use AttributeType::*;
use AttributeGate::*;
use crate::ast::{
self, AssocTyConstraint, AssocTyConstraintKind, NodeId, GenericParam, GenericParamKind,
PatKind, RangeEnd,
};
use crate::attr::{self, check_builtin_attribute, AttributeTemplate};
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 lazy_static::lazy_static;
use std::env;
macro_rules! set {
($field: ident) => {{
fn f(features: &mut Features, _: Span) {
features.$field = true;
}
f as fn(&mut Features, Span)
}}
}
macro_rules! declare_features {
($((active, $feature: ident, $ver: expr, $issue: expr, $edition: expr),)+) => {
const ACTIVE_FEATURES:
&[(Symbol, &str, Option<u32>, Option<Edition>, fn(&mut Features, Span))] =
&[$((sym::$feature, $ver, $issue, $edition, set!($feature))),+];
#[derive(Clone)]
pub struct Features {
pub declared_lang_features: Vec<(Symbol, Span, Option<Symbol>)>,
pub declared_lib_features: Vec<(Symbol, Span)>,
$(pub $feature: bool),+
}
impl Features {
pub fn new() -> Features {
Features {
declared_lang_features: Vec::new(),
declared_lib_features: Vec::new(),
$($feature: false),+
}
}
pub fn walk_feature_fields<F>(&self, mut f: F)
where F: FnMut(&str, bool)
{
$(f(stringify!($feature), self.$feature);)+
}
}
};
($((removed, $feature: ident, $ver: expr, $issue: expr, None, $reason: expr),)+) => {
const REMOVED_FEATURES: &[(Symbol, &str, Option<u32>, Option<&str>)] = &[
$((sym::$feature, $ver, $issue, $reason)),+
];
};
($((stable_removed, $feature: ident, $ver: expr, $issue: expr, None),)+) => {
const STABLE_REMOVED_FEATURES: &[(Symbol, &str, Option<u32>, Option<&str>)] = &[
$((sym::$feature, $ver, $issue, None)),+
];
};
($((accepted, $feature: ident, $ver: expr, $issue: expr, None),)+) => {
const ACCEPTED_FEATURES: &[(Symbol, &str, Option<u32>, Option<&str>)] = &[
$((sym::$feature, $ver, $issue, None)),+
];
}
}
declare_features! (
(active, rustc_private, "1.0.0", Some(27812), None),
(active, intrinsics, "1.0.0", None, None),
(active, lang_items, "1.0.0", None, None),
(active, staged_api, "1.0.0", None, None),
(active, allow_internal_unstable, "1.0.0", None, None),
(active, allow_internal_unsafe, "1.0.0", None, None),
(active, rustc_diagnostic_macros, "1.0.0", None, None),
(active, rustc_const_unstable, "1.0.0", None, None),
(active, link_llvm_intrinsics, "1.0.0", Some(29602), None),
(active, rustc_attrs, "1.0.0", Some(29642), None),
(active, on_unimplemented, "1.0.0", Some(29628), None),
(active, box_syntax, "1.0.0", Some(49733), None),
(active, main, "1.0.0", Some(29634), None),
(active, start, "1.0.0", Some(29633), None),
(active, fundamental, "1.0.0", Some(29635), None),
(active, unboxed_closures, "1.0.0", Some(29625), None),
(active, linkage, "1.0.0", Some(29603), None),
(active, optin_builtin_traits, "1.0.0", Some(13231), None),
(active, box_patterns, "1.0.0", Some(29641), None),
(active, prelude_import, "1.2.0", None, None),
(active, omit_gdb_pretty_printer_section, "1.5.0", None, None),
(active, abi_vectorcall, "1.7.0", None, None),
(active, structural_match, "1.8.0", Some(31434), None),
(active, dropck_eyepatch, "1.10.0", Some(34761), None),
(active, panic_runtime, "1.10.0", Some(32837), None),
(active, needs_panic_runtime, "1.10.0", Some(32837), None),
(active, compiler_builtins, "1.13.0", None, None),
(active, abi_unadjusted, "1.16.0", None, None),
(active, sanitizer_runtime, "1.17.0", None, None),
(active, profiler_runtime, "1.18.0", None, None),
(active, abi_thiscall, "1.19.0", None, None),
(active, allocator_internals, "1.20.0", None, None),
(active, test_2018_feature, "1.31.0", Some(0), Some(Edition::Edition2018)),
(active, arm_target_feature, "1.27.0", Some(44839), None),
(active, aarch64_target_feature, "1.27.0", Some(44839), None),
(active, hexagon_target_feature, "1.27.0", Some(44839), None),
(active, powerpc_target_feature, "1.27.0", Some(44839), None),
(active, mips_target_feature, "1.27.0", Some(44839), None),
(active, avx512_target_feature, "1.27.0", Some(44839), None),
(active, mmx_target_feature, "1.27.0", Some(44839), None),
(active, sse4a_target_feature, "1.27.0", Some(44839), None),
(active, tbm_target_feature, "1.27.0", Some(44839), None),
(active, wasm_target_feature, "1.30.0", Some(44839), None),
(active, adx_target_feature, "1.32.0", Some(44839), None),
(active, cmpxchg16b_target_feature, "1.32.0", Some(44839), None),
(active, movbe_target_feature, "1.34.0", Some(44839), None),
(active, rtm_target_feature, "1.35.0", Some(44839), None),
(active, f16c_target_feature, "1.36.0", Some(44839), None),
(active, link_args, "1.0.0", Some(29596), None),
(active, non_ascii_idents, "1.0.0", Some(55467), None),
(active, plugin_registrar, "1.0.0", Some(29597), None),
(active, plugin, "1.0.0", Some(29597), None),
(active, thread_local, "1.0.0", Some(29594), None),
(active, simd_ffi, "1.0.0", Some(27731), None),
(active, custom_attribute, "1.0.0", Some(29642), None),
(active, nll, "1.0.0", Some(43234), None),
(active, slice_patterns, "1.0.0", Some(62254), None),
(active, const_fn, "1.2.0", Some(57563), None),
(active, associated_type_defaults, "1.2.0", Some(29661), None),
(active, no_core, "1.3.0", Some(29639), None),
(active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
(active, repr_simd, "1.4.0", Some(27731), None),
(active, platform_intrinsics, "1.4.0", Some(27731), None),
(active, unwind_attributes, "1.4.0", Some(58760), None),
(active, no_debug, "1.5.0", Some(29721), None),
(active, stmt_expr_attributes, "1.6.0", Some(15701), None),
(active, type_ascription, "1.6.0", Some(23416), None),
(active, cfg_target_thread_local, "1.7.0", Some(29594), None),
(active, specialization, "1.7.0", Some(31844), None),
(active, naked_functions, "1.9.0", Some(32408), None),
(active, cfg_target_has_atomic, "1.9.0", Some(32976), None),
(active, exclusive_range_pattern, "1.11.0", Some(37854), None),
(active, never_type, "1.13.0", Some(35121), None),
(active, exhaustive_patterns, "1.13.0", Some(51085), None),
(active, untagged_unions, "1.13.0", Some(32836), None),
(active, link_cfg, "1.14.0", Some(37406), None),
(active, abi_ptx, "1.15.0", Some(38788), None),
(active, repr128, "1.16.0", Some(35118), None),
(active, static_nobundle, "1.16.0", Some(37403), None),
(active, abi_msp430_interrupt, "1.16.0", Some(38487), None),
(active, decl_macro, "1.17.0", Some(39412), None),
(active, abi_x86_interrupt, "1.17.0", Some(40180), None),
(active, overlapping_marker_traits, "1.18.0", Some(29864), None),
(active, allow_fail, "1.19.0", Some(46488), None),
(active, unsized_tuple_coercion, "1.20.0", Some(42877), None),
(active, generators, "1.21.0", Some(43122), None),
(active, doc_cfg, "1.21.0", Some(43781), None),
(active, doc_masked, "1.21.0", Some(44027), None),
(active, doc_spotlight, "1.22.0", Some(45040), None),
(active, external_doc, "1.22.0", Some(44732), None),
(active, non_exhaustive, "1.22.0", Some(44109), None),
(active, crate_visibility_modifier, "1.23.0", Some(53120), None),
(active, extern_types, "1.23.0", Some(43467), None),
(active, arbitrary_self_types, "1.23.0", Some(44874), None),
(active, in_band_lifetimes, "1.23.0", Some(44524), None),
(active, generic_associated_types, "1.23.0", Some(44265), None),
(active, trait_alias, "1.24.0", Some(41517), None),
(active, infer_static_outlives_requirements, "1.26.0", Some(54185), None),
(active, macros_in_extern, "1.27.0", Some(49476), None),
(active, const_fn_union, "1.27.0", Some(51909), None),
(active, const_raw_ptr_to_usize_cast, "1.27.0", Some(51910), None),
(active, const_raw_ptr_deref, "1.27.0", Some(51911), None),
(active, const_compare_raw_pointers, "1.27.0", Some(53020), None),
(active, doc_alias, "1.27.0", Some(50146), None),
(active, trivial_bounds, "1.28.0", Some(48214), None),
(active, label_break_value, "1.28.0", Some(48594), None),
(active, doc_keyword, "1.28.0", Some(51315), None),
(active, async_await, "1.28.0", Some(50547), None),
(active, const_transmute, "1.29.0", Some(53605), None),
(active, try_blocks, "1.29.0", Some(31436), None),
(active, alloc_error_handler, "1.29.0", Some(51540), None),
(active, abi_amdgpu_kernel, "1.29.0", Some(51575), None),
(active, const_panic, "1.30.0", Some(51999), None),
(active, marker_trait_attr, "1.30.0", Some(29864), None),
(active, proc_macro_hygiene, "1.30.0", Some(54727), None),
(active, unsized_locals, "1.30.0", Some(48055), None),
(active, custom_test_frameworks, "1.30.0", Some(50297), None),
(active, custom_inner_attributes, "1.30.0", Some(54726), None),
(active, bind_by_move_pattern_guards, "1.30.0", Some(15287), None),
(active, impl_trait_in_bindings, "1.30.0", Some(63065), None),
(active, lint_reasons, "1.31.0", Some(54503), None),
(active, precise_pointer_size_matching, "1.32.0", Some(56354), None),
(active, re_rebalance_coherence, "1.32.0", Some(55437), None),
(active, ffi_returns_twice, "1.34.0", Some(58314), None),
(active, const_generics, "1.34.0", Some(44580), None),
(active, optimize_attribute, "1.34.0", Some(54882), None),
(active, c_variadic, "1.34.0", Some(44930), None),
(active, associated_type_bounds, "1.34.0", Some(52662), None),
(active, param_attrs, "1.36.0", Some(60406), None),
(active, const_constructor, "1.37.0", Some(61456), None),
(active, let_chains, "1.37.0", Some(53667), None),
(active, transparent_enums, "1.37.0", Some(60405), None),
(active, transparent_unions, "1.37.0", Some(60405), None),
(active, arbitrary_enum_discriminant, "1.37.0", Some(60553), None),
(active, member_constraints, "1.37.0", Some(61977), None),
(active, async_closure, "1.37.0", Some(62290), None),
(active, cfg_doctest, "1.37.0", Some(62210), None),
(active, const_in_array_repeat_expressions, "1.37.0", Some(49147), None),
(active, type_alias_impl_trait, "1.38.0", Some(63063), None),
);
pub const INCOMPLETE_FEATURES: &[Symbol] = &[
sym::impl_trait_in_bindings,
sym::generic_associated_types,
sym::const_generics,
sym::let_chains,
];
declare_features! (
(removed, import_shadowing, "1.0.0", None, None, None),
(removed, managed_boxes, "1.0.0", None, None, None),
(removed, negate_unsigned, "1.0.0", Some(29645), None, None),
(removed, reflect, "1.0.0", Some(27749), None, None),
(removed, opt_out_copy, "1.0.0", None, None, None),
(removed, quad_precision_float, "1.0.0", None, None, None),
(removed, struct_inherit, "1.0.0", None, None, None),
(removed, test_removed_feature, "1.0.0", None, None, None),
(removed, visible_private_types, "1.0.0", None, None, None),
(removed, unsafe_no_drop_flag, "1.0.0", None, None, None),
(removed, unmarked_api, "1.0.0", None, None, None),
(removed, allocator, "1.0.0", None, None, None),
(removed, simd, "1.0.0", Some(27731), None,
Some("removed in favor of `#[repr(simd)]`")),
(removed, advanced_slice_patterns, "1.0.0", Some(62254), None,
Some("merged into `#![feature(slice_patterns)]`")),
(removed, macro_reexport, "1.0.0", Some(29638), None,
Some("subsumed by `pub use`")),
(removed, pushpop_unsafe, "1.2.0", None, None, None),
(removed, needs_allocator, "1.4.0", Some(27389), None,
Some("subsumed by `#![feature(allocator_internals)]`")),
(removed, proc_macro_mod, "1.27.0", Some(54727), None,
Some("subsumed by `#![feature(proc_macro_hygiene)]`")),
(removed, proc_macro_expr, "1.27.0", Some(54727), None,
Some("subsumed by `#![feature(proc_macro_hygiene)]`")),
(removed, proc_macro_non_items, "1.27.0", Some(54727), None,
Some("subsumed by `#![feature(proc_macro_hygiene)]`")),
(removed, proc_macro_gen, "1.27.0", Some(54727), None,
Some("subsumed by `#![feature(proc_macro_hygiene)]`")),
(removed, panic_implementation, "1.28.0", Some(44489), None,
Some("subsumed by `#[panic_handler]`")),
(removed, custom_derive, "1.32.0", Some(29644), None,
Some("subsumed by `#[proc_macro_derive]`")),
(removed, extern_in_paths, "1.33.0", Some(55600), None,
Some("subsumed by `::foo::bar` paths")),
(removed, quote, "1.33.0", Some(29601), None, None),
(removed, dropck_parametricity, "1.38.0", Some(28498), None, None),
(removed, await_macro, "1.38.0", Some(50547), None,
Some("subsumed by `.await` syntax")),
(removed, existential_type, "1.38.0", Some(63063), None,
Some("removed in favor of `#![feature(type_alias_impl_trait)]`")),
);
declare_features! (
(stable_removed, no_stack_check, "1.0.0", None, None),
);
declare_features! (
(accepted, issue_5723_bootstrap, "1.0.0", None, None),
(accepted, test_accepted_feature, "1.0.0", None, None),
(accepted, associated_types, "1.0.0", None, None),
(accepted, default_type_params, "1.0.0", None, None),
(accepted, globs, "1.0.0", None, None),
(accepted, macro_rules, "1.0.0", None, None),
(accepted, slicing_syntax, "1.0.0", None, None),
(accepted, struct_variant, "1.0.0", None, None),
(accepted, tuple_indexing, "1.0.0", None, None),
(accepted, if_let, "1.0.0", None, None),
(accepted, while_let, "1.0.0", None, None),
(accepted, no_std, "1.6.0", None, None),
(accepted, augmented_assignments, "1.8.0", Some(28235), None),
(accepted, braced_empty_structs, "1.8.0", Some(29720), None),
(accepted, deprecated, "1.9.0", Some(29935), None),
(accepted, type_macros, "1.13.0", Some(27245), None),
(accepted, question_mark, "1.13.0", Some(31436), None),
(accepted, dotdot_in_tuple_patterns, "1.14.0", Some(33627), None),
(accepted, item_like_imports, "1.15.0", Some(35120), None),
(accepted, more_struct_aliases, "1.16.0", Some(37544), None),
(accepted, static_in_const, "1.17.0", Some(35897), None),
(accepted, field_init_shorthand, "1.17.0", Some(37340), None),
(accepted, static_recursion, "1.17.0", Some(29719), None),
(accepted, pub_restricted, "1.18.0", Some(32409), None),
(accepted, windows_subsystem, "1.18.0", Some(37499), None),
(accepted, loop_break_value, "1.19.0", Some(37339), None),
(accepted, relaxed_adts, "1.19.0", Some(35626), None),
(accepted, closure_to_fn_coercion, "1.19.0", Some(39817), None),
(accepted, struct_field_attributes, "1.20.0", Some(38814), None),
(accepted, associated_consts, "1.20.0", Some(29646), None),
(accepted, compile_error, "1.20.0", Some(40872), None),
(accepted, rvalue_static_promotion, "1.21.0", Some(38865), None),
(accepted, drop_types_in_const, "1.22.0", Some(33156), None),
(accepted, abi_sysv64, "1.24.0", Some(36167), None),
(accepted, repr_align, "1.25.0", Some(33626), None),
(accepted, match_beginning_vert, "1.25.0", Some(44101), None),
(accepted, use_nested_groups, "1.25.0", Some(44494), None),
(accepted, const_indexing, "1.26.0", Some(29947), None),
(accepted, inclusive_range_syntax, "1.26.0", Some(28237), None),
(accepted, dotdoteq_in_patterns, "1.26.0", Some(28237), None),
(accepted, termination_trait, "1.26.0", Some(43301), None),
(accepted, clone_closures, "1.26.0", Some(44490), None),
(accepted, copy_closures, "1.26.0", Some(44490), None),
(accepted, universal_impl_trait, "1.26.0", Some(34511), None),
(accepted, conservative_impl_trait, "1.26.0", Some(34511), None),
(accepted, i128_type, "1.26.0", Some(35118), None),
(accepted, match_default_bindings, "1.26.0", Some(42640), None),
(accepted, underscore_lifetimes, "1.26.0", Some(44524), None),
(accepted, generic_param_attrs, "1.27.0", Some(48848), None),
(accepted, cfg_target_feature, "1.27.0", Some(29717), None),
(accepted, target_feature, "1.27.0", None, None),
(accepted, dyn_trait, "1.27.0", Some(44662), None),
(accepted, fn_must_use, "1.27.0", Some(43302), None),
(accepted, macro_lifetime_matcher, "1.27.0", Some(34303), None),
(accepted, termination_trait_test, "1.27.0", Some(48854), None),
(accepted, global_allocator, "1.28.0", Some(27389), None),
(accepted, repr_transparent, "1.28.0", Some(43036), None),
(accepted, proc_macro, "1.29.0", Some(38356), None),
(accepted, non_modrs_mods, "1.30.0", Some(44660), None),
(accepted, macro_vis_matcher, "1.30.0", Some(41022), None),
(accepted, use_extern_macros, "1.30.0", Some(35896), None),
(accepted, raw_identifiers, "1.30.0", Some(48589), None),
(accepted, tool_attributes, "1.30.0", Some(44690), None),
(accepted, proc_macro_path_invoc, "1.30.0", Some(38356), None),
(accepted, attr_literals, "1.30.0", Some(34981), None),
(accepted, infer_outlives_requirements, "1.30.0", Some(44493), None),
(accepted, panic_handler, "1.30.0", Some(44489), None),
(accepted, used, "1.30.0", Some(40289), None),
(accepted, crate_in_paths, "1.30.0", Some(45477), None),
(accepted, extern_absolute_paths, "1.30.0", Some(44660), None),
(accepted, extern_prelude, "1.30.0", Some(44660), None),
(accepted, pattern_parentheses, "1.31.0", Some(51087), None),
(accepted, min_const_fn, "1.31.0", Some(53555), None),
(accepted, tool_lints, "1.31.0", Some(44690), None),
(accepted, impl_header_lifetime_elision, "1.31.0", Some(15872), None),
(accepted, extern_crate_item_prelude, "1.31.0", Some(55599), None),
(accepted, macro_literal_matcher, "1.32.0", Some(35625), None),
(accepted, macro_at_most_once_rep, "1.32.0", Some(48075), None),
(accepted, self_struct_ctor, "1.32.0", Some(51994), None),
(accepted, self_in_typedefs, "1.32.0", Some(49303), None),
(accepted, uniform_paths, "1.32.0", Some(53130), None),
(accepted, exhaustive_integer_patterns, "1.33.0", Some(50907), None),
(accepted, underscore_imports, "1.33.0", Some(48216), None),
(accepted, repr_packed, "1.33.0", Some(33158), None),
(accepted, irrefutable_let_patterns, "1.33.0", Some(44495), None),
(accepted, min_const_unsafe_fn, "1.33.0", Some(55607), None),
(accepted, const_let, "1.33.0", Some(48821), None),
(accepted, cfg_attr_multi, "1.33.0", Some(54881), None),
(accepted, if_while_or_patterns, "1.33.0", Some(48215), None),
(accepted, cfg_target_vendor, "1.33.0", Some(29718), None),
(accepted, extern_crate_self, "1.34.0", Some(56409), None),
(accepted, unrestricted_attribute_tokens, "1.34.0", Some(55208), None),
(accepted, type_alias_enum_variants, "1.37.0", Some(49683), None),
(accepted, repr_align_enum, "1.37.0", Some(57996), None),
(accepted, underscore_const_names, "1.37.0", Some(54912), None),
);
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum AttributeType {
Normal,
Whitelisted,
CrateLevel,
}
pub enum AttributeGate {
Gated(Stability, Symbol, &'static str, fn(&Features) -> bool),
Ungated,
}
macro_rules! template {
(Word) => { template!(@ true, None, None) };
(List: $descr: expr) => { template!(@ false, Some($descr), None) };
(NameValueStr: $descr: expr) => { template!(@ false, None, Some($descr)) };
(Word, List: $descr: expr) => { template!(@ true, Some($descr), None) };
(Word, NameValueStr: $descr: expr) => { template!(@ true, None, Some($descr)) };
(List: $descr1: expr, NameValueStr: $descr2: expr) => {
template!(@ false, Some($descr1), Some($descr2))
};
(Word, List: $descr1: expr, NameValueStr: $descr2: expr) => {
template!(@ true, Some($descr1), Some($descr2))
};
(@ $word: expr, $list: expr, $name_value_str: expr) => { AttributeTemplate {
word: $word, list: $list, name_value_str: $name_value_str
} };
}
impl AttributeGate {
fn is_deprecated(&self) -> bool {
match *self {
Gated(Stability::Deprecated(_, _), ..) => true,
_ => false,
}
}
}
#[derive(Copy, Clone, Debug)]
pub enum Stability {
Unstable,
Deprecated(&'static str, Option<&'static str>),
}
impl std::fmt::Debug for AttributeGate {
fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match *self {
Gated(ref stab, name, expl, _) =>
write!(fmt, "Gated({:?}, {}, {})", stab, name, expl),
Ungated => write!(fmt, "Ungated")
}
}
}
macro_rules! cfg_fn {
($field: ident) => {{
fn f(features: &Features) -> bool {
features.$field
}
f as fn(&Features) -> bool
}}
}
pub fn deprecated_attributes() -> Vec<&'static (Symbol, AttributeType,
AttributeTemplate, AttributeGate)> {
BUILTIN_ATTRIBUTES.iter().filter(|(.., gate)| gate.is_deprecated()).collect()
}
pub fn is_builtin_attr_name(name: ast::Name) -> bool {
BUILTIN_ATTRIBUTE_MAP.get(&name).is_some()
}
pub fn is_builtin_attr(attr: &ast::Attribute) -> bool {
attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name)).is_some()
}
pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
(
sym::warn,
Normal,
template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
Ungated
),
(
sym::allow,
Normal,
template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
Ungated
),
(
sym::forbid,
Normal,
template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
Ungated
),
(
sym::deny,
Normal,
template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#),
Ungated
),
(sym::macro_use, Normal, template!(Word, List: "name1, name2, ..."), Ungated),
(sym::macro_export, Normal, template!(Word, List: "local_inner_macros"), Ungated),
(sym::plugin_registrar, Normal, template!(Word), Ungated),
(sym::cfg, Normal, template!(List: "predicate"), Ungated),
(sym::cfg_attr, Normal, template!(List: "predicate, attr1, attr2, ..."), Ungated),
(sym::main, Normal, template!(Word), Ungated),
(sym::start, Normal, template!(Word), Ungated),
(sym::repr, Normal, template!(List: "C, packed, ..."), Ungated),
(sym::path, Normal, template!(NameValueStr: "file"), Ungated),
(sym::automatically_derived, Normal, template!(Word), Ungated),
(sym::no_mangle, Whitelisted, template!(Word), Ungated),
(sym::no_link, Normal, template!(Word), Ungated),
(sym::derive, Normal, template!(List: "Trait1, Trait2, ..."), Ungated),
(
sym::should_panic,
Normal,
template!(Word, List: r#"expected = "reason"#, NameValueStr: "reason"),
Ungated
),
(sym::ignore, Normal, template!(Word, NameValueStr: "reason"), Ungated),
(sym::no_implicit_prelude, Normal, template!(Word), Ungated),
(sym::reexport_test_harness_main, Normal, template!(NameValueStr: "name"), Ungated),
(sym::link_args, Normal, template!(NameValueStr: "args"), Gated(Stability::Unstable,
sym::link_args,
"the `link_args` attribute is experimental and not \
portable across platforms, it is recommended to \
use `#[link(name = \"foo\")] instead",
cfg_fn!(link_args))),
(sym::macro_escape, Normal, template!(Word), Ungated),
(sym::structural_match, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::structural_match,
"the semantics of constant patterns is \
not yet settled",
cfg_fn!(structural_match))),
(sym::non_exhaustive, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::non_exhaustive,
"non exhaustive is an experimental feature",
cfg_fn!(non_exhaustive))),
(sym::marker, Normal, template!(Word), Gated(Stability::Unstable,
sym::marker_trait_attr,
"marker traits is an experimental feature",
cfg_fn!(marker_trait_attr))),
(sym::plugin, CrateLevel, template!(List: "name|name(args)"), Gated(Stability::Unstable,
sym::plugin,
"compiler plugins are experimental \
and possibly buggy",
cfg_fn!(plugin))),
(sym::no_std, CrateLevel, template!(Word), Ungated),
(sym::no_core, CrateLevel, template!(Word), Gated(Stability::Unstable,
sym::no_core,
"no_core is experimental",
cfg_fn!(no_core))),
(sym::lang, Normal, template!(NameValueStr: "name"), Gated(Stability::Unstable,
sym::lang_items,
"language items are subject to change",
cfg_fn!(lang_items))),
(sym::linkage, Whitelisted, template!(NameValueStr: "external|internal|..."),
Gated(Stability::Unstable,
sym::linkage,
"the `linkage` attribute is experimental \
and not portable across platforms",
cfg_fn!(linkage))),
(sym::thread_local, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::thread_local,
"`#[thread_local]` is an experimental feature, and does \
not currently handle destructors",
cfg_fn!(thread_local))),
(sym::rustc_on_unimplemented, Whitelisted, template!(List:
r#"/*opt*/ message = "...", /*opt*/ label = "...", /*opt*/ note = "...""#,
NameValueStr: "message"),
Gated(Stability::Unstable,
sym::on_unimplemented,
"the `#[rustc_on_unimplemented]` attribute \
is an experimental feature",
cfg_fn!(on_unimplemented))),
(sym::rustc_const_unstable, Normal, template!(List: r#"feature = "name""#),
Gated(Stability::Unstable,
sym::rustc_const_unstable,
"the `#[rustc_const_unstable]` attribute \
is an internal feature",
cfg_fn!(rustc_const_unstable))),
(sym::default_lib_allocator, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::allocator_internals,
"the `#[default_lib_allocator]` \
attribute is an experimental feature",
cfg_fn!(allocator_internals))),
(sym::needs_allocator, Normal, template!(Word), Gated(Stability::Unstable,
sym::allocator_internals,
"the `#[needs_allocator]` \
attribute is an experimental \
feature",
cfg_fn!(allocator_internals))),
(sym::panic_runtime, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::panic_runtime,
"the `#[panic_runtime]` attribute is \
an experimental feature",
cfg_fn!(panic_runtime))),
(sym::needs_panic_runtime, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::needs_panic_runtime,
"the `#[needs_panic_runtime]` \
attribute is an experimental \
feature",
cfg_fn!(needs_panic_runtime))),
(sym::rustc_outlives, Normal, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_outlives]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_variance, Normal, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_variance]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_layout, Normal, template!(List: "field1, field2, ..."),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_layout]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_layout_scalar_valid_range_start, Whitelisted, template!(List: "value"),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_layout_scalar_valid_range_start]` attribute \
is just used to enable niche optimizations in libcore \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_layout_scalar_valid_range_end, Whitelisted, template!(List: "value"),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_layout_scalar_valid_range_end]` attribute \
is just used to enable niche optimizations in libcore \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_nonnull_optimization_guaranteed, Whitelisted, template!(Word),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_nonnull_optimization_guaranteed]` attribute \
is just used to enable niche optimizations in libcore \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_regions, Normal, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_regions]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_error, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_error]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_dump_user_substs, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_if_this_changed, Whitelisted, template!(Word, List: "DepNode"),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_if_this_changed]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_then_this_would_need, Whitelisted, template!(List: "DepNode"),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_if_this_changed]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_dirty, Whitelisted, template!(List: r#"cfg = "...", /*opt*/ label = "...",
/*opt*/ except = "...""#),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_dirty]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_clean, Whitelisted, template!(List: r#"cfg = "...", /*opt*/ label = "...",
/*opt*/ except = "...""#),
Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_clean]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(
sym::rustc_partition_reused,
Whitelisted,
template!(List: r#"cfg = "...", module = "...""#),
Gated(
Stability::Unstable,
sym::rustc_attrs,
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs)
)
),
(
sym::rustc_partition_codegened,
Whitelisted,
template!(List: r#"cfg = "...", module = "...""#),
Gated(
Stability::Unstable,
sym::rustc_attrs,
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs),
)
),
(sym::rustc_expected_cgu_reuse, Whitelisted, template!(List: r#"cfg = "...", module = "...",
kind = "...""#),
Gated(Stability::Unstable,
sym::rustc_attrs,
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_synthetic, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_symbol_name, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal rustc attributes will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_def_path, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal rustc attributes will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_mir, Whitelisted, template!(List: "arg1, arg2, ..."), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_mir]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
(
sym::rustc_inherit_overflow_checks,
Whitelisted,
template!(Word),
Gated(
Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_inherit_overflow_checks]` \
attribute is just used to control \
overflow checking behavior of several \
libcore functions that are inlined \
across crates and will never be stable",
cfg_fn!(rustc_attrs),
)
),
(sym::rustc_dump_program_clauses, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_dump_program_clauses]` \
attribute is just used for rustc unit \
tests and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_dump_env_program_clauses, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_dump_env_program_clauses]` \
attribute is just used for rustc unit \
tests and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_object_lifetime_default, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_object_lifetime_default]` \
attribute is just used for rustc unit \
tests and will never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_test_marker, Normal, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"the `#[rustc_test_marker]` attribute \
is used internally to track tests",
cfg_fn!(rustc_attrs))),
(sym::rustc_macro_transparency, Whitelisted, template!(NameValueStr:
"transparent|semitransparent|opaque"),
Gated(Stability::Unstable,
sym::rustc_attrs,
"used internally for testing macro hygiene",
cfg_fn!(rustc_attrs))),
(sym::compiler_builtins, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::compiler_builtins,
"the `#[compiler_builtins]` attribute is used to \
identify the `compiler_builtins` crate which \
contains compiler-rt intrinsics and will never be \
stable",
cfg_fn!(compiler_builtins))),
(sym::sanitizer_runtime, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::sanitizer_runtime,
"the `#[sanitizer_runtime]` attribute is used to \
identify crates that contain the runtime of a \
sanitizer and will never be stable",
cfg_fn!(sanitizer_runtime))),
(sym::profiler_runtime, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::profiler_runtime,
"the `#[profiler_runtime]` attribute is used to \
identify the `profiler_builtins` crate which \
contains the profiler runtime and will never be \
stable",
cfg_fn!(profiler_runtime))),
(sym::allow_internal_unstable, Normal, template!(Word, List: "feat1, feat2, ..."),
Gated(Stability::Unstable,
sym::allow_internal_unstable,
EXPLAIN_ALLOW_INTERNAL_UNSTABLE,
cfg_fn!(allow_internal_unstable))),
(sym::allow_internal_unsafe, Normal, template!(Word), Gated(Stability::Unstable,
sym::allow_internal_unsafe,
EXPLAIN_ALLOW_INTERNAL_UNSAFE,
cfg_fn!(allow_internal_unsafe))),
(sym::fundamental, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::fundamental,
"the `#[fundamental]` attribute \
is an experimental feature",
cfg_fn!(fundamental))),
(sym::proc_macro_derive, Normal, template!(List: "TraitName, \
/*opt*/ attributes(name1, name2, ...)"),
Ungated),
(sym::rustc_allocator, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal implementation detail",
cfg_fn!(rustc_attrs))),
(sym::rustc_allocator_nounwind, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal implementation detail",
cfg_fn!(rustc_attrs))),
(sym::rustc_builtin_macro, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal implementation detail",
cfg_fn!(rustc_attrs))),
(sym::rustc_promotable, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal implementation detail",
cfg_fn!(rustc_attrs))),
(sym::rustc_allow_const_fn_ptr, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"internal implementation detail",
cfg_fn!(rustc_attrs))),
(sym::rustc_dummy, Normal, template!(Word ), Gated(Stability::Unstable,
sym::rustc_attrs,
"used by the test suite",
cfg_fn!(rustc_attrs))),
(
sym::doc,
Whitelisted,
template!(List: "hidden|inline|...", NameValueStr: "string"),
Ungated
),
(sym::cold, Whitelisted, template!(Word), Ungated),
(sym::naked, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::naked_functions,
"the `#[naked]` attribute \
is an experimental feature",
cfg_fn!(naked_functions))),
(sym::ffi_returns_twice, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::ffi_returns_twice,
"the `#[ffi_returns_twice]` attribute \
is an experimental feature",
cfg_fn!(ffi_returns_twice))),
(sym::target_feature, Whitelisted, template!(List: r#"enable = "name""#), Ungated),
(sym::export_name, Whitelisted, template!(NameValueStr: "name"), Ungated),
(sym::inline, Whitelisted, template!(Word, List: "always|never"), Ungated),
(sym::link, Whitelisted, template!(List: r#"name = "...", /*opt*/ kind = "dylib|static|...",
/*opt*/ cfg = "...""#), Ungated),
(sym::link_name, Whitelisted, template!(NameValueStr: "name"), Ungated),
(sym::link_section, Whitelisted, template!(NameValueStr: "name"), Ungated),
(sym::no_builtins, Whitelisted, template!(Word), Ungated),
(sym::no_debug, Whitelisted, template!(Word), Gated(
Stability::Deprecated("https://github.com/rust-lang/rust/issues/29721", None),
sym::no_debug,
"the `#[no_debug]` attribute was an experimental feature that has been \
deprecated due to lack of demand",
cfg_fn!(no_debug))),
(
sym::omit_gdb_pretty_printer_section,
Whitelisted,
template!(Word),
Gated(
Stability::Unstable,
sym::omit_gdb_pretty_printer_section,
"the `#[omit_gdb_pretty_printer_section]` \
attribute is just used for the Rust test \
suite",
cfg_fn!(omit_gdb_pretty_printer_section)
)
),
(sym::may_dangle,
Normal,
template!(Word),
Gated(Stability::Unstable,
sym::dropck_eyepatch,
"`may_dangle` has unstable semantics and may be removed in the future",
cfg_fn!(dropck_eyepatch))),
(sym::unwind, Whitelisted, template!(List: "allowed|aborts"), Gated(Stability::Unstable,
sym::unwind_attributes,
"`#[unwind]` is experimental",
cfg_fn!(unwind_attributes))),
(sym::used, Whitelisted, template!(Word), Ungated),
(sym::prelude_import, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::prelude_import,
"`#[prelude_import]` is for use by rustc only",
cfg_fn!(prelude_import))),
(
sym::rustc_deprecated,
Whitelisted,
template!(List: r#"since = "version", reason = "...""#),
Ungated
),
(sym::must_use, Whitelisted, template!(Word, NameValueStr: "reason"), Ungated),
(
sym::stable,
Whitelisted,
template!(List: r#"feature = "name", since = "version""#),
Ungated
),
(
sym::unstable,
Whitelisted,
template!(List: r#"feature = "name", reason = "...", issue = "N""#),
Ungated
),
(sym::deprecated,
Normal,
template!(
Word,
List: r#"/*opt*/ since = "version", /*opt*/ note = "reason""#,
NameValueStr: "reason"
),
Ungated
),
(sym::rustc_paren_sugar, Normal, template!(Word), Gated(Stability::Unstable,
sym::unboxed_closures,
"unboxed_closures are still evolving",
cfg_fn!(unboxed_closures))),
(sym::windows_subsystem, Whitelisted, template!(NameValueStr: "windows|console"), Ungated),
(sym::proc_macro_attribute, Normal, template!(Word), Ungated),
(sym::proc_macro, Normal, template!(Word), Ungated),
(sym::rustc_proc_macro_decls, Normal, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"used internally by rustc",
cfg_fn!(rustc_attrs))),
(sym::allow_fail, Normal, template!(Word), Gated(Stability::Unstable,
sym::allow_fail,
"allow_fail attribute is currently unstable",
cfg_fn!(allow_fail))),
(sym::rustc_std_internal_symbol, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"this is an internal attribute that will \
never be stable",
cfg_fn!(rustc_attrs))),
(sym::rustc_conversion_suggestion, Whitelisted, template!(Word), Gated(Stability::Unstable,
sym::rustc_attrs,
"this is an internal attribute that will \
never be stable",
cfg_fn!(rustc_attrs))),
(
sym::rustc_args_required_const,
Whitelisted,
template!(List: "N"),
Gated(Stability::Unstable, sym::rustc_attrs, "never will be stable",
cfg_fn!(rustc_attrs))
),
(sym::panic_handler, Normal, template!(Word), Ungated),
(sym::alloc_error_handler, Normal, template!(Word), Gated(Stability::Unstable,
sym::alloc_error_handler,
"`#[alloc_error_handler]` is an unstable feature",
cfg_fn!(alloc_error_handler))),
(sym::optimize, Whitelisted, template!(List: "size|speed"), Gated(Stability::Unstable,
sym::optimize_attribute,
"`#[optimize]` attribute is an unstable feature",
cfg_fn!(optimize_attribute))),
(sym::crate_name, CrateLevel, template!(NameValueStr: "name"), Ungated),
(sym::crate_type, CrateLevel, template!(NameValueStr: "bin|lib|..."), Ungated),
(sym::crate_id, CrateLevel, template!(NameValueStr: "ignored"), Ungated),
(sym::feature, CrateLevel, template!(List: "name1, name1, ..."), Ungated),
(sym::no_start, CrateLevel, template!(Word), Ungated),
(sym::no_main, CrateLevel, template!(Word), Ungated),
(sym::recursion_limit, CrateLevel, template!(NameValueStr: "N"), Ungated),
(sym::type_length_limit, CrateLevel, template!(NameValueStr: "N"), Ungated),
(sym::test_runner, CrateLevel, template!(List: "path"), Gated(Stability::Unstable,
sym::custom_test_frameworks,
"custom test frameworks are an unstable feature",
cfg_fn!(custom_test_frameworks))),
];
pub type BuiltinAttribute = (Symbol, AttributeType, AttributeTemplate, AttributeGate);
lazy_static! {
pub static ref BUILTIN_ATTRIBUTE_MAP: FxHashMap<Symbol, &'static BuiltinAttribute> = {
let mut map = FxHashMap::default();
for attr in BUILTIN_ATTRIBUTES.iter() {
if map.insert(attr.0, attr).is_some() {
panic!("duplicate builtin attribute `{}`", attr.0);
}
}
map
};
}
const GATED_CFGS: &[(Symbol, Symbol, fn(&Features) -> bool)] = &[
(sym::target_thread_local, sym::cfg_target_thread_local, cfg_fn!(cfg_target_thread_local)),
(sym::target_has_atomic, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
(sym::rustdoc, sym::doc_cfg, cfg_fn!(doc_cfg)),
(sym::doctest, sym::cfg_doctest, cfg_fn!(cfg_doctest)),
];
#[derive(Debug)]
pub struct GatedCfg {
span: Span,
index: usize,
}
impl GatedCfg {
pub fn gate(cfg: &ast::MetaItem) -> Option<GatedCfg> {
GATED_CFGS.iter()
.position(|info| cfg.check_name(info.0))
.map(|idx| {
GatedCfg {
span: cfg.span,
index: idx
}
})
}
pub fn check_and_emit(&self, sess: &ParseSess, features: &Features) {
let (cfg, feature, has_feature) = GATED_CFGS[self.index];
if !has_feature(features) && !self.span.allows_unstable(feature) {
let explain = format!("`cfg({})` is experimental and subject to change", cfg);
emit_feature_err(sess, feature, self.span, GateIssue::Language, &explain);
}
}
}
struct Context<'a> {
features: &'a Features,
parse_sess: &'a ParseSess,
plugin_attributes: &'a [(Symbol, AttributeType)],
}
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)
};
}
impl<'a> Context<'a> {
fn check_attribute(
&self,
attr: &ast::Attribute,
attr_info: Option<&BuiltinAttribute>,
is_macro: bool
) {
debug!("check_attribute(attr = {:?})", attr);
if let Some(&(name, ty, _template, ref gateage)) = attr_info {
if let Gated(_, name, desc, ref has_feature) = *gateage {
if !attr.span.allows_unstable(name) {
gate_feature_fn!(
self, has_feature, attr.span, name, desc, GateStrength::Hard
);
}
} else if name == sym::doc {
if let Some(content) = attr.meta_item_list() {
if content.iter().any(|c| c.check_name(sym::include)) {
gate_feature!(self, external_doc, attr.span,
"`#[doc(include = \"...\")]` is experimental"
);
}
}
}
debug!("check_attribute: {:?} is builtin, {:?}, {:?}", attr.path, ty, gateage);
return;
} else {
for segment in &attr.path.segments {
if segment.ident.as_str().starts_with("rustc") {
let msg = "attributes starting with `rustc` are \
reserved for use by the `rustc` compiler";
gate_feature!(self, rustc_attrs, segment.ident.span, msg);
}
}
}
for &(n, ty) in self.plugin_attributes {
if attr.path == n {
debug!("check_attribute: {:?} is registered by a plugin, {:?}", attr.path, ty);
return;
}
}
if !is_macro && !attr::is_known(attr) {
let msg = format!("the attribute `{}` is currently unknown to the compiler and \
may have meaning added to it in the future", attr.path);
gate_feature!(self, custom_attribute, attr.span, &msg);
}
}
}
pub fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) {
let cx = Context { features, parse_sess, plugin_attributes: &[] };
cx.check_attribute(
attr,
attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name).map(|a| *a)),
true
);
}
fn find_lang_feature_issue(feature: Symbol) -> Option<u32> {
if let Some(info) = ACTIVE_FEATURES.iter().find(|t| t.0 == feature) {
let issue = info.2;
issue
} else {
let found = ACCEPTED_FEATURES.iter().chain(REMOVED_FEATURES).chain(STABLE_REMOVED_FEATURES)
.find(|t| t.0 == feature);
match found {
Some(&(_, _, 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 {
Hard,
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) => {}
Some(n) => {
err.note(&format!(
"for more information, see https://github.com/rust-lang/rust/issues/{}",
n,
));
}
}
if sess.unstable_features.is_nightly_build() {
err.help(&format!("add `#![feature({})]` to the crate attributes to enable", feature));
}
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> {
context: &'a Context<'a>,
builtin_attributes: &'static FxHashMap<Symbol, &'static BuiltinAttribute>,
}
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.context, $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.context, $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");
},
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| {
self.builtin_attributes.get(&ident.name).map(|a| *a)
});
self.context.check_attribute(attr, attr_info, false);
if attr.check_name(sym::doc) {
if let Some(content) = attr.meta_item_list() {
if content.len() == 1 && content[0].check_name(sym::cfg) {
gate_feature_post!(&self, doc_cfg, attr.span,
"`#[doc(cfg(...))]` is experimental"
);
} else if content.iter().any(|c| c.check_name(sym::masked)) {
gate_feature_post!(&self, doc_masked, attr.span,
"`#[doc(masked)]` is experimental"
);
} else if content.iter().any(|c| c.check_name(sym::spotlight)) {
gate_feature_post!(&self, doc_spotlight, attr.span,
"`#[doc(spotlight)]` is experimental"
);
} else if content.iter().any(|c| c.check_name(sym::alias)) {
gate_feature_post!(&self, doc_alias, attr.span,
"`#[doc(alias = \"...\")]` is experimental"
);
} else if content.iter().any(|c| c.check_name(sym::keyword)) {
gate_feature_post!(&self, doc_keyword, attr.span,
"`#[doc(keyword = \"...\")]` is experimental"
);
}
}
}
match attr_info {
Some(&(name, _, template, _)) if name != sym::rustc_dummy =>
check_builtin_attribute(self.context.parse_sess, attr, name, template),
_ => if let Some(TokenTree::Token(token)) = attr.tokens.trees().next() {
if token == token::Eq {
attr.parse_meta(self.context.parse_sess).map_err(|mut err| err.emit()).ok();
}
}
}
}
fn visit_name(&mut self, sp: Span, name: ast::Name) {
if !name.as_str().is_ascii() {
gate_feature_post!(
&self,
non_ascii_idents,
self.context.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.context.features.arbitrary_enum_discriminant;
if !has_feature && !i.span.allows_unstable(sym::arbitrary_enum_discriminant) {
Parser::maybe_report_invalid_custom_discriminants(
self.context.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 {
} 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(..) => {
if self.context.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");
}
}
ast::ExprKind::Async(..) => {
gate_feature_post!(&self, async_await, e.span, "async blocks are unstable");
}
ast::ExprKind::Await(_) => {
gate_feature_post!(&self, async_await, e.span, "async/await is 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() {
if header.asyncness.node.is_async() {
gate_feature_post!(&self, async_await, span, "async fn is unstable");
}
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.header.asyncness.node.is_async() {
gate_feature_post!(&self, async_await, ti.span, "async fn is unstable");
}
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 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 {
edition_enabled_features.insert(edition.feature_name(), edition);
}
}
for &(name, .., f_edition, set) in ACTIVE_FEATURES {
if let Some(f_edition) = f_edition {
if f_edition <= crate_edition {
set(&mut features, DUMMY_SP);
edition_enabled_features.insert(name, crate_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,
};
for mi in list {
if !mi.is_word() {
continue;
}
let name = mi.name_or_empty();
if let Some(edition) = ALL_EDITIONS.iter().find(|e| name == e.feature_name()) {
if *edition <= crate_edition {
continue;
}
for &(name, .., f_edition, set) in ACTIVE_FEATURES {
if let Some(f_edition) = f_edition {
if f_edition <= *edition {
set(&mut features, DUMMY_SP);
edition_enabled_features.insert(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()) {
continue;
}
let removed = REMOVED_FEATURES.iter().find(|f| name == f.0);
let stable_removed = STABLE_REMOVED_FEATURES.iter().find(|f| name == f.0);
if let Some((.., reason)) = removed.or(stable_removed) {
feature_removed(span_handler, mi.span(), *reason);
continue;
}
if let Some((_, since, ..)) = ACCEPTED_FEATURES.iter().find(|f| name == f.0) {
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((.., set)) = ACTIVE_FEATURES.iter().find(|f| name == f.0) {
set(&mut features, mi.span());
features.declared_lang_features.push((name, mi.span(), None));
continue;
}
features.declared_lib_features.push((name, mi.span()));
}
}
features
}
pub fn check_crate(krate: &ast::Crate,
sess: &ParseSess,
features: &Features,
plugin_attributes: &[(Symbol, AttributeType)],
unstable: UnstableFeatures) {
maybe_stage_features(&sess.span_diagnostic, krate, unstable);
let ctx = Context {
features,
parse_sess: sess,
plugin_attributes,
};
macro_rules! gate_all {
($spans:ident, $gate:ident, $msg:literal) => {
for span in &*sess.$spans.borrow() { gate_feature!(&ctx, $gate, *span, $msg); }
}
}
gate_all!(param_attr_spans, param_attrs, "attributes on function parameters are unstable");
gate_all!(let_chains_spans, let_chains, "`let` expressions in this position are experimental");
gate_all!(async_closure_spans, async_closure, "async closures are unstable");
gate_all!(yield_spans, generators, "yield syntax is experimental");
let visitor = &mut PostExpansionVisitor {
context: &ctx,
builtin_attributes: &*BUILTIN_ATTRIBUTE_MAP,
};
visit::walk_crate(visitor, krate);
}
#[derive(Clone, Copy, Hash)]
pub enum UnstableFeatures {
Disallow,
Allow,
Cheat
}
impl UnstableFeatures {
pub fn from_environment() -> UnstableFeatures {
let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some();
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);
}
}
}
}