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Rollup merge of #80404 - JulianKnodt:arr_ref, r=oli-obk
Remove const_in_array_repeat Fixes #80371. Fixes #81315. Fixes #80767. Fixes #75682. I thought there might be some issue with `Repeats(_, 0)`, but if you increase the items in the array it still ICEs. I'm not sure if this is the best fix but it does fix the given issue.
2 parents 7e3a8ec + 6946534 commit 99f2f5a

27 files changed

+61
-192
lines changed

Diff for: ‎compiler/rustc_feature/src/active.rs

-3
Original file line numberDiff line numberDiff line change
@@ -485,9 +485,6 @@ declare_features! (
485485
/// Allows `async || body` closures.
486486
(active, async_closure, "1.37.0", Some(62290), None),
487487

488-
/// Allows `[x; N]` where `x` is a constant (RFC 2203).
489-
(active, const_in_array_repeat_expressions, "1.37.0", Some(49147), None),
490-
491488
/// Allows `impl Trait` to be used inside type aliases (RFC 2515).
492489
(active, type_alias_impl_trait, "1.38.0", Some(63063), None),
493490

Diff for: ‎compiler/rustc_feature/src/removed.rs

+3
Original file line numberDiff line numberDiff line change
@@ -97,6 +97,9 @@ declare_features! (
9797
(removed, extern_in_paths, "1.33.0", Some(55600), None,
9898
Some("subsumed by `::foo::bar` paths")),
9999
(removed, quote, "1.33.0", Some(29601), None, None),
100+
/// Allows `[x; N]` where `x` is a constant (RFC 2203).
101+
(removed, const_in_array_repeat_expressions, "1.37.0", Some(49147), None,
102+
Some("removed due to causing promotable bugs")),
100103
/// Allows using `#[unsafe_destructor_blind_to_params]` (RFC 1238).
101104
(removed, dropck_parametricity, "1.38.0", Some(28498), None, None),
102105
(removed, await_macro, "1.38.0", Some(50547), None,

Diff for: ‎compiler/rustc_middle/src/traits/mod.rs

+1-2
Original file line numberDiff line numberDiff line change
@@ -228,8 +228,7 @@ pub enum ObligationCauseCode<'tcx> {
228228
/// Inline asm operand type must be `Sized`.
229229
InlineAsmSized,
230230
/// `[T, ..n]` implies that `T` must be `Copy`.
231-
/// If `true`, suggest `const_in_array_repeat_expressions` feature flag.
232-
RepeatVec(bool),
231+
RepeatVec,
233232

234233
/// Types of fields (other than the last, except for packed structs) in a struct must be sized.
235234
FieldSized {

Diff for: ‎compiler/rustc_mir/src/borrow_check/type_check/mod.rs

+1-14
Original file line numberDiff line numberDiff line change
@@ -43,10 +43,6 @@ use rustc_trait_selection::traits::{self, ObligationCause, PredicateObligations}
4343
use crate::dataflow::impls::MaybeInitializedPlaces;
4444
use crate::dataflow::move_paths::MoveData;
4545
use crate::dataflow::ResultsCursor;
46-
use crate::transform::{
47-
check_consts::ConstCx,
48-
promote_consts::should_suggest_const_in_array_repeat_expressions_attribute,
49-
};
5046

5147
use crate::borrow_check::{
5248
borrow_set::BorrowSet,
@@ -1997,22 +1993,13 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
19971993
let span = body.source_info(location).span;
19981994
let ty = operand.ty(body, tcx);
19991995
if !self.infcx.type_is_copy_modulo_regions(self.param_env, ty, span) {
2000-
let ccx = ConstCx::new_with_param_env(tcx, body, self.param_env);
2001-
// To determine if `const_in_array_repeat_expressions` feature gate should
2002-
// be mentioned, need to check if the rvalue is promotable.
2003-
let should_suggest =
2004-
should_suggest_const_in_array_repeat_expressions_attribute(
2005-
&ccx, operand,
2006-
);
2007-
debug!("check_rvalue: should_suggest={:?}", should_suggest);
2008-
20091996
let def_id = body.source.def_id().expect_local();
20101997
self.infcx.report_selection_error(
20111998
&traits::Obligation::new(
20121999
ObligationCause::new(
20132000
span,
20142001
self.tcx().hir().local_def_id_to_hir_id(def_id),
2015-
traits::ObligationCauseCode::RepeatVec(should_suggest),
2002+
traits::ObligationCauseCode::RepeatVec,
20162003
),
20172004
self.param_env,
20182005
ty::Binder::bind(ty::TraitRef::new(

Diff for: ‎compiler/rustc_mir/src/transform/promote_consts.rs

+3-63
Original file line numberDiff line numberDiff line change
@@ -102,9 +102,6 @@ pub enum Candidate {
102102
/// Borrow of a constant temporary, candidate for lifetime extension.
103103
Ref(Location),
104104

105-
/// Promotion of the `x` in `[x; 32]`.
106-
Repeat(Location),
107-
108105
/// Currently applied to function calls where the callee has the unstable
109106
/// `#[rustc_args_required_const]` attribute as well as the SIMD shuffle
110107
/// intrinsic. The intrinsic requires the arguments are indeed constant and
@@ -120,14 +117,14 @@ impl Candidate {
120117
/// Returns `true` if we should use the "explicit" rules for promotability for this `Candidate`.
121118
fn forces_explicit_promotion(&self) -> bool {
122119
match self {
123-
Candidate::Ref(_) | Candidate::Repeat(_) => false,
120+
Candidate::Ref(_) => false,
124121
Candidate::Argument { .. } | Candidate::InlineAsm { .. } => true,
125122
}
126123
}
127124

128125
fn source_info(&self, body: &Body<'_>) -> SourceInfo {
129126
match self {
130-
Candidate::Ref(location) | Candidate::Repeat(location) => *body.source_info(*location),
127+
Candidate::Ref(location) => *body.source_info(*location),
131128
Candidate::Argument { bb, .. } | Candidate::InlineAsm { bb, .. } => {
132129
*body.source_info(body.terminator_loc(*bb))
133130
}
@@ -213,11 +210,6 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
213210
Rvalue::Ref(..) => {
214211
self.candidates.push(Candidate::Ref(location));
215212
}
216-
Rvalue::Repeat(..) if self.ccx.tcx.features().const_in_array_repeat_expressions => {
217-
// FIXME(#49147) only promote the element when it isn't `Copy`
218-
// (so that code that can copy it at runtime is unaffected).
219-
self.candidates.push(Candidate::Repeat(location));
220-
}
221213
_ => {}
222214
}
223215
}
@@ -334,21 +326,6 @@ impl<'tcx> Validator<'_, 'tcx> {
334326
_ => bug!(),
335327
}
336328
}
337-
Candidate::Repeat(loc) => {
338-
assert!(!self.explicit);
339-
340-
let statement = &self.body[loc.block].statements[loc.statement_index];
341-
match &statement.kind {
342-
StatementKind::Assign(box (_, Rvalue::Repeat(ref operand, _))) => {
343-
if !self.tcx.features().const_in_array_repeat_expressions {
344-
return Err(Unpromotable);
345-
}
346-
347-
self.validate_operand(operand)
348-
}
349-
_ => bug!(),
350-
}
351-
}
352329
Candidate::Argument { bb, index } => {
353330
assert!(self.explicit);
354331

@@ -1090,18 +1067,6 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
10901067
_ => bug!(),
10911068
}
10921069
}
1093-
Candidate::Repeat(loc) => {
1094-
let statement = &mut blocks[loc.block].statements[loc.statement_index];
1095-
match statement.kind {
1096-
StatementKind::Assign(box (_, Rvalue::Repeat(ref mut operand, _))) => {
1097-
let ty = operand.ty(local_decls, self.tcx);
1098-
let span = statement.source_info.span;
1099-
1100-
Rvalue::Use(mem::replace(operand, promoted_operand(ty, span)))
1101-
}
1102-
_ => bug!(),
1103-
}
1104-
}
11051070
Candidate::Argument { bb, index } => {
11061071
let terminator = blocks[bb].terminator_mut();
11071072
match terminator.kind {
@@ -1182,8 +1147,7 @@ pub fn promote_candidates<'tcx>(
11821147
let mut extra_statements = vec![];
11831148
for candidate in candidates.into_iter().rev() {
11841149
match candidate {
1185-
Candidate::Repeat(Location { block, statement_index })
1186-
| Candidate::Ref(Location { block, statement_index }) => {
1150+
Candidate::Ref(Location { block, statement_index }) => {
11871151
if let StatementKind::Assign(box (place, _)) =
11881152
&body[block].statements[statement_index].kind
11891153
{
@@ -1267,27 +1231,3 @@ pub fn promote_candidates<'tcx>(
12671231

12681232
promotions
12691233
}
1270-
1271-
/// This function returns `true` if the `const_in_array_repeat_expressions` feature attribute should
1272-
/// be suggested. This function is probably quite expensive, it shouldn't be run in the happy path.
1273-
/// Feature attribute should be suggested if `operand` can be promoted and the feature is not
1274-
/// enabled.
1275-
crate fn should_suggest_const_in_array_repeat_expressions_attribute<'tcx>(
1276-
ccx: &ConstCx<'_, 'tcx>,
1277-
operand: &Operand<'tcx>,
1278-
) -> bool {
1279-
let mut rpo = traversal::reverse_postorder(&ccx.body);
1280-
let (temps, _) = collect_temps_and_candidates(&ccx, &mut rpo);
1281-
let validator = Validator { ccx, temps: &temps, explicit: false };
1282-
1283-
let should_promote = validator.validate_operand(operand).is_ok();
1284-
let feature_flag = validator.ccx.tcx.features().const_in_array_repeat_expressions;
1285-
debug!(
1286-
"should_suggest_const_in_array_repeat_expressions_flag: def_id={:?} \
1287-
should_promote={:?} feature_flag={:?}",
1288-
validator.ccx.def_id(),
1289-
should_promote,
1290-
feature_flag
1291-
);
1292-
should_promote && !feature_flag
1293-
}

Diff for: ‎compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

+1-14
Original file line numberDiff line numberDiff line change
@@ -1881,23 +1881,10 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
18811881
ObligationCauseCode::Coercion { source: _, target } => {
18821882
err.note(&format!("required by cast to type `{}`", self.ty_to_string(target)));
18831883
}
1884-
ObligationCauseCode::RepeatVec(suggest_const_in_array_repeat_expressions) => {
1884+
ObligationCauseCode::RepeatVec => {
18851885
err.note(
18861886
"the `Copy` trait is required because the repeated element will be copied",
18871887
);
1888-
if suggest_const_in_array_repeat_expressions {
1889-
err.note(
1890-
"this array initializer can be evaluated at compile-time, see issue \
1891-
#49147 <https://github.com/rust-lang/rust/issues/49147> \
1892-
for more information",
1893-
);
1894-
if tcx.sess.opts.unstable_features.is_nightly_build() {
1895-
err.help(
1896-
"add `#![feature(const_in_array_repeat_expressions)]` to the \
1897-
crate attributes to enable",
1898-
);
1899-
}
1900-
}
19011888
}
19021889
ObligationCauseCode::VariableType(hir_id) => {
19031890
let parent_node = self.tcx.hir().get_parent_node(hir_id);

Diff for: ‎library/alloc/src/lib.rs

-1
Original file line numberDiff line numberDiff line change
@@ -89,7 +89,6 @@
8989
#![feature(coerce_unsized)]
9090
#![feature(const_btree_new)]
9191
#![feature(const_fn)]
92-
#![feature(const_in_array_repeat_expressions)]
9392
#![feature(cow_is_borrowed)]
9493
#![feature(const_cow_is_borrowed)]
9594
#![feature(dispatch_from_dyn)]

Diff for: ‎src/doc/unstable-book/src/language-features/const-in-array-repeat-expressions.md

-11
This file was deleted.

Diff for: ‎src/test/ui/array-slice-vec/repeat_empty_ok.rs

+15
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
#![crate_type = "lib"]
2+
3+
pub struct Header<'a> {
4+
pub value: &'a [u8],
5+
}
6+
7+
pub fn test() {
8+
let headers = [Header{value: &[]}; 128];
9+
//~^ ERROR the trait bound
10+
}
11+
12+
pub fn test2() {
13+
let headers = [Header{value: &[0]}; 128];
14+
//~^ ERROR the trait bound
15+
}

Diff for: ‎src/test/ui/array-slice-vec/repeat_empty_ok.stderr

+19
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
1+
error[E0277]: the trait bound `Header<'_>: Copy` is not satisfied
2+
--> $DIR/repeat_empty_ok.rs:8:19
3+
|
4+
LL | let headers = [Header{value: &[]}; 128];
5+
| ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Header<'_>`
6+
|
7+
= note: the `Copy` trait is required because the repeated element will be copied
8+
9+
error[E0277]: the trait bound `Header<'_>: Copy` is not satisfied
10+
--> $DIR/repeat_empty_ok.rs:13:19
11+
|
12+
LL | let headers = [Header{value: &[0]}; 128];
13+
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Header<'_>`
14+
|
15+
= note: the `Copy` trait is required because the repeated element will be copied
16+
17+
error: aborting due to 2 previous errors
18+
19+
For more information about this error, try `rustc --explain E0277`.

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/const-repeat.rs renamed to ‎src/test/ui/consts/const-blocks/const-repeat.rs

File renamed without changes.

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/fn-call-in-const.rs renamed to ‎src/test/ui/consts/const-blocks/fn-call-in-const.rs

+3-3
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
// run-pass
22

3-
#![allow(unused)]
4-
#![feature(const_in_array_repeat_expressions)]
3+
#![feature(inline_const)]
4+
#![allow(unused, incomplete_features)]
55

66
// Some type that is not copyable.
77
struct Bar;
@@ -18,6 +18,6 @@ const _: [u32; 2] = [type_copy(); 2];
1818

1919
// This is allowed because all promotion contexts use the explicit rules for promotability when
2020
// inside an explicit const context.
21-
const _: [Option<Bar>; 2] = [type_no_copy(); 2];
21+
const _: [Option<Bar>; 2] = [const { type_no_copy() }; 2];
2222

2323
fn main() {}

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/fn-call-in-non-const.rs renamed to ‎src/test/ui/consts/const-blocks/fn-call-in-non-const.rs

-2
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,3 @@
1-
#![feature(const_in_array_repeat_expressions)]
2-
31
// Some type that is not copyable.
42
struct Bar;
53

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/fn-call-in-non-const.stderr renamed to ‎src/test/ui/consts/const-blocks/fn-call-in-non-const.stderr

+1-1
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0277]: the trait bound `Option<Bar>: Copy` is not satisfied
2-
--> $DIR/fn-call-in-non-const.rs:16:31
2+
--> $DIR/fn-call-in-non-const.rs:14:31
33
|
44
LL | let _: [Option<Bar>; 2] = [no_copy(); 2];
55
| ^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Option<Bar>`

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/migrate-fail.rs renamed to ‎src/test/ui/consts/const-blocks/migrate-fail.rs

-1
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,5 @@
11
// ignore-compare-mode-nll
22
// compile-flags: -Z borrowck=migrate
3-
#![feature(const_in_array_repeat_expressions)]
43
#![allow(warnings)]
54

65
// Some type that is not copyable.

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/migrate-fail.stderr renamed to ‎src/test/ui/consts/const-blocks/migrate-fail.stderr

+2-2
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0277]: the trait bound `Option<Bar>: Copy` is not satisfied
2-
--> $DIR/migrate-fail.rs:14:37
2+
--> $DIR/migrate-fail.rs:13:37
33
|
44
LL | let arr: [Option<Bar>; 2] = [x; 2];
55
| ^^^^^^ the trait `Copy` is not implemented for `Option<Bar>`
@@ -9,7 +9,7 @@ LL | let arr: [Option<Bar>; 2] = [x; 2];
99
= note: the `Copy` trait is required because the repeated element will be copied
1010

1111
error[E0277]: the trait bound `Option<Bar>: Copy` is not satisfied
12-
--> $DIR/migrate-fail.rs:20:37
12+
--> $DIR/migrate-fail.rs:19:37
1313
|
1414
LL | let arr: [Option<Bar>; 2] = [x; 2];
1515
| ^^^^^^ the trait `Copy` is not implemented for `Option<Bar>`

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/migrate-pass.rs renamed to ‎src/test/ui/consts/const-blocks/migrate-pass.rs

-1
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,6 @@
11
// check-pass
22
// compile-flags: -Z borrowck=migrate
33
// ignore-compare-mode-nll
4-
#![feature(const_in_array_repeat_expressions)]
54
#![allow(warnings)]
65

76
// Some type that is not copyable.

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/nll-fail.rs renamed to ‎src/test/ui/consts/const-blocks/nll-fail.rs

-1
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,4 @@
11
// ignore-compare-mode-nll
2-
#![feature(const_in_array_repeat_expressions, nll)]
32
#![allow(warnings)]
43

54
// Some type that is not copyable.

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/nll-fail.stderr renamed to ‎src/test/ui/consts/const-blocks/nll-fail.stderr

+2-2
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0277]: the trait bound `Option<Bar>: Copy` is not satisfied
2-
--> $DIR/nll-fail.rs:13:37
2+
--> $DIR/nll-fail.rs:12:37
33
|
44
LL | let arr: [Option<Bar>; 2] = [x; 2];
55
| ^^^^^^ the trait `Copy` is not implemented for `Option<Bar>`
@@ -9,7 +9,7 @@ LL | let arr: [Option<Bar>; 2] = [x; 2];
99
= note: the `Copy` trait is required because the repeated element will be copied
1010

1111
error[E0277]: the trait bound `Option<Bar>: Copy` is not satisfied
12-
--> $DIR/nll-fail.rs:19:37
12+
--> $DIR/nll-fail.rs:18:37
1313
|
1414
LL | let arr: [Option<Bar>; 2] = [x; 2];
1515
| ^^^^^^ the trait `Copy` is not implemented for `Option<Bar>`

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/nll-pass.rs renamed to ‎src/test/ui/consts/const-blocks/nll-pass.rs

-1
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,6 @@
11
// check-pass
22
// ignore-compare-mode-nll
33
#![allow(warnings)]
4-
#![feature(const_in_array_repeat_expressions, nll)]
54

65
// Some type that is not copyable.
76
struct Bar;

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/run-pass.rs renamed to ‎src/test/ui/consts/const-blocks/run-pass.rs

-1
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,4 @@
11
// run-pass
2-
#![feature(const_in_array_repeat_expressions)]
32

43
#[derive(Debug, Eq, PartialEq)]
54
struct Bar;

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/trait-error.rs renamed to ‎src/test/ui/consts/const-blocks/trait-error.rs

-2
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,3 @@
1-
#![feature(const_in_array_repeat_expressions)]
2-
31
#[derive(Copy, Clone)]
42
struct Foo<T>(T);
53

Diff for: ‎src/test/ui/consts/rfc-2203-const-array-repeat-exprs/trait-error.stderr renamed to ‎src/test/ui/consts/const-blocks/trait-error.stderr

+1-1
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
error[E0277]: the trait bound `Foo<String>: Copy` is not satisfied
2-
--> $DIR/trait-error.rs:7:5
2+
--> $DIR/trait-error.rs:5:5
33
|
44
LL | [Foo(String::new()); 4];
55
| ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Foo<String>`

Diff for: ‎src/test/ui/feature-gates/feature-gate-const_in_array_repeat_expressions.rs

-17
This file was deleted.

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