| use std::borrow::Cow; |
| |
| use rustc_ast::AttrStyle; |
| use rustc_errors::{DiagArgValue, MultiSpan, StashKey}; |
| use rustc_feature::Features; |
| use rustc_hir::attrs::AttributeKind; |
| use rustc_hir::lints::AttributeLintKind; |
| use rustc_hir::{AttrItem, Attribute, MethodKind, Target}; |
| use rustc_span::{BytePos, Span, Symbol, sym}; |
| |
| use crate::AttributeParser; |
| use crate::context::{AcceptContext, Stage}; |
| use crate::errors::{ |
| InvalidAttrAtCrateLevel, ItemFollowingInnerAttr, UnsupportedAttributesInWhere, |
| }; |
| use crate::session_diagnostics::InvalidTarget; |
| use crate::target_checking::Policy::Allow; |
| |
| #[derive(Debug)] |
| pub(crate) enum AllowedTargets { |
| AllowList(&'static [Policy]), |
| AllowListWarnRest(&'static [Policy]), |
| } |
| |
| pub(crate) enum AllowedResult { |
| Allowed, |
| Warn, |
| Error, |
| } |
| |
| impl AllowedTargets { |
| pub(crate) fn is_allowed(&self, target: Target) -> AllowedResult { |
| match self { |
| AllowedTargets::AllowList(list) => { |
| if list.contains(&Policy::Allow(target)) |
| || list.contains(&Policy::AllowSilent(target)) |
| { |
| AllowedResult::Allowed |
| } else if list.contains(&Policy::Warn(target)) { |
| AllowedResult::Warn |
| } else { |
| AllowedResult::Error |
| } |
| } |
| AllowedTargets::AllowListWarnRest(list) => { |
| if list.contains(&Policy::Allow(target)) |
| || list.contains(&Policy::AllowSilent(target)) |
| { |
| AllowedResult::Allowed |
| } else if list.contains(&Policy::Error(target)) { |
| AllowedResult::Error |
| } else { |
| AllowedResult::Warn |
| } |
| } |
| } |
| } |
| |
| pub(crate) fn allowed_targets(&self) -> Vec<Target> { |
| match self { |
| AllowedTargets::AllowList(list) => list, |
| AllowedTargets::AllowListWarnRest(list) => list, |
| } |
| .iter() |
| .filter_map(|target| match target { |
| Policy::Allow(target) => Some(*target), |
| Policy::AllowSilent(_) => None, // Not listed in possible targets |
| Policy::Warn(_) => None, |
| Policy::Error(_) => None, |
| }) |
| .collect() |
| } |
| } |
| |
| /// This policy determines what diagnostics should be emitted based on the `Target` of the attribute. |
| #[derive(Debug, Eq, PartialEq)] |
| pub(crate) enum Policy { |
| /// A target that is allowed. |
| Allow(Target), |
| /// A target that is allowed and not listed in the possible targets. |
| /// This is useful if the target is checked elsewhere. |
| AllowSilent(Target), |
| /// Emits a FCW on this target. |
| /// This is useful if the target was previously allowed but should not be. |
| Warn(Target), |
| /// Emits an error on this target. |
| Error(Target), |
| } |
| |
| impl<'sess, S: Stage> AttributeParser<'sess, S> { |
| pub(crate) fn check_target( |
| allowed_targets: &AllowedTargets, |
| target: Target, |
| cx: &mut AcceptContext<'_, 'sess, S>, |
| ) { |
| // For crate-level attributes we emit a specific set of lints to warn |
| // people about accidentally not using them on the crate. |
| if let &AllowedTargets::AllowList(&[Allow(Target::Crate)]) = allowed_targets { |
| Self::check_crate_level(target, cx); |
| return; |
| } |
| |
| if matches!(cx.attr_path.segments.as_ref(), [sym::repr]) && target == Target::Crate { |
| // The allowed targets of `repr` depend on its arguments. They can't be checked using |
| // the `AttributeParser` code. |
| let span = cx.attr_span; |
| let item = |
| cx.cx.first_line_of_next_item(span).map(|span| ItemFollowingInnerAttr { span }); |
| |
| let pound_to_opening_bracket = cx.attr_span.until(cx.inner_span); |
| |
| cx.dcx() |
| .create_err(InvalidAttrAtCrateLevel { |
| span, |
| pound_to_opening_bracket, |
| name: sym::repr, |
| item, |
| }) |
| .emit(); |
| } |
| |
| match allowed_targets.is_allowed(target) { |
| AllowedResult::Allowed => {} |
| AllowedResult::Warn => { |
| let allowed_targets = allowed_targets.allowed_targets(); |
| let (applied, only) = allowed_targets_applied(allowed_targets, target, cx.features); |
| let name = cx.attr_path.clone(); |
| |
| let lint = if name.segments[0] == sym::deprecated |
| && ![ |
| Target::Closure, |
| Target::Expression, |
| Target::Statement, |
| Target::Arm, |
| Target::MacroCall, |
| ] |
| .contains(&target) |
| { |
| rustc_session::lint::builtin::USELESS_DEPRECATED |
| } else { |
| rustc_session::lint::builtin::UNUSED_ATTRIBUTES |
| }; |
| |
| let attr_span = cx.attr_span; |
| cx.emit_lint( |
| lint, |
| AttributeLintKind::InvalidTarget { |
| name: name.to_string(), |
| target: target.plural_name(), |
| only: if only { "only " } else { "" }, |
| applied, |
| attr_span, |
| }, |
| attr_span, |
| ); |
| } |
| AllowedResult::Error => { |
| let allowed_targets = allowed_targets.allowed_targets(); |
| let (applied, only) = allowed_targets_applied(allowed_targets, target, cx.features); |
| let name = cx.attr_path.clone(); |
| cx.dcx().emit_err(InvalidTarget { |
| span: cx.attr_span.clone(), |
| name, |
| target: target.plural_name(), |
| only: if only { "only " } else { "" }, |
| applied: DiagArgValue::StrListSepByAnd( |
| applied.into_iter().map(Cow::Owned).collect(), |
| ), |
| }); |
| } |
| } |
| } |
| |
| pub(crate) fn check_crate_level(target: Target, cx: &mut AcceptContext<'_, 'sess, S>) { |
| if target == Target::Crate { |
| return; |
| } |
| |
| let kind = AttributeLintKind::InvalidStyle { |
| name: cx.attr_path.to_string(), |
| is_used_as_inner: cx.attr_style == AttrStyle::Inner, |
| target: target.name(), |
| target_span: cx.target_span, |
| }; |
| let attr_span = cx.attr_span; |
| |
| cx.emit_lint(rustc_session::lint::builtin::UNUSED_ATTRIBUTES, kind, attr_span); |
| } |
| |
| // FIXME: Fix "Cannot determine resolution" error and remove built-in macros |
| // from this check. |
| pub(crate) fn check_invalid_crate_level_attr_item(&self, attr: &AttrItem, inner_span: Span) { |
| // Check for builtin attributes at the crate level |
| // which were unsuccessfully resolved due to cannot determine |
| // resolution for the attribute macro error. |
| const ATTRS_TO_CHECK: &[Symbol] = |
| &[sym::derive, sym::test, sym::test_case, sym::global_allocator, sym::bench]; |
| |
| // FIXME(jdonszelmann): all attrs should be combined here cleaning this up some day. |
| if let Some(name) = ATTRS_TO_CHECK.iter().find(|attr_to_check| matches!(attr.path.segments.as_ref(), [segment] if segment == *attr_to_check)) { |
| let span = attr.span; |
| let name = *name; |
| |
| let item = self.first_line_of_next_item(span).map(|span| ItemFollowingInnerAttr { span }); |
| |
| let err = self.dcx().create_err(InvalidAttrAtCrateLevel { |
| span, |
| pound_to_opening_bracket: span.until(inner_span), |
| name, |
| item, |
| }); |
| |
| self.dcx().try_steal_replace_and_emit_err( |
| attr.path.span, |
| StashKey::UndeterminedMacroResolution, |
| err, |
| ); |
| } |
| } |
| |
| fn first_line_of_next_item(&self, span: Span) -> Option<Span> { |
| // We can't exactly call `tcx.hir_free_items()` here because it's too early and querying |
| // this would create a circular dependency. Instead, we resort to getting the original |
| // source code that follows `span` and find the next item from here. |
| |
| self.sess() |
| .source_map() |
| .span_to_source(span, |content, _, span_end| { |
| let mut source = &content[span_end..]; |
| let initial_source_len = source.len(); |
| let span = try { |
| loop { |
| let first = source.chars().next()?; |
| |
| if first.is_whitespace() { |
| let split_idx = source.find(|c: char| !c.is_whitespace())?; |
| source = &source[split_idx..]; |
| } else if source.starts_with("//") { |
| let line_idx = source.find('\n')?; |
| source = &source[line_idx + '\n'.len_utf8()..]; |
| } else if source.starts_with("/*") { |
| // FIXME: support nested comments. |
| let close_idx = source.find("*/")?; |
| source = &source[close_idx + "*/".len()..]; |
| } else if first == '#' { |
| // FIXME: properly find the end of the attributes in order to accurately |
| // skip them. This version just consumes the source code until the next |
| // `]`. |
| let close_idx = source.find(']')?; |
| source = &source[close_idx + ']'.len_utf8()..]; |
| } else { |
| let lo = span_end + initial_source_len - source.len(); |
| let last_line = source.split('\n').next().map(|s| s.trim_end())?; |
| |
| let hi = lo + last_line.len(); |
| let lo = BytePos(lo as u32); |
| let hi = BytePos(hi as u32); |
| let next_item_span = Span::new(lo, hi, span.ctxt(), None); |
| |
| break next_item_span; |
| } |
| } |
| }; |
| |
| Ok(span) |
| }) |
| .ok() |
| .flatten() |
| } |
| |
| pub(crate) fn check_invalid_where_predicate_attrs<'attr>( |
| &self, |
| attrs: impl IntoIterator<Item = &'attr Attribute>, |
| ) { |
| // FIXME(where_clause_attrs): Currently, as the following check shows, |
| // only `#[cfg]` and `#[cfg_attr]` are allowed, but it should be removed |
| // if we allow more attributes (e.g., tool attributes and `allow/deny/warn`) |
| // in where clauses. After that, this function would become useless. |
| let spans = attrs |
| .into_iter() |
| // FIXME: We shouldn't need to special-case `doc`! |
| .filter(|attr| { |
| matches!( |
| attr, |
| Attribute::Parsed(AttributeKind::DocComment { .. } | AttributeKind::Doc(_)) |
| | Attribute::Unparsed(_) |
| ) |
| }) |
| .map(|attr| attr.span()) |
| .collect::<Vec<_>>(); |
| if !spans.is_empty() { |
| self.dcx() |
| .emit_err(UnsupportedAttributesInWhere { span: MultiSpan::from_spans(spans) }); |
| } |
| } |
| } |
| |
| /// Takes a list of `allowed_targets` for an attribute, and the `target` the attribute was applied to. |
| /// Does some heuristic-based filtering to remove uninteresting targets, and formats the targets into a string |
| pub(crate) fn allowed_targets_applied( |
| mut allowed_targets: Vec<Target>, |
| target: Target, |
| features: Option<&Features>, |
| ) -> (Vec<String>, bool) { |
| // Remove unstable targets from `allowed_targets` if their features are not enabled |
| if let Some(features) = features { |
| if !features.fn_delegation() { |
| allowed_targets.retain(|t| !matches!(t, Target::Delegation { .. })); |
| } |
| if !features.stmt_expr_attributes() { |
| allowed_targets.retain(|t| !matches!(t, Target::Expression | Target::Statement)); |
| } |
| if !features.extern_types() { |
| allowed_targets.retain(|t| !matches!(t, Target::ForeignTy)); |
| } |
| } |
| |
| // We define groups of "similar" targets. |
| // If at least two of the targets are allowed, and the `target` is not in the group, |
| // we collapse the entire group to a single entry to simplify the target list |
| const FUNCTION_LIKE: &[Target] = &[ |
| Target::Fn, |
| Target::Closure, |
| Target::ForeignFn, |
| Target::Method(MethodKind::Inherent), |
| Target::Method(MethodKind::Trait { body: false }), |
| Target::Method(MethodKind::Trait { body: true }), |
| Target::Method(MethodKind::TraitImpl), |
| ]; |
| const METHOD_LIKE: &[Target] = &[ |
| Target::Method(MethodKind::Inherent), |
| Target::Method(MethodKind::Trait { body: false }), |
| Target::Method(MethodKind::Trait { body: true }), |
| Target::Method(MethodKind::TraitImpl), |
| ]; |
| const IMPL_LIKE: &[Target] = |
| &[Target::Impl { of_trait: false }, Target::Impl { of_trait: true }]; |
| const ADT_LIKE: &[Target] = &[Target::Struct, Target::Enum, Target::Union]; |
| |
| let mut added_fake_targets = Vec::new(); |
| filter_targets( |
| &mut allowed_targets, |
| FUNCTION_LIKE, |
| "functions", |
| target, |
| &mut added_fake_targets, |
| ); |
| filter_targets(&mut allowed_targets, METHOD_LIKE, "methods", target, &mut added_fake_targets); |
| filter_targets(&mut allowed_targets, IMPL_LIKE, "impl blocks", target, &mut added_fake_targets); |
| filter_targets(&mut allowed_targets, ADT_LIKE, "data types", target, &mut added_fake_targets); |
| |
| let mut target_strings: Vec<_> = added_fake_targets |
| .iter() |
| .copied() |
| .chain(allowed_targets.iter().map(|t| t.plural_name())) |
| .map(|i| i.to_string()) |
| .collect(); |
| |
| // ensure a consistent order |
| target_strings.sort(); |
| |
| // If there is now only 1 target left, show that as the only possible target |
| let only_target = target_strings.len() == 1; |
| |
| (target_strings, only_target) |
| } |
| |
| fn filter_targets( |
| allowed_targets: &mut Vec<Target>, |
| target_group: &'static [Target], |
| target_group_name: &'static str, |
| target: Target, |
| added_fake_targets: &mut Vec<&'static str>, |
| ) { |
| if target_group.contains(&target) { |
| return; |
| } |
| if allowed_targets.iter().filter(|at| target_group.contains(at)).count() < 2 { |
| return; |
| } |
| allowed_targets.retain(|t| !target_group.contains(t)); |
| added_fake_targets.push(target_group_name); |
| } |
| |
| /// This is the list of all targets to which a attribute can be applied |
| /// This is used for: |
| /// - `rustc_dummy`, which can be applied to all targets |
| /// - Attributes that are not parted to the new target system yet can use this list as a placeholder |
| pub(crate) const ALL_TARGETS: &'static [Policy] = { |
| use Policy::Allow; |
| &[ |
| Allow(Target::ExternCrate), |
| Allow(Target::Use), |
| Allow(Target::Static), |
| Allow(Target::Const), |
| Allow(Target::Fn), |
| Allow(Target::Closure), |
| Allow(Target::Mod), |
| Allow(Target::ForeignMod), |
| Allow(Target::GlobalAsm), |
| Allow(Target::TyAlias), |
| Allow(Target::Enum), |
| Allow(Target::Variant), |
| Allow(Target::Struct), |
| Allow(Target::Field), |
| Allow(Target::Union), |
| Allow(Target::Trait), |
| Allow(Target::TraitAlias), |
| Allow(Target::Impl { of_trait: false }), |
| Allow(Target::Impl { of_trait: true }), |
| Allow(Target::Expression), |
| Allow(Target::Statement), |
| Allow(Target::Arm), |
| Allow(Target::AssocConst), |
| Allow(Target::Method(MethodKind::Inherent)), |
| Allow(Target::Method(MethodKind::Trait { body: false })), |
| Allow(Target::Method(MethodKind::Trait { body: true })), |
| Allow(Target::Method(MethodKind::TraitImpl)), |
| Allow(Target::AssocTy), |
| Allow(Target::ForeignFn), |
| Allow(Target::ForeignStatic), |
| Allow(Target::ForeignTy), |
| Allow(Target::MacroDef), |
| Allow(Target::Param), |
| Allow(Target::PatField), |
| Allow(Target::ExprField), |
| Allow(Target::WherePredicate), |
| Allow(Target::MacroCall), |
| Allow(Target::Crate), |
| Allow(Target::Delegation { mac: false }), |
| Allow(Target::Delegation { mac: true }), |
| Allow(Target::GenericParam { |
| kind: rustc_hir::target::GenericParamKind::Const, |
| has_default: false, |
| }), |
| Allow(Target::GenericParam { |
| kind: rustc_hir::target::GenericParamKind::Const, |
| has_default: true, |
| }), |
| Allow(Target::GenericParam { |
| kind: rustc_hir::target::GenericParamKind::Lifetime, |
| has_default: false, |
| }), |
| Allow(Target::GenericParam { |
| kind: rustc_hir::target::GenericParamKind::Lifetime, |
| has_default: true, |
| }), |
| Allow(Target::GenericParam { |
| kind: rustc_hir::target::GenericParamKind::Type, |
| has_default: false, |
| }), |
| Allow(Target::GenericParam { |
| kind: rustc_hir::target::GenericParamKind::Type, |
| has_default: true, |
| }), |
| ] |
| }; |
