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| 1 | +use rustc_ast::Safety; |
| 2 | +use rustc_feature::{AttributeSafety, BUILTIN_ATTRIBUTE_MAP}; |
| 3 | +use rustc_hir::AttrPath; |
| 4 | +use rustc_hir::lints::{AttributeLint, AttributeLintKind}; |
| 5 | +use rustc_span::{Span, sym}; |
| 6 | + |
| 7 | +use crate::context::Stage; |
| 8 | +use crate::{AttributeParser, ShouldEmit}; |
| 9 | + |
| 10 | +impl<'sess, S: Stage> AttributeParser<'sess, S> { |
| 11 | + pub fn check_attribute_safety( |
| 12 | + &mut self, |
| 13 | + attr_path: &AttrPath, |
| 14 | + attr_span: Span, |
| 15 | + attr_safety: Safety, |
| 16 | + emit_lint: &mut impl FnMut(AttributeLint<S::Id>), |
| 17 | + target_id: S::Id, |
| 18 | + ) { |
| 19 | + if matches!(self.stage.should_emit(), ShouldEmit::Nothing) { |
| 20 | + return; |
| 21 | + } |
| 22 | + |
| 23 | + let name = (attr_path.segments.len() == 1).then_some(attr_path.segments[0].name); |
| 24 | + if let Some(name) = name |
| 25 | + && [sym::cfg_trace, sym::cfg_attr_trace].contains(&name) |
| 26 | + { |
| 27 | + return; |
| 28 | + } |
| 29 | + |
| 30 | + // FIXME: We should retrieve this information from the attribute parsers instead of from `BUILTIN_ATTRIBUTE_MAP` |
| 31 | + let builtin_attr_info = name.and_then(|name| BUILTIN_ATTRIBUTE_MAP.get(&name)); |
| 32 | + let builtin_attr_safety = builtin_attr_info.map(|x| x.safety); |
| 33 | + |
| 34 | + match (builtin_attr_safety, attr_safety) { |
| 35 | + // - Unsafe builtin attribute |
| 36 | + // - User wrote `#[unsafe(..)]`, which is permitted on any edition |
| 37 | + (Some(AttributeSafety::Unsafe { .. }), Safety::Unsafe(..)) => { |
| 38 | + // OK |
| 39 | + } |
| 40 | + |
| 41 | + // - Unsafe builtin attribute |
| 42 | + // - User did not write `#[unsafe(..)]` |
| 43 | + (Some(AttributeSafety::Unsafe { unsafe_since }), Safety::Default) => { |
| 44 | + let path_span = attr_path.span; |
| 45 | + |
| 46 | + // If the `attr_item`'s span is not from a macro, then just suggest |
| 47 | + // wrapping it in `unsafe(...)`. Otherwise, we suggest putting the |
| 48 | + // `unsafe(`, `)` right after and right before the opening and closing |
| 49 | + // square bracket respectively. |
| 50 | + let diag_span = attr_span; |
| 51 | + |
| 52 | + // Attributes can be safe in earlier editions, and become unsafe in later ones. |
| 53 | + // |
| 54 | + // Use the span of the attribute's name to determine the edition: the span of the |
| 55 | + // attribute as a whole may be inaccurate if it was emitted by a macro. |
| 56 | + // |
| 57 | + // See https://github.com/rust-lang/rust/issues/142182. |
| 58 | + let emit_error = match unsafe_since { |
| 59 | + None => true, |
| 60 | + Some(unsafe_since) => path_span.edition() >= unsafe_since, |
| 61 | + }; |
| 62 | + |
| 63 | + if emit_error { |
| 64 | + self.stage.emit_err( |
| 65 | + self.sess, |
| 66 | + crate::session_diagnostics::UnsafeAttrOutsideUnsafe { |
| 67 | + span: path_span, |
| 68 | + suggestion: |
| 69 | + crate::session_diagnostics::UnsafeAttrOutsideUnsafeSuggestion { |
| 70 | + left: diag_span.shrink_to_lo(), |
| 71 | + right: diag_span.shrink_to_hi(), |
| 72 | + }, |
| 73 | + }, |
| 74 | + ); |
| 75 | + } else { |
| 76 | + emit_lint(AttributeLint { |
| 77 | + id: target_id, |
| 78 | + span: path_span, |
| 79 | + kind: AttributeLintKind::UnsafeAttrOutsideUnsafe { |
| 80 | + attribute_name_span: path_span, |
| 81 | + sugg_spans: (diag_span.shrink_to_lo(), diag_span.shrink_to_hi()), |
| 82 | + }, |
| 83 | + }) |
| 84 | + } |
| 85 | + } |
| 86 | + |
| 87 | + // - Normal builtin attribute |
| 88 | + // - Writing `#[unsafe(..)]` is not permitted on normal builtin attributes |
| 89 | + (None | Some(AttributeSafety::Normal), Safety::Unsafe(unsafe_span)) => { |
| 90 | + self.stage.emit_err( |
| 91 | + self.sess, |
| 92 | + crate::session_diagnostics::InvalidAttrUnsafe { |
| 93 | + span: unsafe_span, |
| 94 | + name: attr_path.clone(), |
| 95 | + }, |
| 96 | + ); |
| 97 | + } |
| 98 | + |
| 99 | + // - Normal builtin attribute |
| 100 | + // - No explicit `#[unsafe(..)]` written. |
| 101 | + (None | Some(AttributeSafety::Normal), Safety::Default) => { |
| 102 | + // OK |
| 103 | + } |
| 104 | + |
| 105 | + ( |
| 106 | + Some(AttributeSafety::Unsafe { .. } | AttributeSafety::Normal) | None, |
| 107 | + Safety::Safe(..), |
| 108 | + ) => { |
| 109 | + self.sess.dcx().span_delayed_bug( |
| 110 | + attr_span, |
| 111 | + "`check_attribute_safety` does not expect `Safety::Safe` on attributes", |
| 112 | + ); |
| 113 | + } |
| 114 | + } |
| 115 | + } |
| 116 | +} |
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