865 lines
32 KiB
Rust
865 lines
32 KiB
Rust
use super::{active::{ACTIVE_FEATURES, Features}, Feature, State as FeatureState};
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use super::accepted::ACCEPTED_FEATURES;
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use super::removed::{REMOVED_FEATURES, STABLE_REMOVED_FEATURES};
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use super::builtin_attrs::{AttributeGate, BUILTIN_ATTRIBUTE_MAP};
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use crate::ast::{self, NodeId, PatKind, VariantData};
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use crate::attr::{self, check_builtin_attribute};
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use crate::edition::{ALL_EDITIONS, Edition};
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use crate::visit::{self, FnKind, Visitor};
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use crate::parse::token;
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use crate::sess::ParseSess;
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use crate::symbol::{Symbol, sym};
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use crate::tokenstream::TokenTree;
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use errors::{Applicability, DiagnosticBuilder, Handler};
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use rustc_data_structures::fx::FxHashMap;
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use rustc_target::spec::abi::Abi;
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use syntax_pos::{Span, DUMMY_SP, MultiSpan};
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use log::debug;
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use std::env;
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#[derive(Copy, Clone, Debug)]
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pub enum Stability {
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Unstable,
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// First argument is tracking issue link; second argument is an optional
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// help message, which defaults to "remove this attribute"
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Deprecated(&'static str, Option<&'static str>),
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}
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macro_rules! gate_feature_fn {
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($cx: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr, $level: expr) => {{
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let (cx, has_feature, span,
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name, explain, level) = (&*$cx, $has_feature, $span, $name, $explain, $level);
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let has_feature: bool = has_feature(&$cx.features);
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debug!("gate_feature(feature = {:?}, span = {:?}); has? {}", name, span, has_feature);
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if !has_feature && !span.allows_unstable($name) {
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leveled_feature_err(cx.parse_sess, name, span, GateIssue::Language, explain, level)
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.emit();
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}
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}}
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}
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macro_rules! gate_feature {
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($cx: expr, $feature: ident, $span: expr, $explain: expr) => {
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gate_feature_fn!($cx, |x:&Features| x.$feature, $span,
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sym::$feature, $explain, GateStrength::Hard)
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};
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($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => {
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gate_feature_fn!($cx, |x:&Features| x.$feature, $span,
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sym::$feature, $explain, $level)
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};
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}
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pub fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) {
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PostExpansionVisitor { parse_sess, features }.visit_attribute(attr)
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}
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fn find_lang_feature_issue(feature: Symbol) -> Option<u32> {
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if let Some(info) = ACTIVE_FEATURES.iter().find(|t| t.name == feature) {
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// FIXME (#28244): enforce that active features have issue numbers
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// assert!(info.issue.is_some())
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info.issue
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} else {
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// search in Accepted, Removed, or Stable Removed features
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let found = ACCEPTED_FEATURES.iter().chain(REMOVED_FEATURES).chain(STABLE_REMOVED_FEATURES)
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.find(|t| t.name == feature);
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match found {
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Some(&Feature { issue, .. }) => issue,
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None => panic!("Feature `{}` is not declared anywhere", feature),
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}
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}
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}
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pub enum GateIssue {
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Language,
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Library(Option<u32>)
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}
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#[derive(Debug, Copy, Clone, PartialEq)]
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pub enum GateStrength {
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/// A hard error. (Most feature gates should use this.)
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Hard,
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/// Only a warning. (Use this only as backwards-compatibility demands.)
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Soft,
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}
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pub fn emit_feature_err(
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sess: &ParseSess,
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feature: Symbol,
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span: Span,
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issue: GateIssue,
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explain: &str,
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) {
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feature_err(sess, feature, span, issue, explain).emit();
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}
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pub fn feature_err<'a, S: Into<MultiSpan>>(
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sess: &'a ParseSess,
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feature: Symbol,
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span: S,
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issue: GateIssue,
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explain: &str,
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) -> DiagnosticBuilder<'a> {
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leveled_feature_err(sess, feature, span, issue, explain, GateStrength::Hard)
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}
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fn leveled_feature_err<'a, S: Into<MultiSpan>>(
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sess: &'a ParseSess,
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feature: Symbol,
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span: S,
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issue: GateIssue,
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explain: &str,
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level: GateStrength,
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) -> DiagnosticBuilder<'a> {
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let diag = &sess.span_diagnostic;
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let issue = match issue {
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GateIssue::Language => find_lang_feature_issue(feature),
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GateIssue::Library(lib) => lib,
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};
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let mut err = match level {
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GateStrength::Hard => {
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diag.struct_span_err_with_code(span, explain, stringify_error_code!(E0658))
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}
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GateStrength::Soft => diag.struct_span_warn(span, explain),
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};
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match issue {
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None | Some(0) => {} // We still accept `0` as a stand-in for backwards compatibility
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Some(n) => {
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err.note(&format!(
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"for more information, see https://github.com/rust-lang/rust/issues/{}",
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n,
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));
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}
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}
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// #23973: do not suggest `#![feature(...)]` if we are in beta/stable
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if sess.unstable_features.is_nightly_build() {
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err.help(&format!("add `#![feature({})]` to the crate attributes to enable", feature));
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}
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// If we're on stable and only emitting a "soft" warning, add a note to
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// clarify that the feature isn't "on" (rather than being on but
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// warning-worthy).
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if !sess.unstable_features.is_nightly_build() && level == GateStrength::Soft {
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err.help("a nightly build of the compiler is required to enable this feature");
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}
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err
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}
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pub const EXPLAIN_STMT_ATTR_SYNTAX: &str =
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"attributes on expressions are experimental";
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pub const EXPLAIN_ALLOW_INTERNAL_UNSTABLE: &str =
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"allow_internal_unstable side-steps feature gating and stability checks";
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pub const EXPLAIN_ALLOW_INTERNAL_UNSAFE: &str =
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"allow_internal_unsafe side-steps the unsafe_code lint";
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pub const EXPLAIN_UNSIZED_TUPLE_COERCION: &str =
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"unsized tuple coercion is not stable enough for use and is subject to change";
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struct PostExpansionVisitor<'a> {
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parse_sess: &'a ParseSess,
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features: &'a Features,
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}
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macro_rules! gate_feature_post {
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($cx: expr, $feature: ident, $span: expr, $explain: expr) => {{
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let (cx, span) = ($cx, $span);
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if !span.allows_unstable(sym::$feature) {
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gate_feature!(cx, $feature, span, $explain)
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}
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}};
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($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => {{
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let (cx, span) = ($cx, $span);
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if !span.allows_unstable(sym::$feature) {
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gate_feature!(cx, $feature, span, $explain, $level)
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}
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}}
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}
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impl<'a> PostExpansionVisitor<'a> {
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fn check_abi(&self, abi: Abi, span: Span) {
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match abi {
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Abi::RustIntrinsic => {
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gate_feature_post!(&self, intrinsics, span,
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"intrinsics are subject to change");
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},
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Abi::PlatformIntrinsic => {
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gate_feature_post!(&self, platform_intrinsics, span,
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"platform intrinsics are experimental and possibly buggy");
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},
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Abi::Vectorcall => {
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gate_feature_post!(&self, abi_vectorcall, span,
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"vectorcall is experimental and subject to change");
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},
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Abi::Thiscall => {
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gate_feature_post!(&self, abi_thiscall, span,
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"thiscall is experimental and subject to change");
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},
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Abi::RustCall => {
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gate_feature_post!(&self, unboxed_closures, span,
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"rust-call ABI is subject to change");
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},
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Abi::PtxKernel => {
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gate_feature_post!(&self, abi_ptx, span,
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"PTX ABIs are experimental and subject to change");
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},
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Abi::Unadjusted => {
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gate_feature_post!(&self, abi_unadjusted, span,
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"unadjusted ABI is an implementation detail and perma-unstable");
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},
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Abi::Msp430Interrupt => {
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gate_feature_post!(&self, abi_msp430_interrupt, span,
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"msp430-interrupt ABI is experimental and subject to change");
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},
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Abi::X86Interrupt => {
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gate_feature_post!(&self, abi_x86_interrupt, span,
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"x86-interrupt ABI is experimental and subject to change");
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},
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Abi::AmdGpuKernel => {
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gate_feature_post!(&self, abi_amdgpu_kernel, span,
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"amdgpu-kernel ABI is experimental and subject to change");
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},
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Abi::EfiApi => {
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gate_feature_post!(&self, abi_efiapi, span,
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"efiapi ABI is experimental and subject to change");
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},
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// Stable
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Abi::Cdecl |
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Abi::Stdcall |
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Abi::Fastcall |
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Abi::Aapcs |
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Abi::Win64 |
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Abi::SysV64 |
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Abi::Rust |
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Abi::C |
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Abi::System => {}
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}
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}
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fn maybe_report_invalid_custom_discriminants(&self, variants: &[ast::Variant]) {
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let has_fields = variants.iter().any(|variant| match variant.data {
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VariantData::Tuple(..) | VariantData::Struct(..) => true,
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VariantData::Unit(..) => false,
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});
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let discriminant_spans = variants.iter().filter(|variant| match variant.data {
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VariantData::Tuple(..) | VariantData::Struct(..) => false,
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VariantData::Unit(..) => true,
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})
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.filter_map(|variant| variant.disr_expr.as_ref().map(|c| c.value.span))
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.collect::<Vec<_>>();
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if !discriminant_spans.is_empty() && has_fields {
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let mut err = feature_err(
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self.parse_sess,
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sym::arbitrary_enum_discriminant,
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discriminant_spans.clone(),
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crate::feature_gate::GateIssue::Language,
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"custom discriminant values are not allowed in enums with tuple or struct variants",
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);
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for sp in discriminant_spans {
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err.span_label(sp, "disallowed custom discriminant");
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}
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for variant in variants.iter() {
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match &variant.data {
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VariantData::Struct(..) => {
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err.span_label(
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variant.span,
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"struct variant defined here",
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);
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}
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VariantData::Tuple(..) => {
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err.span_label(
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variant.span,
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"tuple variant defined here",
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);
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}
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VariantData::Unit(..) => {}
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}
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}
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err.emit();
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}
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}
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fn check_gat(&self, generics: &ast::Generics, span: Span) {
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if !generics.params.is_empty() {
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gate_feature_post!(
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&self,
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generic_associated_types,
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span,
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"generic associated types are unstable"
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);
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}
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if !generics.where_clause.predicates.is_empty() {
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gate_feature_post!(
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&self,
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generic_associated_types,
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span,
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"where clauses on associated types are unstable"
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);
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}
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}
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}
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impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
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fn visit_attribute(&mut self, attr: &ast::Attribute) {
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let attr_info =
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attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name)).map(|a| **a);
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// Check feature gates for built-in attributes.
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if let Some((.., AttributeGate::Gated(_, name, descr, has_feature))) = attr_info {
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gate_feature_fn!(self, has_feature, attr.span, name, descr, GateStrength::Hard);
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}
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// Check input tokens for built-in and key-value attributes.
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match attr_info {
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// `rustc_dummy` doesn't have any restrictions specific to built-in attributes.
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Some((name, _, template, _)) if name != sym::rustc_dummy =>
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check_builtin_attribute(self.parse_sess, attr, name, template),
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_ => if let Some(TokenTree::Token(token)) = attr.tokens.trees().next() {
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if token == token::Eq {
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// All key-value attributes are restricted to meta-item syntax.
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attr.parse_meta(self.parse_sess).map_err(|mut err| err.emit()).ok();
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}
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}
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}
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// Check unstable flavors of the `#[doc]` attribute.
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if attr.check_name(sym::doc) {
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for nested_meta in attr.meta_item_list().unwrap_or_default() {
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macro_rules! gate_doc { ($($name:ident => $feature:ident)*) => {
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$(if nested_meta.check_name(sym::$name) {
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let msg = concat!("`#[doc(", stringify!($name), ")]` is experimental");
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gate_feature!(self, $feature, attr.span, msg);
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})*
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}}
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gate_doc!(
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include => external_doc
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cfg => doc_cfg
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masked => doc_masked
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spotlight => doc_spotlight
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alias => doc_alias
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keyword => doc_keyword
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);
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}
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}
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}
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fn visit_name(&mut self, sp: Span, name: ast::Name) {
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if !name.as_str().is_ascii() {
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gate_feature_post!(
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&self,
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non_ascii_idents,
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self.parse_sess.source_map().def_span(sp),
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"non-ascii idents are not fully supported"
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);
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}
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}
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fn visit_item(&mut self, i: &'a ast::Item) {
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match i.kind {
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ast::ItemKind::ForeignMod(ref foreign_module) => {
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self.check_abi(foreign_module.abi, i.span);
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}
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ast::ItemKind::Fn(..) => {
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if attr::contains_name(&i.attrs[..], sym::plugin_registrar) {
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gate_feature_post!(&self, plugin_registrar, i.span,
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"compiler plugins are experimental and possibly buggy");
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}
|
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if attr::contains_name(&i.attrs[..], sym::start) {
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gate_feature_post!(&self, start, i.span,
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"a `#[start]` function is an experimental \
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feature whose signature may change \
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over time");
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}
|
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if attr::contains_name(&i.attrs[..], sym::main) {
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gate_feature_post!(&self, main, i.span,
|
|
"declaration of a non-standard `#[main]` \
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function may change over time, for now \
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|
a top-level `fn main()` is required");
|
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}
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}
|
|
|
|
ast::ItemKind::Struct(..) => {
|
|
for attr in attr::filter_by_name(&i.attrs[..], sym::repr) {
|
|
for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
|
|
if item.check_name(sym::simd) {
|
|
gate_feature_post!(&self, repr_simd, attr.span,
|
|
"SIMD types are experimental and possibly buggy");
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
ast::ItemKind::Enum(ast::EnumDef{ref variants, ..}, ..) => {
|
|
for variant in variants {
|
|
match (&variant.data, &variant.disr_expr) {
|
|
(ast::VariantData::Unit(..), _) => {},
|
|
(_, Some(disr_expr)) =>
|
|
gate_feature_post!(
|
|
&self,
|
|
arbitrary_enum_discriminant,
|
|
disr_expr.value.span,
|
|
"discriminants on non-unit variants are experimental"),
|
|
_ => {},
|
|
}
|
|
}
|
|
|
|
let has_feature = self.features.arbitrary_enum_discriminant;
|
|
if !has_feature && !i.span.allows_unstable(sym::arbitrary_enum_discriminant) {
|
|
self.maybe_report_invalid_custom_discriminants(&variants);
|
|
}
|
|
}
|
|
|
|
ast::ItemKind::Impl(_, polarity, defaultness, ..) => {
|
|
if polarity == ast::ImplPolarity::Negative {
|
|
gate_feature_post!(&self, optin_builtin_traits,
|
|
i.span,
|
|
"negative trait bounds are not yet fully implemented; \
|
|
use marker types for now");
|
|
}
|
|
|
|
if let ast::Defaultness::Default = defaultness {
|
|
gate_feature_post!(&self, specialization,
|
|
i.span,
|
|
"specialization is unstable");
|
|
}
|
|
}
|
|
|
|
ast::ItemKind::Trait(ast::IsAuto::Yes, ..) => {
|
|
gate_feature_post!(&self, optin_builtin_traits,
|
|
i.span,
|
|
"auto traits are experimental and possibly buggy");
|
|
}
|
|
|
|
ast::ItemKind::OpaqueTy(..) => {
|
|
gate_feature_post!(
|
|
&self,
|
|
type_alias_impl_trait,
|
|
i.span,
|
|
"`impl Trait` in type aliases is unstable"
|
|
);
|
|
}
|
|
|
|
_ => {}
|
|
}
|
|
|
|
visit::walk_item(self, i);
|
|
}
|
|
|
|
fn visit_foreign_item(&mut self, i: &'a ast::ForeignItem) {
|
|
match i.kind {
|
|
ast::ForeignItemKind::Fn(..) |
|
|
ast::ForeignItemKind::Static(..) => {
|
|
let link_name = attr::first_attr_value_str_by_name(&i.attrs, sym::link_name);
|
|
let links_to_llvm = match link_name {
|
|
Some(val) => val.as_str().starts_with("llvm."),
|
|
_ => false
|
|
};
|
|
if links_to_llvm {
|
|
gate_feature_post!(&self, link_llvm_intrinsics, i.span,
|
|
"linking to LLVM intrinsics is experimental");
|
|
}
|
|
}
|
|
ast::ForeignItemKind::Ty => {
|
|
gate_feature_post!(&self, extern_types, i.span,
|
|
"extern types are experimental");
|
|
}
|
|
ast::ForeignItemKind::Macro(..) => {}
|
|
}
|
|
|
|
visit::walk_foreign_item(self, i)
|
|
}
|
|
|
|
fn visit_ty(&mut self, ty: &'a ast::Ty) {
|
|
match ty.kind {
|
|
ast::TyKind::BareFn(ref bare_fn_ty) => {
|
|
self.check_abi(bare_fn_ty.abi, ty.span);
|
|
}
|
|
ast::TyKind::Never => {
|
|
gate_feature_post!(&self, never_type, ty.span,
|
|
"The `!` type is experimental");
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_ty(self, ty)
|
|
}
|
|
|
|
fn visit_fn_ret_ty(&mut self, ret_ty: &'a ast::FunctionRetTy) {
|
|
if let ast::FunctionRetTy::Ty(ref output_ty) = *ret_ty {
|
|
if let ast::TyKind::Never = output_ty.kind {
|
|
// Do nothing.
|
|
} else {
|
|
self.visit_ty(output_ty)
|
|
}
|
|
}
|
|
}
|
|
|
|
fn visit_expr(&mut self, e: &'a ast::Expr) {
|
|
match e.kind {
|
|
ast::ExprKind::Type(..) => {
|
|
// To avoid noise about type ascription in common syntax errors, only emit if it
|
|
// is the *only* error.
|
|
if self.parse_sess.span_diagnostic.err_count() == 0 {
|
|
gate_feature_post!(&self, type_ascription, e.span,
|
|
"type ascription is experimental");
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_expr(self, e)
|
|
}
|
|
|
|
fn visit_pat(&mut self, pattern: &'a ast::Pat) {
|
|
match &pattern.kind {
|
|
PatKind::Slice(pats) => {
|
|
for pat in &*pats {
|
|
let span = pat.span;
|
|
let inner_pat = match &pat.kind {
|
|
PatKind::Ident(.., Some(pat)) => pat,
|
|
_ => pat,
|
|
};
|
|
if inner_pat.is_rest() {
|
|
gate_feature_post!(
|
|
&self,
|
|
slice_patterns,
|
|
span,
|
|
"subslice patterns are unstable"
|
|
);
|
|
}
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_pat(self, pattern)
|
|
}
|
|
|
|
fn visit_fn(&mut self, fn_kind: FnKind<'a>, fn_decl: &'a ast::FnDecl, span: Span, _: NodeId) {
|
|
if let Some(header) = fn_kind.header() {
|
|
// Stability of const fn methods are covered in
|
|
// `visit_trait_item` and `visit_impl_item` below; this is
|
|
// because default methods don't pass through this point.
|
|
self.check_abi(header.abi, span);
|
|
}
|
|
|
|
if fn_decl.c_variadic() {
|
|
gate_feature_post!(&self, c_variadic, span, "C-variadic functions are unstable");
|
|
}
|
|
|
|
visit::walk_fn(self, fn_kind, fn_decl, span)
|
|
}
|
|
|
|
fn visit_trait_item(&mut self, ti: &'a ast::TraitItem) {
|
|
match ti.kind {
|
|
ast::TraitItemKind::Method(ref sig, ref block) => {
|
|
if block.is_none() {
|
|
self.check_abi(sig.header.abi, ti.span);
|
|
}
|
|
if sig.decl.c_variadic() {
|
|
gate_feature_post!(&self, c_variadic, ti.span,
|
|
"C-variadic functions are unstable");
|
|
}
|
|
if sig.header.constness.node == ast::Constness::Const {
|
|
gate_feature_post!(&self, const_fn, ti.span, "const fn is unstable");
|
|
}
|
|
}
|
|
ast::TraitItemKind::Type(_, ref default) => {
|
|
// We use three if statements instead of something like match guards so that all
|
|
// of these errors can be emitted if all cases apply.
|
|
if default.is_some() {
|
|
gate_feature_post!(&self, associated_type_defaults, ti.span,
|
|
"associated type defaults are unstable");
|
|
}
|
|
self.check_gat(&ti.generics, ti.span);
|
|
}
|
|
_ => {}
|
|
}
|
|
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.kind {
|
|
ast::ImplItemKind::Method(ref sig, _) => {
|
|
if sig.decl.c_variadic() {
|
|
gate_feature_post!(&self, c_variadic, ii.span,
|
|
"C-variadic functions are unstable");
|
|
}
|
|
}
|
|
ast::ImplItemKind::OpaqueTy(..) => {
|
|
gate_feature_post!(
|
|
&self,
|
|
type_alias_impl_trait,
|
|
ii.span,
|
|
"`impl Trait` in type aliases is unstable"
|
|
);
|
|
}
|
|
ast::ImplItemKind::TyAlias(_) => {
|
|
self.check_gat(&ii.generics, ii.span);
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_impl_item(self, ii)
|
|
}
|
|
}
|
|
|
|
pub fn get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute],
|
|
crate_edition: Edition, allow_features: &Option<Vec<String>>) -> Features {
|
|
fn feature_removed(span_handler: &Handler, span: Span, reason: Option<&str>) {
|
|
let mut err = struct_span_err!(span_handler, span, E0557, "feature has been removed");
|
|
if let Some(reason) = reason {
|
|
err.span_note(span, reason);
|
|
} else {
|
|
err.span_label(span, "feature has been removed");
|
|
}
|
|
err.emit();
|
|
}
|
|
|
|
let mut features = Features::new();
|
|
let mut edition_enabled_features = FxHashMap::default();
|
|
|
|
for &edition in ALL_EDITIONS {
|
|
if edition <= crate_edition {
|
|
// The `crate_edition` implies its respective umbrella feature-gate
|
|
// (i.e., `#![feature(rust_20XX_preview)]` isn't needed on edition 20XX).
|
|
edition_enabled_features.insert(edition.feature_name(), edition);
|
|
}
|
|
}
|
|
|
|
for feature in active_features_up_to(crate_edition) {
|
|
feature.set(&mut features, DUMMY_SP);
|
|
edition_enabled_features.insert(feature.name, crate_edition);
|
|
}
|
|
|
|
// Process the edition umbrella feature-gates first, to ensure
|
|
// `edition_enabled_features` is completed before it's queried.
|
|
for attr in krate_attrs {
|
|
if !attr.check_name(sym::feature) {
|
|
continue
|
|
}
|
|
|
|
let list = match attr.meta_item_list() {
|
|
Some(list) => list,
|
|
None => continue,
|
|
};
|
|
|
|
for mi in list {
|
|
if !mi.is_word() {
|
|
continue;
|
|
}
|
|
|
|
let name = mi.name_or_empty();
|
|
|
|
let edition = ALL_EDITIONS.iter().find(|e| name == e.feature_name()).copied();
|
|
if let Some(edition) = edition {
|
|
if edition <= crate_edition {
|
|
continue;
|
|
}
|
|
|
|
for feature in active_features_up_to(edition) {
|
|
// FIXME(Manishearth) there is currently no way to set
|
|
// lib features by edition
|
|
feature.set(&mut features, DUMMY_SP);
|
|
edition_enabled_features.insert(feature.name, edition);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
for attr in krate_attrs {
|
|
if !attr.check_name(sym::feature) {
|
|
continue
|
|
}
|
|
|
|
let list = match attr.meta_item_list() {
|
|
Some(list) => list,
|
|
None => continue,
|
|
};
|
|
|
|
let bad_input = |span| {
|
|
struct_span_err!(span_handler, span, E0556, "malformed `feature` attribute input")
|
|
};
|
|
|
|
for mi in list {
|
|
let name = match mi.ident() {
|
|
Some(ident) if mi.is_word() => ident.name,
|
|
Some(ident) => {
|
|
bad_input(mi.span()).span_suggestion(
|
|
mi.span(),
|
|
"expected just one word",
|
|
format!("{}", ident.name),
|
|
Applicability::MaybeIncorrect,
|
|
).emit();
|
|
continue
|
|
}
|
|
None => {
|
|
bad_input(mi.span()).span_label(mi.span(), "expected just one word").emit();
|
|
continue
|
|
}
|
|
};
|
|
|
|
if let Some(edition) = edition_enabled_features.get(&name) {
|
|
struct_span_warn!(
|
|
span_handler,
|
|
mi.span(),
|
|
E0705,
|
|
"the feature `{}` is included in the Rust {} edition",
|
|
name,
|
|
edition,
|
|
).emit();
|
|
continue;
|
|
}
|
|
|
|
if ALL_EDITIONS.iter().any(|e| name == e.feature_name()) {
|
|
// Handled in the separate loop above.
|
|
continue;
|
|
}
|
|
|
|
let removed = REMOVED_FEATURES.iter().find(|f| name == f.name);
|
|
let stable_removed = STABLE_REMOVED_FEATURES.iter().find(|f| name == f.name);
|
|
if let Some(Feature { state, .. }) = removed.or(stable_removed) {
|
|
if let FeatureState::Removed { reason }
|
|
| FeatureState::Stabilized { reason } = state
|
|
{
|
|
feature_removed(span_handler, mi.span(), *reason);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if let Some(Feature { since, .. }) = ACCEPTED_FEATURES.iter().find(|f| name == f.name) {
|
|
let since = Some(Symbol::intern(since));
|
|
features.declared_lang_features.push((name, mi.span(), since));
|
|
continue;
|
|
}
|
|
|
|
if let Some(allowed) = allow_features.as_ref() {
|
|
if allowed.iter().find(|&f| f == &name.as_str() as &str).is_none() {
|
|
span_err!(span_handler, mi.span(), E0725,
|
|
"the feature `{}` is not in the list of allowed features",
|
|
name);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if let Some(f) = ACTIVE_FEATURES.iter().find(|f| name == f.name) {
|
|
f.set(&mut features, mi.span());
|
|
features.declared_lang_features.push((name, mi.span(), None));
|
|
continue;
|
|
}
|
|
|
|
features.declared_lib_features.push((name, mi.span()));
|
|
}
|
|
}
|
|
|
|
features
|
|
}
|
|
|
|
fn active_features_up_to(edition: Edition) -> impl Iterator<Item=&'static Feature> {
|
|
ACTIVE_FEATURES.iter()
|
|
.filter(move |feature| {
|
|
if let Some(feature_edition) = feature.edition {
|
|
feature_edition <= edition
|
|
} else {
|
|
false
|
|
}
|
|
})
|
|
}
|
|
|
|
pub fn check_crate(krate: &ast::Crate,
|
|
parse_sess: &ParseSess,
|
|
features: &Features,
|
|
unstable: UnstableFeatures) {
|
|
maybe_stage_features(&parse_sess.span_diagnostic, krate, unstable);
|
|
let mut visitor = PostExpansionVisitor { parse_sess, features };
|
|
|
|
macro_rules! gate_all {
|
|
($gate:ident, $msg:literal) => { gate_all!($gate, $gate, $msg); };
|
|
($spans:ident, $gate:ident, $msg:literal) => {
|
|
for span in &*parse_sess.gated_spans.$spans.borrow() {
|
|
gate_feature!(&visitor, $gate, *span, $msg);
|
|
}
|
|
}
|
|
}
|
|
|
|
gate_all!(let_chains, "`let` expressions in this position are experimental");
|
|
gate_all!(async_closure, "async closures are unstable");
|
|
gate_all!(yields, generators, "yield syntax is experimental");
|
|
gate_all!(or_patterns, "or-patterns syntax is experimental");
|
|
gate_all!(const_extern_fn, "`const extern fn` definitions are unstable");
|
|
gate_all!(trait_alias, "trait aliases are experimental");
|
|
gate_all!(associated_type_bounds, "associated type bounds are unstable");
|
|
gate_all!(crate_visibility_modifier, "`crate` visibility modifier is experimental");
|
|
gate_all!(const_generics, "const generics are unstable");
|
|
gate_all!(decl_macro, "`macro` is experimental");
|
|
gate_all!(box_patterns, "box pattern syntax is experimental");
|
|
gate_all!(exclusive_range_pattern, "exclusive range pattern syntax is experimental");
|
|
gate_all!(try_blocks, "`try` blocks are unstable");
|
|
gate_all!(label_break_value, "labels on blocks are unstable");
|
|
gate_all!(box_syntax, "box expression syntax is experimental; you can call `Box::new` instead");
|
|
|
|
// To avoid noise about type ascription in common syntax errors,
|
|
// only emit if it is the *only* error. (Also check it last.)
|
|
if parse_sess.span_diagnostic.err_count() == 0 {
|
|
gate_all!(type_ascription, "type ascription is experimental");
|
|
}
|
|
|
|
visit::walk_crate(&mut visitor, krate);
|
|
}
|
|
|
|
#[derive(Clone, Copy, Hash)]
|
|
pub enum UnstableFeatures {
|
|
/// Hard errors for unstable features are active, as on beta/stable channels.
|
|
Disallow,
|
|
/// Allow features to be activated, as on nightly.
|
|
Allow,
|
|
/// Errors are bypassed for bootstrapping. This is required any time
|
|
/// during the build that feature-related lints are set to warn or above
|
|
/// because the build turns on warnings-as-errors and uses lots of unstable
|
|
/// features. As a result, this is always required for building Rust itself.
|
|
Cheat
|
|
}
|
|
|
|
impl UnstableFeatures {
|
|
pub fn from_environment() -> UnstableFeatures {
|
|
// `true` if this is a feature-staged build, i.e., on the beta or stable channel.
|
|
let disable_unstable_features = option_env!("CFG_DISABLE_UNSTABLE_FEATURES").is_some();
|
|
// `true` if we should enable unstable features for bootstrapping.
|
|
let bootstrap = env::var("RUSTC_BOOTSTRAP").is_ok();
|
|
match (disable_unstable_features, bootstrap) {
|
|
(_, true) => UnstableFeatures::Cheat,
|
|
(true, _) => UnstableFeatures::Disallow,
|
|
(false, _) => UnstableFeatures::Allow
|
|
}
|
|
}
|
|
|
|
pub fn is_nightly_build(&self) -> bool {
|
|
match *self {
|
|
UnstableFeatures::Allow | UnstableFeatures::Cheat => true,
|
|
UnstableFeatures::Disallow => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
fn maybe_stage_features(span_handler: &Handler, krate: &ast::Crate, unstable: UnstableFeatures) {
|
|
if !unstable.is_nightly_build() {
|
|
for attr in krate.attrs.iter().filter(|attr| attr.check_name(sym::feature)) {
|
|
span_err!(
|
|
span_handler, attr.span, E0554,
|
|
"`#![feature]` may not be used on the {} release channel",
|
|
option_env!("CFG_RELEASE_CHANNEL").unwrap_or("(unknown)")
|
|
);
|
|
}
|
|
}
|
|
}
|