| use super::{active::{ACTIVE_FEATURES, Features}, Feature, State as FeatureState}; |
| use super::accepted::ACCEPTED_FEATURES; |
| use super::removed::{REMOVED_FEATURES, STABLE_REMOVED_FEATURES}; |
| use super::builtin_attrs::{AttributeGate, BUILTIN_ATTRIBUTE_MAP}; |
| |
| use crate::ast::{ |
| self, AssocTyConstraint, AssocTyConstraintKind, NodeId, GenericParam, GenericParamKind, |
| PatKind, RangeEnd, |
| }; |
| use crate::attr::{self, check_builtin_attribute}; |
| use crate::source_map::Spanned; |
| use crate::edition::{ALL_EDITIONS, Edition}; |
| use crate::visit::{self, FnKind, Visitor}; |
| use crate::parse::{token, ParseSess}; |
| use crate::parse::parser::Parser; |
| use crate::symbol::{Symbol, sym}; |
| use crate::tokenstream::TokenTree; |
| |
| use errors::{Applicability, DiagnosticBuilder, Handler}; |
| use rustc_data_structures::fx::FxHashMap; |
| use rustc_target::spec::abi::Abi; |
| use syntax_pos::{Span, DUMMY_SP, MultiSpan}; |
| use log::debug; |
| |
| use std::env; |
| |
| #[derive(Copy, Clone, Debug)] |
| pub enum Stability { |
| Unstable, |
| // First argument is tracking issue link; second argument is an optional |
| // help message, which defaults to "remove this attribute" |
| Deprecated(&'static str, Option<&'static str>), |
| } |
| |
| 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) |
| }; |
| } |
| |
| crate fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) { |
| PostExpansionVisitor { parse_sess, features }.visit_attribute(attr) |
| } |
| |
| fn find_lang_feature_issue(feature: Symbol) -> Option<u32> { |
| if let Some(info) = ACTIVE_FEATURES.iter().find(|t| t.name == feature) { |
| // FIXME (#28244): enforce that active features have issue numbers |
| // assert!(info.issue.is_some()) |
| info.issue |
| } else { |
| // search in Accepted, Removed, or Stable Removed features |
| let found = ACCEPTED_FEATURES.iter().chain(REMOVED_FEATURES).chain(STABLE_REMOVED_FEATURES) |
| .find(|t| t.name == feature); |
| match found { |
| Some(&Feature { issue, .. }) => issue, |
| None => panic!("Feature `{}` is not declared anywhere", feature), |
| } |
| } |
| } |
| |
| pub enum GateIssue { |
| Language, |
| Library(Option<u32>) |
| } |
| |
| #[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 emit_feature_err( |
| sess: &ParseSess, |
| feature: Symbol, |
| span: Span, |
| issue: GateIssue, |
| explain: &str, |
| ) { |
| feature_err(sess, feature, span, issue, explain).emit(); |
| } |
| |
| pub fn feature_err<'a, S: Into<MultiSpan>>( |
| sess: &'a ParseSess, |
| feature: Symbol, |
| span: S, |
| issue: GateIssue, |
| explain: &str, |
| ) -> DiagnosticBuilder<'a> { |
| leveled_feature_err(sess, feature, span, issue, explain, GateStrength::Hard) |
| } |
| |
| fn leveled_feature_err<'a, S: Into<MultiSpan>>( |
| sess: &'a ParseSess, |
| feature: Symbol, |
| span: S, |
| issue: GateIssue, |
| explain: &str, |
| level: GateStrength, |
| ) -> DiagnosticBuilder<'a> { |
| let diag = &sess.span_diagnostic; |
| |
| let issue = match issue { |
| GateIssue::Language => find_lang_feature_issue(feature), |
| GateIssue::Library(lib) => lib, |
| }; |
| |
| 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), |
| }; |
| |
| match issue { |
| None | Some(0) => {} // We still accept `0` as a stand-in for backwards compatibility |
| Some(n) => { |
| 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 |
| |
| } |
| |
| const EXPLAIN_BOX_SYNTAX: &str = |
| "box expression syntax is experimental; you can call `Box::new` instead"; |
| |
| pub const EXPLAIN_STMT_ATTR_SYNTAX: &str = |
| "attributes on expressions are experimental"; |
| |
| pub const EXPLAIN_ALLOW_INTERNAL_UNSTABLE: &str = |
| "allow_internal_unstable side-steps feature gating and stability checks"; |
| pub const EXPLAIN_ALLOW_INTERNAL_UNSAFE: &str = |
| "allow_internal_unsafe side-steps the unsafe_code lint"; |
| |
| pub const EXPLAIN_UNSIZED_TUPLE_COERCION: &str = |
| "unsized tuple coercion is not stable enough for use and is subject to change"; |
| |
| 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: Abi, span: Span) { |
| match abi { |
| Abi::RustIntrinsic => { |
| gate_feature_post!(&self, intrinsics, span, |
| "intrinsics are subject to change"); |
| }, |
| Abi::PlatformIntrinsic => { |
| gate_feature_post!(&self, platform_intrinsics, span, |
| "platform intrinsics are experimental and possibly buggy"); |
| }, |
| Abi::Vectorcall => { |
| gate_feature_post!(&self, abi_vectorcall, span, |
| "vectorcall is experimental and subject to change"); |
| }, |
| Abi::Thiscall => { |
| gate_feature_post!(&self, abi_thiscall, span, |
| "thiscall is experimental and subject to change"); |
| }, |
| Abi::RustCall => { |
| gate_feature_post!(&self, unboxed_closures, span, |
| "rust-call ABI is subject to change"); |
| }, |
| Abi::PtxKernel => { |
| gate_feature_post!(&self, abi_ptx, span, |
| "PTX ABIs are experimental and subject to change"); |
| }, |
| Abi::Unadjusted => { |
| gate_feature_post!(&self, abi_unadjusted, span, |
| "unadjusted ABI is an implementation detail and perma-unstable"); |
| }, |
| Abi::Msp430Interrupt => { |
| gate_feature_post!(&self, abi_msp430_interrupt, span, |
| "msp430-interrupt ABI is experimental and subject to change"); |
| }, |
| Abi::X86Interrupt => { |
| gate_feature_post!(&self, abi_x86_interrupt, span, |
| "x86-interrupt ABI is experimental and subject to change"); |
| }, |
| Abi::AmdGpuKernel => { |
| gate_feature_post!(&self, abi_amdgpu_kernel, span, |
| "amdgpu-kernel ABI is experimental and subject to change"); |
| }, |
| // Stable |
| Abi::Cdecl | |
| Abi::Stdcall | |
| Abi::Fastcall | |
| Abi::Aapcs | |
| Abi::Win64 | |
| Abi::SysV64 | |
| Abi::Rust | |
| Abi::C | |
| Abi::System => {} |
| } |
| } |
| } |
| |
| 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 input tokens for built-in and key-value attributes. |
| match attr_info { |
| // `rustc_dummy` doesn't have any restrictions specific to built-in attributes. |
| Some((name, _, template, _)) if name != sym::rustc_dummy => |
| check_builtin_attribute(self.parse_sess, attr, name, template), |
| _ => if let Some(TokenTree::Token(token)) = attr.tokens.trees().next() { |
| if token == token::Eq { |
| // All key-value attributes are restricted to meta-item syntax. |
| attr.parse_meta(self.parse_sess).map_err(|mut err| err.emit()).ok(); |
| } |
| } |
| } |
| // 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.node { |
| ast::ItemKind::ForeignMod(ref foreign_module) => { |
| self.check_abi(foreign_module.abi, i.span); |
| } |
| |
| 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) { |
| Parser::maybe_report_invalid_custom_discriminants(self.parse_sess, &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::OpaqueTy(..) => { |
| gate_feature_post!( |
| &self, |
| type_alias_impl_trait, |
| i.span, |
| "`impl Trait` in type aliases is unstable" |
| ); |
| } |
| |
| _ => {} |
| } |
| |
| visit::walk_item(self, i); |
| } |
| |
| fn visit_foreign_item(&mut self, i: &'a ast::ForeignItem) { |
| match i.node { |
| 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.node { |
| ast::TyKind::BareFn(ref bare_fn_ty) => { |
| self.check_abi(bare_fn_ty.abi, ty.span); |
| } |
| 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.node { |
| // Do nothing. |
| } else { |
| self.visit_ty(output_ty) |
| } |
| } |
| } |
| |
| fn visit_expr(&mut self, e: &'a ast::Expr) { |
| match e.node { |
| ast::ExprKind::Box(_) => { |
| gate_feature_post!(&self, box_syntax, e.span, EXPLAIN_BOX_SYNTAX); |
| } |
| 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.node { |
| PatKind::Slice(pats) => { |
| for pat in &*pats { |
| let span = pat.span; |
| let inner_pat = match &pat.node { |
| 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_abi(header.abi, span); |
| } |
| |
| 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.node { |
| ast::TraitItemKind::Method(ref sig, ref block) => { |
| if block.is_none() { |
| self.check_abi(sig.header.abi, ti.span); |
| } |
| 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) => { |
| // We use three if statements instead of something like match guards so that all |
| // of these errors can be emitted if all cases apply. |
| if default.is_some() { |
| gate_feature_post!(&self, associated_type_defaults, ti.span, |
| "associated type defaults are unstable"); |
| } |
| if !ti.generics.params.is_empty() { |
| gate_feature_post!(&self, generic_associated_types, ti.span, |
| "generic associated types are unstable"); |
| } |
| if !ti.generics.where_clause.predicates.is_empty() { |
| gate_feature_post!(&self, generic_associated_types, ti.span, |
| "where clauses on associated types are unstable"); |
| } |
| } |
| _ => {} |
| } |
| 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.node { |
| ast::ImplItemKind::Method(..) => {} |
| ast::ImplItemKind::OpaqueTy(..) => { |
| gate_feature_post!( |
| &self, |
| type_alias_impl_trait, |
| ii.span, |
| "`impl Trait` in type aliases is unstable" |
| ); |
| } |
| ast::ImplItemKind::TyAlias(_) => { |
| if !ii.generics.params.is_empty() { |
| gate_feature_post!(&self, generic_associated_types, ii.span, |
| "generic associated types are unstable"); |
| } |
| if !ii.generics.where_clause.predicates.is_empty() { |
| gate_feature_post!(&self, generic_associated_types, ii.span, |
| "where clauses on associated types are unstable"); |
| } |
| } |
| _ => {} |
| } |
| 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"); |
| if let Some(reason) = reason { |
| err.span_note(span, reason); |
| } else { |
| err.span_label(span, "feature has been removed"); |
| } |
| err.emit(); |
| } |
| |
| let mut features = Features::new(); |
| 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| *f == name.as_str()).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 }; |
| |
| macro_rules! gate_all { |
| ($gate:ident, $msg:literal) => { gate_all!($gate, $gate, $msg); }; |
| ($spans:ident, $gate:ident, $msg:literal) => { |
| for span in &*parse_sess.gated_spans.$spans.borrow() { |
| gate_feature!(&visitor, $gate, *span, $msg); |
| } |
| } |
| } |
| |
| gate_all!(param_attrs, "attributes on function parameters are unstable"); |
| gate_all!(let_chains, "`let` expressions in this position are experimental"); |
| gate_all!(async_closure, "async closures are unstable"); |
| gate_all!(yields, generators, "yield syntax is experimental"); |
| gate_all!(or_patterns, "or-patterns syntax is experimental"); |
| |
| visit::walk_crate(&mut visitor, krate); |
| } |
| |
| #[derive(Clone, Copy, Hash)] |
| pub enum UnstableFeatures { |
| /// Hard errors for unstable features are active, as on beta/stable channels. |
| Disallow, |
| /// Allow features to be activated, as on nightly. |
| Allow, |
| /// Errors are bypassed for bootstrapping. This is required any time |
| /// during the build that feature-related lints are set to warn or above |
| /// because the build turns on warnings-as-errors and uses lots of unstable |
| /// features. As a result, this is always required for building Rust itself. |
| Cheat |
| } |
| |
| impl UnstableFeatures { |
| pub fn from_environment() -> UnstableFeatures { |
| // `true` if this is a feature-staged build, i.e., on the beta or stable channel. |
| let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some(); |
| // `true` if we should enable unstable features for bootstrapping. |
| let bootstrap = env::var("RUSTC_BOOTSTRAP").is_ok(); |
| match (disable_unstable_features, bootstrap) { |
| (_, true) => UnstableFeatures::Cheat, |
| (true, _) => UnstableFeatures::Disallow, |
| (false, _) => UnstableFeatures::Allow |
| } |
| } |
| |
| pub fn is_nightly_build(&self) -> bool { |
| match *self { |
| UnstableFeatures::Allow | UnstableFeatures::Cheat => true, |
| _ => false, |
| } |
| } |
| } |
| |
| fn maybe_stage_features(span_handler: &Handler, krate: &ast::Crate, unstable: UnstableFeatures) { |
| let allow_features = match unstable { |
| UnstableFeatures::Allow => true, |
| UnstableFeatures::Disallow => false, |
| UnstableFeatures::Cheat => true |
| }; |
| if !allow_features { |
| for attr in &krate.attrs { |
| if attr.check_name(sym::feature) { |
| let release_channel = option_env!("CFG_RELEASE_CHANNEL").unwrap_or("(unknown)"); |
| span_err!(span_handler, attr.span, E0554, |
| "`#![feature]` may not be used on the {} release channel", |
| release_channel); |
| } |
| } |
| } |
| } |
