Unsafe extern blocks #124482
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -15,7 +15,8 @@ use rustc_data_structures::fx::FxIndexMap; | |
| use rustc_feature::Features; | ||
| use rustc_parse::validate_attr; | ||
| use rustc_session::lint::builtin::{ | ||
| DEPRECATED_WHERE_CLAUSE_LOCATION, MISSING_ABI, MISSING_UNSAFE_ON_EXTERN, | ||
| PATTERNS_IN_FNS_WITHOUT_BODY, | ||
| }; | ||
| use rustc_session::lint::{BuiltinLintDiag, LintBuffer}; | ||
| use rustc_session::Session; | ||
|
|
@@ -86,6 +87,9 @@ struct AstValidator<'a> { | |
| /// or `Foo::Bar<impl Trait>` | ||
| is_impl_trait_banned: bool, | ||
|
|
||
| /// Used to ban explicit safety on foreign items when the extern block is not marked as unsafe. | ||
| extern_mod_safety: Option<Safety>, | ||
|
|
||
| lint_buffer: &'a mut LintBuffer, | ||
| } | ||
|
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||
|
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@@ -116,6 +120,12 @@ impl<'a> AstValidator<'a> { | |
| self.outer_trait_or_trait_impl = old; | ||
| } | ||
|
|
||
| fn with_in_extern_mod(&mut self, extern_mod_safety: Safety, f: impl FnOnce(&mut Self)) { | ||
| let old = mem::replace(&mut self.extern_mod_safety, Some(extern_mod_safety)); | ||
| f(self); | ||
| self.extern_mod_safety = old; | ||
| } | ||
|
|
||
| fn with_banned_impl_trait(&mut self, f: impl FnOnce(&mut Self)) { | ||
| let old = mem::replace(&mut self.is_impl_trait_banned, true); | ||
| f(self); | ||
|
|
@@ -429,6 +439,19 @@ impl<'a> AstValidator<'a> { | |
| } | ||
| } | ||
|
|
||
| fn check_foreign_item_safety(&self, item_span: Span, safety: Safety) { | ||
| if matches!(safety, Safety::Unsafe(_) | Safety::Safe(_)) | ||
| && (self.features.unsafe_extern_blocks | ||
| && self.extern_mod_safety == Some(Safety::Default) | ||
| || !self.features.unsafe_extern_blocks) | ||
| { | ||
| self.dcx().emit_err(errors::InvalidSafetyOnExtern { | ||
| item_span, | ||
| block: self.current_extern_span(), | ||
| }); | ||
| } | ||
| } | ||
|
|
||
| fn check_defaultness(&self, span: Span, defaultness: Defaultness) { | ||
| if let Defaultness::Default(def_span) = defaultness { | ||
| let span = self.session.source_map().guess_head_span(span); | ||
|
|
@@ -518,18 +541,14 @@ impl<'a> AstValidator<'a> { | |
| fn check_foreign_fn_headerless( | ||
| &self, | ||
| // Deconstruct to ensure exhaustiveness | ||
| FnHeader { safety: _, coroutine_kind, constness, ext }: FnHeader, | ||
| ) { | ||
| let report_err = |span| { | ||
| self.dcx().emit_err(errors::FnQualifierInExtern { | ||
| span: span, | ||
| block: self.current_extern_span(), | ||
| }); | ||
| }; | ||
| match coroutine_kind { | ||
| Some(knd) => report_err(knd.span()), | ||
| None => (), | ||
|
|
@@ -1017,19 +1036,34 @@ impl<'a> Visitor<'a> for AstValidator<'a> { | |
| return; // Avoid visiting again. | ||
| } | ||
| ItemKind::ForeignMod(ForeignMod { abi, safety, .. }) => { | ||
| self.with_in_extern_mod(*safety, |this| { | ||
| let old_item = mem::replace(&mut this.extern_mod, Some(item)); | ||
| this.visibility_not_permitted( | ||
| &item.vis, | ||
| errors::VisibilityNotPermittedNote::IndividualForeignItems, | ||
| ); | ||
|
|
||
| if this.features.unsafe_extern_blocks { | ||
| if &Safety::Default == safety { | ||
| this.lint_buffer.buffer_lint( | ||
| MISSING_UNSAFE_ON_EXTERN, | ||
| item.id, | ||
| item.span, | ||
| BuiltinLintDiag::MissingUnsafeOnExtern, | ||
| ); | ||
| } | ||
|
Comment on lines
+1047
to
+1054
There was a problem hiding this comment. Either here or in follow-up work, we need to make this into a hard error (rather than just (@oli-obk, what's your preference on whether this is done in this PR or later?) |
||
| } else { | ||
| if let &Safety::Unsafe(span) = safety { | ||
| this.dcx().emit_err(errors::UnsafeItem { span, kind: "extern block" }); | ||
| } | ||
| } | ||
|
|
||
| if abi.is_none() { | ||
| this.maybe_lint_missing_abi(item.span, item.id); | ||
| } | ||
| visit::walk_item(this, item); | ||
| this.extern_mod = old_item; | ||
| }); | ||
| return; // Avoid visiting again. | ||
| } | ||
| ItemKind::Enum(def, _) => { | ||
|
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@@ -1161,6 +1195,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> { | |
| fn visit_foreign_item(&mut self, fi: &'a ForeignItem) { | ||
| match &fi.kind { | ||
| ForeignItemKind::Fn(box Fn { defaultness, sig, body, .. }) => { | ||
| self.check_foreign_item_safety(fi.span, sig.header.safety); | ||
| self.check_defaultness(fi.span, *defaultness); | ||
| self.check_foreign_fn_bodyless(fi.ident, body.as_deref()); | ||
| self.check_foreign_fn_headerless(sig.header); | ||
|
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@@ -1180,7 +1215,8 @@ impl<'a> Visitor<'a> for AstValidator<'a> { | |
| self.check_foreign_ty_genericless(generics, where_clauses); | ||
| self.check_foreign_item_ascii_only(fi.ident); | ||
| } | ||
| ForeignItemKind::Static(box StaticForeignItem { expr, safety, .. }) => { | ||
| self.check_foreign_item_safety(fi.span, *safety); | ||
| self.check_foreign_kind_bodyless(fi.ident, "static", expr.as_ref().map(|b| b.span)); | ||
| self.check_foreign_item_ascii_only(fi.ident); | ||
| } | ||
|
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@@ -1736,6 +1772,7 @@ pub fn check_crate( | |
| outer_impl_trait: None, | ||
| disallow_tilde_const: Some(DisallowTildeConstContext::Item), | ||
| is_impl_trait_banned: false, | ||
| extern_mod_safety: None, | ||
| lint_buffer: lints, | ||
| }; | ||
| visit::walk_crate(&mut validator, krate); | ||
|
|
||
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This is unfortunate but making
StaticItemandStaticForeignItemcarry different types would require a major refactor mainly due to https://github.com/spastorino/rust/blob/f6f8e91adcaf446eb4b38fe960a97d0c1ab88417/compiler/rustc_parse/src/parser/item.rs#L1184 which is an ungreat way of code reusing.I can refactor this code to disentangle it after this PR lands and then remove this safety field and likely the expr one but I wouldn't block landing this PR on this pre-existing issue.