use self::AttributeType::*;
use self::AttributeGate::*;
use abi::Abi;
use ast::{self, NodeId, PatKind, RangeEnd, RangeSyntax};
use attr;
use codemap::Spanned;
use syntax_pos::Span;
use errors::{DiagnosticBuilder, Handler, FatalError};
use visit::{self, FnKind, Visitor};
use parse::ParseSess;
use symbol::{keywords, Symbol};
use std::{env, path};
macro_rules! set {
(proc_macro) => {{
fn f(features: &mut Features, span: Span) {
features.declared_lib_features.push((Symbol::intern("proc_macro"), span));
features.proc_macro = true;
}
f as fn(&mut Features, Span)
}};
($field: ident) => {{
fn f(features: &mut Features, _: Span) {
features.$field = true;
}
f as fn(&mut Features, Span)
}}
}
macro_rules! declare_features {
($((active, $feature: ident, $ver: expr, $issue: expr),)+) => {
const ACTIVE_FEATURES:
&'static [(&'static str, &'static str, Option<u32>, fn(&mut Features, Span))] =
&[$((stringify!($feature), $ver, $issue, set!($feature))),+];
pub struct Features {
pub declared_stable_lang_features: Vec<(Symbol, Span)>,
pub declared_lib_features: Vec<(Symbol, Span)>,
$(pub $feature: bool),+
}
impl Features {
pub fn new() -> Features {
Features {
declared_stable_lang_features: Vec::new(),
declared_lib_features: Vec::new(),
$($feature: false),+
}
}
}
};
($((removed, $feature: ident, $ver: expr, $issue: expr),)+) => {
const REMOVED_FEATURES: &'static [(&'static str, &'static str, Option<u32>)] = &[
$((stringify!($feature), $ver, $issue)),+
];
};
($((stable_removed, $feature: ident, $ver: expr, $issue: expr),)+) => {
const STABLE_REMOVED_FEATURES: &'static [(&'static str, &'static str, Option<u32>)] = &[
$((stringify!($feature), $ver, $issue)),+
];
};
($((accepted, $feature: ident, $ver: expr, $issue: expr),)+) => {
const ACCEPTED_FEATURES: &'static [(&'static str, &'static str, Option<u32>)] = &[
$((stringify!($feature), $ver, $issue)),+
];
}
}
declare_features! (
(active, asm, "1.0.0", Some(29722)),
(active, concat_idents, "1.0.0", Some(29599)),
(active, link_args, "1.0.0", Some(29596)),
(active, log_syntax, "1.0.0", Some(29598)),
(active, non_ascii_idents, "1.0.0", Some(28979)),
(active, plugin_registrar, "1.0.0", Some(29597)),
(active, thread_local, "1.0.0", Some(29594)),
(active, trace_macros, "1.0.0", Some(29598)),
(active, intrinsics, "1.0.0", None),
(active, lang_items, "1.0.0", None),
(active, link_llvm_intrinsics, "1.0.0", Some(29602)),
(active, linkage, "1.0.0", Some(29603)),
(active, quote, "1.0.0", Some(29601)),
(active, rustc_diagnostic_macros, "1.0.0", None),
(active, rustc_const_unstable, "1.0.0", None),
(active, advanced_slice_patterns, "1.0.0", Some(23121)),
(active, box_syntax, "1.0.0", Some(27779)),
(active, placement_in_syntax, "1.0.0", Some(27779)),
(active, unboxed_closures, "1.0.0", Some(29625)),
(active, fundamental, "1.0.0", Some(29635)),
(active, main, "1.0.0", Some(29634)),
(active, needs_allocator, "1.4.0", Some(27389)),
(active, on_unimplemented, "1.0.0", Some(29628)),
(active, plugin, "1.0.0", Some(29597)),
(active, simd_ffi, "1.0.0", Some(27731)),
(active, start, "1.0.0", Some(29633)),
(active, structural_match, "1.8.0", Some(31434)),
(active, panic_runtime, "1.10.0", Some(32837)),
(active, needs_panic_runtime, "1.10.0", Some(32837)),
(active, optin_builtin_traits, "1.0.0", Some(13231)),
(active, macro_reexport, "1.0.0", Some(29638)),
(active, staged_api, "1.0.0", None),
(active, no_core, "1.3.0", Some(29639)),
(active, box_patterns, "1.0.0", Some(29641)),
(active, dropck_parametricity, "1.3.0", Some(28498)),
(active, dropck_eyepatch, "1.10.0", Some(34761)),
(active, custom_attribute, "1.0.0", Some(29642)),
(active, custom_derive, "1.0.0", Some(29644)),
(active, rustc_attrs, "1.0.0", Some(29642)),
(active, nll, "1.0.0", Some(44928)),
(active, allow_internal_unstable, "1.0.0", None),
(active, allow_internal_unsafe, "1.0.0", None),
(active, slice_patterns, "1.0.0", Some(23121)),
(active, const_fn, "1.2.0", Some(24111)),
(active, const_indexing, "1.4.0", Some(29947)),
(active, prelude_import, "1.2.0", None),
(active, default_type_parameter_fallback, "1.3.0", Some(27336)),
(active, associated_type_defaults, "1.2.0", Some(29661)),
(active, repr_simd, "1.4.0", Some(27731)),
(active, cfg_target_feature, "1.4.0", Some(29717)),
(active, platform_intrinsics, "1.4.0", Some(27731)),
(active, unwind_attributes, "1.4.0", None),
(active, naked_functions, "1.9.0", Some(32408)),
(active, no_debug, "1.5.0", Some(29721)),
(active, omit_gdb_pretty_printer_section, "1.5.0", None),
(active, cfg_target_vendor, "1.5.0", Some(29718)),
(active, stmt_expr_attributes, "1.6.0", Some(15701)),
(active, type_ascription, "1.6.0", Some(23416)),
(active, cfg_target_thread_local, "1.7.0", Some(29594)),
(active, abi_vectorcall, "1.7.0", None),
(active, inclusive_range_syntax, "1.7.0", Some(28237)),
(active, exclusive_range_pattern, "1.11.0", Some(37854)),
(active, specialization, "1.7.0", Some(31844)),
(active, cfg_target_has_atomic, "1.9.0", Some(32976)),
(active, conservative_impl_trait, "1.12.0", Some(34511)),
(active, universal_impl_trait, "1.23.0", Some(34511)),
(active, never_type, "1.13.0", Some(35121)),
(active, attr_literals, "1.13.0", Some(34981)),
(active, untagged_unions, "1.13.0", Some(32836)),
(active, compiler_builtins, "1.13.0", None),
(active, generic_param_attrs, "1.11.0", Some(34761)),
(active, link_cfg, "1.14.0", Some(37406)),
(active, use_extern_macros, "1.15.0", Some(35896)),
(active, target_feature, "1.15.0", None),
(active, abi_ptx, "1.15.0", None),
(active, i128_type, "1.16.0", Some(35118)),
(active, repr128, "1.16.0", Some(35118)),
(active, abi_unadjusted, "1.16.0", None),
(active, proc_macro, "1.16.0", Some(38356)),
(active, decl_macro, "1.17.0", Some(39412)),
(active, static_nobundle, "1.16.0", Some(37403)),
(active, abi_msp430_interrupt, "1.16.0", Some(38487)),
(active, sanitizer_runtime, "1.17.0", None),
(active, profiler_runtime, "1.18.0", None),
(active, abi_x86_interrupt, "1.17.0", Some(40180)),
(active, catch_expr, "1.17.0", Some(31436)),
(active, used, "1.18.0", Some(40289)),
(active, global_asm, "1.18.0", Some(35119)),
(active, overlapping_marker_traits, "1.18.0", Some(29864)),
(active, macro_vis_matcher, "1.18.0", Some(41022)),
(active, abi_thiscall, "1.19.0", None),
(active, allow_fail, "1.19.0", Some(42219)),
(active, unsized_tuple_coercion, "1.20.0", Some(42877)),
(active, generators, "1.21.0", None),
(active, trait_alias, "1.24.0", Some(41517)),
(active, global_allocator, "1.20.0", None),
(active, allocator_internals, "1.20.0", None),
(active, doc_cfg, "1.21.0", Some(43781)),
(active, doc_masked, "1.21.0", Some(44027)),
(active, doc_spotlight, "1.22.0", Some(45040)),
(active, external_doc, "1.22.0", Some(44732)),
(active, fn_must_use, "1.21.0", Some(43302)),
(active, non_exhaustive, "1.22.0", Some(44109)),
(active, clone_closures, "1.22.0", Some(44490)),
(active, copy_closures, "1.22.0", Some(44490)),
(active, underscore_lifetimes, "1.22.0", Some(44524)),
(active, dotdoteq_in_patterns, "1.22.0", Some(28237)),
(active, match_default_bindings, "1.22.0", Some(42640)),
(active, dyn_trait, "1.22.0", Some(44662)),
(active, crate_visibility_modifier, "1.23.0", Some(45388)),
(active, extern_types, "1.23.0", Some(43467)),
(active, arbitrary_self_types, "1.23.0", Some(44874)),
(active, wasm_import_memory, "1.22.0", None),
(active, crate_in_paths, "1.23.0", Some(45477)),
(active, in_band_lifetimes, "1.23.0", Some(44524)),
(active, generic_associated_types, "1.23.0", Some(44265)),
(active, extern_absolute_paths, "1.24.0", Some(44660)),
(active, non_modrs_mods, "1.24.0", Some(44660)),
(active, nested_impl_trait, "1.24.0", Some(34511)),
(active, termination_trait, "1.24.0", Some(43301)),
(active, macro_lifetime_matcher, "1.24.0", Some(46895)),
(active, extern_in_paths, "1.23.0", Some(44660)),
(active, repr_transparent, "1.25.0", Some(43036)),
);
declare_features! (
(removed, import_shadowing, "1.0.0", None),
(removed, managed_boxes, "1.0.0", None),
(removed, negate_unsigned, "1.0.0", Some(29645)),
(removed, reflect, "1.0.0", Some(27749)),
(removed, opt_out_copy, "1.0.0", None),
(removed, quad_precision_float, "1.0.0", None),
(removed, struct_inherit, "1.0.0", None),
(removed, test_removed_feature, "1.0.0", None),
(removed, visible_private_types, "1.0.0", None),
(removed, unsafe_no_drop_flag, "1.0.0", None),
(removed, unmarked_api, "1.0.0", None),
(removed, pushpop_unsafe, "1.2.0", None),
(removed, allocator, "1.0.0", None),
(removed, simd, "1.0.0", Some(27731)),
);
declare_features! (
(stable_removed, no_stack_check, "1.0.0", None),
);
declare_features! (
(accepted, associated_types, "1.0.0", None),
(accepted, augmented_assignments, "1.8.0", Some(28235)),
(accepted, braced_empty_structs, "1.8.0", Some(29720)),
(accepted, default_type_params, "1.0.0", None),
(accepted, globs, "1.0.0", None),
(accepted, if_let, "1.0.0", None),
(accepted, issue_5723_bootstrap, "1.0.0", None),
(accepted, macro_rules, "1.0.0", None),
(accepted, no_std, "1.6.0", None),
(accepted, slicing_syntax, "1.0.0", None),
(accepted, struct_variant, "1.0.0", None),
(accepted, test_accepted_feature, "1.0.0", None),
(accepted, tuple_indexing, "1.0.0", None),
(accepted, type_macros, "1.13.0", Some(27245)),
(accepted, while_let, "1.0.0", None),
(accepted, deprecated, "1.9.0", Some(29935)),
(accepted, question_mark, "1.13.0", Some(31436)),
(accepted, dotdot_in_tuple_patterns, "1.14.0", Some(33627)),
(accepted, item_like_imports, "1.15.0", Some(35120)),
(accepted, more_struct_aliases, "1.16.0", Some(37544)),
(accepted, static_in_const, "1.17.0", Some(35897)),
(accepted, field_init_shorthand, "1.17.0", Some(37340)),
(accepted, static_recursion, "1.17.0", Some(29719)),
(accepted, pub_restricted, "1.18.0", Some(32409)),
(accepted, windows_subsystem, "1.18.0", Some(37499)),
(accepted, loop_break_value, "1.19.0", Some(37339)),
(accepted, relaxed_adts, "1.19.0", Some(35626)),
(accepted, closure_to_fn_coercion, "1.19.0", Some(39817)),
(accepted, struct_field_attributes, "1.20.0", Some(38814)),
(accepted, associated_consts, "1.20.0", Some(29646)),
(accepted, compile_error, "1.20.0", Some(40872)),
(accepted, rvalue_static_promotion, "1.21.0", Some(38865)),
(accepted, drop_types_in_const, "1.22.0", Some(33156)),
(accepted, abi_sysv64, "1.24.0", Some(36167)),
(accepted, repr_align, "1.24.0", Some(33626)),
(accepted, match_beginning_vert, "1.25.0", Some(44101)),
(accepted, use_nested_groups, "1.25.0", Some(44494)),
);
#[derive(PartialEq, Copy, Clone, Debug)]
pub enum AttributeType {
Normal,
Whitelisted,
CrateLevel,
}
pub enum AttributeGate {
Gated(Stability, &'static str, &'static str, fn(&Features) -> bool),
Ungated,
}
impl AttributeGate {
fn is_deprecated(&self) -> bool {
match *self {
Gated(Stability::Deprecated(_), ..) => true,
_ => false,
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Stability {
Unstable,
Deprecated(&'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 (&'static str, AttributeType, AttributeGate)> {
BUILTIN_ATTRIBUTES.iter().filter(|a| a.2.is_deprecated()).collect()
}
pub fn is_builtin_attr(attr: &ast::Attribute) -> bool {
BUILTIN_ATTRIBUTES.iter().any(|&(builtin_name, _, _)| attr.check_name(builtin_name))
}
pub const BUILTIN_ATTRIBUTES: &'static [(&'static str, AttributeType, AttributeGate)] = &[
("warn", Normal, Ungated),
("allow", Normal, Ungated),
("forbid", Normal, Ungated),
("deny", Normal, Ungated),
("macro_reexport", Normal, Ungated),
("macro_use", Normal, Ungated),
("macro_export", Normal, Ungated),
("plugin_registrar", Normal, Ungated),
("cfg", Normal, Ungated),
("cfg_attr", Normal, Ungated),
("main", Normal, Ungated),
("start", Normal, Ungated),
("test", Normal, Ungated),
("bench", Normal, Ungated),
("repr", Normal, Ungated),
("path", Normal, Ungated),
("abi", Normal, Ungated),
("automatically_derived", Normal, Ungated),
("no_mangle", Normal, Ungated),
("no_link", Normal, Ungated),
("derive", Normal, Ungated),
("should_panic", Normal, Ungated),
("ignore", Normal, Ungated),
("no_implicit_prelude", Normal, Ungated),
("reexport_test_harness_main", Normal, Ungated),
("link_args", Normal, Gated(Stability::Unstable,
"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))),
("macro_escape", Normal, Ungated),
("structural_match", Whitelisted, Gated(Stability::Unstable,
"structural_match",
"the semantics of constant patterns is \
not yet settled",
cfg_fn!(structural_match))),
("non_exhaustive", Whitelisted, Gated(Stability::Unstable,
"non_exhaustive",
"non exhaustive is an experimental feature",
cfg_fn!(non_exhaustive))),
("plugin", CrateLevel, Gated(Stability::Unstable,
"plugin",
"compiler plugins are experimental \
and possibly buggy",
cfg_fn!(plugin))),
("no_std", CrateLevel, Ungated),
("no_core", CrateLevel, Gated(Stability::Unstable,
"no_core",
"no_core is experimental",
cfg_fn!(no_core))),
("lang", Normal, Gated(Stability::Unstable,
"lang_items",
"language items are subject to change",
cfg_fn!(lang_items))),
("linkage", Whitelisted, Gated(Stability::Unstable,
"linkage",
"the `linkage` attribute is experimental \
and not portable across platforms",
cfg_fn!(linkage))),
("thread_local", Whitelisted, Gated(Stability::Unstable,
"thread_local",
"`#[thread_local]` is an experimental feature, and does \
not currently handle destructors.",
cfg_fn!(thread_local))),
("rustc_on_unimplemented", Normal, Gated(Stability::Unstable,
"on_unimplemented",
"the `#[rustc_on_unimplemented]` attribute \
is an experimental feature",
cfg_fn!(on_unimplemented))),
("rustc_const_unstable", Normal, Gated(Stability::Unstable,
"rustc_const_unstable",
"the `#[rustc_const_unstable]` attribute \
is an internal feature",
cfg_fn!(rustc_const_unstable))),
("global_allocator", Normal, Gated(Stability::Unstable,
"global_allocator",
"the `#[global_allocator]` attribute is \
an experimental feature",
cfg_fn!(global_allocator))),
("default_lib_allocator", Whitelisted, Gated(Stability::Unstable,
"allocator_internals",
"the `#[default_lib_allocator]` \
attribute is an experimental feature",
cfg_fn!(allocator_internals))),
("needs_allocator", Normal, Gated(Stability::Unstable,
"allocator_internals",
"the `#[needs_allocator]` \
attribute is an experimental \
feature",
cfg_fn!(allocator_internals))),
("panic_runtime", Whitelisted, Gated(Stability::Unstable,
"panic_runtime",
"the `#[panic_runtime]` attribute is \
an experimental feature",
cfg_fn!(panic_runtime))),
("needs_panic_runtime", Whitelisted, Gated(Stability::Unstable,
"needs_panic_runtime",
"the `#[needs_panic_runtime]` \
attribute is an experimental \
feature",
cfg_fn!(needs_panic_runtime))),
("rustc_variance", Normal, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_variance]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_regions", Normal, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_regions]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_error", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_error]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_if_this_changed", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_if_this_changed]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_then_this_would_need", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_if_this_changed]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_dirty", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_dirty]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_clean", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_clean]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_partition_reused", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_partition_translated", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_serialize_exclude_null", Normal, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_serialize_exclude_null]` attribute \
is an internal-only feature",
cfg_fn!(rustc_attrs))),
("rustc_synthetic", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"this attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_symbol_name", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"internal rustc attributes will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_item_path", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"internal rustc attributes will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_mir", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_mir]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_inherit_overflow_checks", Whitelisted, Gated(Stability::Unstable,
"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))),
("nll", Whitelisted, Gated(Stability::Unstable,
"nll",
"Non lexical lifetimes",
cfg_fn!(nll))),
("compiler_builtins", Whitelisted, Gated(Stability::Unstable,
"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))),
("sanitizer_runtime", Whitelisted, Gated(Stability::Unstable,
"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))),
("profiler_runtime", Whitelisted, Gated(Stability::Unstable,
"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))),
("allow_internal_unstable", Normal, Gated(Stability::Unstable,
"allow_internal_unstable",
EXPLAIN_ALLOW_INTERNAL_UNSTABLE,
cfg_fn!(allow_internal_unstable))),
("allow_internal_unsafe", Normal, Gated(Stability::Unstable,
"allow_internal_unsafe",
EXPLAIN_ALLOW_INTERNAL_UNSAFE,
cfg_fn!(allow_internal_unsafe))),
("fundamental", Whitelisted, Gated(Stability::Unstable,
"fundamental",
"the `#[fundamental]` attribute \
is an experimental feature",
cfg_fn!(fundamental))),
("proc_macro_derive", Normal, Ungated),
("rustc_copy_clone_marker", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"internal implementation detail",
cfg_fn!(rustc_attrs))),
("doc", Whitelisted, Ungated),
("cold", Whitelisted, Ungated),
("naked", Whitelisted, Gated(Stability::Unstable,
"naked_functions",
"the `#[naked]` attribute \
is an experimental feature",
cfg_fn!(naked_functions))),
("target_feature", Whitelisted, Gated(
Stability::Unstable, "target_feature",
"the `#[target_feature]` attribute is an experimental feature",
cfg_fn!(target_feature))),
("export_name", Whitelisted, Ungated),
("inline", Whitelisted, Ungated),
("link", Whitelisted, Ungated),
("link_name", Whitelisted, Ungated),
("link_section", Whitelisted, Ungated),
("no_builtins", Whitelisted, Ungated),
("no_mangle", Whitelisted, Ungated),
("no_debug", Whitelisted, Gated(
Stability::Deprecated("https://github.com/rust-lang/rust/issues/29721"),
"no_debug",
"the `#[no_debug]` attribute was an experimental feature that has been \
deprecated due to lack of demand",
cfg_fn!(no_debug))),
("omit_gdb_pretty_printer_section", Whitelisted, Gated(Stability::Unstable,
"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))),
("unsafe_destructor_blind_to_params",
Normal,
Gated(Stability::Deprecated("https://github.com/rust-lang/rust/issues/34761"),
"dropck_parametricity",
"unsafe_destructor_blind_to_params has been replaced by \
may_dangle and will be removed in the future",
cfg_fn!(dropck_parametricity))),
("may_dangle",
Normal,
Gated(Stability::Unstable,
"dropck_eyepatch",
"may_dangle has unstable semantics and may be removed in the future",
cfg_fn!(dropck_eyepatch))),
("unwind", Whitelisted, Gated(Stability::Unstable,
"unwind_attributes",
"#[unwind] is experimental",
cfg_fn!(unwind_attributes))),
("used", Whitelisted, Gated(
Stability::Unstable, "used",
"the `#[used]` attribute is an experimental feature",
cfg_fn!(used))),
("prelude_import", Whitelisted, Gated(Stability::Unstable,
"prelude_import",
"`#[prelude_import]` is for use by rustc only",
cfg_fn!(prelude_import))),
("rustc_deprecated", Whitelisted, Ungated),
("must_use", Whitelisted, Ungated),
("stable", Whitelisted, Ungated),
("unstable", Whitelisted, Ungated),
("deprecated", Normal, Ungated),
("rustc_paren_sugar", Normal, Gated(Stability::Unstable,
"unboxed_closures",
"unboxed_closures are still evolving",
cfg_fn!(unboxed_closures))),
("windows_subsystem", Whitelisted, Ungated),
("proc_macro_attribute", Normal, Gated(Stability::Unstable,
"proc_macro",
"attribute proc macros are currently unstable",
cfg_fn!(proc_macro))),
("proc_macro", Normal, Gated(Stability::Unstable,
"proc_macro",
"function-like proc macros are currently unstable",
cfg_fn!(proc_macro))),
("rustc_derive_registrar", Normal, Gated(Stability::Unstable,
"rustc_derive_registrar",
"used internally by rustc",
cfg_fn!(rustc_attrs))),
("allow_fail", Normal, Gated(Stability::Unstable,
"allow_fail",
"allow_fail attribute is currently unstable",
cfg_fn!(allow_fail))),
("rustc_std_internal_symbol", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"this is an internal attribute that will \
never be stable",
cfg_fn!(rustc_attrs))),
("rustc_conversion_suggestion", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"this is an internal attribute that will \
never be stable",
cfg_fn!(rustc_attrs))),
("wasm_import_memory", Whitelisted, Gated(Stability::Unstable,
"wasm_import_memory",
"wasm_import_memory attribute is currently unstable",
cfg_fn!(wasm_import_memory))),
("rustc_args_required_const", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"never will be stable",
cfg_fn!(rustc_attrs))),
("crate_name", CrateLevel, Ungated),
("crate_type", CrateLevel, Ungated),
("crate_id", CrateLevel, Ungated),
("feature", CrateLevel, Ungated),
("no_start", CrateLevel, Ungated),
("no_main", CrateLevel, Ungated),
("no_builtins", CrateLevel, Ungated),
("recursion_limit", CrateLevel, Ungated),
("type_length_limit", CrateLevel, Ungated),
];
const GATED_CFGS: &[(&str, &str, fn(&Features) -> bool)] = &[
("target_feature", "cfg_target_feature", cfg_fn!(cfg_target_feature)),
("target_vendor", "cfg_target_vendor", cfg_fn!(cfg_target_vendor)),
("target_thread_local", "cfg_target_thread_local", cfg_fn!(cfg_target_thread_local)),
("target_has_atomic", "cfg_target_has_atomic", cfg_fn!(cfg_target_has_atomic)),
];
#[derive(Debug, Eq, PartialEq)]
pub struct GatedCfg {
span: Span,
index: usize,
}
impl GatedCfg {
pub fn gate(cfg: &ast::MetaItem) -> Option<GatedCfg> {
let name = cfg.name().as_str();
GATED_CFGS.iter()
.position(|info| info.0 == name)
.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() {
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 [(String, 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() {
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, $span,
stringify!($feature), $explain, GateStrength::Hard)
};
($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => {
gate_feature_fn!($cx, |x:&Features| x.$feature, $span,
stringify!($feature), $explain, $level)
};
}
impl<'a> Context<'a> {
fn check_attribute(&self, attr: &ast::Attribute, is_macro: bool) {
debug!("check_attribute(attr = {:?})", attr);
let name = unwrap_or!(attr.name(), return).as_str();
for &(n, ty, ref gateage) in BUILTIN_ATTRIBUTES {
if name == n {
if let Gated(_, name, desc, ref has_feature) = *gateage {
gate_feature_fn!(self, has_feature, attr.span, name, desc, GateStrength::Hard);
} else if name == "doc" {
if let Some(content) = attr.meta_item_list() {
if content.iter().any(|c| c.check_name("include")) {
gate_feature!(self, external_doc, attr.span,
"#[doc(include = \"...\")] is experimental"
);
}
}
}
debug!("check_attribute: {:?} is builtin, {:?}, {:?}", attr.path, ty, gateage);
return;
}
}
for &(ref n, ref ty) in self.plugin_attributes {
if attr.path == &**n {
debug!("check_attribute: {:?} is registered by a plugin, {:?}", attr.path, ty);
return;
}
}
if name.starts_with("rustc_") {
gate_feature!(self, rustc_attrs, attr.span,
"unless otherwise specified, attributes \
with the prefix `rustc_` \
are reserved for internal compiler diagnostics");
} else if name.starts_with("derive_") {
gate_feature!(self, custom_derive, attr.span, EXPLAIN_DERIVE_UNDERSCORE);
} else if !attr::is_known(attr) {
if !is_macro {
gate_feature!(self, custom_attribute, attr.span,
&format!("The attribute `{}` is currently \
unknown to the compiler and \
may have meaning \
added to it in the future",
attr.path));
}
}
}
}
pub fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) {
let cx = Context { features: features, parse_sess: parse_sess, plugin_attributes: &[] };
cx.check_attribute(attr, true);
}
pub fn find_lang_feature_accepted_version(feature: &str) -> Option<&'static str> {
ACCEPTED_FEATURES.iter().find(|t| t.0 == feature).map(|t| t.1)
}
fn find_lang_feature_issue(feature: &str) -> 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, Eq)]
pub enum GateStrength {
Hard,
Soft,
}
pub fn emit_feature_err(sess: &ParseSess, feature: &str, span: Span, issue: GateIssue,
explain: &str) {
feature_err(sess, feature, span, issue, explain).emit();
}
pub fn feature_err<'a>(sess: &'a ParseSess, feature: &str, span: Span, issue: GateIssue,
explain: &str) -> DiagnosticBuilder<'a> {
leveled_feature_err(sess, feature, span, issue, explain, GateStrength::Hard)
}
fn leveled_feature_err<'a>(sess: &'a ParseSess, feature: &str, span: Span, 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 explanation = if let Some(n) = issue {
format!("{} (see issue #{})", explain, n)
} else {
explain.to_owned()
};
let mut err = match level {
GateStrength::Hard => {
diag.struct_span_err_with_code(span, &explanation, stringify_error_code!(E0658))
}
GateStrength::Soft => diag.struct_span_warn(span, &explanation),
};
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: &'static str =
"box expression syntax is experimental; you can call `Box::new` instead.";
pub const EXPLAIN_STMT_ATTR_SYNTAX: &'static str =
"attributes on non-item statements and expressions are experimental.";
pub const EXPLAIN_ASM: &'static str =
"inline assembly is not stable enough for use and is subject to change";
pub const EXPLAIN_GLOBAL_ASM: &'static str =
"`global_asm!` is not stable enough for use and is subject to change";
pub const EXPLAIN_LOG_SYNTAX: &'static str =
"`log_syntax!` is not stable enough for use and is subject to change";
pub const EXPLAIN_CONCAT_IDENTS: &'static str =
"`concat_idents` is not stable enough for use and is subject to change";
pub const EXPLAIN_TRACE_MACROS: &'static str =
"`trace_macros` is not stable enough for use and is subject to change";
pub const EXPLAIN_ALLOW_INTERNAL_UNSTABLE: &'static str =
"allow_internal_unstable side-steps feature gating and stability checks";
pub const EXPLAIN_ALLOW_INTERNAL_UNSAFE: &'static str =
"allow_internal_unsafe side-steps the unsafe_code lint";
pub const EXPLAIN_CUSTOM_DERIVE: &'static str =
"`#[derive]` for custom traits is deprecated and will be removed in the future.";
pub const EXPLAIN_DEPR_CUSTOM_DERIVE: &'static str =
"`#[derive]` for custom traits is deprecated and will be removed in the future. \
Prefer using procedural macro custom derive.";
pub const EXPLAIN_DERIVE_UNDERSCORE: &'static str =
"attributes of the form `#[derive_*]` are reserved for the compiler";
pub const EXPLAIN_VIS_MATCHER: &'static str =
":vis fragment specifier is experimental and subject to change";
pub const EXPLAIN_LIFETIME_MATCHER: &'static str =
":lifetime fragment specifier is experimental and subject to change";
pub const EXPLAIN_PLACEMENT_IN: &'static str =
"placement-in expression syntax is experimental and subject to change.";
pub const EXPLAIN_UNSIZED_TUPLE_COERCION: &'static str =
"Unsized tuple coercion is not stable enough for use and is subject to change";
struct PostExpansionVisitor<'a> {
context: &'a Context<'a>,
}
macro_rules! gate_feature_post {
($cx: expr, $feature: ident, $span: expr, $explain: expr) => {{
let (cx, span) = ($cx, $span);
if !span.allows_unstable() {
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() {
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::Cdecl |
Abi::Stdcall |
Abi::Fastcall |
Abi::Aapcs |
Abi::Win64 |
Abi::SysV64 |
Abi::Rust |
Abi::C |
Abi::System => {}
}
}
}
fn contains_novel_literal(item: &ast::MetaItem) -> bool {
use ast::MetaItemKind::*;
use ast::NestedMetaItemKind::*;
match item.node {
Word => false,
NameValue(ref lit) => !lit.node.is_str(),
List(ref list) => list.iter().any(|li| {
match li.node {
MetaItem(ref mi) => contains_novel_literal(mi),
Literal(_) => true,
}
}),
}
}
struct NestedImplTraitVisitor<'a> {
context: &'a Context<'a>,
is_in_impl_trait: bool,
}
impl<'a> NestedImplTraitVisitor<'a> {
fn with_impl_trait<F>(&mut self, is_in_impl_trait: bool, f: F)
where F: FnOnce(&mut NestedImplTraitVisitor<'a>)
{
let old_is_in_impl_trait = self.is_in_impl_trait;
self.is_in_impl_trait = is_in_impl_trait;
f(self);
self.is_in_impl_trait = old_is_in_impl_trait;
}
}
impl<'a> Visitor<'a> for NestedImplTraitVisitor<'a> {
fn visit_ty(&mut self, t: &'a ast::Ty) {
if let ast::TyKind::ImplTrait(_) = t.node {
if self.is_in_impl_trait {
gate_feature_post!(&self, nested_impl_trait, t.span,
"nested `impl Trait` is experimental"
);
}
self.with_impl_trait(true, |this| visit::walk_ty(this, t));
} else {
visit::walk_ty(self, t);
}
}
fn visit_path_parameters(&mut self, _: Span, path_parameters: &'a ast::PathParameters) {
match *path_parameters {
ast::PathParameters::AngleBracketed(ref params) => {
for type_ in ¶ms.types {
self.visit_ty(type_);
}
for type_binding in ¶ms.bindings {
self.with_impl_trait(false, |this| visit::walk_ty(this, &type_binding.ty));
}
}
ast::PathParameters::Parenthesized(ref params) => {
for type_ in ¶ms.inputs {
self.visit_ty(type_);
}
if let Some(ref type_) = params.output {
self.with_impl_trait(false, |this| visit::walk_ty(this, type_));
}
}
}
}
}
impl<'a> PostExpansionVisitor<'a> {
fn whole_crate_feature_gates(&mut self, krate: &ast::Crate) {
visit::walk_crate(
&mut NestedImplTraitVisitor {
context: self.context,
is_in_impl_trait: false,
}, krate);
for &(ident, span) in &*self.context.parse_sess.non_modrs_mods.borrow() {
if !span.allows_unstable() {
let cx = &self.context;
let level = GateStrength::Hard;
let has_feature = cx.features.non_modrs_mods;
let name = "non_modrs_mods";
debug!("gate_feature(feature = {:?}, span = {:?}); has? {}",
name, span, has_feature);
if !has_feature && !span.allows_unstable() {
leveled_feature_err(
cx.parse_sess, name, span, GateIssue::Language,
"mod statements in non-mod.rs files are unstable", level
)
.help(&format!("on stable builds, rename this file to {}{}mod.rs",
ident, path::MAIN_SEPARATOR))
.emit();
}
}
}
}
}
impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
fn visit_attribute(&mut self, attr: &ast::Attribute) {
if !attr.span.allows_unstable() {
self.context.check_attribute(attr, false);
}
if attr.check_name("doc") {
if let Some(content) = attr.meta_item_list() {
if content.len() == 1 && content[0].check_name("cfg") {
gate_feature_post!(&self, doc_cfg, attr.span,
"#[doc(cfg(...))] is experimental"
);
} else if content.iter().any(|c| c.check_name("masked")) {
gate_feature_post!(&self, doc_masked, attr.span,
"#[doc(masked)] is experimental"
);
} else if content.iter().any(|c| c.check_name("spotlight")) {
gate_feature_post!(&self, doc_spotlight, attr.span,
"#[doc(spotlight)] is experimental"
);
}
}
}
let mut is_repr_align = false;
if attr.path == "repr" {
if let Some(content) = attr.meta_item_list() {
is_repr_align = content.iter().any(|c| c.check_name("align"));
}
}
if self.context.features.proc_macro && attr::is_known(attr) {
return
}
if !is_repr_align {
let meta = panictry!(attr.parse_meta(self.context.parse_sess));
if contains_novel_literal(&meta) {
gate_feature_post!(&self, attr_literals, attr.span,
"non-string literals in attributes, or string \
literals in top-level positions, are experimental");
}
}
}
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.codemap().def_span(sp),
"non-ascii idents are not fully supported.");
}
}
fn visit_item(&mut self, i: &'a ast::Item) {
match i.node {
ast::ItemKind::ExternCrate(_) => {
if let Some(attr) = attr::find_by_name(&i.attrs[..], "macro_reexport") {
gate_feature_post!(&self, macro_reexport, attr.span,
"macros re-exports are experimental \
and possibly buggy");
}
}
ast::ItemKind::ForeignMod(ref foreign_module) => {
self.check_abi(foreign_module.abi, i.span);
}
ast::ItemKind::Fn(..) => {
if attr::contains_name(&i.attrs[..], "plugin_registrar") {
gate_feature_post!(&self, plugin_registrar, i.span,
"compiler plugins are experimental and possibly buggy");
}
if attr::contains_name(&i.attrs[..], "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[..], "main") {
gate_feature_post!(&self, main, i.span,
"declaration of a nonstandard #[main] \
function may change over time, for now \
a top-level `fn main()` is required");
}
if let Some(attr) = attr::find_by_name(&i.attrs[..], "must_use") {
gate_feature_post!(&self, fn_must_use, attr.span,
"`#[must_use]` on functions is experimental",
GateStrength::Soft);
}
}
ast::ItemKind::Struct(..) => {
if let Some(attr) = attr::find_by_name(&i.attrs[..], "repr") {
for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
if item.check_name("simd") {
gate_feature_post!(&self, repr_simd, attr.span,
"SIMD types are experimental and possibly buggy");
}
if item.check_name("transparent") {
gate_feature_post!(&self, repr_transparent, attr.span,
"the `#[repr(transparent)]` attribute \
is experimental");
}
}
}
}
ast::ItemKind::TraitAlias(..) => {
gate_feature_post!(&self, trait_alias,
i.span,
"trait aliases are not yet fully implemented");
}
ast::ItemKind::Impl(_, polarity, defaultness, _, _, _, ref impl_items) => {
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");
}
for impl_item in impl_items {
if let ast::ImplItemKind::Method(..) = impl_item.node {
if let Some(attr) = attr::find_by_name(&impl_item.attrs[..], "must_use") {
gate_feature_post!(&self, fn_must_use, attr.span,
"`#[must_use]` on methods is experimental",
GateStrength::Soft);
}
}
}
}
ast::ItemKind::Trait(ast::IsAuto::Yes, ..) => {
gate_feature_post!(&self, optin_builtin_traits,
i.span,
"auto traits are experimental and possibly buggy");
}
ast::ItemKind::MacroDef(ast::MacroDef { legacy: false, .. }) => {
let msg = "`macro` is experimental";
gate_feature_post!(&self, decl_macro, i.span, msg);
}
_ => {}
}
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, "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");
}
}
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");
},
ast::TyKind::TraitObject(_, ast::TraitObjectSyntax::Dyn) => {
gate_feature_post!(&self, dyn_trait, ty.span,
"`dyn Trait` syntax is unstable");
}
_ => {}
}
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 output_ty.node != ast::TyKind::Never {
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(..) => {
gate_feature_post!(&self, type_ascription, e.span,
"type ascription is experimental");
}
ast::ExprKind::Range(_, _, ast::RangeLimits::Closed) => {
gate_feature_post!(&self, inclusive_range_syntax,
e.span,
"inclusive range syntax is experimental");
}
ast::ExprKind::InPlace(..) => {
gate_feature_post!(&self, placement_in_syntax, e.span, EXPLAIN_PLACEMENT_IN);
}
ast::ExprKind::Yield(..) => {
gate_feature_post!(&self, generators,
e.span,
"yield syntax is experimental");
}
ast::ExprKind::Lit(ref lit) => {
if let ast::LitKind::Int(_, ref ty) = lit.node {
match *ty {
ast::LitIntType::Signed(ast::IntTy::I128) |
ast::LitIntType::Unsigned(ast::UintTy::U128) => {
gate_feature_post!(&self, i128_type, e.span,
"128-bit integers are not stable");
}
_ => {}
}
}
}
ast::ExprKind::Catch(_) => {
gate_feature_post!(&self, catch_expr, e.span, "`catch` expression is experimental");
}
_ => {}
}
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(_, Some(_), ref last) if !last.is_empty() => {
gate_feature_post!(&self, advanced_slice_patterns,
pattern.span,
"multiple-element slice matches anywhere \
but at the end of a slice (e.g. \
`[0, ..xs, 0]`) are experimental")
}
PatKind::Slice(..) => {
gate_feature_post!(&self, slice_patterns,
pattern.span,
"slice pattern syntax is experimental");
}
PatKind::Box(..) => {
gate_feature_post!(&self, box_patterns,
pattern.span,
"box pattern syntax is experimental");
}
PatKind::Range(_, _, RangeEnd::Excluded) => {
gate_feature_post!(&self, exclusive_range_pattern, pattern.span,
"exclusive range pattern syntax is experimental");
}
PatKind::Range(_, _, RangeEnd::Included(RangeSyntax::DotDotEq)) => {
gate_feature_post!(&self, dotdoteq_in_patterns, pattern.span,
"`..=` syntax in patterns 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 FnKind::ItemFn(_, _, Spanned { node: ast::Constness::Const, .. }, _, _, _) =
fn_kind {
gate_feature_post!(&self, const_fn, span, "const fn is unstable");
}
match fn_kind {
FnKind::ItemFn(_, _, _, abi, _, _) |
FnKind::Method(_, &ast::MethodSig { abi, .. }, _, _) => {
self.check_abi(abi, span);
}
_ => {}
}
visit::walk_fn(self, fn_kind, fn_decl, span);
}
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.abi, ti.span);
}
if sig.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.is_parameterized() {
gate_feature_post!(&self, generic_associated_types, ti.span,
"generic 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(ref sig, _) => {
if sig.constness.node == ast::Constness::Const {
gate_feature_post!(&self, const_fn, ii.span, "const fn is unstable");
}
}
ast::ImplItemKind::Type(_) if ii.generics.is_parameterized() => {
gate_feature_post!(&self, generic_associated_types, ii.span,
"generic associated types are unstable");
}
_ => {}
}
visit::walk_impl_item(self, ii);
}
fn visit_path(&mut self, path: &'a ast::Path, _id: NodeId) {
for segment in &path.segments {
if segment.identifier.name == keywords::Crate.name() {
gate_feature_post!(&self, crate_in_paths, segment.span,
"`crate` in paths is experimental");
} else if segment.identifier.name == keywords::Extern.name() {
gate_feature_post!(&self, extern_in_paths, segment.span,
"`extern` in paths is experimental");
}
}
visit::walk_path(self, path);
}
fn visit_vis(&mut self, vis: &'a ast::Visibility) {
if let ast::Visibility::Crate(span, ast::CrateSugar::JustCrate) = *vis {
gate_feature_post!(&self, crate_visibility_modifier, span,
"`crate` visibility modifier is experimental");
}
visit::walk_vis(self, vis);
}
fn visit_generic_param(&mut self, param: &'a ast::GenericParam) {
let (attrs, explain) = match *param {
ast::GenericParam::Lifetime(ref ld) =>
(&ld.attrs, "attributes on lifetime bindings are experimental"),
ast::GenericParam::Type(ref t) =>
(&t.attrs, "attributes on type parameter bindings are experimental"),
};
if !attrs.is_empty() {
gate_feature_post!(&self, generic_param_attrs, attrs[0].span, explain);
}
visit::walk_generic_param(self, param)
}
fn visit_lifetime(&mut self, lt: &'a ast::Lifetime) {
if lt.ident.name == "'_" {
gate_feature_post!(&self, underscore_lifetimes, lt.span,
"underscore lifetimes are unstable");
}
visit::walk_lifetime(self, lt)
}
}
pub fn get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute]) -> Features {
let mut features = Features::new();
let mut feature_checker = FeatureChecker::default();
for attr in krate_attrs {
if !attr.check_name("feature") {
continue
}
match attr.meta_item_list() {
None => {
span_err!(span_handler, attr.span, E0555,
"malformed feature attribute, expected #![feature(...)]");
}
Some(list) => {
for mi in list {
let name = if let Some(word) = mi.word() {
word.name()
} else {
span_err!(span_handler, mi.span, E0556,
"malformed feature, expected just one word");
continue
};
if let Some(&(_, _, _, set)) = ACTIVE_FEATURES.iter()
.find(|& &(n, _, _, _)| name == n) {
set(&mut features, mi.span);
feature_checker.collect(&features, mi.span);
}
else if let Some(&(_, _, _)) = REMOVED_FEATURES.iter()
.find(|& &(n, _, _)| name == n)
.or_else(|| STABLE_REMOVED_FEATURES.iter()
.find(|& &(n, _, _)| name == n)) {
span_err!(span_handler, mi.span, E0557, "feature has been removed");
}
else if let Some(&(_, _, _)) = ACCEPTED_FEATURES.iter()
.find(|& &(n, _, _)| name == n) {
features.declared_stable_lang_features.push((name, mi.span));
} else {
features.declared_lib_features.push((name, mi.span));
}
}
}
}
}
feature_checker.check(span_handler);
features
}
#[derive(Default)]
struct FeatureChecker {
proc_macro: Option<Span>,
custom_attribute: Option<Span>,
copy_closures: Option<Span>,
clone_closures: Option<Span>,
}
impl FeatureChecker {
fn collect(&mut self, features: &Features, span: Span) {
if features.proc_macro {
self.proc_macro = self.proc_macro.or(Some(span));
}
if features.custom_attribute {
self.custom_attribute = self.custom_attribute.or(Some(span));
}
if features.copy_closures {
self.copy_closures = self.copy_closures.or(Some(span));
}
if features.clone_closures {
self.clone_closures = self.clone_closures.or(Some(span));
}
}
fn check(self, handler: &Handler) {
if let (Some(pm_span), Some(ca_span)) = (self.proc_macro, self.custom_attribute) {
handler.struct_span_err(pm_span, "Cannot use `#![feature(proc_macro)]` and \
`#![feature(custom_attribute)] at the same time")
.span_note(ca_span, "`#![feature(custom_attribute)]` declared here")
.emit();
FatalError.raise();
}
if let (Some(span), None) = (self.copy_closures, self.clone_closures) {
handler.struct_span_err(span, "`#![feature(copy_closures)]` can only be used with \
`#![feature(clone_closures)]`")
.span_note(span, "`#![feature(copy_closures)]` declared here")
.emit();
FatalError.raise();
}
}
}
pub fn check_crate(krate: &ast::Crate,
sess: &ParseSess,
features: &Features,
plugin_attributes: &[(String, AttributeType)],
unstable: UnstableFeatures) {
maybe_stage_features(&sess.span_diagnostic, krate, unstable);
let ctx = Context {
features,
parse_sess: sess,
plugin_attributes,
};
let visitor = &mut PostExpansionVisitor { context: &ctx };
visitor.whole_crate_feature_gates(krate);
visit::walk_crate(visitor, krate);
}
#[derive(Clone, Copy, PartialEq, Eq, 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("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);
}
}
}
}