730 lines
26 KiB
Rust
730 lines
26 KiB
Rust
use rustc_error_codes::*;
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use rustc_errors::{struct_span_err, Handler};
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use rustc_feature::{AttributeGate, BUILTIN_ATTRIBUTE_MAP};
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use rustc_feature::{Features, GateIssue, UnstableFeatures};
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use rustc_span::source_map::Spanned;
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use rustc_span::symbol::sym;
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use rustc_span::Span;
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use syntax::ast::{self, AssocTyConstraint, AssocTyConstraintKind, NodeId};
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use syntax::ast::{GenericParam, GenericParamKind, PatKind, RangeEnd, VariantData};
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use syntax::attr;
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use syntax::sess::{feature_err, leveled_feature_err, GateStrength, ParseSess};
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use syntax::visit::{self, FnKind, Visitor};
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use log::debug;
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macro_rules! gate_feature_fn {
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($cx: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr, $level: expr) => {{
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let (cx, has_feature, span, name, explain, level) =
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(&*$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, $explain: expr) => {
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gate_feature_fn!(
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$cx,
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|x: &Features| x.$feature,
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$span,
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sym::$feature,
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$explain,
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GateStrength::Hard
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)
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};
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($cx: expr, $feature: ident, $span: expr, $explain: expr, $level: expr) => {
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gate_feature_fn!($cx, |x: &Features| x.$feature, $span, sym::$feature, $explain, $level)
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};
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}
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pub fn check_attribute(attr: &ast::Attribute, parse_sess: &ParseSess, features: &Features) {
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PostExpansionVisitor { parse_sess, features }.visit_attribute(attr)
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}
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struct PostExpansionVisitor<'a> {
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parse_sess: &'a ParseSess,
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features: &'a Features,
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}
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macro_rules! gate_feature_post {
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($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: ast::StrLit) {
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let ast::StrLit { symbol_unescaped, span, .. } = abi;
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match &*symbol_unescaped.as_str() {
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// Stable
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"Rust" | "C" | "cdecl" | "stdcall" | "fastcall" | "aapcs" | "win64" | "sysv64"
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| "system" => {}
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"rust-intrinsic" => {
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gate_feature_post!(&self, intrinsics, span, "intrinsics are subject to change");
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}
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"platform-intrinsic" => {
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gate_feature_post!(
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&self,
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platform_intrinsics,
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span,
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"platform intrinsics are experimental and possibly buggy"
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);
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}
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"vectorcall" => {
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gate_feature_post!(
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&self,
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abi_vectorcall,
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span,
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"vectorcall is experimental and subject to change"
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);
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}
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"thiscall" => {
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gate_feature_post!(
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&self,
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abi_thiscall,
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span,
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"thiscall is experimental and subject to change"
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);
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}
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"rust-call" => {
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gate_feature_post!(
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&self,
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unboxed_closures,
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span,
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"rust-call ABI is subject to change"
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);
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}
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"ptx-kernel" => {
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gate_feature_post!(
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&self,
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abi_ptx,
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span,
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"PTX ABIs are experimental and subject to change"
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);
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}
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"unadjusted" => {
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gate_feature_post!(
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&self,
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abi_unadjusted,
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span,
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"unadjusted ABI is an implementation detail and perma-unstable"
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);
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}
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"msp430-interrupt" => {
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gate_feature_post!(
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&self,
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abi_msp430_interrupt,
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span,
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"msp430-interrupt ABI is experimental and subject to change"
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);
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}
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"x86-interrupt" => {
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gate_feature_post!(
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&self,
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abi_x86_interrupt,
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span,
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"x86-interrupt ABI is experimental and subject to change"
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);
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}
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"amdgpu-kernel" => {
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gate_feature_post!(
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&self,
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abi_amdgpu_kernel,
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span,
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"amdgpu-kernel ABI is experimental and subject to change"
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);
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}
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"efiapi" => {
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gate_feature_post!(
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&self,
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abi_efiapi,
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span,
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"efiapi ABI is experimental and subject to change"
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);
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}
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abi => self
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.parse_sess
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.span_diagnostic
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.delay_span_bug(span, &format!("unrecognized ABI not caught in lowering: {}", abi)),
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}
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}
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fn check_extern(&self, ext: ast::Extern) {
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if let ast::Extern::Explicit(abi) = ext {
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self.check_abi(abi);
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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
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.iter()
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.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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"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(variant.span, "struct variant defined here");
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}
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VariantData::Tuple(..) => {
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err.span_label(variant.span, "tuple variant defined here");
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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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/// Feature gate `impl Trait` inside `type Alias = $type_expr;`.
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fn check_impl_trait(&self, ty: &ast::Ty) {
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struct ImplTraitVisitor<'a> {
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vis: &'a PostExpansionVisitor<'a>,
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}
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impl Visitor<'_> for ImplTraitVisitor<'_> {
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fn visit_ty(&mut self, ty: &ast::Ty) {
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if let ast::TyKind::ImplTrait(..) = ty.kind {
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gate_feature_post!(
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&self.vis,
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type_alias_impl_trait,
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ty.span,
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"`impl Trait` in type aliases is unstable"
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);
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}
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visit::walk_ty(self, ty);
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}
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}
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ImplTraitVisitor { vis: self }.visit_ty(ty);
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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 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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if let Some(abi) = foreign_module.abi {
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self.check_abi(abi);
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}
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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!(
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&self,
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plugin_registrar,
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i.span,
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"compiler plugins are experimental and possibly buggy"
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);
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}
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if attr::contains_name(&i.attrs[..], sym::start) {
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gate_feature_post!(
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&self,
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start,
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i.span,
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"`#[start]` functions are experimental \
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and their signature may change \
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over time"
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);
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}
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if attr::contains_name(&i.attrs[..], sym::main) {
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gate_feature_post!(
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&self,
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main,
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i.span,
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"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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}
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}
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ast::ItemKind::Struct(..) => {
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for attr in attr::filter_by_name(&i.attrs[..], sym::repr) {
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for item in attr.meta_item_list().unwrap_or_else(Vec::new) {
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if item.check_name(sym::simd) {
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gate_feature_post!(
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&self,
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repr_simd,
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attr.span,
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"SIMD types are experimental and possibly buggy"
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);
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}
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}
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}
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}
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ast::ItemKind::Enum(ast::EnumDef { ref variants, .. }, ..) => {
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for variant in variants {
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match (&variant.data, &variant.disr_expr) {
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(ast::VariantData::Unit(..), _) => {}
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(_, Some(disr_expr)) => gate_feature_post!(
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&self,
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arbitrary_enum_discriminant,
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disr_expr.value.span,
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"discriminants on non-unit variants are experimental"
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),
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_ => {}
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}
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}
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let has_feature = self.features.arbitrary_enum_discriminant;
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if !has_feature && !i.span.allows_unstable(sym::arbitrary_enum_discriminant) {
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self.maybe_report_invalid_custom_discriminants(&variants);
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}
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}
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ast::ItemKind::Impl(_, polarity, defaultness, ..) => {
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if polarity == ast::ImplPolarity::Negative {
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gate_feature_post!(
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&self,
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optin_builtin_traits,
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i.span,
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"negative trait bounds are not yet fully implemented; \
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use marker types for now"
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);
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}
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if let ast::Defaultness::Default = defaultness {
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gate_feature_post!(&self, specialization, i.span, "specialization is unstable");
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}
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}
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ast::ItemKind::Trait(ast::IsAuto::Yes, ..) => {
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gate_feature_post!(
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&self,
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optin_builtin_traits,
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i.span,
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"auto traits are experimental and possibly buggy"
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);
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}
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ast::ItemKind::TraitAlias(..) => {
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gate_feature_post!(&self, trait_alias, i.span, "trait aliases are experimental");
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}
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ast::ItemKind::MacroDef(ast::MacroDef { legacy: false, .. }) => {
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let msg = "`macro` is experimental";
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gate_feature_post!(&self, decl_macro, i.span, msg);
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}
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ast::ItemKind::TyAlias(ref ty, ..) => self.check_impl_trait(&ty),
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_ => {}
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}
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visit::walk_item(self, i);
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}
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fn visit_foreign_item(&mut self, i: &'a ast::ForeignItem) {
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match i.kind {
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ast::ForeignItemKind::Fn(..) | ast::ForeignItemKind::Static(..) => {
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let link_name = attr::first_attr_value_str_by_name(&i.attrs, sym::link_name);
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let links_to_llvm = match link_name {
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Some(val) => val.as_str().starts_with("llvm."),
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_ => false,
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};
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if links_to_llvm {
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gate_feature_post!(
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&self,
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link_llvm_intrinsics,
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i.span,
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"linking to LLVM intrinsics is experimental"
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);
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}
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}
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ast::ForeignItemKind::Ty => {
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gate_feature_post!(&self, extern_types, i.span, "extern types are experimental");
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}
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ast::ForeignItemKind::Macro(..) => {}
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}
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visit::walk_foreign_item(self, i)
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}
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fn visit_ty(&mut self, ty: &'a ast::Ty) {
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match ty.kind {
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ast::TyKind::BareFn(ref bare_fn_ty) => {
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self.check_extern(bare_fn_ty.ext);
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}
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ast::TyKind::Never => {
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gate_feature_post!(&self, never_type, ty.span, "The `!` type is experimental");
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}
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_ => {}
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}
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visit::walk_ty(self, ty)
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}
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fn visit_fn_ret_ty(&mut self, ret_ty: &'a ast::FunctionRetTy) {
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if let ast::FunctionRetTy::Ty(ref output_ty) = *ret_ty {
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if let ast::TyKind::Never = output_ty.kind {
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// Do nothing.
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} else {
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self.visit_ty(output_ty)
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}
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}
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}
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fn visit_expr(&mut self, e: &'a ast::Expr) {
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match e.kind {
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ast::ExprKind::Box(_) => {
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gate_feature_post!(
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&self,
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box_syntax,
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e.span,
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"box expression syntax is experimental; you can call `Box::new` instead"
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);
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}
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ast::ExprKind::Type(..) => {
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// To avoid noise about type ascription in common syntax errors, only emit if it
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// is the *only* error.
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if self.parse_sess.span_diagnostic.err_count() == 0 {
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gate_feature_post!(
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&self,
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type_ascription,
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e.span,
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"type ascription is experimental"
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);
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}
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}
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ast::ExprKind::TryBlock(_) => {
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gate_feature_post!(&self, try_blocks, e.span, "`try` expression is experimental");
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}
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ast::ExprKind::Block(_, opt_label) => {
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if let Some(label) = opt_label {
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gate_feature_post!(
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&self,
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label_break_value,
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label.ident.span,
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"labels on blocks are unstable"
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);
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}
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}
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_ => {}
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}
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visit::walk_expr(self, e)
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}
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|
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fn visit_arm(&mut self, arm: &'a ast::Arm) {
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visit::walk_arm(self, arm)
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}
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|
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fn visit_pat(&mut self, pattern: &'a ast::Pat) {
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match &pattern.kind {
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PatKind::Slice(pats) => {
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for pat in &*pats {
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let span = pat.span;
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let inner_pat = match &pat.kind {
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PatKind::Ident(.., Some(pat)) => pat,
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_ => pat,
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};
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if inner_pat.is_rest() {
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gate_feature_post!(
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&self,
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slice_patterns,
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span,
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"subslice patterns are unstable"
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);
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}
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}
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}
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|
PatKind::Box(..) => {
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|
gate_feature_post!(
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&self,
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box_patterns,
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pattern.span,
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"box pattern syntax is experimental"
|
|
);
|
|
}
|
|
PatKind::Range(_, _, Spanned { node: RangeEnd::Excluded, .. }) => {
|
|
gate_feature_post!(
|
|
&self,
|
|
exclusive_range_pattern,
|
|
pattern.span,
|
|
"exclusive range pattern syntax is experimental"
|
|
);
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_pat(self, pattern)
|
|
}
|
|
|
|
fn visit_fn(
|
|
&mut self,
|
|
fn_kind: FnKind<'a>,
|
|
fn_decl: &'a ast::FnDecl,
|
|
span: Span,
|
|
_node_id: NodeId,
|
|
) {
|
|
if let Some(header) = fn_kind.header() {
|
|
// 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_extern(header.ext);
|
|
}
|
|
|
|
if fn_decl.c_variadic() {
|
|
gate_feature_post!(&self, c_variadic, span, "C-variadic functions are unstable");
|
|
}
|
|
|
|
visit::walk_fn(self, fn_kind, fn_decl, span)
|
|
}
|
|
|
|
fn visit_generic_param(&mut self, param: &'a GenericParam) {
|
|
match param.kind {
|
|
GenericParamKind::Const { .. } => gate_feature_post!(
|
|
&self,
|
|
const_generics,
|
|
param.ident.span,
|
|
"const generics are unstable"
|
|
),
|
|
_ => {}
|
|
}
|
|
visit::walk_generic_param(self, param)
|
|
}
|
|
|
|
fn visit_assoc_ty_constraint(&mut self, constraint: &'a AssocTyConstraint) {
|
|
match constraint.kind {
|
|
AssocTyConstraintKind::Bound { .. } => gate_feature_post!(
|
|
&self,
|
|
associated_type_bounds,
|
|
constraint.span,
|
|
"associated type bounds are unstable"
|
|
),
|
|
_ => {}
|
|
}
|
|
visit::walk_assoc_ty_constraint(self, constraint)
|
|
}
|
|
|
|
fn visit_trait_item(&mut self, ti: &'a ast::AssocItem) {
|
|
match ti.kind {
|
|
ast::AssocItemKind::Fn(ref sig, ref block) => {
|
|
if block.is_none() {
|
|
self.check_extern(sig.header.ext);
|
|
}
|
|
if sig.header.constness.node == ast::Constness::Const {
|
|
gate_feature_post!(&self, const_fn, ti.span, "const fn is unstable");
|
|
}
|
|
}
|
|
ast::AssocItemKind::TyAlias(_, ref default) => {
|
|
if let Some(_) = default {
|
|
gate_feature_post!(
|
|
&self,
|
|
associated_type_defaults,
|
|
ti.span,
|
|
"associated type defaults are unstable"
|
|
);
|
|
}
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_trait_item(self, ti)
|
|
}
|
|
|
|
fn visit_assoc_item(&mut self, ii: &'a ast::AssocItem) {
|
|
if ii.defaultness == ast::Defaultness::Default {
|
|
gate_feature_post!(&self, specialization, ii.span, "specialization is unstable");
|
|
}
|
|
|
|
match ii.kind {
|
|
ast::AssocItemKind::Fn(ref sig, _) => {
|
|
if sig.decl.c_variadic() {
|
|
gate_feature_post!(
|
|
&self,
|
|
c_variadic,
|
|
ii.span,
|
|
"C-variadic functions are unstable"
|
|
);
|
|
}
|
|
}
|
|
ast::AssocItemKind::TyAlias(_, ref ty) => {
|
|
if let Some(ty) = ty {
|
|
self.check_impl_trait(ty);
|
|
}
|
|
self.check_gat(&ii.generics, ii.span);
|
|
}
|
|
_ => {}
|
|
}
|
|
visit::walk_assoc_item(self, ii)
|
|
}
|
|
|
|
fn visit_vis(&mut self, vis: &'a ast::Visibility) {
|
|
if let ast::VisibilityKind::Crate(ast::CrateSugar::JustCrate) = vis.node {
|
|
gate_feature_post!(
|
|
&self,
|
|
crate_visibility_modifier,
|
|
vis.span,
|
|
"`crate` visibility modifier is experimental"
|
|
);
|
|
}
|
|
visit::walk_vis(self, vis)
|
|
}
|
|
}
|
|
|
|
pub fn 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 };
|
|
|
|
let spans = parse_sess.gated_spans.spans.borrow();
|
|
macro_rules! gate_all {
|
|
($gate:ident, $msg:literal) => {
|
|
for span in spans.get(&sym::$gate).unwrap_or(&vec![]) {
|
|
gate_feature!(&visitor, $gate, *span, $msg);
|
|
}
|
|
};
|
|
}
|
|
gate_all!(let_chains, "`let` expressions in this position are experimental");
|
|
gate_all!(async_closure, "async closures are unstable");
|
|
gate_all!(generators, "yield syntax is experimental");
|
|
gate_all!(or_patterns, "or-patterns syntax is experimental");
|
|
gate_all!(const_extern_fn, "`const extern fn` definitions are unstable");
|
|
gate_all!(raw_ref_op, "raw address of syntax is experimental");
|
|
gate_all!(const_trait_bound_opt_out, "`?const` on trait bounds is experimental");
|
|
gate_all!(const_trait_impl, "const trait impls are experimental");
|
|
gate_all!(half_open_range_patterns, "half-open range patterns are unstable");
|
|
|
|
// All uses of `gate_all!` below this point were added in #65742,
|
|
// and subsequently disabled (with the non-early gating readded).
|
|
macro_rules! gate_all {
|
|
($gate:ident, $msg:literal) => {
|
|
// FIXME(eddyb) do something more useful than always
|
|
// disabling these uses of early feature-gatings.
|
|
if false {
|
|
for span in spans.get(&sym::$gate).unwrap_or(&vec![]) {
|
|
gate_feature!(&visitor, $gate, *span, $msg);
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
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)) {
|
|
struct_span_err!(
|
|
span_handler,
|
|
attr.span,
|
|
E0554,
|
|
"`#![feature]` may not be used on the {} release channel",
|
|
option_env!("CFG_RELEASE_CHANNEL").unwrap_or("(unknown)")
|
|
)
|
|
.emit();
|
|
}
|
|
}
|
|
}
|