1053 lines
40 KiB
Rust
1053 lines
40 KiB
Rust
//! Parsing and validation of builtin attributes
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use rustc_ast::{self as ast, Attribute, Lit, LitKind, MetaItem, MetaItemKind, NestedMetaItem};
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use rustc_ast_pretty::pprust;
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use rustc_errors::{struct_span_err, Applicability};
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use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg};
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use rustc_macros::HashStable_Generic;
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use rustc_session::parse::{feature_err, ParseSess};
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use rustc_session::Session;
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use rustc_span::hygiene::Transparency;
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use rustc_span::{symbol::sym, symbol::Symbol, Span};
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use std::num::NonZeroU32;
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use version_check::Version;
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pub fn is_builtin_attr(attr: &Attribute) -> bool {
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attr.is_doc_comment() || attr.ident().filter(|ident| is_builtin_attr_name(ident.name)).is_some()
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}
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enum AttrError {
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MultipleItem(String),
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UnknownMetaItem(String, &'static [&'static str]),
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MissingSince,
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NonIdentFeature,
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MissingFeature,
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MultipleStabilityLevels,
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UnsupportedLiteral(&'static str, /* is_bytestr */ bool),
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}
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fn handle_errors(sess: &ParseSess, span: Span, error: AttrError) {
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let diag = &sess.span_diagnostic;
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match error {
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AttrError::MultipleItem(item) => {
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struct_span_err!(diag, span, E0538, "multiple '{}' items", item).emit();
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}
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AttrError::UnknownMetaItem(item, expected) => {
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let expected = expected.iter().map(|name| format!("`{}`", name)).collect::<Vec<_>>();
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struct_span_err!(diag, span, E0541, "unknown meta item '{}'", item)
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.span_label(span, format!("expected one of {}", expected.join(", ")))
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.emit();
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}
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AttrError::MissingSince => {
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struct_span_err!(diag, span, E0542, "missing 'since'").emit();
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}
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AttrError::NonIdentFeature => {
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struct_span_err!(diag, span, E0546, "'feature' is not an identifier").emit();
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}
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AttrError::MissingFeature => {
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struct_span_err!(diag, span, E0546, "missing 'feature'").emit();
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}
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AttrError::MultipleStabilityLevels => {
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struct_span_err!(diag, span, E0544, "multiple stability levels").emit();
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}
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AttrError::UnsupportedLiteral(msg, is_bytestr) => {
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let mut err = struct_span_err!(diag, span, E0565, "{}", msg);
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if is_bytestr {
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if let Ok(lint_str) = sess.source_map().span_to_snippet(span) {
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err.span_suggestion(
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span,
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"consider removing the prefix",
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lint_str[1..].to_string(),
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Applicability::MaybeIncorrect,
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);
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}
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}
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err.emit();
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}
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}
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}
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#[derive(Clone, PartialEq, Encodable, Decodable)]
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pub enum InlineAttr {
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None,
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Hint,
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Always,
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Never,
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}
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#[derive(Clone, Encodable, Decodable)]
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pub enum InstructionSetAttr {
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ArmA32,
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ArmT32,
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}
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#[derive(Clone, Encodable, Decodable)]
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pub enum OptimizeAttr {
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None,
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Speed,
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Size,
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}
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#[derive(Copy, Clone, PartialEq)]
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pub enum UnwindAttr {
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Allowed,
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Aborts,
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}
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/// Determine what `#[unwind]` attribute is present in `attrs`, if any.
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pub fn find_unwind_attr(sess: &Session, attrs: &[Attribute]) -> Option<UnwindAttr> {
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attrs.iter().fold(None, |ia, attr| {
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if sess.check_name(attr, sym::unwind) {
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if let Some(meta) = attr.meta() {
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if let MetaItemKind::List(items) = meta.kind {
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if items.len() == 1 {
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if items[0].has_name(sym::allowed) {
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return Some(UnwindAttr::Allowed);
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} else if items[0].has_name(sym::aborts) {
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return Some(UnwindAttr::Aborts);
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}
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}
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struct_span_err!(
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sess.diagnostic(),
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attr.span,
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E0633,
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"malformed `unwind` attribute input"
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)
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.span_label(attr.span, "invalid argument")
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.span_suggestions(
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attr.span,
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"the allowed arguments are `allowed` and `aborts`",
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(vec!["allowed", "aborts"])
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.into_iter()
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.map(|s| format!("#[unwind({})]", s)),
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Applicability::MachineApplicable,
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)
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.emit();
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}
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}
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}
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ia
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})
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}
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/// Represents the following attributes:
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///
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/// - `#[stable]`
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/// - `#[unstable]`
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#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
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#[derive(HashStable_Generic)]
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pub struct Stability {
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pub level: StabilityLevel,
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pub feature: Symbol,
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}
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/// Represents the `#[rustc_const_unstable]` and `#[rustc_const_stable]` attributes.
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#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
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#[derive(HashStable_Generic)]
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pub struct ConstStability {
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pub level: StabilityLevel,
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pub feature: Symbol,
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/// whether the function has a `#[rustc_promotable]` attribute
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pub promotable: bool,
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}
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/// The available stability levels.
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#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
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#[derive(HashStable_Generic)]
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pub enum StabilityLevel {
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// Reason for the current stability level and the relevant rust-lang issue
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Unstable { reason: Option<Symbol>, issue: Option<NonZeroU32>, is_soft: bool },
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Stable { since: Symbol },
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}
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impl StabilityLevel {
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pub fn is_unstable(&self) -> bool {
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matches!(self, StabilityLevel::Unstable { .. })
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}
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pub fn is_stable(&self) -> bool {
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matches!(self, StabilityLevel::Stable { .. })
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}
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}
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/// Collects stability info from all stability attributes in `attrs`.
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/// Returns `None` if no stability attributes are found.
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pub fn find_stability(
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sess: &Session,
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attrs: &[Attribute],
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item_sp: Span,
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) -> (Option<Stability>, Option<ConstStability>) {
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find_stability_generic(sess, attrs.iter(), item_sp)
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}
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fn find_stability_generic<'a, I>(
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sess: &Session,
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attrs_iter: I,
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item_sp: Span,
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) -> (Option<Stability>, Option<ConstStability>)
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where
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I: Iterator<Item = &'a Attribute>,
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{
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use StabilityLevel::*;
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let mut stab: Option<Stability> = None;
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let mut const_stab: Option<ConstStability> = None;
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let mut promotable = false;
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let diagnostic = &sess.parse_sess.span_diagnostic;
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'outer: for attr in attrs_iter {
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if ![
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sym::rustc_const_unstable,
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sym::rustc_const_stable,
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sym::unstable,
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sym::stable,
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sym::rustc_promotable,
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]
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.iter()
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.any(|&s| attr.has_name(s))
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{
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continue; // not a stability level
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}
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sess.mark_attr_used(attr);
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let meta = attr.meta();
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if attr.has_name(sym::rustc_promotable) {
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promotable = true;
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}
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// attributes with data
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else if let Some(MetaItem { kind: MetaItemKind::List(ref metas), .. }) = meta {
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let meta = meta.as_ref().unwrap();
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let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
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if item.is_some() {
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handle_errors(
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&sess.parse_sess,
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meta.span,
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AttrError::MultipleItem(pprust::path_to_string(&meta.path)),
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);
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return false;
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}
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if let Some(v) = meta.value_str() {
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*item = Some(v);
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true
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} else {
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struct_span_err!(diagnostic, meta.span, E0539, "incorrect meta item").emit();
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false
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}
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};
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let meta_name = meta.name_or_empty();
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match meta_name {
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sym::rustc_const_unstable | sym::unstable => {
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if meta_name == sym::unstable && stab.is_some() {
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handle_errors(
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&sess.parse_sess,
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attr.span,
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AttrError::MultipleStabilityLevels,
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);
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break;
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} else if meta_name == sym::rustc_const_unstable && const_stab.is_some() {
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handle_errors(
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&sess.parse_sess,
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attr.span,
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AttrError::MultipleStabilityLevels,
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);
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break;
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}
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let mut feature = None;
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let mut reason = None;
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let mut issue = None;
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let mut issue_num = None;
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let mut is_soft = false;
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for meta in metas {
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if let Some(mi) = meta.meta_item() {
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match mi.name_or_empty() {
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sym::feature => {
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if !get(mi, &mut feature) {
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continue 'outer;
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}
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}
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sym::reason => {
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if !get(mi, &mut reason) {
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continue 'outer;
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}
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}
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sym::issue => {
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if !get(mi, &mut issue) {
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continue 'outer;
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}
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// These unwraps are safe because `get` ensures the meta item
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// is a name/value pair string literal.
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issue_num = match &*issue.unwrap().as_str() {
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"none" => None,
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issue => {
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let emit_diag = |msg: &str| {
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struct_span_err!(
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diagnostic,
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mi.span,
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E0545,
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"`issue` must be a non-zero numeric string \
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or \"none\"",
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)
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.span_label(
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mi.name_value_literal().unwrap().span,
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msg,
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)
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.emit();
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};
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match issue.parse() {
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Ok(0) => {
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emit_diag(
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"`issue` must not be \"0\", \
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use \"none\" instead",
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);
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continue 'outer;
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}
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Ok(num) => NonZeroU32::new(num),
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Err(err) => {
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emit_diag(&err.to_string());
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continue 'outer;
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}
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}
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}
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};
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}
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sym::soft => {
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if !mi.is_word() {
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let msg = "`soft` should not have any arguments";
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sess.parse_sess.span_diagnostic.span_err(mi.span, msg);
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}
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is_soft = true;
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}
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_ => {
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handle_errors(
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&sess.parse_sess,
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meta.span(),
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AttrError::UnknownMetaItem(
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pprust::path_to_string(&mi.path),
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&["feature", "reason", "issue", "soft"],
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),
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);
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continue 'outer;
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}
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}
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} else {
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handle_errors(
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&sess.parse_sess,
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meta.span(),
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AttrError::UnsupportedLiteral("unsupported literal", false),
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);
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continue 'outer;
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}
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}
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match (feature, reason, issue) {
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(Some(feature), reason, Some(_)) => {
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if !rustc_lexer::is_ident(&feature.as_str()) {
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handle_errors(
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&sess.parse_sess,
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attr.span,
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AttrError::NonIdentFeature,
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);
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continue;
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}
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let level = Unstable { reason, issue: issue_num, is_soft };
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if sym::unstable == meta_name {
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stab = Some(Stability { level, feature });
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} else {
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const_stab =
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Some(ConstStability { level, feature, promotable: false });
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}
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}
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(None, _, _) => {
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handle_errors(&sess.parse_sess, attr.span, AttrError::MissingFeature);
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continue;
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}
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_ => {
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struct_span_err!(diagnostic, attr.span, E0547, "missing 'issue'")
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.emit();
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continue;
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}
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}
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}
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sym::rustc_const_stable | sym::stable => {
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if meta_name == sym::stable && stab.is_some() {
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handle_errors(
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&sess.parse_sess,
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attr.span,
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AttrError::MultipleStabilityLevels,
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);
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break;
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} else if meta_name == sym::rustc_const_stable && const_stab.is_some() {
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handle_errors(
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&sess.parse_sess,
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attr.span,
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AttrError::MultipleStabilityLevels,
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);
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break;
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}
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let mut feature = None;
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let mut since = None;
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for meta in metas {
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match meta {
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NestedMetaItem::MetaItem(mi) => match mi.name_or_empty() {
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sym::feature => {
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if !get(mi, &mut feature) {
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continue 'outer;
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}
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}
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sym::since => {
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if !get(mi, &mut since) {
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continue 'outer;
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}
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}
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_ => {
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handle_errors(
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&sess.parse_sess,
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meta.span(),
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AttrError::UnknownMetaItem(
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pprust::path_to_string(&mi.path),
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&["since", "note"],
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),
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);
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continue 'outer;
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}
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},
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NestedMetaItem::Literal(lit) => {
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handle_errors(
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&sess.parse_sess,
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lit.span,
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AttrError::UnsupportedLiteral("unsupported literal", false),
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);
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continue 'outer;
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}
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}
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}
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match (feature, since) {
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(Some(feature), Some(since)) => {
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let level = Stable { since };
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if sym::stable == meta_name {
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stab = Some(Stability { level, feature });
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} else {
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const_stab =
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Some(ConstStability { level, feature, promotable: false });
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}
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}
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(None, _) => {
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handle_errors(&sess.parse_sess, attr.span, AttrError::MissingFeature);
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continue;
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}
|
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_ => {
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handle_errors(&sess.parse_sess, attr.span, AttrError::MissingSince);
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continue;
|
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}
|
|
}
|
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}
|
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_ => unreachable!(),
|
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}
|
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}
|
|
}
|
|
|
|
// Merge the const-unstable info into the stability info
|
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if promotable {
|
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if let Some(ref mut stab) = const_stab {
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stab.promotable = promotable;
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} else {
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struct_span_err!(
|
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diagnostic,
|
|
item_sp,
|
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E0717,
|
|
"`rustc_promotable` attribute must be paired with either a `rustc_const_unstable` \
|
|
or a `rustc_const_stable` attribute"
|
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)
|
|
.emit();
|
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}
|
|
}
|
|
|
|
(stab, const_stab)
|
|
}
|
|
|
|
pub fn find_crate_name(sess: &Session, attrs: &[Attribute]) -> Option<Symbol> {
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sess.first_attr_value_str_by_name(attrs, sym::crate_name)
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}
|
|
|
|
/// Tests if a cfg-pattern matches the cfg set
|
|
pub fn cfg_matches(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) -> bool {
|
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eval_condition(cfg, sess, features, &mut |cfg| {
|
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try_gate_cfg(cfg, sess, features);
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|
let error = |span, msg| {
|
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sess.span_diagnostic.span_err(span, msg);
|
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true
|
|
};
|
|
if cfg.path.segments.len() != 1 {
|
|
return error(cfg.path.span, "`cfg` predicate key must be an identifier");
|
|
}
|
|
match &cfg.kind {
|
|
MetaItemKind::List(..) => {
|
|
error(cfg.span, "unexpected parentheses after `cfg` predicate key")
|
|
}
|
|
MetaItemKind::NameValue(lit) if !lit.kind.is_str() => {
|
|
handle_errors(
|
|
sess,
|
|
lit.span,
|
|
AttrError::UnsupportedLiteral(
|
|
"literal in `cfg` predicate value must be a string",
|
|
lit.kind.is_bytestr(),
|
|
),
|
|
);
|
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true
|
|
}
|
|
MetaItemKind::NameValue(..) | MetaItemKind::Word => {
|
|
let ident = cfg.ident().expect("multi-segment cfg predicate");
|
|
sess.config.contains(&(ident.name, cfg.value_str()))
|
|
}
|
|
}
|
|
})
|
|
}
|
|
|
|
fn try_gate_cfg(cfg: &ast::MetaItem, sess: &ParseSess, features: Option<&Features>) {
|
|
let gate = find_gated_cfg(|sym| cfg.has_name(sym));
|
|
if let (Some(feats), Some(gated_cfg)) = (features, gate) {
|
|
gate_cfg(&gated_cfg, cfg.span, sess, feats);
|
|
}
|
|
}
|
|
|
|
fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &ParseSess, features: &Features) {
|
|
let (cfg, feature, has_feature) = gated_cfg;
|
|
if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
|
|
let explain = format!("`cfg({})` is experimental and subject to change", cfg);
|
|
feature_err(sess, *feature, cfg_span, &explain).emit();
|
|
}
|
|
}
|
|
|
|
/// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to
|
|
/// evaluate individual items.
|
|
pub fn eval_condition(
|
|
cfg: &ast::MetaItem,
|
|
sess: &ParseSess,
|
|
features: Option<&Features>,
|
|
eval: &mut impl FnMut(&ast::MetaItem) -> bool,
|
|
) -> bool {
|
|
match cfg.kind {
|
|
ast::MetaItemKind::List(ref mis) if cfg.name_or_empty() == sym::version => {
|
|
try_gate_cfg(cfg, sess, features);
|
|
let (min_version, span) = match &mis[..] {
|
|
[NestedMetaItem::Literal(Lit { kind: LitKind::Str(sym, ..), span, .. })] => {
|
|
(sym, span)
|
|
}
|
|
[NestedMetaItem::Literal(Lit { span, .. })
|
|
| NestedMetaItem::MetaItem(MetaItem { span, .. })] => {
|
|
sess.span_diagnostic
|
|
.struct_span_err(*span, "expected a version literal")
|
|
.emit();
|
|
return false;
|
|
}
|
|
[..] => {
|
|
sess.span_diagnostic
|
|
.struct_span_err(cfg.span, "expected single version literal")
|
|
.emit();
|
|
return false;
|
|
}
|
|
};
|
|
let min_version = match Version::parse(&min_version.as_str()) {
|
|
Some(ver) => ver,
|
|
None => {
|
|
sess.span_diagnostic.struct_span_err(*span, "invalid version literal").emit();
|
|
return false;
|
|
}
|
|
};
|
|
let channel = env!("CFG_RELEASE_CHANNEL");
|
|
let nightly = channel == "nightly" || channel == "dev";
|
|
let rustc_version = Version::parse(env!("CFG_RELEASE")).unwrap();
|
|
|
|
// See https://github.com/rust-lang/rust/issues/64796#issuecomment-625474439 for details
|
|
if nightly { rustc_version > min_version } else { rustc_version >= min_version }
|
|
}
|
|
ast::MetaItemKind::List(ref mis) => {
|
|
for mi in mis.iter() {
|
|
if !mi.is_meta_item() {
|
|
handle_errors(
|
|
sess,
|
|
mi.span(),
|
|
AttrError::UnsupportedLiteral("unsupported literal", false),
|
|
);
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// The unwraps below may look dangerous, but we've already asserted
|
|
// that they won't fail with the loop above.
|
|
match cfg.name_or_empty() {
|
|
sym::any => mis
|
|
.iter()
|
|
.any(|mi| eval_condition(mi.meta_item().unwrap(), sess, features, eval)),
|
|
sym::all => mis
|
|
.iter()
|
|
.all(|mi| eval_condition(mi.meta_item().unwrap(), sess, features, eval)),
|
|
sym::not => {
|
|
if mis.len() != 1 {
|
|
struct_span_err!(
|
|
sess.span_diagnostic,
|
|
cfg.span,
|
|
E0536,
|
|
"expected 1 cfg-pattern"
|
|
)
|
|
.emit();
|
|
return false;
|
|
}
|
|
|
|
!eval_condition(mis[0].meta_item().unwrap(), sess, features, eval)
|
|
}
|
|
_ => {
|
|
struct_span_err!(
|
|
sess.span_diagnostic,
|
|
cfg.span,
|
|
E0537,
|
|
"invalid predicate `{}`",
|
|
pprust::path_to_string(&cfg.path)
|
|
)
|
|
.emit();
|
|
false
|
|
}
|
|
}
|
|
}
|
|
ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => eval(cfg),
|
|
}
|
|
}
|
|
|
|
#[derive(Encodable, Decodable, Clone, HashStable_Generic)]
|
|
pub struct Deprecation {
|
|
pub since: Option<Symbol>,
|
|
/// The note to issue a reason.
|
|
pub note: Option<Symbol>,
|
|
/// A text snippet used to completely replace any use of the deprecated item in an expression.
|
|
///
|
|
/// This is currently unstable.
|
|
pub suggestion: Option<Symbol>,
|
|
|
|
/// Whether to treat the since attribute as being a Rust version identifier
|
|
/// (rather than an opaque string).
|
|
pub is_since_rustc_version: bool,
|
|
}
|
|
|
|
/// Finds the deprecation attribute. `None` if none exists.
|
|
pub fn find_deprecation(sess: &Session, attrs: &[Attribute], item_sp: Span) -> Option<Deprecation> {
|
|
find_deprecation_generic(sess, attrs.iter(), item_sp)
|
|
}
|
|
|
|
fn find_deprecation_generic<'a, I>(
|
|
sess: &Session,
|
|
attrs_iter: I,
|
|
item_sp: Span,
|
|
) -> Option<Deprecation>
|
|
where
|
|
I: Iterator<Item = &'a Attribute>,
|
|
{
|
|
let mut depr: Option<Deprecation> = None;
|
|
let diagnostic = &sess.parse_sess.span_diagnostic;
|
|
|
|
'outer: for attr in attrs_iter {
|
|
if !(sess.check_name(attr, sym::deprecated) || sess.check_name(attr, sym::rustc_deprecated))
|
|
{
|
|
continue;
|
|
}
|
|
|
|
if depr.is_some() {
|
|
struct_span_err!(diagnostic, item_sp, E0550, "multiple deprecated attributes").emit();
|
|
break;
|
|
}
|
|
|
|
let meta = match attr.meta() {
|
|
Some(meta) => meta,
|
|
None => continue,
|
|
};
|
|
let mut since = None;
|
|
let mut note = None;
|
|
let mut suggestion = None;
|
|
match &meta.kind {
|
|
MetaItemKind::Word => {}
|
|
MetaItemKind::NameValue(..) => note = meta.value_str(),
|
|
MetaItemKind::List(list) => {
|
|
let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
|
|
if item.is_some() {
|
|
handle_errors(
|
|
&sess.parse_sess,
|
|
meta.span,
|
|
AttrError::MultipleItem(pprust::path_to_string(&meta.path)),
|
|
);
|
|
return false;
|
|
}
|
|
if let Some(v) = meta.value_str() {
|
|
*item = Some(v);
|
|
true
|
|
} else {
|
|
if let Some(lit) = meta.name_value_literal() {
|
|
handle_errors(
|
|
&sess.parse_sess,
|
|
lit.span,
|
|
AttrError::UnsupportedLiteral(
|
|
"literal in `deprecated` \
|
|
value must be a string",
|
|
lit.kind.is_bytestr(),
|
|
),
|
|
);
|
|
} else {
|
|
struct_span_err!(diagnostic, meta.span, E0551, "incorrect meta item")
|
|
.emit();
|
|
}
|
|
|
|
false
|
|
}
|
|
};
|
|
|
|
for meta in list {
|
|
match meta {
|
|
NestedMetaItem::MetaItem(mi) => match mi.name_or_empty() {
|
|
sym::since => {
|
|
if !get(mi, &mut since) {
|
|
continue 'outer;
|
|
}
|
|
}
|
|
sym::note if sess.check_name(attr, sym::deprecated) => {
|
|
if !get(mi, &mut note) {
|
|
continue 'outer;
|
|
}
|
|
}
|
|
sym::reason if sess.check_name(attr, sym::rustc_deprecated) => {
|
|
if !get(mi, &mut note) {
|
|
continue 'outer;
|
|
}
|
|
}
|
|
sym::suggestion if sess.check_name(attr, sym::rustc_deprecated) => {
|
|
if !get(mi, &mut suggestion) {
|
|
continue 'outer;
|
|
}
|
|
}
|
|
_ => {
|
|
handle_errors(
|
|
&sess.parse_sess,
|
|
meta.span(),
|
|
AttrError::UnknownMetaItem(
|
|
pprust::path_to_string(&mi.path),
|
|
if sess.check_name(attr, sym::deprecated) {
|
|
&["since", "note"]
|
|
} else {
|
|
&["since", "reason", "suggestion"]
|
|
},
|
|
),
|
|
);
|
|
continue 'outer;
|
|
}
|
|
},
|
|
NestedMetaItem::Literal(lit) => {
|
|
handle_errors(
|
|
&sess.parse_sess,
|
|
lit.span,
|
|
AttrError::UnsupportedLiteral(
|
|
"item in `deprecated` must be a key/value pair",
|
|
false,
|
|
),
|
|
);
|
|
continue 'outer;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if suggestion.is_some() && sess.check_name(attr, sym::deprecated) {
|
|
unreachable!("only allowed on rustc_deprecated")
|
|
}
|
|
|
|
if sess.check_name(attr, sym::rustc_deprecated) {
|
|
if since.is_none() {
|
|
handle_errors(&sess.parse_sess, attr.span, AttrError::MissingSince);
|
|
continue;
|
|
}
|
|
|
|
if note.is_none() {
|
|
struct_span_err!(diagnostic, attr.span, E0543, "missing 'reason'").emit();
|
|
continue;
|
|
}
|
|
}
|
|
|
|
sess.mark_attr_used(&attr);
|
|
|
|
let is_since_rustc_version = sess.check_name(attr, sym::rustc_deprecated);
|
|
depr = Some(Deprecation { since, note, suggestion, is_since_rustc_version });
|
|
}
|
|
|
|
depr
|
|
}
|
|
|
|
#[derive(PartialEq, Debug, Encodable, Decodable, Copy, Clone)]
|
|
pub enum ReprAttr {
|
|
ReprInt(IntType),
|
|
ReprC,
|
|
ReprPacked(u32),
|
|
ReprSimd,
|
|
ReprTransparent,
|
|
ReprAlign(u32),
|
|
ReprNoNiche,
|
|
}
|
|
|
|
#[derive(Eq, PartialEq, Debug, Copy, Clone)]
|
|
#[derive(Encodable, Decodable, HashStable_Generic)]
|
|
pub enum IntType {
|
|
SignedInt(ast::IntTy),
|
|
UnsignedInt(ast::UintTy),
|
|
}
|
|
|
|
impl IntType {
|
|
#[inline]
|
|
pub fn is_signed(self) -> bool {
|
|
use IntType::*;
|
|
|
|
match self {
|
|
SignedInt(..) => true,
|
|
UnsignedInt(..) => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Parse #[repr(...)] forms.
|
|
///
|
|
/// Valid repr contents: any of the primitive integral type names (see
|
|
/// `int_type_of_word`, below) to specify enum discriminant type; `C`, to use
|
|
/// the same discriminant size that the corresponding C enum would or C
|
|
/// structure layout, `packed` to remove padding, and `transparent` to elegate representation
|
|
/// concerns to the only non-ZST field.
|
|
pub fn find_repr_attrs(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
|
|
use ReprAttr::*;
|
|
|
|
let mut acc = Vec::new();
|
|
let diagnostic = &sess.parse_sess.span_diagnostic;
|
|
if attr.has_name(sym::repr) {
|
|
if let Some(items) = attr.meta_item_list() {
|
|
sess.mark_attr_used(attr);
|
|
for item in items {
|
|
if !item.is_meta_item() {
|
|
handle_errors(
|
|
&sess.parse_sess,
|
|
item.span(),
|
|
AttrError::UnsupportedLiteral(
|
|
"meta item in `repr` must be an identifier",
|
|
false,
|
|
),
|
|
);
|
|
continue;
|
|
}
|
|
|
|
let mut recognised = false;
|
|
if item.is_word() {
|
|
let hint = match item.name_or_empty() {
|
|
sym::C => Some(ReprC),
|
|
sym::packed => Some(ReprPacked(1)),
|
|
sym::simd => Some(ReprSimd),
|
|
sym::transparent => Some(ReprTransparent),
|
|
sym::no_niche => Some(ReprNoNiche),
|
|
name => int_type_of_word(name).map(ReprInt),
|
|
};
|
|
|
|
if let Some(h) = hint {
|
|
recognised = true;
|
|
acc.push(h);
|
|
}
|
|
} else if let Some((name, value)) = item.name_value_literal() {
|
|
let parse_alignment = |node: &ast::LitKind| -> Result<u32, &'static str> {
|
|
if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node {
|
|
if literal.is_power_of_two() {
|
|
// rustc_middle::ty::layout::Align restricts align to <= 2^29
|
|
if *literal <= 1 << 29 {
|
|
Ok(*literal as u32)
|
|
} else {
|
|
Err("larger than 2^29")
|
|
}
|
|
} else {
|
|
Err("not a power of two")
|
|
}
|
|
} else {
|
|
Err("not an unsuffixed integer")
|
|
}
|
|
};
|
|
|
|
let mut literal_error = None;
|
|
if name == sym::align {
|
|
recognised = true;
|
|
match parse_alignment(&value.kind) {
|
|
Ok(literal) => acc.push(ReprAlign(literal)),
|
|
Err(message) => literal_error = Some(message),
|
|
};
|
|
} else if name == sym::packed {
|
|
recognised = true;
|
|
match parse_alignment(&value.kind) {
|
|
Ok(literal) => acc.push(ReprPacked(literal)),
|
|
Err(message) => literal_error = Some(message),
|
|
};
|
|
}
|
|
if let Some(literal_error) = literal_error {
|
|
struct_span_err!(
|
|
diagnostic,
|
|
item.span(),
|
|
E0589,
|
|
"invalid `repr(align)` attribute: {}",
|
|
literal_error
|
|
)
|
|
.emit();
|
|
}
|
|
} else if let Some(meta_item) = item.meta_item() {
|
|
if meta_item.has_name(sym::align) {
|
|
if let MetaItemKind::NameValue(ref value) = meta_item.kind {
|
|
recognised = true;
|
|
let mut err = struct_span_err!(
|
|
diagnostic,
|
|
item.span(),
|
|
E0693,
|
|
"incorrect `repr(align)` attribute format"
|
|
);
|
|
match value.kind {
|
|
ast::LitKind::Int(int, ast::LitIntType::Unsuffixed) => {
|
|
err.span_suggestion(
|
|
item.span(),
|
|
"use parentheses instead",
|
|
format!("align({})", int),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
ast::LitKind::Str(s, _) => {
|
|
err.span_suggestion(
|
|
item.span(),
|
|
"use parentheses instead",
|
|
format!("align({})", s),
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
_ => {}
|
|
}
|
|
err.emit();
|
|
}
|
|
}
|
|
}
|
|
if !recognised {
|
|
// Not a word we recognize
|
|
struct_span_err!(
|
|
diagnostic,
|
|
item.span(),
|
|
E0552,
|
|
"unrecognized representation hint"
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
acc
|
|
}
|
|
|
|
fn int_type_of_word(s: Symbol) -> Option<IntType> {
|
|
use IntType::*;
|
|
|
|
match s {
|
|
sym::i8 => Some(SignedInt(ast::IntTy::I8)),
|
|
sym::u8 => Some(UnsignedInt(ast::UintTy::U8)),
|
|
sym::i16 => Some(SignedInt(ast::IntTy::I16)),
|
|
sym::u16 => Some(UnsignedInt(ast::UintTy::U16)),
|
|
sym::i32 => Some(SignedInt(ast::IntTy::I32)),
|
|
sym::u32 => Some(UnsignedInt(ast::UintTy::U32)),
|
|
sym::i64 => Some(SignedInt(ast::IntTy::I64)),
|
|
sym::u64 => Some(UnsignedInt(ast::UintTy::U64)),
|
|
sym::i128 => Some(SignedInt(ast::IntTy::I128)),
|
|
sym::u128 => Some(UnsignedInt(ast::UintTy::U128)),
|
|
sym::isize => Some(SignedInt(ast::IntTy::Isize)),
|
|
sym::usize => Some(UnsignedInt(ast::UintTy::Usize)),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
pub enum TransparencyError {
|
|
UnknownTransparency(Symbol, Span),
|
|
MultipleTransparencyAttrs(Span, Span),
|
|
}
|
|
|
|
pub fn find_transparency(
|
|
sess: &Session,
|
|
attrs: &[Attribute],
|
|
macro_rules: bool,
|
|
) -> (Transparency, Option<TransparencyError>) {
|
|
let mut transparency = None;
|
|
let mut error = None;
|
|
for attr in attrs {
|
|
if sess.check_name(attr, sym::rustc_macro_transparency) {
|
|
if let Some((_, old_span)) = transparency {
|
|
error = Some(TransparencyError::MultipleTransparencyAttrs(old_span, attr.span));
|
|
break;
|
|
} else if let Some(value) = attr.value_str() {
|
|
transparency = Some((
|
|
match value {
|
|
sym::transparent => Transparency::Transparent,
|
|
sym::semitransparent => Transparency::SemiTransparent,
|
|
sym::opaque => Transparency::Opaque,
|
|
_ => {
|
|
error = Some(TransparencyError::UnknownTransparency(value, attr.span));
|
|
continue;
|
|
}
|
|
},
|
|
attr.span,
|
|
));
|
|
}
|
|
}
|
|
}
|
|
let fallback = if macro_rules { Transparency::SemiTransparent } else { Transparency::Opaque };
|
|
(transparency.map_or(fallback, |t| t.0), error)
|
|
}
|
|
|
|
pub fn allow_internal_unstable<'a>(
|
|
sess: &'a Session,
|
|
attrs: &'a [Attribute],
|
|
) -> Option<impl Iterator<Item = Symbol> + 'a> {
|
|
allow_unstable(sess, attrs, sym::allow_internal_unstable)
|
|
}
|
|
|
|
pub fn rustc_allow_const_fn_unstable<'a>(
|
|
sess: &'a Session,
|
|
attrs: &'a [Attribute],
|
|
) -> Option<impl Iterator<Item = Symbol> + 'a> {
|
|
allow_unstable(sess, attrs, sym::rustc_allow_const_fn_unstable)
|
|
}
|
|
|
|
fn allow_unstable<'a>(
|
|
sess: &'a Session,
|
|
attrs: &'a [Attribute],
|
|
symbol: Symbol,
|
|
) -> Option<impl Iterator<Item = Symbol> + 'a> {
|
|
let attrs = sess.filter_by_name(attrs, symbol);
|
|
let list = attrs
|
|
.filter_map(move |attr| {
|
|
attr.meta_item_list().or_else(|| {
|
|
sess.diagnostic().span_err(
|
|
attr.span,
|
|
&format!("`{}` expects a list of feature names", symbol.to_ident_string()),
|
|
);
|
|
None
|
|
})
|
|
})
|
|
.flatten();
|
|
|
|
Some(list.into_iter().filter_map(move |it| {
|
|
let name = it.ident().map(|ident| ident.name);
|
|
if name.is_none() {
|
|
sess.diagnostic().span_err(
|
|
it.span(),
|
|
&format!("`{}` expects feature names", symbol.to_ident_string()),
|
|
);
|
|
}
|
|
name
|
|
}))
|
|
}
|