use self::AttributeType::*;
use self::AttributeGate::*;
use abi::Abi;
use ast::{self, NodeId, PatKind, RangeEnd};
use attr;
use codemap::Spanned;
use syntax_pos::Span;
use errors::{DiagnosticBuilder, Handler, FatalError};
use visit::{self, FnKind, Visitor};
use parse::ParseSess;
use symbol::Symbol;
use std::ascii::AsciiExt;
use std::env;
macro_rules! setter {
($field: ident) => {{
fn f(features: &mut Features) -> &mut bool {
&mut features.$field
}
f as fn(&mut Features) -> &mut bool
}}
}
macro_rules! declare_features {
($((active, $feature: ident, $ver: expr, $issue: expr),)+) => {
const ACTIVE_FEATURES: &'static [(&'static str, &'static str,
Option<u32>, fn(&mut Features) -> &mut bool)] = &[
$((stringify!($feature), $ver, $issue, setter!($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, simd, "1.0.0", Some(27731)),
(active, rustc_diagnostic_macros, "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, allocator, "1.0.0", Some(27389)),
(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, allow_internal_unstable, "1.0.0", None),
(active, slice_patterns, "1.0.0", Some(23121)),
(active, associated_consts, "1.0.0", Some(29646)),
(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, drop_types_in_const, "1.9.0", Some(33156)),
(active, cfg_target_has_atomic, "1.9.0", Some(32976)),
(active, conservative_impl_trait, "1.12.0", Some(34511)),
(active, never_type, "1.13.0", Some(35121)),
(active, attr_literals, "1.13.0", Some(34981)),
(active, abi_sysv64, "1.13.0", Some(36167)),
(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, abi_unadjusted, "1.16.0", None),
(active, proc_macro, "1.16.0", Some(38356)),
(active, decl_macro, "1.17.0", Some(39412)),
(active, struct_field_attributes, "1.16.0", Some(38814)),
(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, abi_x86_interrupt, "1.17.0", Some(40180)),
(active, catch_expr, "1.17.0", Some(31436)),
(active, repr_align, "1.17.0", Some(33626)),
(active, rvalue_static_promotion, "1.15.1", Some(38865)),
(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),
);
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),
);
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)),
);
#[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),
("simd", 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, Ungated),
("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))),
("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. There is no \
corresponding `#[task_local]` mapping to the task \
model",
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))),
("allocator", Whitelisted, Gated(Stability::Unstable,
"allocator",
"the `#[allocator]` attribute is an experimental feature",
cfg_fn!(allocator))),
("needs_allocator", Normal, Gated(Stability::Unstable,
"needs_allocator",
"the `#[needs_allocator]` \
attribute is an experimental \
feature",
cfg_fn!(needs_allocator))),
("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_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_metadata_dirty", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_metadata_dirty]` attribute \
is just used for rustc unit tests \
and will never be stable",
cfg_fn!(rustc_attrs))),
("rustc_metadata_clean", Whitelisted, Gated(Stability::Unstable,
"rustc_attrs",
"the `#[rustc_metadata_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_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))),
("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))),
("allow_internal_unstable", Normal, Gated(Stability::Unstable,
"allow_internal_unstable",
EXPLAIN_ALLOW_INTERNAL_UNSTABLE,
cfg_fn!(allow_internal_unstable))),
("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 is an experimental feature",
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))),
("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, $explain: expr) => {{
let (cx, has_feature, span, name, explain) = ($cx, $has_feature, $span, $name, $explain);
let has_feature: bool = has_feature(&$cx.features);
debug!("gate_feature(feature = {:?}, span = {:?}); has? {}", name, span, has_feature);
if !has_feature && !span.allows_unstable() {
emit_feature_err(cx.parse_sess, name, span, GateIssue::Language, explain);
}
}}
}
macro_rules! gate_feature {
($cx: expr, $feature: ident, $span: expr, $explain: expr) => {
gate_feature_fn!($cx, |x:&Features| x.$feature, $span, stringify!($feature), $explain)
}
}
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);
}
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>)
}
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> {
let diag = &sess.span_diagnostic;
let issue = match issue {
GateIssue::Language => find_lang_feature_issue(feature),
GateIssue::Library(lib) => lib,
};
let mut err = if let Some(n) = issue {
diag.struct_span_err(span, &format!("{} (see issue #{})", explain, n))
} else {
diag.struct_span_err(span, explain)
};
if sess.unstable_features.is_nightly_build() {
err.help(&format!("add #![feature({})] to the \
crate attributes to enable",
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_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_PLACEMENT_IN: &'static str =
"placement-in expression syntax is experimental and 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)
}
}}
}
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::SysV64 => {
gate_feature_post!(&self, abi_sysv64, span,
"sysv64 ABI is experimental and 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::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,
}
}),
}
}
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 self.context.features.proc_macro && attr::is_known(attr) {
return
}
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, sp,
"non-ascii idents are not fully supported.");
}
}
fn visit_item(&mut self, i: &'a ast::Item) {
match i.node {
ast::ItemKind::ExternCrate(_) => {
if attr::contains_name(&i.attrs[..], "macro_reexport") {
gate_feature_post!(&self, macro_reexport, i.span,
"macros reexports are experimental \
and possibly buggy");
}
}
ast::ItemKind::ForeignMod(ref foreign_module) => {
if attr::contains_name(&i.attrs[..], "link_args") {
gate_feature_post!(&self, link_args, i.span,
"the `link_args` attribute is not portable \
across platforms, it is recommended to \
use `#[link(name = \"foo\")]` instead")
}
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");
}
}
ast::ItemKind::Struct(..) => {
if attr::contains_name(&i.attrs[..], "simd") {
gate_feature_post!(&self, simd, i.span,
"SIMD types are experimental and possibly buggy");
self.context.parse_sess.span_diagnostic.span_warn(i.span,
"the `#[simd]` attribute \
is deprecated, use \
`#[repr(simd)]` instead");
}
for attr in &i.attrs {
if attr.path == "repr" {
for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
if item.check_name("simd") {
gate_feature_post!(&self, repr_simd, i.span,
"SIMD types are experimental \
and possibly buggy");
}
if item.check_name("align") {
gate_feature_post!(&self, repr_align, i.span,
"the struct `#[repr(align(u16))]` attribute \
is experimental");
}
}
}
}
}
ast::ItemKind::DefaultImpl(..) => {
gate_feature_post!(&self, optin_builtin_traits,
i.span,
"default trait implementations are experimental \
and possibly buggy");
}
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::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) {
let links_to_llvm = match attr::first_attr_value_str_by_name(&i.attrs, "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");
}
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::ImplTrait(..) => {
gate_feature_post!(&self, conservative_impl_trait, ty.span,
"`impl Trait` is experimental");
}
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 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::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_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");
}
_ => {}
}
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::Const(..) => {
gate_feature_post!(&self, associated_consts,
ti.span,
"associated constants are experimental")
}
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(_, Some(_)) => {
gate_feature_post!(&self, associated_type_defaults, ti.span,
"associated type defaults 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::Const(..) => {
gate_feature_post!(&self, associated_consts,
ii.span,
"associated constants are experimental")
}
ast::ImplItemKind::Method(ref sig, _) => {
if sig.constness.node == ast::Constness::Const {
gate_feature_post!(&self, const_fn, ii.span, "const fn is unstable");
}
}
_ => {}
}
visit::walk_impl_item(self, ii);
}
fn visit_generics(&mut self, g: &'a ast::Generics) {
for t in &g.ty_params {
if !t.attrs.is_empty() {
gate_feature_post!(&self, generic_param_attrs, t.attrs[0].span,
"attributes on type parameter bindings are experimental");
}
}
visit::walk_generics(self, g)
}
fn visit_lifetime_def(&mut self, lifetime_def: &'a ast::LifetimeDef) {
if !lifetime_def.attrs.is_empty() {
gate_feature_post!(&self, generic_param_attrs, lifetime_def.attrs[0].span,
"attributes on lifetime bindings are experimental");
}
visit::walk_lifetime_def(self, lifetime_def)
}
}
pub fn get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute]) -> Features {
let mut features = Features::new();
let mut feature_checker = MutexFeatureChecker::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(&(_, _, _, setter)) = ACTIVE_FEATURES.iter()
.find(|& &(n, _, _, _)| name == n) {
*(setter(&mut features)) = true;
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 MutexFeatureChecker {
proc_macro: Option<Span>,
custom_attribute: Option<Span>,
}
impl MutexFeatureChecker {
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));
}
}
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();
panic!(FatalError);
}
}
}
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: features,
parse_sess: sess,
plugin_attributes: plugin_attributes,
};
visit::walk_crate(&mut PostExpansionVisitor { context: &ctx }, 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);
}
}
}
}