bjoernager/rust
bjoernager/rust
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implement generic_arg_infer for array lengths

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This commit is contained in:
lcnr 2021-12-23 10:01:51 +01:00
parent 5aa0239b16
commit e3f5cc6c38
19 changed files with 161 additions and 51 deletions
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2
compiler/rustc_ast_lowering/src/expr.rs
View file

@ -34,7 +34,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
}
ExprKind::Repeat(ref expr, ref count) => {
let expr = self.lower_expr(expr);
let count = self.lower_anon_const(count);
let count = self.lower_array_length(count);
hir::ExprKind::Repeat(expr, count)
}
ExprKind::Tup(ref elts) => hir::ExprKind::Tup(self.lower_exprs(elts)),

23
compiler/rustc_ast_lowering/src/lib.rs
View file

@ -56,6 +56,7 @@ use rustc_hir::{ConstArg, GenericArg, ParamName};
use rustc_index::vec::{Idx, IndexVec};
use rustc_query_system::ich::StableHashingContext;
use rustc_session::lint::LintBuffer;
use rustc_session::parse::feature_err;
use rustc_session::utils::{FlattenNonterminals, NtToTokenstream};
use rustc_session::Session;
use rustc_span::hygiene::ExpnId;
@ -1248,7 +1249,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
))
}
TyKind::Array(ref ty, ref length) => {
hir::TyKind::Array(self.lower_ty(ty, itctx), self.lower_anon_const(length))
hir::TyKind::Array(self.lower_ty(ty, itctx), self.lower_array_length(length))
}
TyKind::Typeof(ref expr) => hir::TyKind::Typeof(self.lower_anon_const(expr)),
TyKind::TraitObject(ref bounds, kind) => {
@ -2039,6 +2040,26 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
self.expr_block(block, AttrVec::new())
}
fn lower_array_length(&mut self, c: &AnonConst) -> hir::ArrayLen {
match c.value.kind {
ExprKind::Underscore => {
if self.sess.features_untracked().generic_arg_infer {
hir::ArrayLen::Infer(self.lower_node_id(c.id), c.value.span)
} else {
feature_err(
&self.sess.parse_sess,
sym::generic_arg_infer,
c.value.span,
"using `_` for array lengths is unstable",
)
.emit();
hir::ArrayLen::Body(self.lower_anon_const(c))
}
}
_ => hir::ArrayLen::Body(self.lower_anon_const(c)),
}
}
fn lower_anon_const(&mut self, c: &AnonConst) -> hir::AnonConst {
self.with_new_scopes(|this| hir::AnonConst {
hir_id: this.lower_node_id(c.id),