| use rustc_error_codes::*; |
| use rustc_errors::{struct_span_err, Handler}; |
| use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP}; |
| use rustc_feature::{Features, GateIssue, UnstableFeatures}; |
| use rustc_span::source_map::Spanned; |
| use rustc_span::symbol::sym; |
| use rustc_span::Span; |
| use syntax::ast::{self, AssocTyConstraint, AssocTyConstraintKind, NodeId}; |
| use syntax::ast::{GenericParam, GenericParamKind, PatKind, RangeEnd, VariantData}; |
| use syntax::attr; |
| use syntax::sess::{feature_err, feature_err_issue, ParseSess}; |
| use syntax::visit::{self, FnKind, Visitor}; |
| |
| use log::debug; |
| |
| macro_rules! gate_feature_fn { |
| ($cx: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr) => {{ |
| let (cx, has_feature, span, name, explain) = (&*$cx, $has_feature, $span, $name, $explain); |
| let has_feature: bool = has_feature(&$cx.features); |
| debug!("gate_feature(feature = {:?}, span = {:?}); has? {}", name, span, has_feature); |
| if !has_feature && !span.allows_unstable($name) { |
| feature_err_issue(cx.parse_sess, name, span, GateIssue::Language, explain).emit(); |
| } |
| }}; |
| } |
| |
| macro_rules! gate_feature_post { |
| ($cx: expr, $feature: ident, $span: expr, $explain: expr) => { |
| gate_feature_fn!($cx, |x: &Features| x.$feature, $span, sym::$feature, $explain) |
| }; |
| } |
| |
| pub fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) { |
| PostExpansionVisitor { parse_sess, features }.visit_attribute(attr) |
| } |
| |
| struct PostExpansionVisitor<'a> { |
| parse_sess: &'a ParseSess, |
| features: &'a Features, |
| } |
| |
| impl<'a> PostExpansionVisitor<'a> { |
| fn check_abi(&self, abi: ast::StrLit) { |
| let ast::StrLit { symbol_unescaped, span, .. } = abi; |
| |
| match &*symbol_unescaped.as_str() { |
| // Stable |
| "Rust" | "C" | "cdecl" | "stdcall" | "fastcall" | "aapcs" | "win64" | "sysv64" |
| | "system" => {} |
| "rust-intrinsic" => { |
| gate_feature_post!(&self, intrinsics, span, "intrinsics are subject to change"); |
| } |
| "platform-intrinsic" => { |
| gate_feature_post!( |
| &self, |
| platform_intrinsics, |
| span, |
| "platform intrinsics are experimental and possibly buggy" |
| ); |
| } |
| "vectorcall" => { |
| gate_feature_post!( |
| &self, |
| abi_vectorcall, |
| span, |
| "vectorcall is experimental and subject to change" |
| ); |
| } |
| "thiscall" => { |
| gate_feature_post!( |
| &self, |
| abi_thiscall, |
| span, |
| "thiscall is experimental and subject to change" |
| ); |
| } |
| "rust-call" => { |
| gate_feature_post!( |
| &self, |
| unboxed_closures, |
| span, |
| "rust-call ABI is subject to change" |
| ); |
| } |
| "ptx-kernel" => { |
| gate_feature_post!( |
| &self, |
| abi_ptx, |
| span, |
| "PTX ABIs are experimental and subject to change" |
| ); |
| } |
| "unadjusted" => { |
| gate_feature_post!( |
| &self, |
| abi_unadjusted, |
| span, |
| "unadjusted ABI is an implementation detail and perma-unstable" |
| ); |
| } |
| "msp430-interrupt" => { |
| gate_feature_post!( |
| &self, |
| abi_msp430_interrupt, |
| span, |
| "msp430-interrupt ABI is experimental and subject to change" |
| ); |
| } |
| "x86-interrupt" => { |
| gate_feature_post!( |
| &self, |
| abi_x86_interrupt, |
| span, |
| "x86-interrupt ABI is experimental and subject to change" |
| ); |
| } |
| "amdgpu-kernel" => { |
| gate_feature_post!( |
| &self, |
| abi_amdgpu_kernel, |
| span, |
| "amdgpu-kernel ABI is experimental and subject to change" |
| ); |
| } |
| "efiapi" => { |
| gate_feature_post!( |
| &self, |
| abi_efiapi, |
| span, |
| "efiapi ABI is experimental and subject to change" |
| ); |
| } |
| abi => self |
| .parse_sess |
| .span_diagnostic |
| .delay_span_bug(span, &format!("unrecognized ABI not caught in lowering: {}", abi)), |
| } |
| } |
| |
| fn check_extern(&self, ext: ast::Extern) { |
| if let ast::Extern::Explicit(abi) = ext { |
| self.check_abi(abi); |
| } |
| } |
| |
| fn maybe_report_invalid_custom_discriminants(&self, variants: &[ast::Variant]) { |
| let has_fields = variants.iter().any(|variant| match variant.data { |
| VariantData::Tuple(..) | VariantData::Struct(..) => true, |
| VariantData::Unit(..) => false, |
| }); |
| |
| let discriminant_spans = variants |
| .iter() |
| .filter(|variant| match variant.data { |
| VariantData::Tuple(..) | VariantData::Struct(..) => false, |
| VariantData::Unit(..) => true, |
| }) |
| .filter_map(|variant| variant.disr_expr.as_ref().map(|c| c.value.span)) |
| .collect::<Vec<_>>(); |
| |
| if !discriminant_spans.is_empty() && has_fields { |
| let mut err = feature_err( |
| self.parse_sess, |
| sym::arbitrary_enum_discriminant, |
| discriminant_spans.clone(), |
| "custom discriminant values are not allowed in enums with tuple or struct variants", |
| ); |
| for sp in discriminant_spans { |
| err.span_label(sp, "disallowed custom discriminant"); |
| } |
| for variant in variants.iter() { |
| match &variant.data { |
| VariantData::Struct(..) => { |
| err.span_label(variant.span, "struct variant defined here"); |
| } |
| VariantData::Tuple(..) => { |
| err.span_label(variant.span, "tuple variant defined here"); |
| } |
| VariantData::Unit(..) => {} |
| } |
| } |
| err.emit(); |
| } |
| } |
| |
| fn check_gat(&self, generics: &ast::Generics, span: Span) { |
| if !generics.params.is_empty() { |
| gate_feature_post!( |
| &self, |
| generic_associated_types, |
| span, |
| "generic associated types are unstable" |
| ); |
| } |
| if !generics.where_clause.predicates.is_empty() { |
| gate_feature_post!( |
| &self, |
| generic_associated_types, |
| span, |
| "where clauses on associated types are unstable" |
| ); |
| } |
| } |
| |
| /// Feature gate `impl Trait` inside `type Alias = $type_expr;`. |
| fn check_impl_trait(&self, ty: &ast::Ty) { |
| struct ImplTraitVisitor<'a> { |
| vis: &'a PostExpansionVisitor<'a>, |
| } |
| impl Visitor<'_> for ImplTraitVisitor<'_> { |
| fn visit_ty(&mut self, ty: &ast::Ty) { |
| if let ast::TyKind::ImplTrait(..) = ty.kind { |
| gate_feature_post!( |
| &self.vis, |
| type_alias_impl_trait, |
| ty.span, |
| "`impl Trait` in type aliases is unstable" |
| ); |
| } |
| visit::walk_ty(self, ty); |
| } |
| } |
| ImplTraitVisitor { vis: self }.visit_ty(ty); |
| } |
| } |
| |
| impl<'a> Visitor<'a> for PostExpansionVisitor<'a> { |
| fn visit_attribute(&mut self, attr: &ast::Attribute) { |
| let attr_info = |
| attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name)).map(|a| **a); |
| // Check feature gates for built-in attributes. |
| if let Some((.., AttributeGate::Gated(_, name, descr, has_feature))) = attr_info { |
| gate_feature_fn!(self, has_feature, attr.span, name, descr); |
| } |
| // Check unstable flavors of the `#[doc]` attribute. |
| if attr.check_name(sym::doc) { |
| for nested_meta in attr.meta_item_list().unwrap_or_default() { |
| macro_rules! gate_doc { ($($name:ident => $feature:ident)*) => { |
| $(if nested_meta.check_name(sym::$name) { |
| let msg = concat!("`#[doc(", stringify!($name), ")]` is experimental"); |
| gate_feature_post!(self, $feature, attr.span, msg); |
| })* |
| }} |
| |
| gate_doc!( |
| include => external_doc |
| cfg => doc_cfg |
| masked => doc_masked |
| spotlight => doc_spotlight |
| alias => doc_alias |
| keyword => doc_keyword |
| ); |
| } |
| } |
| } |
| |
| fn visit_name(&mut self, sp: Span, name: ast::Name) { |
| if !name.as_str().is_ascii() { |
| gate_feature_post!( |
| &self, |
| non_ascii_idents, |
| self.parse_sess.source_map().def_span(sp), |
| "non-ascii idents are not fully supported" |
| ); |
| } |
| } |
| |
| fn visit_item(&mut self, i: &'a ast::Item) { |
| match i.kind { |
| ast::ItemKind::ForeignMod(ref foreign_module) => { |
| if let Some(abi) = foreign_module.abi { |
| self.check_abi(abi); |
| } |
| } |
| |
| ast::ItemKind::Fn(..) => { |
| if attr::contains_name(&i.attrs[..], sym::plugin_registrar) { |
| gate_feature_post!( |
| &self, |
| plugin_registrar, |
| i.span, |
| "compiler plugins are experimental and possibly buggy" |
| ); |
| } |
| if attr::contains_name(&i.attrs[..], sym::start) { |
| gate_feature_post!( |
| &self, |
| start, |
| i.span, |
| "`#[start]` functions are experimental \ |
| and their signature may change \ |
| over time" |
| ); |
| } |
| if attr::contains_name(&i.attrs[..], sym::main) { |
| gate_feature_post!( |
| &self, |
| main, |
| i.span, |
| "declaration of a non-standard `#[main]` \ |
| function may change over time, for now \ |
| a top-level `fn main()` is required" |
| ); |
| } |
| } |
| |
| ast::ItemKind::Struct(..) => { |
| for attr in attr::filter_by_name(&i.attrs[..], sym::repr) { |
| for item in attr.meta_item_list().unwrap_or_else(Vec::new) { |
| if item.check_name(sym::simd) { |
| gate_feature_post!( |
| &self, |
| repr_simd, |
| attr.span, |
| "SIMD types are experimental and possibly buggy" |
| ); |
| } |
| } |
| } |
| } |
| |
| ast::ItemKind::Enum(ast::EnumDef { ref variants, .. }, ..) => { |
| for variant in variants { |
| match (&variant.data, &variant.disr_expr) { |
| (ast::VariantData::Unit(..), _) => {} |
| (_, Some(disr_expr)) => gate_feature_post!( |
| &self, |
| arbitrary_enum_discriminant, |
| disr_expr.value.span, |
| "discriminants on non-unit variants are experimental" |
| ), |
| _ => {} |
| } |
| } |
| |
| let has_feature = self.features.arbitrary_enum_discriminant; |
| if !has_feature && !i.span.allows_unstable(sym::arbitrary_enum_discriminant) { |
| self.maybe_report_invalid_custom_discriminants(&variants); |
| } |
| } |
| |
| ast::ItemKind::Impl(_, polarity, defaultness, ..) => { |
| if polarity == ast::ImplPolarity::Negative { |
| gate_feature_post!( |
| &self, |
| optin_builtin_traits, |
| i.span, |
| "negative trait bounds are not yet fully implemented; \ |
| use marker types for now" |
| ); |
| } |
| |
| if let ast::Defaultness::Default = defaultness { |
| gate_feature_post!(&self, specialization, i.span, "specialization is unstable"); |
| } |
| } |
| |
| ast::ItemKind::Trait(ast::IsAuto::Yes, ..) => { |
| gate_feature_post!( |
| &self, |
| optin_builtin_traits, |
| i.span, |
| "auto traits are experimental and possibly buggy" |
| ); |
| } |
| |
| ast::ItemKind::TraitAlias(..) => { |
| gate_feature_post!(&self, trait_alias, i.span, "trait aliases are experimental"); |
| } |
| |
| ast::ItemKind::MacroDef(ast::MacroDef { legacy: false, .. }) => { |
| let msg = "`macro` is experimental"; |
| gate_feature_post!(&self, decl_macro, i.span, msg); |
| } |
| |
| ast::ItemKind::TyAlias(ref ty, ..) => self.check_impl_trait(&ty), |
| |
| _ => {} |
| } |
| |
| visit::walk_item(self, i); |
| } |
| |
| fn visit_foreign_item(&mut self, i: &'a ast::ForeignItem) { |
| match i.kind { |
| ast::ForeignItemKind::Fn(..) | ast::ForeignItemKind::Static(..) => { |
| let link_name = attr::first_attr_value_str_by_name(&i.attrs, sym::link_name); |
| let links_to_llvm = match link_name { |
| Some(val) => val.as_str().starts_with("llvm."), |
| _ => false, |
| }; |
| if links_to_llvm { |
| gate_feature_post!( |
| &self, |
| link_llvm_intrinsics, |
| i.span, |
| "linking to LLVM intrinsics is experimental" |
| ); |
| } |
| } |
| ast::ForeignItemKind::Ty => { |
| gate_feature_post!(&self, extern_types, i.span, "extern types are experimental"); |
| } |
| ast::ForeignItemKind::Macro(..) => {} |
| } |
| |
| visit::walk_foreign_item(self, i) |
| } |
| |
| fn visit_ty(&mut self, ty: &'a ast::Ty) { |
| match ty.kind { |
| ast::TyKind::BareFn(ref bare_fn_ty) => { |
| self.check_extern(bare_fn_ty.ext); |
| } |
| ast::TyKind::Never => { |
| gate_feature_post!(&self, never_type, ty.span, "The `!` type is experimental"); |
| } |
| _ => {} |
| } |
| visit::walk_ty(self, ty) |
| } |
| |
| fn visit_fn_ret_ty(&mut self, ret_ty: &'a ast::FunctionRetTy) { |
| if let ast::FunctionRetTy::Ty(ref output_ty) = *ret_ty { |
| if let ast::TyKind::Never = output_ty.kind { |
| // Do nothing. |
| } else { |
| self.visit_ty(output_ty) |
| } |
| } |
| } |
| |
| fn visit_expr(&mut self, e: &'a ast::Expr) { |
| match e.kind { |
| ast::ExprKind::Box(_) => { |
| gate_feature_post!( |
| &self, |
| box_syntax, |
| e.span, |
| "box expression syntax is experimental; you can call `Box::new` instead" |
| ); |
| } |
| ast::ExprKind::Type(..) => { |
| // To avoid noise about type ascription in common syntax errors, only emit if it |
| // is the *only* error. |
| if self.parse_sess.span_diagnostic.err_count() == 0 { |
| gate_feature_post!( |
| &self, |
| type_ascription, |
| e.span, |
| "type ascription is experimental" |
| ); |
| } |
| } |
| ast::ExprKind::TryBlock(_) => { |
| gate_feature_post!(&self, try_blocks, e.span, "`try` expression is experimental"); |
| } |
| ast::ExprKind::Block(_, opt_label) => { |
| if let Some(label) = opt_label { |
| gate_feature_post!( |
| &self, |
| label_break_value, |
| label.ident.span, |
| "labels on blocks are unstable" |
| ); |
| } |
| } |
| _ => {} |
| } |
| visit::walk_expr(self, e) |
| } |
| |
| fn visit_arm(&mut self, arm: &'a ast::Arm) { |
| visit::walk_arm(self, arm) |
| } |
| |
| fn visit_pat(&mut self, pattern: &'a ast::Pat) { |
| match &pattern.kind { |
| PatKind::Slice(pats) => { |
| for pat in &*pats { |
| let span = pat.span; |
| let inner_pat = match &pat.kind { |
| PatKind::Ident(.., Some(pat)) => pat, |
| _ => pat, |
| }; |
| if inner_pat.is_rest() { |
| gate_feature_post!( |
| &self, |
| slice_patterns, |
| span, |
| "subslice patterns are unstable" |
| ); |
| } |
| } |
| } |
| PatKind::Box(..) => { |
| gate_feature_post!( |
| &self, |
| box_patterns, |
| pattern.span, |
| "box pattern syntax is experimental" |
| ); |
| } |
| PatKind::Range(_, _, Spanned { node: RangeEnd::Excluded, .. }) => { |
| gate_feature_post!( |
| &self, |
| exclusive_range_pattern, |
| pattern.span, |
| "exclusive range pattern syntax is experimental" |
| ); |
| } |
| _ => {} |
| } |
| visit::walk_pat(self, pattern) |
| } |
| |
| fn visit_fn( |
| &mut self, |
| fn_kind: FnKind<'a>, |
| fn_decl: &'a ast::FnDecl, |
| span: Span, |
| _node_id: NodeId, |
| ) { |
| if let Some(header) = fn_kind.header() { |
| // Stability of const fn methods are covered in |
| // `visit_trait_item` and `visit_impl_item` below; this is |
| // because default methods don't pass through this point. |
| self.check_extern(header.ext); |
| } |
| |
| if fn_decl.c_variadic() { |
| gate_feature_post!(&self, c_variadic, span, "C-variadic functions are unstable"); |
| } |
| |
| visit::walk_fn(self, fn_kind, fn_decl, span) |
| } |
| |
| fn visit_generic_param(&mut self, param: &'a GenericParam) { |
| match param.kind { |
| GenericParamKind::Const { .. } => gate_feature_post!( |
| &self, |
| const_generics, |
| param.ident.span, |
| "const generics are unstable" |
| ), |
| _ => {} |
| } |
| visit::walk_generic_param(self, param) |
| } |
| |
| fn visit_assoc_ty_constraint(&mut self, constraint: &'a AssocTyConstraint) { |
| match constraint.kind { |
| AssocTyConstraintKind::Bound { .. } => gate_feature_post!( |
| &self, |
| associated_type_bounds, |
| constraint.span, |
| "associated type bounds are unstable" |
| ), |
| _ => {} |
| } |
| visit::walk_assoc_ty_constraint(self, constraint) |
| } |
| |
| fn visit_trait_item(&mut self, ti: &'a ast::AssocItem) { |
| match ti.kind { |
| ast::AssocItemKind::Fn(ref sig, ref block) => { |
| if block.is_none() { |
| self.check_extern(sig.header.ext); |
| } |
| if sig.header.constness.node == ast::Constness::Const { |
| gate_feature_post!(&self, const_fn, ti.span, "const fn is unstable"); |
| } |
| } |
| ast::AssocItemKind::TyAlias(_, ref default) => { |
| if let Some(_) = default { |
| gate_feature_post!( |
| &self, |
| associated_type_defaults, |
| ti.span, |
| "associated type defaults are unstable" |
| ); |
| } |
| } |
| _ => {} |
| } |
| visit::walk_trait_item(self, ti) |
| } |
| |
| fn visit_assoc_item(&mut self, ii: &'a ast::AssocItem) { |
| if ii.defaultness == ast::Defaultness::Default { |
| gate_feature_post!(&self, specialization, ii.span, "specialization is unstable"); |
| } |
| |
| match ii.kind { |
| ast::AssocItemKind::Fn(ref sig, _) => { |
| if sig.decl.c_variadic() { |
| gate_feature_post!( |
| &self, |
| c_variadic, |
| ii.span, |
| "C-variadic functions are unstable" |
| ); |
| } |
| } |
| ast::AssocItemKind::TyAlias(_, ref ty) => { |
| if let Some(ty) = ty { |
| self.check_impl_trait(ty); |
| } |
| self.check_gat(&ii.generics, ii.span); |
| } |
| _ => {} |
| } |
| visit::walk_assoc_item(self, ii) |
| } |
| |
| fn visit_vis(&mut self, vis: &'a ast::Visibility) { |
| if let ast::VisibilityKind::Crate(ast::CrateSugar::JustCrate) = vis.node { |
| gate_feature_post!( |
| &self, |
| crate_visibility_modifier, |
| vis.span, |
| "`crate` visibility modifier is experimental" |
| ); |
| } |
| visit::walk_vis(self, vis) |
| } |
| } |
| |
| pub fn check_crate( |
| krate: &ast::Crate, |
| parse_sess: &ParseSess, |
| features: &Features, |
| unstable: UnstableFeatures, |
| ) { |
| maybe_stage_features(&parse_sess.span_diagnostic, krate, unstable); |
| let mut visitor = PostExpansionVisitor { parse_sess, features }; |
| |
| let spans = parse_sess.gated_spans.spans.borrow(); |
| macro_rules! gate_all { |
| ($gate:ident, $msg:literal) => { |
| for span in spans.get(&sym::$gate).unwrap_or(&vec![]) { |
| gate_feature_post!(&visitor, $gate, *span, $msg); |
| } |
| }; |
| } |
| gate_all!(let_chains, "`let` expressions in this position are experimental"); |
| gate_all!(async_closure, "async closures are unstable"); |
| gate_all!(generators, "yield syntax is experimental"); |
| gate_all!(or_patterns, "or-patterns syntax is experimental"); |
| gate_all!(const_extern_fn, "`const extern fn` definitions are unstable"); |
| gate_all!(raw_ref_op, "raw address of syntax is experimental"); |
| gate_all!(const_trait_bound_opt_out, "`?const` on trait bounds is experimental"); |
| gate_all!(const_trait_impl, "const trait impls are experimental"); |
| gate_all!(half_open_range_patterns, "half-open range patterns are unstable"); |
| |
| // All uses of `gate_all!` below this point were added in #65742, |
| // and subsequently disabled (with the non-early gating readded). |
| macro_rules! gate_all { |
| ($gate:ident, $msg:literal) => { |
| // FIXME(eddyb) do something more useful than always |
| // disabling these uses of early feature-gatings. |
| if false { |
| for span in spans.get(&sym::$gate).unwrap_or(&vec![]) { |
| gate_feature_post!(&visitor, $gate, *span, $msg); |
| } |
| } |
| }; |
| } |
| |
| gate_all!(trait_alias, "trait aliases are experimental"); |
| gate_all!(associated_type_bounds, "associated type bounds are unstable"); |
| gate_all!(crate_visibility_modifier, "`crate` visibility modifier is experimental"); |
| gate_all!(const_generics, "const generics are unstable"); |
| gate_all!(decl_macro, "`macro` is experimental"); |
| gate_all!(box_patterns, "box pattern syntax is experimental"); |
| gate_all!(exclusive_range_pattern, "exclusive range pattern syntax is experimental"); |
| gate_all!(try_blocks, "`try` blocks are unstable"); |
| gate_all!(label_break_value, "labels on blocks are unstable"); |
| gate_all!(box_syntax, "box expression syntax is experimental; you can call `Box::new` instead"); |
| // To avoid noise about type ascription in common syntax errors, |
| // only emit if it is the *only* error. (Also check it last.) |
| if parse_sess.span_diagnostic.err_count() == 0 { |
| gate_all!(type_ascription, "type ascription is experimental"); |
| } |
| |
| visit::walk_crate(&mut visitor, krate); |
| } |
| |
| fn maybe_stage_features(span_handler: &Handler, krate: &ast::Crate, unstable: UnstableFeatures) { |
| if !unstable.is_nightly_build() { |
| for attr in krate.attrs.iter().filter(|attr| attr.check_name(sym::feature)) { |
| struct_span_err!( |
| span_handler, |
| attr.span, |
| E0554, |
| "`#![feature]` may not be used on the {} release channel", |
| option_env!("CFG_RELEASE_CHANNEL").unwrap_or("(unknown)") |
| ) |
| .emit(); |
| } |
| } |
| } |