| use rustc_feature::{ACCEPTED_FEATURES, ACTIVE_FEATURES, REMOVED_FEATURES, STABLE_REMOVED_FEATURES}; |
| use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP}; |
| use rustc_feature::{Features, Feature, State as FeatureState, UnstableFeatures}; |
| use rustc_feature::{find_feature_issue, GateIssue}; |
| |
| use crate::ast::{self, AssocTyConstraint, AssocTyConstraintKind, NodeId}; |
| use crate::ast::{GenericParam, GenericParamKind, PatKind, RangeEnd, VariantData}; |
| use crate::attr; |
| use crate::source_map::Spanned; |
| use crate::edition::{ALL_EDITIONS, Edition}; |
| use crate::visit::{self, FnKind, Visitor}; |
| use crate::sess::ParseSess; |
| use crate::symbol::{Symbol, sym}; |
| |
| use errors::{Applicability, DiagnosticBuilder, Handler}; |
| use rustc_data_structures::fx::FxHashMap; |
| use syntax_pos::{Span, DUMMY_SP, MultiSpan}; |
| use log::debug; |
| |
| use rustc_error_codes::*; |
| |
| macro_rules! gate_feature_fn { |
| ($cx: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr, $level: expr) => {{ |
| let (cx, has_feature, span, |
| name, explain, level) = (&*$cx, $has_feature, $span, $name, $explain, $level); |
| let has_feature: bool = has_feature(&$cx.features); |
| debug!("gate_feature(feature = {:?}, span = {:?}); has? {}", name, span, has_feature); |
| if !has_feature && !span.allows_unstable($name) { |
| leveled_feature_err(cx.parse_sess, name, span, GateIssue::Language, explain, level) |
| .emit(); |
| } |
| }} |
| } |
| |
| macro_rules! gate_feature { |
| ($cx: expr, $feature: ident, $span: expr, $explain: expr) => { |
| gate_feature_fn!($cx, |x:&Features| x.$feature, $span, |
| sym::$feature, $explain, GateStrength::Hard) |
| }; |
| ($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => { |
| gate_feature_fn!($cx, |x:&Features| x.$feature, $span, |
| sym::$feature, $explain, $level) |
| }; |
| } |
| |
| pub fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) { |
| PostExpansionVisitor { parse_sess, features }.visit_attribute(attr) |
| } |
| |
| #[derive(Debug, Copy, Clone, PartialEq)] |
| pub enum GateStrength { |
| /// A hard error. (Most feature gates should use this.) |
| Hard, |
| /// Only a warning. (Use this only as backwards-compatibility demands.) |
| Soft, |
| } |
| |
| pub fn feature_err<'a>( |
| sess: &'a ParseSess, |
| feature: Symbol, |
| span: impl Into<MultiSpan>, |
| explain: &str, |
| ) -> DiagnosticBuilder<'a> { |
| feature_err_issue(sess, feature, span, GateIssue::Language, explain) |
| } |
| |
| pub fn feature_err_issue<'a>( |
| sess: &'a ParseSess, |
| feature: Symbol, |
| span: impl Into<MultiSpan>, |
| issue: GateIssue, |
| explain: &str, |
| ) -> DiagnosticBuilder<'a> { |
| leveled_feature_err(sess, feature, span, issue, explain, GateStrength::Hard) |
| } |
| |
| fn leveled_feature_err<'a>( |
| sess: &'a ParseSess, |
| feature: Symbol, |
| span: impl Into<MultiSpan>, |
| issue: GateIssue, |
| explain: &str, |
| level: GateStrength, |
| ) -> DiagnosticBuilder<'a> { |
| let diag = &sess.span_diagnostic; |
| |
| let mut err = match level { |
| GateStrength::Hard => { |
| diag.struct_span_err_with_code(span, explain, stringify_error_code!(E0658)) |
| } |
| GateStrength::Soft => diag.struct_span_warn(span, explain), |
| }; |
| |
| if let Some(n) = find_feature_issue(feature, issue) { |
| err.note(&format!( |
| "for more information, see https://github.com/rust-lang/rust/issues/{}", |
| n, |
| )); |
| } |
| |
| // #23973: do not suggest `#![feature(...)]` if we are in beta/stable |
| if sess.unstable_features.is_nightly_build() { |
| err.help(&format!("add `#![feature({})]` to the crate attributes to enable", feature)); |
| } |
| |
| // If we're on stable and only emitting a "soft" warning, add a note to |
| // clarify that the feature isn't "on" (rather than being on but |
| // warning-worthy). |
| if !sess.unstable_features.is_nightly_build() && level == GateStrength::Soft { |
| err.help("a nightly build of the compiler is required to enable this feature"); |
| } |
| |
| err |
| |
| } |
| |
| struct PostExpansionVisitor<'a> { |
| parse_sess: &'a ParseSess, |
| features: &'a Features, |
| } |
| |
| macro_rules! gate_feature_post { |
| ($cx: expr, $feature: ident, $span: expr, $explain: expr) => {{ |
| let (cx, span) = ($cx, $span); |
| if !span.allows_unstable(sym::$feature) { |
| gate_feature!(cx, $feature, span, $explain) |
| } |
| }}; |
| ($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => {{ |
| let (cx, span) = ($cx, $span); |
| if !span.allows_unstable(sym::$feature) { |
| gate_feature!(cx, $feature, span, $explain, $level) |
| } |
| }} |
| } |
| |
| 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 = $type_expr;`. |
| fn check_impl_trait(&self, ty: &ast::Ty) { |
| struct ImplTraitVisitor<'a> { |
| vis: &'a PostExpansionVisitor<'a>, |
| } |
| impl Visitor<'_> for ImplTraitVisitor<'_> { |
| fn visit_ty(&mut self, ty: &ast::Ty) { |
| if let ast::TyKind::ImplTrait(..) = ty.kind { |
| gate_feature_post!( |
| &self.vis, |
| type_alias_impl_trait, |
| ty.span, |
| "`impl Trait` in type aliases is unstable" |
| ); |
| } |
| visit::walk_ty(self, ty); |
| } |
| } |
| ImplTraitVisitor { vis: self }.visit_ty(ty); |
| } |
| } |
| |
| impl<'a> Visitor<'a> for PostExpansionVisitor<'a> { |
| fn visit_attribute(&mut self, attr: &ast::Attribute) { |
| let attr_info = |
| attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name)).map(|a| **a); |
| // Check feature gates for built-in attributes. |
| if let Some((.., AttributeGate::Gated(_, name, descr, has_feature))) = attr_info { |
| gate_feature_fn!(self, has_feature, attr.span, name, descr, GateStrength::Hard); |
| } |
| // Check unstable flavors of the `#[doc]` attribute. |
| if attr.check_name(sym::doc) { |
| for nested_meta in attr.meta_item_list().unwrap_or_default() { |
| macro_rules! gate_doc { ($($name:ident => $feature:ident)*) => { |
| $(if nested_meta.check_name(sym::$name) { |
| let msg = concat!("`#[doc(", stringify!($name), ")]` is experimental"); |
| gate_feature!(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, |
| "a `#[start]` function is an experimental \ |
| feature whose 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); |
| } |
| _ => {} |
| } |
| visit::walk_ty(self, 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_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::TraitItem) { |
| match ti.kind { |
| ast::TraitItemKind::Method(ref sig, ref block) => { |
| if block.is_none() { |
| self.check_extern(sig.header.ext); |
| } |
| if sig.decl.c_variadic() { |
| gate_feature_post!(&self, c_variadic, ti.span, |
| "C-variadic functions are unstable"); |
| } |
| if sig.header.constness.node == ast::Constness::Const { |
| gate_feature_post!(&self, const_fn, ti.span, "const fn is unstable"); |
| } |
| } |
| ast::TraitItemKind::Type(_, ref default) => { |
| if let Some(ty) = default { |
| self.check_impl_trait(ty); |
| gate_feature_post!(&self, associated_type_defaults, ti.span, |
| "associated type defaults are unstable"); |
| } |
| self.check_gat(&ti.generics, ti.span); |
| } |
| _ => {} |
| } |
| visit::walk_trait_item(self, ti) |
| } |
| |
| fn visit_impl_item(&mut self, ii: &'a ast::ImplItem) { |
| if ii.defaultness == ast::Defaultness::Default { |
| gate_feature_post!(&self, specialization, |
| ii.span, |
| "specialization is unstable"); |
| } |
| |
| match ii.kind { |
| ast::ImplItemKind::Method(ref sig, _) => { |
| if sig.decl.c_variadic() { |
| gate_feature_post!(&self, c_variadic, ii.span, |
| "C-variadic functions are unstable"); |
| } |
| } |
| ast::ImplItemKind::TyAlias(ref ty) => { |
| self.check_impl_trait(ty); |
| self.check_gat(&ii.generics, ii.span); |
| } |
| _ => {} |
| } |
| visit::walk_impl_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 get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute], |
| crate_edition: Edition, allow_features: &Option<Vec<String>>) -> Features { |
| fn feature_removed(span_handler: &Handler, span: Span, reason: Option<&str>) { |
| let mut err = struct_span_err!(span_handler, span, E0557, "feature has been removed"); |
| err.span_label(span, "feature has been removed"); |
| if let Some(reason) = reason { |
| err.note(reason); |
| } |
| err.emit(); |
| } |
| |
| let mut features = Features::default(); |
| let mut edition_enabled_features = FxHashMap::default(); |
| |
| for &edition in ALL_EDITIONS { |
| if edition <= crate_edition { |
| // The `crate_edition` implies its respective umbrella feature-gate |
| // (i.e., `#![feature(rust_20XX_preview)]` isn't needed on edition 20XX). |
| edition_enabled_features.insert(edition.feature_name(), edition); |
| } |
| } |
| |
| for feature in active_features_up_to(crate_edition) { |
| feature.set(&mut features, DUMMY_SP); |
| edition_enabled_features.insert(feature.name, crate_edition); |
| } |
| |
| // Process the edition umbrella feature-gates first, to ensure |
| // `edition_enabled_features` is completed before it's queried. |
| for attr in krate_attrs { |
| if !attr.check_name(sym::feature) { |
| continue |
| } |
| |
| let list = match attr.meta_item_list() { |
| Some(list) => list, |
| None => continue, |
| }; |
| |
| for mi in list { |
| if !mi.is_word() { |
| continue; |
| } |
| |
| let name = mi.name_or_empty(); |
| |
| let edition = ALL_EDITIONS.iter().find(|e| name == e.feature_name()).copied(); |
| if let Some(edition) = edition { |
| if edition <= crate_edition { |
| continue; |
| } |
| |
| for feature in active_features_up_to(edition) { |
| // FIXME(Manishearth) there is currently no way to set |
| // lib features by edition |
| feature.set(&mut features, DUMMY_SP); |
| edition_enabled_features.insert(feature.name, edition); |
| } |
| } |
| } |
| } |
| |
| for attr in krate_attrs { |
| if !attr.check_name(sym::feature) { |
| continue |
| } |
| |
| let list = match attr.meta_item_list() { |
| Some(list) => list, |
| None => continue, |
| }; |
| |
| let bad_input = |span| { |
| struct_span_err!(span_handler, span, E0556, "malformed `feature` attribute input") |
| }; |
| |
| for mi in list { |
| let name = match mi.ident() { |
| Some(ident) if mi.is_word() => ident.name, |
| Some(ident) => { |
| bad_input(mi.span()).span_suggestion( |
| mi.span(), |
| "expected just one word", |
| format!("{}", ident.name), |
| Applicability::MaybeIncorrect, |
| ).emit(); |
| continue |
| } |
| None => { |
| bad_input(mi.span()).span_label(mi.span(), "expected just one word").emit(); |
| continue |
| } |
| }; |
| |
| if let Some(edition) = edition_enabled_features.get(&name) { |
| struct_span_warn!( |
| span_handler, |
| mi.span(), |
| E0705, |
| "the feature `{}` is included in the Rust {} edition", |
| name, |
| edition, |
| ).emit(); |
| continue; |
| } |
| |
| if ALL_EDITIONS.iter().any(|e| name == e.feature_name()) { |
| // Handled in the separate loop above. |
| continue; |
| } |
| |
| let removed = REMOVED_FEATURES.iter().find(|f| name == f.name); |
| let stable_removed = STABLE_REMOVED_FEATURES.iter().find(|f| name == f.name); |
| if let Some(Feature { state, .. }) = removed.or(stable_removed) { |
| if let FeatureState::Removed { reason } |
| | FeatureState::Stabilized { reason } = state |
| { |
| feature_removed(span_handler, mi.span(), *reason); |
| continue; |
| } |
| } |
| |
| if let Some(Feature { since, .. }) = ACCEPTED_FEATURES.iter().find(|f| name == f.name) { |
| let since = Some(Symbol::intern(since)); |
| features.declared_lang_features.push((name, mi.span(), since)); |
| continue; |
| } |
| |
| if let Some(allowed) = allow_features.as_ref() { |
| if allowed.iter().find(|&f| name.as_str() == *f).is_none() { |
| span_err!(span_handler, mi.span(), E0725, |
| "the feature `{}` is not in the list of allowed features", |
| name); |
| continue; |
| } |
| } |
| |
| if let Some(f) = ACTIVE_FEATURES.iter().find(|f| name == f.name) { |
| f.set(&mut features, mi.span()); |
| features.declared_lang_features.push((name, mi.span(), None)); |
| continue; |
| } |
| |
| features.declared_lib_features.push((name, mi.span())); |
| } |
| } |
| |
| features |
| } |
| |
| fn active_features_up_to(edition: Edition) -> impl Iterator<Item=&'static Feature> { |
| ACTIVE_FEATURES.iter() |
| .filter(move |feature| { |
| if let Some(feature_edition) = feature.edition { |
| feature_edition <= edition |
| } else { |
| false |
| } |
| }) |
| } |
| |
| 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!(&visitor, $gate, *span, $msg); |
| } |
| } |
| } |
| gate_all!(let_chains, "`let` expressions in this position are experimental"); |
| gate_all!(async_closure, "async closures are unstable"); |
| gate_all!(generators, "yield syntax is experimental"); |
| gate_all!(or_patterns, "or-patterns syntax is experimental"); |
| gate_all!(const_extern_fn, "`const extern fn` definitions are unstable"); |
| gate_all!(raw_ref_op, "raw address of syntax is experimental"); |
| |
| // All uses of `gate_all!` below this point were added in #65742, |
| // and subsequently disabled (with the non-early gating readded). |
| macro_rules! gate_all { |
| ($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!(&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)) { |
| span_err!( |
| span_handler, attr.span, E0554, |
| "`#![feature]` may not be used on the {} release channel", |
| option_env!("CFG_RELEASE_CHANNEL").unwrap_or("(unknown)") |
| ); |
| } |
| } |
| } |
