bjoernager/rust
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Suggest async {} for async || {}

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Fixes #76011

This adds support for adding help diagnostics to the feature gating checks and
then uses it for the async_closure gate to add the extra bit of help
information as described in the issue.
This commit is contained in:
Andy Weiss 2020-09-09 15:16:34 -07:00
parent 25b2f48612
commit 5b475a4618
5 changed files with 34 additions and 17 deletions
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27
compiler/rustc_ast_passes/src/feature_gate.rs
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@ -14,6 +14,17 @@ use rustc_span::Span;
use tracing::debug;
macro_rules! gate_feature_fn {
($visitor: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr, $help: expr) => {{
let (visitor, has_feature, span, name, explain, help) =
(&*$visitor, $has_feature, $span, $name, $explain, $help);
let has_feature: bool = has_feature(visitor.features);
debug!("gate_feature(feature = {:?}, span = {:?}); has? {}", name, span, has_feature);
if !has_feature && !span.allows_unstable($name) {
feature_err_issue(&visitor.sess.parse_sess, name, span, GateIssue::Language, explain)
.help(help)
.emit();
}
}};
($visitor: expr, $has_feature: expr, $span: expr, $name: expr, $explain: expr) => {{
let (visitor, has_feature, span, name, explain) =
(&*$visitor, $has_feature, $span, $name, $explain);
@ -27,6 +38,9 @@ macro_rules! gate_feature_fn {
}
macro_rules! gate_feature_post {
($visitor: expr, $feature: ident, $span: expr, $explain: expr, $help: expr) => {
gate_feature_fn!($visitor, |x: &Features| x.$feature, $span, sym::$feature, $explain, $help)
};
($visitor: expr, $feature: ident, $span: expr, $explain: expr) => {
gate_feature_fn!($visitor, |x: &Features| x.$feature, $span, sym::$feature, $explain)
};
@ -613,6 +627,13 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
let spans = sess.parse_sess.gated_spans.spans.borrow();
macro_rules! gate_all {
($gate:ident, $msg:literal, $help:literal) => {
if let Some(spans) = spans.get(&sym::$gate) {
for span in spans {
gate_feature_post!(&visitor, $gate, *span, $msg, $help);
}
}
};
($gate:ident, $msg:literal) => {
if let Some(spans) = spans.get(&sym::$gate) {
for span in spans {
@ -623,7 +644,11 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session) {
}
gate_all!(if_let_guard, "`if let` guard is not implemented");
gate_all!(let_chains, "`let` expressions in this position are experimental");
gate_all!(async_closure, "async closures are unstable");
gate_all!(
async_closure,
"async closures are unstable",
"to use an async block, remove the `||`: `async {`"
);
gate_all!(generators, "yield syntax is experimental");
gate_all!(or_patterns, "or-patterns syntax is experimental");
gate_all!(raw_ref_op, "raw address of syntax is experimental");