Mirrors/rust
1
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2026-04-27 18:57:42 +03:00
Code Issues Packages Projects Releases Wiki Activity

Sort pre-expansion gates and add more visible disclaimers

Browse Source
This commit is contained in:
León Orell Valerian Liehr
2026-04-01 14:28:01 +02:00
parent 98688ef1f9
commit dd96eff769
2 changed files with 99 additions and 70 deletions
Download Patch File Download Diff File Expand all files Collapse all files
compiler/rustc_ast_passes/src/feature_gate.rs
+89 -60
View File
@@ -59,6 +59,15 @@ struct PostExpansionVisitor<'a> {
features: &'a Features,
}
// -----------------------------------------------------------------------------
// POST-EXPANSION FEATURE GATES FOR UNSTABLE ATTRIBUTES ETC.
// **LEGACY** POST-EXPANSION FEATURE GATES FOR UNSTABLE SYNTAX **LEGACY**
// -----------------------------------------------------------------------------
// IMPORTANT: Don't add any new post-expansion feature gates for new unstable syntax!
// It's a legacy mechanism for them.
// Instead, register a pre-expansion feature gate using `gate_all` in fn `check_crate`.
impl<'a> PostExpansionVisitor<'a> {
/// Feature gate `impl Trait` inside `type Alias = $type_expr;`.
fn check_impl_trait(&self, ty: &ast::Ty, in_associated_ty: bool) {
@@ -448,6 +457,8 @@ fn visit_assoc_item(&mut self, i: &'a ast::AssocItem, ctxt: AssocCtxt) {
}
}
// -----------------------------------------------------------------------------
pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
maybe_stage_features(sess, features, krate);
check_incompatible_features(sess, features);
@@ -456,6 +467,10 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
let mut visitor = PostExpansionVisitor { sess, features };
// -----------------------------------------------------------------------------
// PRE-EXPANSION FEATURE GATES FOR UNSTABLE SYNTAX
// -----------------------------------------------------------------------------
let spans = sess.psess.gated_spans.spans.borrow();
macro_rules! gate_all {
($feature:ident, $explain:literal $(, $help:literal)?) => {
@@ -464,54 +479,63 @@ macro_rules! gate_all {
}
};
}
// tidy-alphabetical-start
gate_all!(async_for_loop, "`for await` loops are experimental");
gate_all!(builtin_syntax, "`builtin #` syntax is unstable");
gate_all!(const_block_items, "const block items are experimental");
gate_all!(const_closures, "const closures are experimental");
gate_all!(const_trait_impl, "const trait impls are experimental");
gate_all!(contracts, "contracts are incomplete");
gate_all!(contracts_internals, "contract internal machinery is for internal use only");
gate_all!(coroutines, "coroutine syntax is experimental");
gate_all!(default_field_values, "default values on fields are experimental");
gate_all!(ergonomic_clones, "ergonomic clones are experimental");
gate_all!(explicit_tail_calls, "`become` expression is experimental");
gate_all!(final_associated_functions, "`final` on trait functions is experimental");
gate_all!(fn_delegation, "functions delegation is not yet fully implemented");
gate_all!(frontmatter, "frontmatters are experimental");
gate_all!(gen_blocks, "gen blocks are experimental");
gate_all!(generic_const_items, "generic const items are experimental");
gate_all!(global_registration, "global registration is experimental");
gate_all!(guard_patterns, "guard patterns are experimental", "consider using match arm guards");
gate_all!(impl_restriction, "`impl` restrictions are experimental");
gate_all!(min_generic_const_args, "unbraced const blocks as const args are experimental");
gate_all!(more_qualified_paths, "usage of qualified paths in this context is experimental");
gate_all!(mut_ref, "mutable by-reference bindings are experimental");
gate_all!(pin_ergonomics, "pinned reference syntax is experimental");
gate_all!(postfix_match, "postfix match is experimental");
gate_all!(return_type_notation, "return type notation is experimental");
gate_all!(super_let, "`super let` is experimental");
gate_all!(try_blocks_heterogeneous, "`try bikeshed` expression is experimental");
gate_all!(unsafe_binders, "unsafe binder types are experimental");
gate_all!(unsafe_fields, "`unsafe` fields are experimental");
gate_all!(where_clause_attrs, "attributes in `where` clause are unstable");
gate_all!(yeet_expr, "`do yeet` expression is experimental");
// tidy-alphabetical-end
gate_all!(
async_trait_bounds,
"`async` trait bounds are unstable",
"use the desugared name of the async trait, such as `AsyncFn`"
);
gate_all!(async_for_loop, "`for await` loops are experimental");
gate_all!(
closure_lifetime_binder,
"`for<...>` binders for closures are experimental",
"consider removing `for<...>`"
);
gate_all!(more_qualified_paths, "usage of qualified paths in this context is experimental");
// Yield exprs can be enabled either by `yield_expr`, by `coroutines` or by `gen_blocks`.
for &span in spans.get(&sym::yield_expr).into_iter().flatten() {
if (!visitor.features.coroutines() && !span.allows_unstable(sym::coroutines))
&& (!visitor.features.gen_blocks() && !span.allows_unstable(sym::gen_blocks))
&& (!visitor.features.yield_expr() && !span.allows_unstable(sym::yield_expr))
{
// Emit yield_expr as the error, since that will be sufficient. You can think of it
// as coroutines and gen_blocks imply yield_expr.
feature_err(visitor.sess, sym::yield_expr, span, "yield syntax is experimental").emit();
}
}
gate_all!(gen_blocks, "gen blocks are experimental");
gate_all!(const_trait_impl, "const trait impls are experimental");
gate_all!(
half_open_range_patterns_in_slices,
"half-open range patterns in slices are unstable"
);
gate_all!(try_blocks_heterogeneous, "`try bikeshed` expression is experimental");
gate_all!(yeet_expr, "`do yeet` expression is experimental");
gate_all!(const_closures, "const closures are experimental");
gate_all!(builtin_syntax, "`builtin #` syntax is unstable");
gate_all!(ergonomic_clones, "ergonomic clones are experimental");
gate_all!(explicit_tail_calls, "`become` expression is experimental");
gate_all!(generic_const_items, "generic const items are experimental");
gate_all!(guard_patterns, "guard patterns are experimental", "consider using match arm guards");
gate_all!(default_field_values, "default values on fields are experimental");
gate_all!(fn_delegation, "functions delegation is not yet fully implemented");
gate_all!(postfix_match, "postfix match is experimental");
gate_all!(mut_ref, "mutable by-reference bindings are experimental");
gate_all!(min_generic_const_args, "unbraced const blocks as const args are experimental");
// `associated_const_equality` will be stabilized as part of `min_generic_const_args`.
// `associated_const_equality` will be stabilized as part of `min_generic_const_args`.
for &span in spans.get(&sym::associated_const_equality).into_iter().flatten() {
gate!(visitor, min_generic_const_args, span, "associated const equality is incomplete");
}
// `mgca_type_const_syntax` is part of `min_generic_const_args` so either
// or both are enabled we don't need to emit a feature error.
// `mgca_type_const_syntax` is part of `min_generic_const_args` so if
// either or both are enabled we don't need to emit a feature error.
for &span in spans.get(&sym::mgca_type_const_syntax).into_iter().flatten() {
if visitor.features.min_generic_const_args()
|| visitor.features.mgca_type_const_syntax()
@@ -529,33 +553,23 @@ macro_rules! gate_all {
.emit();
}
gate_all!(global_registration, "global registration is experimental");
gate_all!(return_type_notation, "return type notation is experimental");
gate_all!(pin_ergonomics, "pinned reference syntax is experimental");
gate_all!(unsafe_fields, "`unsafe` fields are experimental");
gate_all!(unsafe_binders, "unsafe binder types are experimental");
gate_all!(contracts, "contracts are incomplete");
gate_all!(contracts_internals, "contract internal machinery is for internal use only");
gate_all!(where_clause_attrs, "attributes in `where` clause are unstable");
gate_all!(super_let, "`super let` is experimental");
gate_all!(frontmatter, "frontmatters are experimental");
gate_all!(coroutines, "coroutine syntax is experimental");
gate_all!(const_block_items, "const block items are experimental");
gate_all!(final_associated_functions, "`final` on trait functions is experimental");
gate_all!(impl_restriction, "`impl` restrictions are experimental");
// Negative bounds are *super* internal.
// Under no circumstances do we want to advertise the feature name to users!
if !visitor.features.negative_bounds() {
for &span in spans.get(&sym::negative_bounds).into_iter().flatten() {
sess.dcx().emit_err(errors::NegativeBoundUnsupported { span });
}
}
if !visitor.features.never_patterns() {
for &span in spans.get(&sym::never_patterns).into_iter().flatten() {
if span.allows_unstable(sym::never_patterns) {
continue;
}
let sm = sess.source_map();
// We gate two types of spans: the span of a `!` pattern, and the span of a
// match arm without a body. For the latter we want to give the user a normal
// error.
if let Ok(snippet) = sm.span_to_snippet(span)
&& snippet == "!"
{
if let Ok("!") = sess.source_map().span_to_snippet(span).as_deref() {
feature_err(sess, sym::never_patterns, span, "`!` patterns are experimental")
.emit();
} else {
@@ -565,16 +579,27 @@ macro_rules! gate_all {
}
}
if !visitor.features.negative_bounds() {
for &span in spans.get(&sym::negative_bounds).into_iter().flatten() {
sess.dcx().emit_err(errors::NegativeBoundUnsupported { span });
// Yield exprs can be enabled either by `yield_expr`, by `coroutines` or by `gen_blocks`.
for &span in spans.get(&sym::yield_expr).into_iter().flatten() {
if (!visitor.features.coroutines() && !span.allows_unstable(sym::coroutines))
&& (!visitor.features.gen_blocks() && !span.allows_unstable(sym::gen_blocks))
&& (!visitor.features.yield_expr() && !span.allows_unstable(sym::yield_expr))
{
// Only mentioned `yield_expr` in the diagnostic since that'll be sufficient.
// You can think of it as `coroutines` and `gen_blocks` implying `yield_expr`.
feature_err(visitor.sess, sym::yield_expr, span, "yield syntax is experimental").emit();
}
}
// All uses of `gate_all_legacy_dont_use!` below this point were added in #65742,
// and subsequently disabled (with the non-early gating readded).
// We emit an early future-incompatible warning for these.
// New syntax gates should go above here to get a hard error gate.
// -----------------------------------------------------------------------------
// **LEGACY** SOFT PRE-EXPANSION FEATURE GATES FOR UNSTABLE SYNTAX **LEGACY**
// -----------------------------------------------------------------------------
// IMPORTANT: Do not extend the list below! New syntax should go above and use `gate_all`.
// FIXME(#154045): Migrate all of these to erroring feature gates and
// remove the corresponding post-expansion feature gates.
macro_rules! soft_gate_all_legacy_dont_use {
($feature:ident, $explain:literal) => {
for &span in spans.get(&sym::$feature).into_iter().flatten() {
@@ -585,11 +610,15 @@ macro_rules! soft_gate_all_legacy_dont_use {
};
}
soft_gate_all_legacy_dont_use!(box_patterns, "box pattern syntax is experimental");
soft_gate_all_legacy_dont_use!(trait_alias, "trait aliases are experimental");
soft_gate_all_legacy_dont_use!(decl_macro, "`macro` is experimental");
soft_gate_all_legacy_dont_use!(try_blocks, "`try` blocks are unstable");
// tidy-alphabetical-start
soft_gate_all_legacy_dont_use!(auto_traits, "`auto` traits are unstable");
soft_gate_all_legacy_dont_use!(box_patterns, "box pattern syntax is experimental");
soft_gate_all_legacy_dont_use!(decl_macro, "`macro` is experimental");
soft_gate_all_legacy_dont_use!(trait_alias, "trait aliases are experimental");
soft_gate_all_legacy_dont_use!(try_blocks, "`try` blocks are unstable");
// tidy-alphabetical-end
// -----------------------------------------------------------------------------
visit::walk_crate(&mut visitor, krate);
}
tests/ui/impl-trait/precise-capturing/bound-modifiers.stderr
+10 -10
View File
@@ -46,6 +46,16 @@ error[E0405]: cannot find trait `r#use` in this scope
LL | fn binder() -> impl Sized + for<'a> use<> {}
| ^^^ not found in this scope
error[E0658]: const trait impls are experimental
--> $DIR/bound-modifiers.rs:12:32
|
LL | fn constness() -> impl Sized + const use<> {}
| ^^^^^
|
= note: see issue #143874 <https://github.com/rust-lang/rust/issues/143874> for more information
= help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
error[E0658]: `async` trait bounds are unstable
--> $DIR/bound-modifiers.rs:7:32
|
@@ -57,16 +67,6 @@ LL | fn asyncness() -> impl Sized + async use<> {}
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
= help: use the desugared name of the async trait, such as `AsyncFn`
error[E0658]: const trait impls are experimental
--> $DIR/bound-modifiers.rs:12:32
|
LL | fn constness() -> impl Sized + const use<> {}
| ^^^^^
|
= note: see issue #143874 <https://github.com/rust-lang/rust/issues/143874> for more information
= help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
error: aborting due to 10 previous errors
Some errors have detailed explanations: E0405, E0658.