rust/compiler/rustc_feature/src/builtin_attrs.rs
2021-11-18 16:10:26 -08:00

754 lines
31 KiB
Rust

//! Built-in attributes and `cfg` flag gating.
use AttributeDuplicates::*;
use AttributeGate::*;
use AttributeType::*;
use crate::{Features, Stability};
use rustc_data_structures::fx::FxHashMap;
use rustc_span::symbol::{sym, Symbol};
use std::lazy::SyncLazy;
type GateFn = fn(&Features) -> bool;
macro_rules! cfg_fn {
($field: ident) => {
(|features| features.$field) as GateFn
};
}
pub type GatedCfg = (Symbol, Symbol, GateFn);
/// `cfg(...)`'s that are feature gated.
const GATED_CFGS: &[GatedCfg] = &[
// (name in cfg, feature, function to check if the feature is enabled)
(sym::target_abi, sym::cfg_target_abi, cfg_fn!(cfg_target_abi)),
(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::target_has_atomic_load_store, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
(
sym::target_has_atomic_equal_alignment,
sym::cfg_target_has_atomic,
cfg_fn!(cfg_target_has_atomic),
),
(sym::sanitize, sym::cfg_sanitize, cfg_fn!(cfg_sanitize)),
(sym::version, sym::cfg_version, cfg_fn!(cfg_version)),
(sym::panic, sym::cfg_panic, cfg_fn!(cfg_panic)),
];
/// Find a gated cfg determined by the `pred`icate which is given the cfg's name.
pub fn find_gated_cfg(pred: impl Fn(Symbol) -> bool) -> Option<&'static GatedCfg> {
GATED_CFGS.iter().find(|(cfg_sym, ..)| pred(*cfg_sym))
}
// If you change this, please modify `src/doc/unstable-book` as well. You must
// move that documentation into the relevant place in the other docs, and
// remove the chapter on the flag.
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum AttributeType {
/// Normal, builtin attribute that is consumed
/// by the compiler before the unused_attribute check
Normal,
/// Builtin attribute that is only allowed at the crate level
CrateLevel,
}
#[derive(Clone, Copy)]
pub enum AttributeGate {
/// Is gated by a given feature gate, reason
/// and function to check if enabled
Gated(Stability, Symbol, &'static str, fn(&Features) -> bool),
/// Ungated attribute, can be used on all release channels
Ungated,
}
// fn() is not Debug
impl std::fmt::Debug for AttributeGate {
fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match *self {
Self::Gated(ref stab, name, expl, _) => {
write!(fmt, "Gated({:?}, {}, {})", stab, name, expl)
}
Self::Ungated => write!(fmt, "Ungated"),
}
}
}
impl AttributeGate {
fn is_deprecated(&self) -> bool {
matches!(*self, Self::Gated(Stability::Deprecated(_, _), ..))
}
}
/// A template that the attribute input must match.
/// Only top-level shape (`#[attr]` vs `#[attr(...)]` vs `#[attr = ...]`) is considered now.
#[derive(Clone, Copy, Default)]
pub struct AttributeTemplate {
/// If `true`, the attribute is allowed to be a bare word like `#[test]`.
pub word: bool,
/// If `Some`, the attribute is allowed to take a list of items like `#[allow(..)]`.
pub list: Option<&'static str>,
/// If `Some`, the attribute is allowed to be a name/value pair where the
/// value is a string, like `#[must_use = "reason"]`.
pub name_value_str: Option<&'static str>,
}
/// How to handle multiple duplicate attributes on the same item.
#[derive(Clone, Copy, Default)]
pub enum AttributeDuplicates {
/// Duplicates of this attribute are allowed.
///
/// This should only be used with attributes where duplicates have semantic
/// meaning, or some kind of "additive" behavior. For example, `#[warn(..)]`
/// can be specified multiple times, and it combines all the entries. Or use
/// this if there is validation done elsewhere.
#[default]
DuplicatesOk,
/// Duplicates after the first attribute will be an unused_attribute warning.
///
/// This is usually used for "word" attributes, where they are used as a
/// boolean marker, like `#[used]`. It is not necessarily wrong that there
/// are duplicates, but the others should probably be removed.
WarnFollowing,
/// Same as `WarnFollowing`, but only issues warnings for word-style attributes.
///
/// This is only for special cases, for example multiple `#[macro_use]` can
/// be warned, but multiple `#[macro_use(...)]` should not because the list
/// form has different meaning from the word form.
WarnFollowingWordOnly,
/// Duplicates after the first attribute will be an error.
///
/// This should be used where duplicates would be ignored, but carry extra
/// meaning that could cause confusion. For example, `#[stable(since="1.0")]
/// #[stable(since="2.0")]`, which version should be used for `stable`?
ErrorFollowing,
/// Duplicates preceding the last instance of the attribute will be an error.
///
/// This is the same as `ErrorFollowing`, except the last attribute is the
/// one that is "used". This is typically used in cases like codegen
/// attributes which usually only honor the last attribute.
ErrorPreceding,
/// Duplicates after the first attribute will be an unused_attribute warning
/// with a note that this will be an error in the future.
///
/// This should be used for attributes that should be `ErrorFollowing`, but
/// because older versions of rustc silently accepted (and ignored) the
/// attributes, this is used to transition.
FutureWarnFollowing,
/// Duplicates preceding the last instance of the attribute will be a
/// warning, with a note that this will be an error in the future.
///
/// This is the same as `FutureWarnFollowing`, except the last attribute is
/// the one that is "used". Ideally these can eventually migrate to
/// `ErrorPreceding`.
FutureWarnPreceding,
}
/// A convenience macro for constructing attribute templates.
/// E.g., `template!(Word, List: "description")` means that the attribute
/// supports forms `#[attr]` and `#[attr(description)]`.
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: $name_value_str
} };
}
macro_rules! ungated {
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
type_: $typ,
template: $tpl,
gate: Ungated,
duplicates: $duplicates,
}
};
}
macro_rules! gated {
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $gate:ident, $msg:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
type_: $typ,
template: $tpl,
duplicates: $duplicates,
gate: Gated(Stability::Unstable, sym::$gate, $msg, cfg_fn!($gate)),
}
};
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $msg:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
type_: $typ,
template: $tpl,
duplicates: $duplicates,
gate: Gated(Stability::Unstable, sym::$attr, $msg, cfg_fn!($attr)),
}
};
}
macro_rules! rustc_attr {
(TEST, $attr:ident, $typ:expr, $tpl:expr, $duplicate:expr $(,)?) => {
rustc_attr!(
$attr,
$typ,
$tpl,
$duplicate,
concat!(
"the `#[",
stringify!($attr),
"]` attribute is just used for rustc unit tests \
and will never be stable",
),
)
};
($attr:ident, $typ:expr, $tpl:expr, $duplicates:expr, $msg:expr $(,)?) => {
BuiltinAttribute {
name: sym::$attr,
type_: $typ,
template: $tpl,
duplicates: $duplicates,
gate: Gated(Stability::Unstable, sym::rustc_attrs, $msg, cfg_fn!(rustc_attrs)),
}
};
}
macro_rules! experimental {
($attr:ident) => {
concat!("the `#[", stringify!($attr), "]` attribute is an experimental feature")
};
}
const IMPL_DETAIL: &str = "internal implementation detail";
const INTERNAL_UNSTABLE: &str = "this is an internal attribute that will never be stable";
pub struct BuiltinAttribute {
pub name: Symbol,
pub type_: AttributeType,
pub template: AttributeTemplate,
pub duplicates: AttributeDuplicates,
pub gate: AttributeGate,
}
/// Attributes that have a special meaning to rustc or rustdoc.
#[rustfmt::skip]
pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
// ==========================================================================
// Stable attributes:
// ==========================================================================
// Conditional compilation:
ungated!(cfg, Normal, template!(List: "predicate"), DuplicatesOk),
ungated!(cfg_attr, Normal, template!(List: "predicate, attr1, attr2, ..."), DuplicatesOk),
// Testing:
ungated!(ignore, Normal, template!(Word, NameValueStr: "reason"), WarnFollowing),
ungated!(
should_panic, Normal,
template!(Word, List: r#"expected = "reason"#, NameValueStr: "reason"), FutureWarnFollowing,
),
// FIXME(Centril): This can be used on stable but shouldn't.
ungated!(reexport_test_harness_main, CrateLevel, template!(NameValueStr: "name"), ErrorFollowing),
// Macros:
ungated!(automatically_derived, Normal, template!(Word), WarnFollowing),
ungated!(macro_use, Normal, template!(Word, List: "name1, name2, ..."), WarnFollowingWordOnly),
ungated!(macro_escape, Normal, template!(Word), WarnFollowing), // Deprecated synonym for `macro_use`.
ungated!(macro_export, Normal, template!(Word, List: "local_inner_macros"), WarnFollowing),
ungated!(proc_macro, Normal, template!(Word), ErrorFollowing),
ungated!(
proc_macro_derive, Normal,
template!(List: "TraitName, /*opt*/ attributes(name1, name2, ...)"), ErrorFollowing,
),
ungated!(proc_macro_attribute, Normal, template!(Word), ErrorFollowing),
// Lints:
ungated!(
warn, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk
),
ungated!(
allow, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk
),
ungated!(
forbid, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk
),
ungated!(
deny, Normal, template!(List: r#"lint1, lint2, ..., /*opt*/ reason = "...""#), DuplicatesOk
),
ungated!(must_use, Normal, template!(Word, NameValueStr: "reason"), FutureWarnFollowing),
gated!(
must_not_suspend, Normal, template!(Word, NameValueStr: "reason"), WarnFollowing,
must_not_suspend, experimental!(must_not_suspend)
),
ungated!(
deprecated, Normal,
template!(
Word,
List: r#"/*opt*/ since = "version", /*opt*/ note = "reason""#,
NameValueStr: "reason"
),
// This has special duplicate handling in E0550 to handle duplicates with rustc_deprecated
DuplicatesOk
),
// Crate properties:
ungated!(crate_name, CrateLevel, template!(NameValueStr: "name"), FutureWarnFollowing),
ungated!(crate_type, CrateLevel, template!(NameValueStr: "bin|lib|..."), FutureWarnFollowing),
// crate_id is deprecated
ungated!(crate_id, CrateLevel, template!(NameValueStr: "ignored"), FutureWarnFollowing),
// ABI, linking, symbols, and FFI
ungated!(
link, Normal,
template!(List: r#"name = "...", /*opt*/ kind = "dylib|static|...", /*opt*/ wasm_import_module = "...""#),
DuplicatesOk,
),
ungated!(link_name, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
ungated!(no_link, Normal, template!(Word), WarnFollowing),
ungated!(repr, Normal, template!(List: "C"), DuplicatesOk),
ungated!(export_name, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
ungated!(link_section, Normal, template!(NameValueStr: "name"), FutureWarnPreceding),
ungated!(no_mangle, Normal, template!(Word), WarnFollowing),
ungated!(used, Normal, template!(Word), WarnFollowing),
// Limits:
ungated!(recursion_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing),
ungated!(type_length_limit, CrateLevel, template!(NameValueStr: "N"), FutureWarnFollowing),
gated!(
const_eval_limit, CrateLevel, template!(NameValueStr: "N"), ErrorFollowing,
const_eval_limit, experimental!(const_eval_limit)
),
gated!(
move_size_limit, CrateLevel, template!(NameValueStr: "N"), ErrorFollowing,
large_assignments, experimental!(move_size_limit)
),
// Entry point:
ungated!(main, Normal, template!(Word), WarnFollowing),
ungated!(start, Normal, template!(Word), WarnFollowing),
ungated!(no_start, CrateLevel, template!(Word), WarnFollowing),
ungated!(no_main, CrateLevel, template!(Word), WarnFollowing),
// Modules, prelude, and resolution:
ungated!(path, Normal, template!(NameValueStr: "file"), FutureWarnFollowing),
ungated!(no_std, CrateLevel, template!(Word), WarnFollowing),
ungated!(no_implicit_prelude, Normal, template!(Word), WarnFollowing),
ungated!(non_exhaustive, Normal, template!(Word), WarnFollowing),
// Runtime
ungated!(
windows_subsystem, Normal,
template!(NameValueStr: "windows|console"), FutureWarnFollowing
),
ungated!(panic_handler, Normal, template!(Word), WarnFollowing), // RFC 2070
// Code generation:
ungated!(inline, Normal, template!(Word, List: "always|never"), FutureWarnFollowing),
ungated!(cold, Normal, template!(Word), WarnFollowing),
ungated!(no_builtins, Normal, template!(Word), WarnFollowing),
ungated!(target_feature, Normal, template!(List: r#"enable = "name""#), DuplicatesOk),
ungated!(track_caller, Normal, template!(Word), WarnFollowing),
gated!(
no_sanitize, Normal,
template!(List: "address, memory, thread"), DuplicatesOk,
experimental!(no_sanitize)
),
gated!(no_coverage, Normal, template!(Word), WarnFollowing, experimental!(no_coverage)),
ungated!(
doc, Normal, template!(List: "hidden|inline|...", NameValueStr: "string"), DuplicatesOk
),
// ==========================================================================
// Unstable attributes:
// ==========================================================================
// Linking:
gated!(naked, Normal, template!(Word), WarnFollowing, naked_functions, experimental!(naked)),
gated!(
link_ordinal, Normal, template!(List: "ordinal"), ErrorPreceding, raw_dylib,
experimental!(link_ordinal)
),
// Plugins:
BuiltinAttribute {
name: sym::plugin,
type_: CrateLevel,
template: template!(List: "name"),
duplicates: DuplicatesOk,
gate: Gated(
Stability::Deprecated(
"https://github.com/rust-lang/rust/pull/64675",
Some("may be removed in a future compiler version"),
),
sym::plugin,
"compiler plugins are deprecated",
cfg_fn!(plugin)
),
},
// Testing:
gated!(allow_fail, Normal, template!(Word), WarnFollowing, experimental!(allow_fail)),
gated!(
test_runner, CrateLevel, template!(List: "path"), ErrorFollowing, custom_test_frameworks,
"custom test frameworks are an unstable feature",
),
// RFC #1268
gated!(
marker, Normal, template!(Word), WarnFollowing, marker_trait_attr, experimental!(marker)
),
gated!(
thread_local, Normal, template!(Word), WarnFollowing,
"`#[thread_local]` is an experimental feature, and does not currently handle destructors",
),
gated!(no_core, CrateLevel, template!(Word), WarnFollowing, experimental!(no_core)),
// RFC 2412
gated!(
optimize, Normal, template!(List: "size|speed"), ErrorPreceding, optimize_attribute,
experimental!(optimize),
),
// RFC 2867
gated!(
instruction_set, Normal, template!(List: "set"), ErrorPreceding,
isa_attribute, experimental!(instruction_set)
),
gated!(
ffi_returns_twice, Normal, template!(Word), WarnFollowing, experimental!(ffi_returns_twice)
),
gated!(ffi_pure, Normal, template!(Word), WarnFollowing, experimental!(ffi_pure)),
gated!(ffi_const, Normal, template!(Word), WarnFollowing, experimental!(ffi_const)),
gated!(
register_attr, CrateLevel, template!(List: "attr1, attr2, ..."), DuplicatesOk,
experimental!(register_attr),
),
gated!(
register_tool, CrateLevel, template!(List: "tool1, tool2, ..."), DuplicatesOk,
experimental!(register_tool),
),
gated!(
cmse_nonsecure_entry, Normal, template!(Word), WarnFollowing,
experimental!(cmse_nonsecure_entry)
),
// RFC 2632
gated!(
default_method_body_is_const, Normal, template!(Word), WarnFollowing, const_trait_impl,
"`default_method_body_is_const` is a temporary placeholder for declaring default bodies \
as `const`, which may be removed or renamed in the future."
),
// ==========================================================================
// Internal attributes: Stability, deprecation, and unsafe:
// ==========================================================================
ungated!(feature, CrateLevel, template!(List: "name1, name1, ..."), DuplicatesOk),
// DuplicatesOk since it has its own validation
ungated!(
rustc_deprecated, Normal,
template!(List: r#"since = "version", reason = "...""#), DuplicatesOk // See E0550
),
// DuplicatesOk since it has its own validation
ungated!(
stable, Normal, template!(List: r#"feature = "name", since = "version""#), DuplicatesOk
),
ungated!(
unstable, Normal,
template!(List: r#"feature = "name", reason = "...", issue = "N""#), DuplicatesOk,
),
ungated!(rustc_const_unstable, Normal, template!(List: r#"feature = "name""#), DuplicatesOk),
ungated!(rustc_const_stable, Normal, template!(List: r#"feature = "name""#), DuplicatesOk),
gated!(
allow_internal_unstable, Normal, template!(Word, List: "feat1, feat2, ..."), DuplicatesOk,
"allow_internal_unstable side-steps feature gating and stability checks",
),
gated!(
rustc_allow_const_fn_unstable, Normal,
template!(Word, List: "feat1, feat2, ..."), DuplicatesOk,
"rustc_allow_const_fn_unstable side-steps feature gating and stability checks"
),
gated!(
allow_internal_unsafe, Normal, template!(Word), WarnFollowing,
"allow_internal_unsafe side-steps the unsafe_code lint",
),
// ==========================================================================
// Internal attributes: Type system related:
// ==========================================================================
gated!(fundamental, Normal, template!(Word), WarnFollowing, experimental!(fundamental)),
gated!(
may_dangle, Normal, template!(Word), WarnFollowing, dropck_eyepatch,
"`may_dangle` has unstable semantics and may be removed in the future",
),
// ==========================================================================
// Internal attributes: Runtime related:
// ==========================================================================
rustc_attr!(rustc_allocator, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
rustc_attr!(rustc_allocator_nounwind, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
gated!(
alloc_error_handler, Normal, template!(Word), WarnFollowing,
experimental!(alloc_error_handler)
),
gated!(
default_lib_allocator, Normal, template!(Word), WarnFollowing, allocator_internals,
experimental!(default_lib_allocator),
),
gated!(
needs_allocator, Normal, template!(Word), WarnFollowing, allocator_internals,
experimental!(needs_allocator),
),
gated!(panic_runtime, Normal, template!(Word), WarnFollowing, experimental!(panic_runtime)),
gated!(
needs_panic_runtime, Normal, template!(Word), WarnFollowing,
experimental!(needs_panic_runtime)
),
gated!(
compiler_builtins, Normal, template!(Word), WarnFollowing,
"the `#[compiler_builtins]` attribute is used to identify the `compiler_builtins` crate \
which contains compiler-rt intrinsics and will never be stable",
),
gated!(
profiler_runtime, Normal, template!(Word), WarnFollowing,
"the `#[profiler_runtime]` attribute is used to identify the `profiler_builtins` crate \
which contains the profiler runtime and will never be stable",
),
// ==========================================================================
// Internal attributes, Linkage:
// ==========================================================================
gated!(
linkage, Normal, template!(NameValueStr: "external|internal|..."), ErrorPreceding,
"the `linkage` attribute is experimental and not portable across platforms",
),
rustc_attr!(
rustc_std_internal_symbol, Normal, template!(Word), WarnFollowing, INTERNAL_UNSTABLE
),
// ==========================================================================
// Internal attributes, Macro related:
// ==========================================================================
rustc_attr!(
rustc_builtin_macro, Normal,
template!(Word, List: "name, /*opt*/ attributes(name1, name2, ...)"), ErrorFollowing,
IMPL_DETAIL,
),
rustc_attr!(rustc_proc_macro_decls, Normal, template!(Word), WarnFollowing, INTERNAL_UNSTABLE),
rustc_attr!(
rustc_macro_transparency, Normal,
template!(NameValueStr: "transparent|semitransparent|opaque"), ErrorFollowing,
"used internally for testing macro hygiene",
),
// ==========================================================================
// Internal attributes, Diagnostics related:
// ==========================================================================
rustc_attr!(
rustc_on_unimplemented, Normal,
template!(
List: r#"/*opt*/ message = "...", /*opt*/ label = "...", /*opt*/ note = "...""#,
NameValueStr: "message"
),
ErrorFollowing,
INTERNAL_UNSTABLE
),
// Enumerates "identity-like" conversion methods to suggest on type mismatch.
rustc_attr!(
rustc_conversion_suggestion, Normal, template!(Word), WarnFollowing, INTERNAL_UNSTABLE
),
// Prevents field reads in the marked trait or method to be considered
// during dead code analysis.
rustc_attr!(
rustc_trivial_field_reads, Normal, template!(Word), WarnFollowing, INTERNAL_UNSTABLE
),
// ==========================================================================
// Internal attributes, Const related:
// ==========================================================================
rustc_attr!(rustc_promotable, Normal, template!(Word), WarnFollowing, IMPL_DETAIL),
rustc_attr!(
rustc_legacy_const_generics, Normal, template!(List: "N"), ErrorFollowing,
INTERNAL_UNSTABLE
),
// Do not const-check this function's body. It will always get replaced during CTFE.
rustc_attr!(
rustc_do_not_const_check, Normal, template!(Word), WarnFollowing, INTERNAL_UNSTABLE
),
// ==========================================================================
// Internal attributes, Layout related:
// ==========================================================================
rustc_attr!(
rustc_layout_scalar_valid_range_start, Normal, template!(List: "value"), ErrorFollowing,
"the `#[rustc_layout_scalar_valid_range_start]` attribute is just used to enable \
niche optimizations in libcore and will never be stable",
),
rustc_attr!(
rustc_layout_scalar_valid_range_end, Normal, template!(List: "value"), ErrorFollowing,
"the `#[rustc_layout_scalar_valid_range_end]` attribute is just used to enable \
niche optimizations in libcore and will never be stable",
),
rustc_attr!(
rustc_nonnull_optimization_guaranteed, Normal, template!(Word), WarnFollowing,
"the `#[rustc_nonnull_optimization_guaranteed]` attribute is just used to enable \
niche optimizations in libcore and will never be stable",
),
// ==========================================================================
// Internal attributes, Misc:
// ==========================================================================
gated!(
lang, Normal, template!(NameValueStr: "name"), DuplicatesOk, lang_items,
"language items are subject to change",
),
BuiltinAttribute {
name: sym::rustc_diagnostic_item,
type_: Normal,
template: template!(NameValueStr: "name"),
duplicates: ErrorFollowing,
gate: Gated(
Stability::Unstable,
sym::rustc_attrs,
"diagnostic items compiler internal support for linting",
cfg_fn!(rustc_attrs),
),
},
gated!(
// Used in resolve:
prelude_import, Normal, template!(Word), WarnFollowing,
"`#[prelude_import]` is for use by rustc only",
),
gated!(
rustc_paren_sugar, Normal, template!(Word), WarnFollowing, unboxed_closures,
"unboxed_closures are still evolving",
),
rustc_attr!(
rustc_inherit_overflow_checks, Normal, template!(Word), WarnFollowing,
"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",
),
rustc_attr!(
rustc_reservation_impl, Normal,
template!(NameValueStr: "reservation message"), ErrorFollowing,
"the `#[rustc_reservation_impl]` attribute is internally used \
for reserving for `for<T> From<!> for T` impl"
),
rustc_attr!(
rustc_test_marker, Normal, template!(Word), WarnFollowing,
"the `#[rustc_test_marker]` attribute is used internally to track tests",
),
rustc_attr!(
rustc_unsafe_specialization_marker, Normal, template!(Word), WarnFollowing,
"the `#[rustc_unsafe_specialization_marker]` attribute is used to check specializations"
),
rustc_attr!(
rustc_specialization_trait, Normal, template!(Word), WarnFollowing,
"the `#[rustc_specialization_trait]` attribute is used to check specializations"
),
rustc_attr!(
rustc_main, Normal, template!(Word), WarnFollowing,
"the `#[rustc_main]` attribute is used internally to specify test entry point function",
),
rustc_attr!(
rustc_skip_array_during_method_dispatch, Normal, template!(Word), WarnFollowing,
"the `#[rustc_skip_array_during_method_dispatch]` attribute is used to exclude a trait \
from method dispatch when the receiver is an array, for compatibility in editions < 2021."
),
// ==========================================================================
// Internal attributes, Testing:
// ==========================================================================
rustc_attr!(TEST, rustc_outlives, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_capture_analysis, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_insignificant_dtor, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_strict_coherence, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_variance, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_layout, Normal, template!(List: "field1, field2, ..."), WarnFollowing),
rustc_attr!(TEST, rustc_regions, Normal, template!(Word), WarnFollowing),
rustc_attr!(
TEST, rustc_error, Normal,
template!(Word, List: "delay_span_bug_from_inside_query"), WarnFollowingWordOnly
),
rustc_attr!(TEST, rustc_dump_user_substs, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_evaluate_where_clauses, Normal, template!(Word), WarnFollowing),
rustc_attr!(
TEST, rustc_if_this_changed, Normal, template!(Word, List: "DepNode"), DuplicatesOk
),
rustc_attr!(
TEST, rustc_then_this_would_need, Normal, template!(List: "DepNode"), DuplicatesOk
),
rustc_attr!(
TEST, rustc_clean, Normal,
template!(List: r#"cfg = "...", /*opt*/ label = "...", /*opt*/ except = "...""#),
DuplicatesOk,
),
rustc_attr!(
TEST, rustc_partition_reused, Normal,
template!(List: r#"cfg = "...", module = "...""#), DuplicatesOk,
),
rustc_attr!(
TEST, rustc_partition_codegened, Normal,
template!(List: r#"cfg = "...", module = "...""#), DuplicatesOk,
),
rustc_attr!(
TEST, rustc_expected_cgu_reuse, Normal,
template!(List: r#"cfg = "...", module = "...", kind = "...""#), DuplicatesOk,
),
rustc_attr!(TEST, rustc_symbol_name, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_polymorphize_error, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_def_path, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_mir, Normal, template!(List: "arg1, arg2, ..."), DuplicatesOk),
rustc_attr!(TEST, rustc_dump_program_clauses, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_dump_env_program_clauses, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_object_lifetime_default, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_dump_vtable, Normal, template!(Word), WarnFollowing),
rustc_attr!(TEST, rustc_dummy, Normal, template!(Word /* doesn't matter*/), DuplicatesOk),
gated!(
omit_gdb_pretty_printer_section, Normal, template!(Word), WarnFollowing,
"the `#[omit_gdb_pretty_printer_section]` attribute is just used for the Rust test suite",
),
];
pub fn deprecated_attributes() -> Vec<&'static BuiltinAttribute> {
BUILTIN_ATTRIBUTES.iter().filter(|attr| attr.gate.is_deprecated()).collect()
}
pub fn is_builtin_attr_name(name: Symbol) -> bool {
BUILTIN_ATTRIBUTE_MAP.get(&name).is_some()
}
pub static BUILTIN_ATTRIBUTE_MAP: SyncLazy<FxHashMap<Symbol, &BuiltinAttribute>> =
SyncLazy::new(|| {
let mut map = FxHashMap::default();
for attr in BUILTIN_ATTRIBUTES.iter() {
if map.insert(attr.name, attr).is_some() {
panic!("duplicate builtin attribute `{}`", attr.name);
}
}
map
});