
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sym::rustc_const_unstable,
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sym::rustc_const_stable,
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];
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let mut has_error = false;
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for attr in attrs {
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let name = attr.name_or_empty();
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if unstable_attrs.contains(&name) {
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self.tcx.sess.mark_attr_used(attr);
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struct_span_err!(
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self.tcx.sess,
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attr.span,
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E0734,
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"stability attributes may not be used outside of the standard library",
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)
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.emit();
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has_error = true;
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}
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}
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// Propagate unstability. This can happen even for non-staged-api crates in case
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// -Zforce-unstable-if-unmarked is set.
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if let Some(stab) = self.parent_stab {
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if stab.level.is_unstable() {
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self.index.stab_map.insert(hir_id, stab);
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}
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}
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has_error
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for Annotator<'a, 'tcx> {
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/// Because stability levels are scoped lexically, we want to walk
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/// nested items in the context of the outer item, so enable
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/// deep-walking.
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type Map = Map<'tcx>;
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fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
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NestedVisitorMap::All(self.tcx.hir())
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}
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fn visit_item(&mut self, i: &'tcx Item<'tcx>) {
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let orig_in_trait_impl = self.in_trait_impl;
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let mut kind = AnnotationKind::Required;
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match i.kind {
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// Inherent impls and foreign modules serve only as containers for other items,
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// they don't have their own stability. They still can be annotated as unstable
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// and propagate this unstability to children, but this annotation is completely
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// optional. They inherit stability from their parents when unannotated.
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hir::ItemKind::Impl { of_trait: None, .. } | hir::ItemKind::ForeignMod(..) => {
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self.in_trait_impl = false;
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kind = AnnotationKind::Container;
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}
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hir::ItemKind::Impl { of_trait: Some(_), .. } => {
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self.in_trait_impl = true;
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}
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hir::ItemKind::Struct(ref sd, _) => {
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if let Some(ctor_hir_id) = sd.ctor_hir_id() {
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self.annotate(ctor_hir_id, &i.attrs, i.span, AnnotationKind::Required, |_| {})
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}
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}
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_ => {}
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}
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self.annotate(i.hir_id, &i.attrs, i.span, kind, |v| intravisit::walk_item(v, i));
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self.in_trait_impl = orig_in_trait_impl;
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}
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fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem<'tcx>) {
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self.annotate(ti.hir_id, &ti.attrs, ti.span, AnnotationKind::Required, |v| {
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intravisit::walk_trait_item(v, ti);
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});
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}
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fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem<'tcx>) {
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let kind =
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if self.in_trait_impl { AnnotationKind::Prohibited } else { AnnotationKind::Required };
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self.annotate(ii.hir_id, &ii.attrs, ii.span, kind, |v| {
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intravisit::walk_impl_item(v, ii);
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});
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}
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fn visit_variant(&mut self, var: &'tcx Variant<'tcx>, g: &'tcx Generics<'tcx>, item_id: HirId) {
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self.annotate(var.id, &var.attrs, var.span, AnnotationKind::Required, |v| {
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if let Some(ctor_hir_id) = var.data.ctor_hir_id() {
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v.annotate(ctor_hir_id, &var.attrs, var.span, AnnotationKind::Required, |_| {});
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}
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intravisit::walk_variant(v, var, g, item_id)
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})
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}
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fn visit_struct_field(&mut self, s: &'tcx StructField<'tcx>) {
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self.annotate(s.hir_id, &s.attrs, s.span, AnnotationKind::Required, |v| {
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intravisit::walk_struct_field(v, s);
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});
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}
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fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem<'tcx>) {
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self.annotate(i.hir_id, &i.attrs, i.span, AnnotationKind::Required, |v| {
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intravisit::walk_foreign_item(v, i);
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});
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}
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fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef<'tcx>) {
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self.annotate(md.hir_id, &md.attrs, md.span, AnnotationKind::Required, |_| {});
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}
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}
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struct MissingStabilityAnnotations<'tcx> {
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tcx: TyCtxt<'tcx>,
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access_levels: &'tcx AccessLevels,
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}
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impl<'tcx> MissingStabilityAnnotations<'tcx> {
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fn check_missing_stability(&self, hir_id: HirId, span: Span) {
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let stab = self.tcx.stability().local_stability(hir_id);
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let is_error =
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!self.tcx.sess.opts.test && stab.is_none() && self.access_levels.is_reachable(hir_id);
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if is_error {
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let def_id = self.tcx.hir().local_def_id(hir_id);
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let descr = self.tcx.def_kind(def_id).descr(def_id.to_def_id());
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self.tcx.sess.span_err(span, &format!("{} has missing stability attribute", descr));
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}
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}
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}
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impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> {
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type Map = Map<'tcx>;
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fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
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NestedVisitorMap::OnlyBodies(self.tcx.hir())
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}
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fn visit_item(&mut self, i: &'tcx Item<'tcx>) {
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match i.kind {
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// Inherent impls and foreign modules serve only as containers for other items,
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// they don't have their own stability. They still can be annotated as unstable
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// and propagate this unstability to children, but this annotation is completely
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// optional. They inherit stability from their parents when unannotated.
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hir::ItemKind::Impl { of_trait: None, .. } | hir::ItemKind::ForeignMod(..) => {}
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_ => self.check_missing_stability(i.hir_id, i.span),
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}
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intravisit::walk_item(self, i)
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}
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fn visit_trait_item(&mut self, ti: &'tcx hir::TraitItem<'tcx>) {
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self.check_missing_stability(ti.hir_id, ti.span);
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intravisit::walk_trait_item(self, ti);
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}
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fn visit_impl_item(&mut self, ii: &'tcx hir::ImplItem<'tcx>) {
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let impl_def_id = self.tcx.hir().local_def_id(self.tcx.hir().get_parent_item(ii.hir_id));
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if self.tcx.impl_trait_ref(impl_def_id).is_none() {
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self.check_missing_stability(ii.hir_id, ii.span);
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}
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intravisit::walk_impl_item(self, ii);
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}
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fn visit_variant(&mut self, var: &'tcx Variant<'tcx>, g: &'tcx Generics<'tcx>, item_id: HirId) {
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self.check_missing_stability(var.id, var.span);
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intravisit::walk_variant(self, var, g, item_id);
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}
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fn visit_struct_field(&mut self, s: &'tcx StructField<'tcx>) {
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self.check_missing_stability(s.hir_id, s.span);
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intravisit::walk_struct_field(self, s);
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}
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fn visit_foreign_item(&mut self, i: &'tcx hir::ForeignItem<'tcx>) {
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self.check_missing_stability(i.hir_id, i.span);
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intravisit::walk_foreign_item(self, i);
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}
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fn visit_macro_def(&mut self, md: &'tcx hir::MacroDef<'tcx>) {
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self.check_missing_stability(md.hir_id, md.span);
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}
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}
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fn new_index(tcx: TyCtxt<'tcx>) -> Index<'tcx> {
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let is_staged_api =
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tcx.sess.opts.debugging_opts.force_unstable_if_unmarked || tcx.features().staged_api;
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let mut staged_api = FxHashMap::default();
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staged_api.insert(LOCAL_CRATE, is_staged_api);
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let mut index = Index {
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staged_api,
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stab_map: Default::default(),
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const_stab_map: Default::default(),
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depr_map: Default::default(),
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active_features: Default::default(),
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};
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let active_lib_features = &tcx.features().declared_lib_features;
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let active_lang_features = &tcx.features().declared_lang_features;
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// Put the active features into a map for quick lookup.
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index.active_features = active_lib_features
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.iter()
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.map(|&(s, ..)| s)
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.chain(active_lang_features.iter().map(|&(s, ..)| s))
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.collect();
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{
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let krate = tcx.hir().krate();
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let mut annotator = Annotator {
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tcx,
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index: &mut index,
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parent_stab: None,
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parent_const_stab: None,
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parent_depr: None,
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in_trait_impl: false,
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};
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|
|
|
// If the `-Z force-unstable-if-unmarked` flag is passed then we provide
|
|
// a parent stability annotation which indicates that this is private
|
|
// with the `rustc_private` feature. This is intended for use when
|
|
// compiling `librustc_*` crates themselves so we can leverage crates.io
|
|
// while maintaining the invariant that all sysroot crates are unstable
|
|
// by default and are unable to be used.
|
|
if tcx.sess.opts.debugging_opts.force_unstable_if_unmarked {
|
|
let reason = "this crate is being loaded from the sysroot, an \
|
|
unstable location; did you mean to load this crate \
|
|
from crates.io via `Cargo.toml` instead?";
|
|
let stability = tcx.intern_stability(Stability {
|
|
level: attr::StabilityLevel::Unstable {
|
|
reason: Some(Symbol::intern(reason)),
|
|
issue: NonZeroU32::new(27812),
|
|
is_soft: false,
|
|
},
|
|
feature: sym::rustc_private,
|
|
});
|
|
annotator.parent_stab = Some(stability);
|
|
}
|
|
|
|
annotator.annotate(
|
|
hir::CRATE_HIR_ID,
|
|
&krate.item.attrs,
|
|
krate.item.span,
|
|
AnnotationKind::Required,
|
|
|v| intravisit::walk_crate(v, krate),
|
|
);
|
|
}
|
|
index
|
|
}
|
|
|
|
/// Cross-references the feature names of unstable APIs with enabled
|
|
/// features and possibly prints errors.
|
|
fn check_mod_unstable_api_usage(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
|
|
tcx.hir().visit_item_likes_in_module(module_def_id, &mut Checker { tcx }.as_deep_visitor());
|
|
}
|
|
|
|
pub(crate) fn provide(providers: &mut Providers) {
|
|
*providers = Providers { check_mod_unstable_api_usage, ..*providers };
|
|
providers.stability_index = |tcx, cnum| {
|
|
assert_eq!(cnum, LOCAL_CRATE);
|
|
new_index(tcx)
|
|
};
|
|
}
|
|
|
|
struct Checker<'tcx> {
|
|
tcx: TyCtxt<'tcx>,
|
|
}
|
|
|
|
impl Visitor<'tcx> for Checker<'tcx> {
|
|
type Map = Map<'tcx>;
|
|
|
|
/// Because stability levels are scoped lexically, we want to walk
|
|
/// nested items in the context of the outer item, so enable
|
|
/// deep-walking.
|
|
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
|
|
NestedVisitorMap::OnlyBodies(self.tcx.hir())
|
|
}
|
|
|
|
fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
|
|
match item.kind {
|
|
hir::ItemKind::ExternCrate(_) => {
|
|
// compiler-generated `extern crate` items have a dummy span.
|
|
// `std` is still checked for the `restricted-std` feature.
|
|
if item.span.is_dummy() && item.ident.as_str() != "std" {
|
|
return;
|
|
}
|
|
|
|
let def_id = self.tcx.hir().local_def_id(item.hir_id);
|
|
let cnum = match self.tcx.extern_mod_stmt_cnum(def_id) {
|
|
Some(cnum) => cnum,
|
|
None => return,
|
|
};
|
|
let def_id = DefId { krate: cnum, index: CRATE_DEF_INDEX };
|
|
self.tcx.check_stability(def_id, Some(item.hir_id), item.span);
|
|
}
|
|
|
|
// For implementations of traits, check the stability of each item
|
|
// individually as it's possible to have a stable trait with unstable
|
|
// items.
|
|
hir::ItemKind::Impl { of_trait: Some(ref t), items, .. } => {
|
|
if let Res::Def(DefKind::Trait, trait_did) = t.path.res {
|
|
for impl_item_ref in items {
|
|
let impl_item = self.tcx.hir().impl_item(impl_item_ref.id);
|
|
let trait_item_def_id = self
|
|
.tcx
|
|
.associated_items(trait_did)
|
|
.filter_by_name_unhygienic(impl_item.ident.name)
|
|
.next()
|
|
.map(|item| item.def_id);
|
|
if let Some(def_id) = trait_item_def_id {
|
|
// Pass `None` to skip deprecation warnings.
|
|
self.tcx.check_stability(def_id, None, impl_item.span);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// There's no good place to insert stability check for non-Copy unions,
|
|
// so semi-randomly perform it here in stability.rs
|
|
hir::ItemKind::Union(..) if !self.tcx.features().untagged_unions => {
|
|
let def_id = self.tcx.hir().local_def_id(item.hir_id);
|
|
let adt_def = self.tcx.adt_def(def_id);
|
|
let ty = self.tcx.type_of(def_id);
|
|
|
|
if adt_def.has_dtor(self.tcx) {
|
|
feature_err(
|
|
&self.tcx.sess.parse_sess,
|
|
sym::untagged_unions,
|
|
item.span,
|
|
"unions with `Drop` implementations are unstable",
|
|
)
|
|
.emit();
|
|
} else {
|
|
let param_env = self.tcx.param_env(def_id);
|
|
if can_type_implement_copy(self.tcx, param_env, ty).is_err() {
|
|
feature_err(
|
|
&self.tcx.sess.parse_sess,
|
|
sym::untagged_unions,
|
|
item.span,
|
|
"unions with non-`Copy` fields are unstable",
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
|
|
_ => (/* pass */),
|
|
}
|
|
intravisit::walk_item(self, item);
|
|
}
|
|
|
|
fn visit_path(&mut self, path: &'tcx hir::Path<'tcx>, id: hir::HirId) {
|
|
if let Some(def_id) = path.res.opt_def_id() {
|
|
self.tcx.check_stability(def_id, Some(id), path.span)
|
|
}
|
|
intravisit::walk_path(self, path)
|
|
}
|
|
}
|
|
|
|
/// Given the list of enabled features that were not language features (i.e., that
|
|
/// were expected to be library features), and the list of features used from
|
|
/// libraries, identify activated features that don't exist and error about them.
|
|
pub fn check_unused_or_stable_features(tcx: TyCtxt<'_>) {
|
|
let access_levels = &tcx.privacy_access_levels(LOCAL_CRATE);
|
|
|
|
if tcx.stability().staged_api[&LOCAL_CRATE] {
|
|
let krate = tcx.hir().krate();
|
|
let mut missing = MissingStabilityAnnotations { tcx, access_levels };
|
|
missing.check_missing_stability(hir::CRATE_HIR_ID, krate.item.span);
|
|
intravisit::walk_crate(&mut missing, krate);
|
|
krate.visit_all_item_likes(&mut missing.as_deep_visitor());
|
|
}
|
|
|
|
let declared_lang_features = &tcx.features().declared_lang_features;
|
|
let mut lang_features = FxHashSet::default();
|
|
for &(feature, span, since) in declared_lang_features {
|
|
if let Some(since) = since {
|
|
// Warn if the user has enabled an already-stable lang feature.
|
|
unnecessary_stable_feature_lint(tcx, span, feature, since);
|
|
}
|
|
if !lang_features.insert(feature) {
|
|
// Warn if the user enables a lang feature multiple times.
|
|
duplicate_feature_err(tcx.sess, span, feature);
|
|
}
|
|
}
|
|
|
|
let declared_lib_features = &tcx.features().declared_lib_features;
|
|
let mut remaining_lib_features = FxHashMap::default();
|
|
for (feature, span) in declared_lib_features {
|
|
if remaining_lib_features.contains_key(&feature) {
|
|
// Warn if the user enables a lib feature multiple times.
|
|
duplicate_feature_err(tcx.sess, *span, *feature);
|
|
}
|
|
remaining_lib_features.insert(feature, *span);
|
|
}
|
|
// `stdbuild` has special handling for `libc`, so we need to
|
|
// recognise the feature when building std.
|
|
// Likewise, libtest is handled specially, so `test` isn't
|
|
// available as we'd like it to be.
|
|
// FIXME: only remove `libc` when `stdbuild` is active.
|
|
// FIXME: remove special casing for `test`.
|
|
remaining_lib_features.remove(&sym::libc);
|
|
remaining_lib_features.remove(&sym::test);
|
|
|
|
let check_features = |remaining_lib_features: &mut FxHashMap<_, _>, defined_features: &[_]| {
|
|
for &(feature, since) in defined_features {
|
|
if let Some(since) = since {
|
|
if let Some(span) = remaining_lib_features.get(&feature) {
|
|
// Warn if the user has enabled an already-stable lib feature.
|
|
unnecessary_stable_feature_lint(tcx, *span, feature, since);
|
|
}
|
|
}
|
|
remaining_lib_features.remove(&feature);
|
|
if remaining_lib_features.is_empty() {
|
|
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 {
|
|
struct_span_err!(tcx.sess, span, E0635, "unknown feature `{}`", feature).emit();
|
|
}
|
|
|
|
// FIXME(#44232): the `used_features` table no longer exists, so we
|
|
// don't lint about unused features. We should re-enable this one day!
|
|
}
|
|
|
|
fn unnecessary_stable_feature_lint(tcx: TyCtxt<'_>, span: Span, feature: Symbol, since: Symbol) {
|
|
tcx.struct_span_lint_hir(lint::builtin::STABLE_FEATURES, hir::CRATE_HIR_ID, span, |lint| {
|
|
lint.build(&format!(
|
|
"the feature `{}` has been stable since {} and no longer requires \
|
|
an attribute to enable",
|
|
feature, since
|
|
))
|
|
.emit();
|
|
});
|
|
}
|
|
|
|
fn duplicate_feature_err(sess: &Session, span: Span, feature: Symbol) {
|
|
struct_span_err!(sess, span, E0636, "the feature `{}` has already been declared", feature)
|
|
.emit();
|
|
}
|