bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Rollup merge of #136584 - oli-obk:pattern-types-generic, r=BoxyUwU

Browse source 
Prevent generic pattern types from being used in libstd

Pattern types should follow the same rules that patterns follow. So a pattern type range must not wrap and not be empty. While we reject such invalid ranges at layout computation time, that only happens during monomorphization in the case of const generics. This is the exact same issue as other const generic math has, and since there's no solution there yet, I put these pattern types behind a separate incomplete feature.

These are not necessary for the pattern types MVP (replacing the layout range attributes in libcore and rustc).

cc #136574 (new tracking issue for the `generic_pattern_types` feature gate)

r? ``@lcnr``

cc ``@scottmcm`` ``@joshtriplett``
This commit is contained in:
Matthias Krüger 2025-02-11 02:53:44 +01:00 • committed by GitHub
commit c92aae90e4
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
7 changed files with 101 additions and 11 deletions
Download patch file Download diff file Expand all files Collapse all files

44
compiler/rustc_trait_selection/src/traits/wf.rs
View file

@ -8,8 +8,9 @@ use rustc_middle::ty::{
self, GenericArg, GenericArgKind, GenericArgsRef, Ty, TyCtxt, TypeSuperVisitable,
TypeVisitable, TypeVisitableExt, TypeVisitor,
};
use rustc_span::Span;
use rustc_session::parse::feature_err;
use rustc_span::def_id::{DefId, LocalDefId};
use rustc_span::{Span, sym};
use tracing::{debug, instrument, trace};
use crate::infer::InferCtxt;
@ -704,8 +705,47 @@ impl<'a, 'tcx> TypeVisitor<TyCtxt<'tcx>> for WfPredicates<'a, 'tcx> {
));
}
ty::Pat(subty, _) => {
ty::Pat(subty, pat) => {
self.require_sized(subty, ObligationCauseCode::Misc);
match *pat {
ty::PatternKind::Range { start, end, include_end: _ } => {
let mut check = |c| {
let cause = self.cause(ObligationCauseCode::Misc);
self.out.push(traits::Obligation::with_depth(
tcx,
cause.clone(),
self.recursion_depth,
self.param_env,
ty::Binder::dummy(ty::PredicateKind::Clause(
ty::ClauseKind::ConstArgHasType(c, subty),
)),
));
if !tcx.features().generic_pattern_types() {
if c.has_param() {
if self.span.is_dummy() {
self.tcx().dcx().delayed_bug(
"feature error should be reported elsewhere, too",
);
} else {
feature_err(
&self.tcx().sess,
sym::generic_pattern_types,
self.span,
"wraparound pattern type ranges cause monomorphization time errors",
)
.emit();
}
}
}
};
if let Some(start) = start {
check(start)
}
if let Some(end) = end {
check(end)
}
}
}
}
ty::Tuple(tys) => {