| //! Parsing and validation of builtin attributes |
| |
| use rustc_ast::{self as ast, attr}; |
| use rustc_ast::{Attribute, LitKind, MetaItem, MetaItemKind, MetaItemLit, NestedMetaItem, NodeId}; |
| use rustc_ast_pretty::pprust; |
| use rustc_errors::ErrorGuaranteed; |
| use rustc_feature::{find_gated_cfg, is_builtin_attr_name, Features, GatedCfg}; |
| use rustc_macros::HashStable_Generic; |
| use rustc_session::config::ExpectedValues; |
| use rustc_session::lint::builtin::UNEXPECTED_CFGS; |
| use rustc_session::lint::BuiltinLintDiag; |
| use rustc_session::parse::feature_err; |
| use rustc_session::{RustcVersion, Session}; |
| use rustc_span::hygiene::Transparency; |
| use rustc_span::{symbol::sym, symbol::Symbol, Span}; |
| use std::num::NonZero; |
| |
| use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause}; |
| |
| /// The version placeholder that recently stabilized features contain inside the |
| /// `since` field of the `#[stable]` attribute. |
| /// |
| /// For more, see [this pull request](https://github.com/rust-lang/rust/pull/100591). |
| pub const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION"; |
| |
| pub fn is_builtin_attr(attr: &Attribute) -> bool { |
| attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name)) |
| } |
| |
| pub(crate) enum UnsupportedLiteralReason { |
| Generic, |
| CfgString, |
| DeprecatedString, |
| DeprecatedKvPair, |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)] |
| pub enum InlineAttr { |
| None, |
| Hint, |
| Always, |
| Never, |
| } |
| |
| #[derive(Clone, Encodable, Decodable, Debug, PartialEq, Eq, HashStable_Generic)] |
| pub enum InstructionSetAttr { |
| ArmA32, |
| ArmT32, |
| } |
| |
| #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)] |
| pub enum OptimizeAttr { |
| None, |
| Speed, |
| Size, |
| } |
| |
| /// Represents the following attributes: |
| /// |
| /// - `#[stable]` |
| /// - `#[unstable]` |
| #[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub struct Stability { |
| pub level: StabilityLevel, |
| pub feature: Symbol, |
| } |
| |
| impl Stability { |
| pub fn is_unstable(&self) -> bool { |
| self.level.is_unstable() |
| } |
| |
| pub fn is_stable(&self) -> bool { |
| self.level.is_stable() |
| } |
| } |
| |
| /// Represents the `#[rustc_const_unstable]` and `#[rustc_const_stable]` attributes. |
| #[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub struct ConstStability { |
| pub level: StabilityLevel, |
| pub feature: Symbol, |
| /// whether the function has a `#[rustc_promotable]` attribute |
| pub promotable: bool, |
| } |
| |
| impl ConstStability { |
| pub fn is_const_unstable(&self) -> bool { |
| self.level.is_unstable() |
| } |
| |
| pub fn is_const_stable(&self) -> bool { |
| self.level.is_stable() |
| } |
| } |
| |
| /// Represents the `#[rustc_default_body_unstable]` attribute. |
| #[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub struct DefaultBodyStability { |
| pub level: StabilityLevel, |
| pub feature: Symbol, |
| } |
| |
| /// The available stability levels. |
| #[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub enum StabilityLevel { |
| /// `#[unstable]` |
| Unstable { |
| /// Reason for the current stability level. |
| reason: UnstableReason, |
| /// Relevant `rust-lang/rust` issue. |
| issue: Option<NonZero<u32>>, |
| is_soft: bool, |
| /// If part of a feature is stabilized and a new feature is added for the remaining parts, |
| /// then the `implied_by` attribute is used to indicate which now-stable feature previously |
| /// contained an item. |
| /// |
| /// ```pseudo-Rust |
| /// #[unstable(feature = "foo", issue = "...")] |
| /// fn foo() {} |
| /// #[unstable(feature = "foo", issue = "...")] |
| /// fn foobar() {} |
| /// ``` |
| /// |
| /// ...becomes... |
| /// |
| /// ```pseudo-Rust |
| /// #[stable(feature = "foo", since = "1.XX.X")] |
| /// fn foo() {} |
| /// #[unstable(feature = "foobar", issue = "...", implied_by = "foo")] |
| /// fn foobar() {} |
| /// ``` |
| implied_by: Option<Symbol>, |
| }, |
| /// `#[stable]` |
| Stable { |
| /// Rust release which stabilized this feature. |
| since: StableSince, |
| /// Is this item allowed to be referred to on stable, despite being contained in unstable |
| /// modules? |
| allowed_through_unstable_modules: bool, |
| }, |
| } |
| |
| /// Rust release in which a feature is stabilized. |
| #[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub enum StableSince { |
| Version(RustcVersion), |
| /// Stabilized in the upcoming version, whatever number that is. |
| Current, |
| /// Failed to parse a stabilization version. |
| Err, |
| } |
| |
| impl StabilityLevel { |
| pub fn is_unstable(&self) -> bool { |
| matches!(self, StabilityLevel::Unstable { .. }) |
| } |
| pub fn is_stable(&self) -> bool { |
| matches!(self, StabilityLevel::Stable { .. }) |
| } |
| } |
| |
| #[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)] |
| #[derive(HashStable_Generic)] |
| pub enum UnstableReason { |
| None, |
| Default, |
| Some(Symbol), |
| } |
| |
| impl UnstableReason { |
| fn from_opt_reason(reason: Option<Symbol>) -> Self { |
| // UnstableReason::Default constructed manually |
| match reason { |
| Some(r) => Self::Some(r), |
| None => Self::None, |
| } |
| } |
| |
| pub fn to_opt_reason(&self) -> Option<Symbol> { |
| match self { |
| Self::None => None, |
| Self::Default => Some(sym::unstable_location_reason_default), |
| Self::Some(r) => Some(*r), |
| } |
| } |
| } |
| |
| /// Collects stability info from `stable`/`unstable`/`rustc_allowed_through_unstable_modules` |
| /// attributes in `attrs`. Returns `None` if no stability attributes are found. |
| pub fn find_stability( |
| sess: &Session, |
| attrs: &[Attribute], |
| item_sp: Span, |
| ) -> Option<(Stability, Span)> { |
| let mut stab: Option<(Stability, Span)> = None; |
| let mut allowed_through_unstable_modules = false; |
| |
| for attr in attrs { |
| match attr.name_or_empty() { |
| sym::rustc_allowed_through_unstable_modules => allowed_through_unstable_modules = true, |
| sym::unstable => { |
| if stab.is_some() { |
| sess.dcx() |
| .emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span }); |
| break; |
| } |
| |
| if let Some((feature, level)) = parse_unstability(sess, attr) { |
| stab = Some((Stability { level, feature }, attr.span)); |
| } |
| } |
| sym::stable => { |
| if stab.is_some() { |
| sess.dcx() |
| .emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span }); |
| break; |
| } |
| if let Some((feature, level)) = parse_stability(sess, attr) { |
| stab = Some((Stability { level, feature }, attr.span)); |
| } |
| } |
| _ => {} |
| } |
| } |
| |
| if allowed_through_unstable_modules { |
| match &mut stab { |
| Some(( |
| Stability { |
| level: StabilityLevel::Stable { allowed_through_unstable_modules, .. }, |
| .. |
| }, |
| _, |
| )) => *allowed_through_unstable_modules = true, |
| _ => { |
| sess.dcx() |
| .emit_err(session_diagnostics::RustcAllowedUnstablePairing { span: item_sp }); |
| } |
| } |
| } |
| |
| stab |
| } |
| |
| /// Collects stability info from `rustc_const_stable`/`rustc_const_unstable`/`rustc_promotable` |
| /// attributes in `attrs`. Returns `None` if no stability attributes are found. |
| pub fn find_const_stability( |
| sess: &Session, |
| attrs: &[Attribute], |
| item_sp: Span, |
| ) -> Option<(ConstStability, Span)> { |
| let mut const_stab: Option<(ConstStability, Span)> = None; |
| let mut promotable = false; |
| |
| for attr in attrs { |
| match attr.name_or_empty() { |
| sym::rustc_promotable => promotable = true, |
| sym::rustc_const_unstable => { |
| if const_stab.is_some() { |
| sess.dcx() |
| .emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span }); |
| break; |
| } |
| |
| if let Some((feature, level)) = parse_unstability(sess, attr) { |
| const_stab = |
| Some((ConstStability { level, feature, promotable: false }, attr.span)); |
| } |
| } |
| sym::rustc_const_stable => { |
| if const_stab.is_some() { |
| sess.dcx() |
| .emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span }); |
| break; |
| } |
| if let Some((feature, level)) = parse_stability(sess, attr) { |
| const_stab = |
| Some((ConstStability { level, feature, promotable: false }, attr.span)); |
| } |
| } |
| _ => {} |
| } |
| } |
| |
| // Merge the const-unstable info into the stability info |
| if promotable { |
| match &mut const_stab { |
| Some((stab, _)) => stab.promotable = promotable, |
| _ => { |
| _ = sess |
| .dcx() |
| .emit_err(session_diagnostics::RustcPromotablePairing { span: item_sp }) |
| } |
| } |
| } |
| |
| const_stab |
| } |
| |
| /// Collects stability info from `rustc_default_body_unstable` attributes in `attrs`. |
| /// Returns `None` if no stability attributes are found. |
| pub fn find_body_stability( |
| sess: &Session, |
| attrs: &[Attribute], |
| ) -> Option<(DefaultBodyStability, Span)> { |
| let mut body_stab: Option<(DefaultBodyStability, Span)> = None; |
| |
| for attr in attrs { |
| if attr.has_name(sym::rustc_default_body_unstable) { |
| if body_stab.is_some() { |
| sess.dcx() |
| .emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span }); |
| break; |
| } |
| |
| if let Some((feature, level)) = parse_unstability(sess, attr) { |
| body_stab = Some((DefaultBodyStability { level, feature }, attr.span)); |
| } |
| } |
| } |
| |
| body_stab |
| } |
| |
| fn insert_or_error(sess: &Session, meta: &MetaItem, item: &mut Option<Symbol>) -> Option<()> { |
| if item.is_some() { |
| sess.dcx().emit_err(session_diagnostics::MultipleItem { |
| span: meta.span, |
| item: pprust::path_to_string(&meta.path), |
| }); |
| None |
| } else if let Some(v) = meta.value_str() { |
| *item = Some(v); |
| Some(()) |
| } else { |
| sess.dcx().emit_err(session_diagnostics::IncorrectMetaItem { span: meta.span }); |
| None |
| } |
| } |
| |
| /// Read the content of a `stable`/`rustc_const_stable` attribute, and return the feature name and |
| /// its stability information. |
| fn parse_stability(sess: &Session, attr: &Attribute) -> Option<(Symbol, StabilityLevel)> { |
| let meta = attr.meta()?; |
| let MetaItem { kind: MetaItemKind::List(ref metas), .. } = meta else { return None }; |
| |
| let mut feature = None; |
| let mut since = None; |
| for meta in metas { |
| let Some(mi) = meta.meta_item() else { |
| sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral { |
| span: meta.span(), |
| reason: UnsupportedLiteralReason::Generic, |
| is_bytestr: false, |
| start_point_span: sess.source_map().start_point(meta.span()), |
| }); |
| return None; |
| }; |
| |
| match mi.name_or_empty() { |
| sym::feature => insert_or_error(sess, mi, &mut feature)?, |
| sym::since => insert_or_error(sess, mi, &mut since)?, |
| _ => { |
| sess.dcx().emit_err(session_diagnostics::UnknownMetaItem { |
| span: meta.span(), |
| item: pprust::path_to_string(&mi.path), |
| expected: &["feature", "since"], |
| }); |
| return None; |
| } |
| } |
| } |
| |
| let feature = match feature { |
| Some(feature) if rustc_lexer::is_ident(feature.as_str()) => Ok(feature), |
| Some(_bad_feature) => { |
| Err(sess.dcx().emit_err(session_diagnostics::NonIdentFeature { span: attr.span })) |
| } |
| None => Err(sess.dcx().emit_err(session_diagnostics::MissingFeature { span: attr.span })), |
| }; |
| |
| let since = if let Some(since) = since { |
| if since.as_str() == VERSION_PLACEHOLDER { |
| StableSince::Current |
| } else if let Some(version) = parse_version(since) { |
| StableSince::Version(version) |
| } else { |
| sess.dcx().emit_err(session_diagnostics::InvalidSince { span: attr.span }); |
| StableSince::Err |
| } |
| } else { |
| sess.dcx().emit_err(session_diagnostics::MissingSince { span: attr.span }); |
| StableSince::Err |
| }; |
| |
| match feature { |
| Ok(feature) => { |
| let level = StabilityLevel::Stable { since, allowed_through_unstable_modules: false }; |
| Some((feature, level)) |
| } |
| Err(ErrorGuaranteed { .. }) => None, |
| } |
| } |
| |
| /// Read the content of a `unstable`/`rustc_const_unstable`/`rustc_default_body_unstable` |
| /// attribute, and return the feature name and its stability information. |
| fn parse_unstability(sess: &Session, attr: &Attribute) -> Option<(Symbol, StabilityLevel)> { |
| let meta = attr.meta()?; |
| let MetaItem { kind: MetaItemKind::List(ref metas), .. } = meta else { return None }; |
| |
| let mut feature = None; |
| let mut reason = None; |
| let mut issue = None; |
| let mut issue_num = None; |
| let mut is_soft = false; |
| let mut implied_by = None; |
| for meta in metas { |
| let Some(mi) = meta.meta_item() else { |
| sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral { |
| span: meta.span(), |
| reason: UnsupportedLiteralReason::Generic, |
| is_bytestr: false, |
| start_point_span: sess.source_map().start_point(meta.span()), |
| }); |
| return None; |
| }; |
| |
| match mi.name_or_empty() { |
| sym::feature => insert_or_error(sess, mi, &mut feature)?, |
| sym::reason => insert_or_error(sess, mi, &mut reason)?, |
| sym::issue => { |
| insert_or_error(sess, mi, &mut issue)?; |
| |
| // These unwraps are safe because `insert_or_error` ensures the meta item |
| // is a name/value pair string literal. |
| issue_num = match issue.unwrap().as_str() { |
| "none" => None, |
| issue => match issue.parse::<NonZero<u32>>() { |
| Ok(num) => Some(num), |
| Err(err) => { |
| sess.dcx().emit_err( |
| session_diagnostics::InvalidIssueString { |
| span: mi.span, |
| cause: session_diagnostics::InvalidIssueStringCause::from_int_error_kind( |
| mi.name_value_literal_span().unwrap(), |
| err.kind(), |
| ), |
| }, |
| ); |
| return None; |
| } |
| }, |
| }; |
| } |
| sym::soft => { |
| if !mi.is_word() { |
| sess.dcx().emit_err(session_diagnostics::SoftNoArgs { span: mi.span }); |
| } |
| is_soft = true; |
| } |
| sym::implied_by => insert_or_error(sess, mi, &mut implied_by)?, |
| _ => { |
| sess.dcx().emit_err(session_diagnostics::UnknownMetaItem { |
| span: meta.span(), |
| item: pprust::path_to_string(&mi.path), |
| expected: &["feature", "reason", "issue", "soft", "implied_by"], |
| }); |
| return None; |
| } |
| } |
| } |
| |
| let feature = match feature { |
| Some(feature) if rustc_lexer::is_ident(feature.as_str()) => Ok(feature), |
| Some(_bad_feature) => { |
| Err(sess.dcx().emit_err(session_diagnostics::NonIdentFeature { span: attr.span })) |
| } |
| None => Err(sess.dcx().emit_err(session_diagnostics::MissingFeature { span: attr.span })), |
| }; |
| |
| let issue = issue |
| .ok_or_else(|| sess.dcx().emit_err(session_diagnostics::MissingIssue { span: attr.span })); |
| |
| match (feature, issue) { |
| (Ok(feature), Ok(_)) => { |
| let level = StabilityLevel::Unstable { |
| reason: UnstableReason::from_opt_reason(reason), |
| issue: issue_num, |
| is_soft, |
| implied_by, |
| }; |
| Some((feature, level)) |
| } |
| (Err(ErrorGuaranteed { .. }), _) | (_, Err(ErrorGuaranteed { .. })) => None, |
| } |
| } |
| |
| pub fn find_crate_name(attrs: &[Attribute]) -> Option<Symbol> { |
| attr::first_attr_value_str_by_name(attrs, sym::crate_name) |
| } |
| |
| #[derive(Clone, Debug)] |
| pub struct Condition { |
| pub name: Symbol, |
| pub name_span: Span, |
| pub value: Option<Symbol>, |
| pub value_span: Option<Span>, |
| pub span: Span, |
| } |
| |
| /// Tests if a cfg-pattern matches the cfg set |
| #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable |
| pub fn cfg_matches( |
| cfg: &ast::MetaItem, |
| sess: &Session, |
| lint_node_id: NodeId, |
| features: Option<&Features>, |
| ) -> bool { |
| eval_condition(cfg, sess, features, &mut |cfg| { |
| try_gate_cfg(cfg.name, cfg.span, sess, features); |
| match sess.psess.check_config.expecteds.get(&cfg.name) { |
| Some(ExpectedValues::Some(values)) if !values.contains(&cfg.value) => { |
| sess.psess.buffer_lint_with_diagnostic( |
| UNEXPECTED_CFGS, |
| cfg.span, |
| lint_node_id, |
| if let Some(value) = cfg.value { |
| format!("unexpected `cfg` condition value: `{value}`") |
| } else { |
| format!("unexpected `cfg` condition value: (none)") |
| }, |
| BuiltinLintDiag::UnexpectedCfgValue( |
| (cfg.name, cfg.name_span), |
| cfg.value.map(|v| (v, cfg.value_span.unwrap())), |
| ), |
| ); |
| } |
| None if sess.psess.check_config.exhaustive_names => { |
| sess.psess.buffer_lint_with_diagnostic( |
| UNEXPECTED_CFGS, |
| cfg.span, |
| lint_node_id, |
| format!("unexpected `cfg` condition name: `{}`", cfg.name), |
| BuiltinLintDiag::UnexpectedCfgName( |
| (cfg.name, cfg.name_span), |
| cfg.value.map(|v| (v, cfg.value_span.unwrap())), |
| ), |
| ); |
| } |
| _ => { /* not unexpected */ } |
| } |
| sess.psess.config.contains(&(cfg.name, cfg.value)) |
| }) |
| } |
| |
| fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, features: Option<&Features>) { |
| let gate = find_gated_cfg(|sym| sym == name); |
| if let (Some(feats), Some(gated_cfg)) = (features, gate) { |
| gate_cfg(gated_cfg, span, sess, feats); |
| } |
| } |
| |
| #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable |
| fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) { |
| let (cfg, feature, has_feature) = gated_cfg; |
| if !has_feature(features) && !cfg_span.allows_unstable(*feature) { |
| let explain = format!("`cfg({cfg})` is experimental and subject to change"); |
| feature_err(sess, *feature, cfg_span, explain).emit(); |
| } |
| } |
| |
| /// Parse a rustc version number written inside string literal in an attribute, |
| /// like appears in `since = "1.0.0"`. Suffixes like "-dev" and "-nightly" are |
| /// not accepted in this position, unlike when parsing CFG_RELEASE. |
| fn parse_version(s: Symbol) -> Option<RustcVersion> { |
| let mut components = s.as_str().split('-'); |
| let d = components.next()?; |
| if components.next().is_some() { |
| return None; |
| } |
| let mut digits = d.splitn(3, '.'); |
| let major = digits.next()?.parse().ok()?; |
| let minor = digits.next()?.parse().ok()?; |
| let patch = digits.next().unwrap_or("0").parse().ok()?; |
| Some(RustcVersion { major, minor, patch }) |
| } |
| |
| /// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to |
| /// evaluate individual items. |
| #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable |
| pub fn eval_condition( |
| cfg: &ast::MetaItem, |
| sess: &Session, |
| features: Option<&Features>, |
| eval: &mut impl FnMut(Condition) -> bool, |
| ) -> bool { |
| let dcx = &sess.psess.dcx; |
| match &cfg.kind { |
| ast::MetaItemKind::List(mis) if cfg.name_or_empty() == sym::version => { |
| try_gate_cfg(sym::version, cfg.span, sess, features); |
| let (min_version, span) = match &mis[..] { |
| [NestedMetaItem::Lit(MetaItemLit { kind: LitKind::Str(sym, ..), span, .. })] => { |
| (sym, span) |
| } |
| [ |
| NestedMetaItem::Lit(MetaItemLit { span, .. }) |
| | NestedMetaItem::MetaItem(MetaItem { span, .. }), |
| ] => { |
| dcx.emit_err(session_diagnostics::ExpectedVersionLiteral { span: *span }); |
| return false; |
| } |
| [..] => { |
| dcx.emit_err(session_diagnostics::ExpectedSingleVersionLiteral { |
| span: cfg.span, |
| }); |
| return false; |
| } |
| }; |
| let Some(min_version) = parse_version(*min_version) else { |
| dcx.emit_warn(session_diagnostics::UnknownVersionLiteral { span: *span }); |
| return false; |
| }; |
| |
| // See https://github.com/rust-lang/rust/issues/64796#issuecomment-640851454 for details |
| if sess.psess.assume_incomplete_release { |
| RustcVersion::CURRENT > min_version |
| } else { |
| RustcVersion::CURRENT >= min_version |
| } |
| } |
| ast::MetaItemKind::List(mis) => { |
| for mi in mis.iter() { |
| if !mi.is_meta_item() { |
| dcx.emit_err(session_diagnostics::UnsupportedLiteral { |
| span: mi.span(), |
| reason: UnsupportedLiteralReason::Generic, |
| is_bytestr: false, |
| start_point_span: sess.source_map().start_point(mi.span()), |
| }); |
| 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() |
| // We don't use any() here, because we want to evaluate all cfg condition |
| // as eval_condition can (and does) extra checks |
| .fold(false, |res, mi| { |
| res | eval_condition(mi.meta_item().unwrap(), sess, features, eval) |
| }), |
| sym::all => mis |
| .iter() |
| // We don't use all() here, because we want to evaluate all cfg condition |
| // as eval_condition can (and does) extra checks |
| .fold(true, |res, mi| { |
| res & eval_condition(mi.meta_item().unwrap(), sess, features, eval) |
| }), |
| sym::not => { |
| if mis.len() != 1 { |
| dcx.emit_err(session_diagnostics::ExpectedOneCfgPattern { span: cfg.span }); |
| return false; |
| } |
| |
| !eval_condition(mis[0].meta_item().unwrap(), sess, features, eval) |
| } |
| sym::target => { |
| if let Some(features) = features |
| && !features.cfg_target_compact |
| { |
| feature_err( |
| sess, |
| sym::cfg_target_compact, |
| cfg.span, |
| "compact `cfg(target(..))` is experimental and subject to change", |
| ) |
| .emit(); |
| } |
| |
| mis.iter().fold(true, |res, mi| { |
| let mut mi = mi.meta_item().unwrap().clone(); |
| if let [seg, ..] = &mut mi.path.segments[..] { |
| seg.ident.name = Symbol::intern(&format!("target_{}", seg.ident.name)); |
| } |
| |
| res & eval_condition(&mi, sess, features, eval) |
| }) |
| } |
| _ => { |
| dcx.emit_err(session_diagnostics::InvalidPredicate { |
| span: cfg.span, |
| predicate: pprust::path_to_string(&cfg.path), |
| }); |
| false |
| } |
| } |
| } |
| ast::MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => { |
| dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span }); |
| true |
| } |
| MetaItemKind::NameValue(lit) if !lit.kind.is_str() => { |
| dcx.emit_err(session_diagnostics::UnsupportedLiteral { |
| span: lit.span, |
| reason: UnsupportedLiteralReason::CfgString, |
| is_bytestr: lit.kind.is_bytestr(), |
| start_point_span: sess.source_map().start_point(lit.span), |
| }); |
| true |
| } |
| ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => { |
| let ident = cfg.ident().expect("multi-segment cfg predicate"); |
| eval(Condition { |
| name: ident.name, |
| name_span: ident.span, |
| value: cfg.value_str(), |
| value_span: cfg.name_value_literal_span(), |
| span: cfg.span, |
| }) |
| } |
| } |
| } |
| |
| #[derive(Copy, Debug, Encodable, Decodable, Clone, HashStable_Generic)] |
| pub struct Deprecation { |
| pub since: DeprecatedSince, |
| /// 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>, |
| } |
| |
| /// Release in which an API is deprecated. |
| #[derive(Copy, Debug, Encodable, Decodable, Clone, HashStable_Generic)] |
| pub enum DeprecatedSince { |
| RustcVersion(RustcVersion), |
| /// Deprecated in the future ("to be determined"). |
| Future, |
| /// `feature(staged_api)` is off. Deprecation versions outside the standard |
| /// library are allowed to be arbitrary strings, for better or worse. |
| NonStandard(Symbol), |
| /// Deprecation version is unspecified but optional. |
| Unspecified, |
| /// Failed to parse a deprecation version, or the deprecation version is |
| /// unspecified and required. An error has already been emitted. |
| Err, |
| } |
| |
| impl Deprecation { |
| /// Whether an item marked with #[deprecated(since = "X")] is currently |
| /// deprecated (i.e., whether X is not greater than the current rustc |
| /// version). |
| pub fn is_in_effect(&self) -> bool { |
| match self.since { |
| DeprecatedSince::RustcVersion(since) => since <= RustcVersion::CURRENT, |
| DeprecatedSince::Future => false, |
| // The `since` field doesn't have semantic purpose without `#![staged_api]`. |
| DeprecatedSince::NonStandard(_) => true, |
| // Assume deprecation is in effect if "since" field is absent or invalid. |
| DeprecatedSince::Unspecified | DeprecatedSince::Err => true, |
| } |
| } |
| |
| pub fn is_since_rustc_version(&self) -> bool { |
| matches!(self.since, DeprecatedSince::RustcVersion(_)) |
| } |
| } |
| |
| /// Finds the deprecation attribute. `None` if none exists. |
| pub fn find_deprecation( |
| sess: &Session, |
| features: &Features, |
| attrs: &[Attribute], |
| ) -> Option<(Deprecation, Span)> { |
| let mut depr: Option<(Deprecation, Span)> = None; |
| let is_rustc = features.staged_api; |
| |
| 'outer: for attr in attrs { |
| if !attr.has_name(sym::deprecated) { |
| continue; |
| } |
| |
| let Some(meta) = attr.meta() else { |
| 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() { |
| sess.dcx().emit_err(session_diagnostics::MultipleItem { |
| span: meta.span, |
| item: 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() { |
| sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral { |
| span: lit.span, |
| reason: UnsupportedLiteralReason::DeprecatedString, |
| is_bytestr: lit.kind.is_bytestr(), |
| start_point_span: sess.source_map().start_point(lit.span), |
| }); |
| } else { |
| sess.dcx().emit_err(session_diagnostics::IncorrectMetaItem { |
| span: meta.span, |
| }); |
| } |
| |
| 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 !get(mi, &mut note) { |
| continue 'outer; |
| } |
| } |
| sym::suggestion => { |
| if !features.deprecated_suggestion { |
| sess.dcx().emit_err( |
| session_diagnostics::DeprecatedItemSuggestion { |
| span: mi.span, |
| is_nightly: sess.is_nightly_build().then_some(()), |
| details: (), |
| }, |
| ); |
| } |
| |
| if !get(mi, &mut suggestion) { |
| continue 'outer; |
| } |
| } |
| _ => { |
| sess.dcx().emit_err(session_diagnostics::UnknownMetaItem { |
| span: meta.span(), |
| item: pprust::path_to_string(&mi.path), |
| expected: if features.deprecated_suggestion { |
| &["since", "note", "suggestion"] |
| } else { |
| &["since", "note"] |
| }, |
| }); |
| continue 'outer; |
| } |
| }, |
| NestedMetaItem::Lit(lit) => { |
| sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral { |
| span: lit.span, |
| reason: UnsupportedLiteralReason::DeprecatedKvPair, |
| is_bytestr: false, |
| start_point_span: sess.source_map().start_point(lit.span), |
| }); |
| continue 'outer; |
| } |
| } |
| } |
| } |
| } |
| |
| let since = if let Some(since) = since { |
| if since.as_str() == "TBD" { |
| DeprecatedSince::Future |
| } else if !is_rustc { |
| DeprecatedSince::NonStandard(since) |
| } else if let Some(version) = parse_version(since) { |
| DeprecatedSince::RustcVersion(version) |
| } else { |
| sess.dcx().emit_err(session_diagnostics::InvalidSince { span: attr.span }); |
| DeprecatedSince::Err |
| } |
| } else if is_rustc { |
| sess.dcx().emit_err(session_diagnostics::MissingSince { span: attr.span }); |
| DeprecatedSince::Err |
| } else { |
| DeprecatedSince::Unspecified |
| }; |
| |
| if is_rustc && note.is_none() { |
| sess.dcx().emit_err(session_diagnostics::MissingNote { span: attr.span }); |
| continue; |
| } |
| |
| depr = Some((Deprecation { since, note, suggestion }, attr.span)); |
| } |
| |
| depr |
| } |
| |
| #[derive(PartialEq, Debug, Encodable, Decodable, Copy, Clone)] |
| pub enum ReprAttr { |
| ReprInt(IntType), |
| ReprRust, |
| ReprC, |
| ReprPacked(u32), |
| ReprSimd, |
| ReprTransparent, |
| ReprAlign(u32), |
| } |
| |
| #[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 delegate representation |
| /// concerns to the only non-ZST field. |
| pub fn find_repr_attrs(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> { |
| if attr.has_name(sym::repr) { parse_repr_attr(sess, attr) } else { Vec::new() } |
| } |
| |
| pub fn parse_repr_attr(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> { |
| assert!(attr.has_name(sym::repr), "expected `#[repr(..)]`, found: {attr:?}"); |
| use ReprAttr::*; |
| let mut acc = Vec::new(); |
| let dcx = sess.dcx(); |
| |
| if let Some(items) = attr.meta_item_list() { |
| for item in items { |
| let mut recognised = false; |
| if item.is_word() { |
| let hint = match item.name_or_empty() { |
| sym::Rust => Some(ReprRust), |
| sym::C => Some(ReprC), |
| sym::packed => Some(ReprPacked(1)), |
| sym::simd => Some(ReprSimd), |
| sym::transparent => Some(ReprTransparent), |
| sym::align => { |
| sess.dcx().emit_err(session_diagnostics::InvalidReprAlignNeedArg { |
| span: item.span(), |
| }); |
| recognised = true; |
| None |
| } |
| 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 mut literal_error = None; |
| let mut err_span = item.span(); |
| if name == sym::align { |
| recognised = true; |
| match parse_alignment(&value.kind) { |
| Ok(literal) => acc.push(ReprAlign(literal)), |
| Err(message) => { |
| err_span = value.span; |
| literal_error = Some(message) |
| } |
| }; |
| } else if name == sym::packed { |
| recognised = true; |
| match parse_alignment(&value.kind) { |
| Ok(literal) => acc.push(ReprPacked(literal)), |
| Err(message) => { |
| err_span = value.span; |
| literal_error = Some(message) |
| } |
| }; |
| } else if matches!(name, sym::Rust | sym::C | sym::simd | sym::transparent) |
| || int_type_of_word(name).is_some() |
| { |
| recognised = true; |
| sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoParen { |
| span: item.span(), |
| name: name.to_ident_string(), |
| }); |
| } |
| if let Some(literal_error) = literal_error { |
| sess.dcx().emit_err(session_diagnostics::InvalidReprGeneric { |
| span: err_span, |
| repr_arg: name.to_ident_string(), |
| error_part: literal_error, |
| }); |
| } |
| } else if let Some(meta_item) = item.meta_item() { |
| match &meta_item.kind { |
| MetaItemKind::NameValue(value) => { |
| if meta_item.has_name(sym::align) || meta_item.has_name(sym::packed) { |
| let name = meta_item.name_or_empty().to_ident_string(); |
| recognised = true; |
| sess.dcx().emit_err(session_diagnostics::IncorrectReprFormatGeneric { |
| span: item.span(), |
| repr_arg: &name, |
| cause: IncorrectReprFormatGenericCause::from_lit_kind( |
| item.span(), |
| &value.kind, |
| &name, |
| ), |
| }); |
| } else if matches!( |
| meta_item.name_or_empty(), |
| sym::Rust | sym::C | sym::simd | sym::transparent |
| ) || int_type_of_word(meta_item.name_or_empty()).is_some() |
| { |
| recognised = true; |
| sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoValue { |
| span: meta_item.span, |
| name: meta_item.name_or_empty().to_ident_string(), |
| }); |
| } |
| } |
| MetaItemKind::List(nested_items) => { |
| if meta_item.has_name(sym::align) { |
| recognised = true; |
| if nested_items.len() == 1 { |
| sess.dcx().emit_err( |
| session_diagnostics::IncorrectReprFormatExpectInteger { |
| span: nested_items[0].span(), |
| }, |
| ); |
| } else { |
| sess.dcx().emit_err( |
| session_diagnostics::IncorrectReprFormatAlignOneArg { |
| span: meta_item.span, |
| }, |
| ); |
| } |
| } else if meta_item.has_name(sym::packed) { |
| recognised = true; |
| if nested_items.len() == 1 { |
| sess.dcx().emit_err( |
| session_diagnostics::IncorrectReprFormatPackedExpectInteger { |
| span: nested_items[0].span(), |
| }, |
| ); |
| } else { |
| sess.dcx().emit_err( |
| session_diagnostics::IncorrectReprFormatPackedOneOrZeroArg { |
| span: meta_item.span, |
| }, |
| ); |
| } |
| } else if matches!( |
| meta_item.name_or_empty(), |
| sym::Rust | sym::C | sym::simd | sym::transparent |
| ) || int_type_of_word(meta_item.name_or_empty()).is_some() |
| { |
| recognised = true; |
| sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoParen { |
| span: meta_item.span, |
| name: meta_item.name_or_empty().to_ident_string(), |
| }); |
| } |
| } |
| _ => (), |
| } |
| } |
| if !recognised { |
| // Not a word we recognize. This will be caught and reported by |
| // the `check_mod_attrs` pass, but this pass doesn't always run |
| // (e.g. if we only pretty-print the source), so we have to gate |
| // the `span_delayed_bug` call as follows: |
| if sess.opts.pretty.map_or(true, |pp| pp.needs_analysis()) { |
| dcx.span_delayed_bug(item.span(), "unrecognized representation hint"); |
| } |
| } |
| } |
| } |
| 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( |
| attrs: &[Attribute], |
| macro_rules: bool, |
| ) -> (Transparency, Option<TransparencyError>) { |
| let mut transparency = None; |
| let mut error = None; |
| for attr in attrs { |
| if attr.has_name(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], |
| ) -> 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], |
| ) -> 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, |
| ) -> impl Iterator<Item = Symbol> + 'a { |
| let attrs = attr::filter_by_name(attrs, symbol); |
| let list = attrs |
| .filter_map(move |attr| { |
| attr.meta_item_list().or_else(|| { |
| sess.dcx().emit_err(session_diagnostics::ExpectsFeatureList { |
| span: attr.span, |
| name: symbol.to_ident_string(), |
| }); |
| None |
| }) |
| }) |
| .flatten(); |
| |
| list.into_iter().filter_map(move |it| { |
| let name = it.ident().map(|ident| ident.name); |
| if name.is_none() { |
| sess.dcx().emit_err(session_diagnostics::ExpectsFeatures { |
| span: it.span(), |
| name: symbol.to_ident_string(), |
| }); |
| } |
| name |
| }) |
| } |
| |
| pub fn parse_alignment(node: &ast::LitKind) -> Result<u32, &'static str> { |
| if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node { |
| if literal.get().is_power_of_two() { |
| // rustc_middle::ty::layout::Align restricts align to <= 2^29 |
| if *literal <= 1 << 29 { Ok(literal.get() as u32) } else { Err("larger than 2^29") } |
| } else { |
| Err("not a power of two") |
| } |
| } else { |
| Err("not an unsuffixed integer") |
| } |
| } |
| |
| /// Read the content of a `rustc_confusables` attribute, and return the list of candidate names. |
| pub fn parse_confusables(attr: &Attribute) -> Option<Vec<Symbol>> { |
| let meta = attr.meta()?; |
| let MetaItem { kind: MetaItemKind::List(ref metas), .. } = meta else { return None }; |
| |
| let mut candidates = Vec::new(); |
| |
| for meta in metas { |
| let NestedMetaItem::Lit(meta_lit) = meta else { |
| return None; |
| }; |
| candidates.push(meta_lit.symbol); |
| } |
| |
| return Some(candidates); |
| } |
