Auto merge of #116482 - matthewjasper:thir-unsafeck-inline-constants, r=b-naber

Fix inline const pattern unsafety checking in THIR

Fix THIR unsafety checking of inline constants.
- Steal THIR in THIR unsafety checking (if enabled) instead of MIR lowering.
- Represent inline constants in THIR patterns.
This commit is contained in:
bors 2023-10-25 00:03:57 +00:00
commit 848a387967
24 changed files with 246 additions and 63 deletions

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@ -775,12 +775,16 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
rustc_hir_analysis::check_crate(tcx)?;
sess.time("MIR_borrow_checking", || {
tcx.hir().par_body_owners(|def_id| tcx.ensure().mir_borrowck(def_id));
tcx.hir().par_body_owners(|def_id| {
// Run THIR unsafety check because it's responsible for stealing
// and deallocating THIR when enabled.
tcx.ensure().thir_check_unsafety(def_id);
tcx.ensure().mir_borrowck(def_id)
});
});
sess.time("MIR_effect_checking", || {
for def_id in tcx.hir().body_owners() {
tcx.ensure().thir_check_unsafety(def_id);
if !tcx.sess.opts.unstable_opts.thir_unsafeck {
rustc_mir_transform::check_unsafety::check_unsafety(tcx, def_id);
}

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@ -636,7 +636,8 @@ fn walk_(&self, it: &mut impl FnMut(&Pat<'tcx>) -> bool) {
Wild | Range(..) | Binding { subpattern: None, .. } | Constant { .. } | Error(_) => {}
AscribeUserType { subpattern, .. }
| Binding { subpattern: Some(subpattern), .. }
| Deref { subpattern } => subpattern.walk_(it),
| Deref { subpattern }
| InlineConstant { subpattern, .. } => subpattern.walk_(it),
Leaf { subpatterns } | Variant { subpatterns, .. } => {
subpatterns.iter().for_each(|field| field.pattern.walk_(it))
}
@ -764,6 +765,22 @@ pub enum PatKind<'tcx> {
value: mir::Const<'tcx>,
},
/// Inline constant found while lowering a pattern.
InlineConstant {
/// [LocalDefId] of the constant, we need this so that we have a
/// reference that can be used by unsafety checking to visit nested
/// unevaluated constants.
def: LocalDefId,
/// If the inline constant is used in a range pattern, this subpattern
/// represents the range (if both ends are inline constants, there will
/// be multiple InlineConstant wrappers).
///
/// Otherwise, the actual pattern that the constant lowered to. As with
/// other constants, inline constants are matched structurally where
/// possible.
subpattern: Box<Pat<'tcx>>,
},
Range(Box<PatRange<'tcx>>),
/// Matches against a slice, checking the length and extracting elements.
@ -924,6 +941,9 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{subpattern}")
}
PatKind::Constant { value } => write!(f, "{value}"),
PatKind::InlineConstant { def: _, ref subpattern } => {
write!(f, "{} (from inline const)", subpattern)
}
PatKind::Range(box PatRange { lo, hi, end }) => {
write!(f, "{lo}")?;
write!(f, "{end}")?;

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@ -233,16 +233,17 @@ pub fn walk_pat<'a, 'tcx: 'a, V: Visitor<'a, 'tcx>>(visitor: &mut V, pat: &Pat<'
}
}
Constant { value: _ } => {}
InlineConstant { def: _, subpattern } => visitor.visit_pat(subpattern),
Range(_) => {}
Slice { prefix, slice, suffix } | Array { prefix, slice, suffix } => {
for subpattern in prefix.iter() {
visitor.visit_pat(&subpattern);
visitor.visit_pat(subpattern);
}
if let Some(pat) = slice {
visitor.visit_pat(&pat);
visitor.visit_pat(pat);
}
for subpattern in suffix.iter() {
visitor.visit_pat(&subpattern);
visitor.visit_pat(subpattern);
}
}
Or { pats } => {

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@ -847,6 +847,10 @@ pub(super) fn visit_primary_bindings(
self.visit_primary_bindings(subpattern, subpattern_user_ty, f)
}
PatKind::InlineConstant { ref subpattern, .. } => {
self.visit_primary_bindings(subpattern, pattern_user_ty.clone(), f)
}
PatKind::Leaf { ref subpatterns } => {
for subpattern in subpatterns {
let subpattern_user_ty = pattern_user_ty.clone().leaf(subpattern.field);

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@ -204,6 +204,12 @@ fn simplify_match_pair<'pat>(
Err(match_pair)
}
PatKind::InlineConstant { subpattern: ref pattern, def: _ } => {
candidate.match_pairs.push(MatchPair::new(match_pair.place, pattern, self));
Ok(())
}
PatKind::Range(box PatRange { lo, hi, end }) => {
let (range, bias) = match *lo.ty().kind() {
ty::Char => {
@ -229,8 +235,8 @@ fn simplify_match_pair<'pat>(
// correct the comparison. This is achieved by XORing with a bias (see
// pattern/_match.rs for another pertinent example of this pattern).
//
// Also, for performance, it's important to only do the second `try_to_bits` if
// necessary.
// Also, for performance, it's important to only do the second
// `try_to_bits` if necessary.
let lo = lo.try_to_bits(sz).unwrap() ^ bias;
if lo <= min {
let hi = hi.try_to_bits(sz).unwrap() ^ bias;

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@ -73,6 +73,7 @@ pub(super) fn test<'pat>(&mut self, match_pair: &MatchPair<'pat, 'tcx>) -> Test<
PatKind::Or { .. } => bug!("or-patterns should have already been handled"),
PatKind::AscribeUserType { .. }
| PatKind::InlineConstant { .. }
| PatKind::Array { .. }
| PatKind::Wild
| PatKind::Binding { .. }
@ -111,6 +112,7 @@ pub(super) fn add_cases_to_switch<'pat>(
| PatKind::Or { .. }
| PatKind::Binding { .. }
| PatKind::AscribeUserType { .. }
| PatKind::InlineConstant { .. }
| PatKind::Leaf { .. }
| PatKind::Deref { .. }
| PatKind::Error(_) => {

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@ -53,10 +53,7 @@ pub(crate) fn closure_saved_names_of_captured_variables<'tcx>(
}
/// Construct the MIR for a given `DefId`.
fn mir_build(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
// Ensure unsafeck and abstract const building is ran before we steal the THIR.
tcx.ensure_with_value()
.thir_check_unsafety(tcx.typeck_root_def_id(def.to_def_id()).expect_local());
fn mir_build<'tcx>(tcx: TyCtxt<'tcx>, def: LocalDefId) -> Body<'tcx> {
tcx.ensure_with_value().thir_abstract_const(def);
if let Err(e) = tcx.check_match(def) {
return construct_error(tcx, def, e);
@ -65,20 +62,27 @@ fn mir_build(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
let body = match tcx.thir_body(def) {
Err(error_reported) => construct_error(tcx, def, error_reported),
Ok((thir, expr)) => {
// We ran all queries that depended on THIR at the beginning
// of `mir_build`, so now we can steal it
let thir = thir.steal();
let build_mir = |thir: &Thir<'tcx>| match thir.body_type {
thir::BodyTy::Fn(fn_sig) => construct_fn(tcx, def, thir, expr, fn_sig),
thir::BodyTy::Const(ty) => construct_const(tcx, def, thir, expr, ty),
};
tcx.ensure().check_match(def);
// this must run before MIR dump, because
// "not all control paths return a value" is reported here.
//
// maybe move the check to a MIR pass?
tcx.ensure().check_liveness(def);
match thir.body_type {
thir::BodyTy::Fn(fn_sig) => construct_fn(tcx, def, &thir, expr, fn_sig),
thir::BodyTy::Const(ty) => construct_const(tcx, def, &thir, expr, ty),
if tcx.sess.opts.unstable_opts.thir_unsafeck {
// Don't steal here if THIR unsafeck is being used. Instead
// steal in unsafeck. This is so that pattern inline constants
// can be evaluated as part of building the THIR of the parent
// function without a cycle.
build_mir(&thir.borrow())
} else {
// We ran all queries that depended on THIR at the beginning
// of `mir_build`, so now we can steal it
build_mir(&thir.steal())
}
}
};

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@ -124,7 +124,9 @@ fn unsafe_op_in_unsafe_fn_allowed(&self) -> bool {
/// Handle closures/coroutines/inline-consts, which is unsafecked with their parent body.
fn visit_inner_body(&mut self, def: LocalDefId) {
if let Ok((inner_thir, expr)) = self.tcx.thir_body(def) {
let inner_thir = &inner_thir.borrow();
// Runs all other queries that depend on THIR.
self.tcx.ensure_with_value().mir_built(def);
let inner_thir = &inner_thir.steal();
let hir_context = self.tcx.hir().local_def_id_to_hir_id(def);
let mut inner_visitor = UnsafetyVisitor { thir: inner_thir, hir_context, ..*self };
inner_visitor.visit_expr(&inner_thir[expr]);
@ -224,6 +226,7 @@ fn visit_pat(&mut self, pat: &Pat<'tcx>) {
PatKind::Wild |
// these just wrap other patterns
PatKind::Or { .. } |
PatKind::InlineConstant { .. } |
PatKind::AscribeUserType { .. } |
PatKind::Error(_) => {}
}
@ -277,6 +280,9 @@ fn visit_pat(&mut self, pat: &Pat<'tcx>) {
visit::walk_pat(self, pat);
self.inside_adt = old_inside_adt;
}
PatKind::InlineConstant { def, .. } => {
self.visit_inner_body(*def);
}
_ => {
visit::walk_pat(self, pat);
}
@ -788,7 +794,9 @@ pub fn thir_check_unsafety(tcx: TyCtxt<'_>, def: LocalDefId) {
}
let Ok((thir, expr)) = tcx.thir_body(def) else { return };
let thir = &thir.borrow();
// Runs all other queries that depend on THIR.
tcx.ensure_with_value().mir_built(def);
let thir = &thir.steal();
// If `thir` is empty, a type error occurred, skip this body.
if thir.exprs.is_empty() {
return;

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@ -1326,7 +1326,8 @@ pub(crate) fn from_pat(cx: &MatchCheckCtxt<'p, 'tcx>, pat: &Pat<'tcx>) -> Self {
let ctor;
let fields;
match &pat.kind {
PatKind::AscribeUserType { subpattern, .. } => return mkpat(subpattern),
PatKind::AscribeUserType { subpattern, .. }
| PatKind::InlineConstant { subpattern, .. } => return mkpat(subpattern),
PatKind::Binding { subpattern: Some(subpat), .. } => return mkpat(subpat),
PatKind::Binding { subpattern: None, .. } | PatKind::Wild => {
ctor = Wildcard;

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@ -27,6 +27,7 @@
self, AdtDef, CanonicalUserTypeAnnotation, GenericArg, GenericArgsRef, Region, Ty, TyCtxt,
TypeVisitableExt, UserType,
};
use rustc_span::def_id::LocalDefId;
use rustc_span::{ErrorGuaranteed, Span, Symbol};
use rustc_target::abi::{FieldIdx, Integer};
@ -88,15 +89,21 @@ fn lower_pattern(&mut self, pat: &'tcx hir::Pat<'tcx>) -> Box<Pat<'tcx>> {
fn lower_pattern_range_endpoint(
&mut self,
expr: Option<&'tcx hir::Expr<'tcx>>,
) -> Result<(Option<mir::Const<'tcx>>, Option<Ascription<'tcx>>), ErrorGuaranteed> {
) -> Result<
(Option<mir::Const<'tcx>>, Option<Ascription<'tcx>>, Option<LocalDefId>),
ErrorGuaranteed,
> {
match expr {
None => Ok((None, None)),
None => Ok((None, None, None)),
Some(expr) => {
let (kind, ascr) = match self.lower_lit(expr) {
PatKind::AscribeUserType { ascription, subpattern: box Pat { kind, .. } } => {
(kind, Some(ascription))
let (kind, ascr, inline_const) = match self.lower_lit(expr) {
PatKind::InlineConstant { subpattern, def } => {
(subpattern.kind, None, Some(def))
}
kind => (kind, None),
PatKind::AscribeUserType { ascription, subpattern: box Pat { kind, .. } } => {
(kind, Some(ascription), None)
}
kind => (kind, None, None),
};
let value = if let PatKind::Constant { value } = kind {
value
@ -106,7 +113,7 @@ fn lower_pattern_range_endpoint(
);
return Err(self.tcx.sess.delay_span_bug(expr.span, msg));
};
Ok((Some(value), ascr))
Ok((Some(value), ascr, inline_const))
}
}
}
@ -177,8 +184,8 @@ fn lower_pattern_range(
return Err(self.tcx.sess.delay_span_bug(span, msg));
}
let (lo, lo_ascr) = self.lower_pattern_range_endpoint(lo_expr)?;
let (hi, hi_ascr) = self.lower_pattern_range_endpoint(hi_expr)?;
let (lo, lo_ascr, lo_inline) = self.lower_pattern_range_endpoint(lo_expr)?;
let (hi, hi_ascr, hi_inline) = self.lower_pattern_range_endpoint(hi_expr)?;
let lo = lo.unwrap_or_else(|| {
// Unwrap is ok because the type is known to be numeric.
@ -237,6 +244,12 @@ fn lower_pattern_range(
};
}
}
for inline_const in [lo_inline, hi_inline] {
if let Some(def) = inline_const {
kind =
PatKind::InlineConstant { def, subpattern: Box::new(Pat { span, ty, kind }) };
}
}
Ok(kind)
}
@ -599,11 +612,9 @@ fn lower_inline_const(
// const eval path below.
// FIXME: investigate the performance impact of removing this.
let lit_input = match expr.kind {
hir::ExprKind::Lit(ref lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: false }),
hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => match expr.kind {
hir::ExprKind::Lit(ref lit) => {
Some(LitToConstInput { lit: &lit.node, ty, neg: true })
}
hir::ExprKind::Lit(lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: false }),
hir::ExprKind::Unary(hir::UnOp::Neg, expr) => match expr.kind {
hir::ExprKind::Lit(lit) => Some(LitToConstInput { lit: &lit.node, ty, neg: true }),
_ => None,
},
_ => None,
@ -633,13 +644,13 @@ fn lower_inline_const(
if let Ok(Some(valtree)) =
self.tcx.const_eval_resolve_for_typeck(self.param_env, ct, Some(span))
{
self.const_to_pat(
let subpattern = self.const_to_pat(
Const::Ty(ty::Const::new_value(self.tcx, valtree, ty)),
id,
span,
None,
)
.kind
);
PatKind::InlineConstant { subpattern, def: def_id }
} else {
// If that fails, convert it to an opaque constant pattern.
match tcx.const_eval_resolve(self.param_env, uneval, Some(span)) {
@ -822,6 +833,9 @@ fn super_fold_with<F: PatternFolder<'tcx>>(&self, folder: &mut F) -> Self {
PatKind::Deref { subpattern: subpattern.fold_with(folder) }
}
PatKind::Constant { value } => PatKind::Constant { value },
PatKind::InlineConstant { def, subpattern: ref pattern } => {
PatKind::InlineConstant { def, subpattern: pattern.fold_with(folder) }
}
PatKind::Range(ref range) => PatKind::Range(range.clone()),
PatKind::Slice { ref prefix, ref slice, ref suffix } => PatKind::Slice {
prefix: prefix.fold_with(folder),

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@ -692,7 +692,7 @@ fn print_pat_kind(&mut self, pat_kind: &PatKind<'tcx>, depth_lvl: usize) {
}
PatKind::Deref { subpattern } => {
print_indented!(self, "Deref { ", depth_lvl + 1);
print_indented!(self, "subpattern: ", depth_lvl + 2);
print_indented!(self, "subpattern:", depth_lvl + 2);
self.print_pat(subpattern, depth_lvl + 2);
print_indented!(self, "}", depth_lvl + 1);
}
@ -701,6 +701,13 @@ fn print_pat_kind(&mut self, pat_kind: &PatKind<'tcx>, depth_lvl: usize) {
print_indented!(self, format!("value: {:?}", value), depth_lvl + 2);
print_indented!(self, "}", depth_lvl + 1);
}
PatKind::InlineConstant { def, subpattern } => {
print_indented!(self, "InlineConstant {", depth_lvl + 1);
print_indented!(self, format!("def: {:?}", def), depth_lvl + 2);
print_indented!(self, "subpattern:", depth_lvl + 2);
self.print_pat(subpattern, depth_lvl + 2);
print_indented!(self, "}", depth_lvl + 1);
}
PatKind::Range(pat_range) => {
print_indented!(self, format!("Range ( {:?} )", pat_range), depth_lvl + 1);
}

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@ -23,7 +23,7 @@ LL | S::f();
= note: consult the function's documentation for information on how to avoid undefined behavior
error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
--> $DIR/async-unsafe-fn-call-in-safe.rs:24:5
--> $DIR/async-unsafe-fn-call-in-safe.rs:26:5
|
LL | f();
| ^^^ call to unsafe function

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@ -20,6 +20,10 @@ async fn g() {
}
fn main() {
S::f(); //[mir]~ ERROR call to unsafe function is unsafe
f(); //[mir]~ ERROR call to unsafe function is unsafe
S::f();
//[mir]~^ ERROR call to unsafe function is unsafe
//[thir]~^^ ERROR call to unsafe function `S::f` is unsafe
f();
//[mir]~^ ERROR call to unsafe function is unsafe
//[thir]~^^ ERROR call to unsafe function `f` is unsafe
}

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@ -14,6 +14,22 @@ LL | f();
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error: aborting due to 2 previous errors
error[E0133]: call to unsafe function `S::f` is unsafe and requires unsafe function or block
--> $DIR/async-unsafe-fn-call-in-safe.rs:23:5
|
LL | S::f();
| ^^^^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error[E0133]: call to unsafe function `f` is unsafe and requires unsafe function or block
--> $DIR/async-unsafe-fn-call-in-safe.rs:26:5
|
LL | f();
| ^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error: aborting due to 4 previous errors
For more information about this error, try `rustc --explain E0133`.

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@ -11,4 +11,5 @@ fn main() {
//[thir]~^^ call to unsafe function `foo` is unsafe and requires unsafe function or block
foo();
//[mir]~^ ERROR call to unsafe function is unsafe and requires unsafe function or block
//[thir]~^^ ERROR call to unsafe function `foo` is unsafe and requires unsafe function or block
}

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@ -1,3 +1,11 @@
error[E0133]: call to unsafe function `foo` is unsafe and requires unsafe function or block
--> $DIR/const-extern-fn-requires-unsafe.rs:12:5
|
LL | foo();
| ^^^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error[E0133]: call to unsafe function `foo` is unsafe and requires unsafe function or block
--> $DIR/const-extern-fn-requires-unsafe.rs:9:17
|
@ -6,6 +14,6 @@ LL | let a: [u8; foo()];
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error: aborting due to previous error
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0133`.

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@ -1,11 +1,13 @@
// ignore-test This is currently broken
// revisions: mir thir
// [mir]ignore-test This is currently broken
// [thir]compile-flags: -Z thir-unsafeck
#![allow(incomplete_features)]
#![feature(inline_const_pat)]
const unsafe fn require_unsafe() -> usize { 1 }
const unsafe fn require_unsafe() -> usize {
1
}
fn main() {
match () {
@ -14,4 +16,12 @@ fn main() {
//~^ ERROR [E0133]
} => (),
}
match 1 {
const {
require_unsafe()
//~^ ERROR [E0133]
}..=4 => (),
_ => (),
}
}

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@ -0,0 +1,19 @@
error[E0133]: call to unsafe function `require_unsafe` is unsafe and requires unsafe function or block
--> $DIR/pat-unsafe-err.rs:15:13
|
LL | require_unsafe();
| ^^^^^^^^^^^^^^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error[E0133]: call to unsafe function `require_unsafe` is unsafe and requires unsafe function or block
--> $DIR/pat-unsafe-err.rs:22:13
|
LL | require_unsafe()
| ^^^^^^^^^^^^^^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0133`.

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@ -1,13 +1,15 @@
// ignore-test This is currently broken
// check-pass
// revisions: mir thir
// [mir]ignore-test This is currently broken
// [thir]compile-flags: -Z thir-unsafeck
#![allow(incomplete_features)]
#![warn(unused_unsafe)]
#![feature(inline_const_pat)]
const unsafe fn require_unsafe() -> usize { 1 }
const unsafe fn require_unsafe() -> usize {
1
}
fn main() {
unsafe {
@ -18,5 +20,14 @@ fn main() {
//~^ WARNING unnecessary `unsafe` block
} => (),
}
match 1 {
const {
unsafe {}
//~^ WARNING unnecessary `unsafe` block
require_unsafe()
}..=4 => (),
_ => (),
}
}
}

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@ -0,0 +1,26 @@
warning: unnecessary `unsafe` block
--> $DIR/pat-unsafe.rs:19:17
|
LL | unsafe {
| ------ because it's nested under this `unsafe` block
...
LL | unsafe {}
| ^^^^^^ unnecessary `unsafe` block
|
note: the lint level is defined here
--> $DIR/pat-unsafe.rs:7:9
|
LL | #![warn(unused_unsafe)]
| ^^^^^^^^^^^^^
warning: unnecessary `unsafe` block
--> $DIR/pat-unsafe.rs:26:17
|
LL | unsafe {
| ------ because it's nested under this `unsafe` block
...
LL | unsafe {}
| ^^^^^^ unnecessary `unsafe` block
warning: 2 warnings emitted

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@ -0,0 +1,14 @@
error: `{closure@$DIR/non-structural-match-types.rs:12:17: 12:19}` cannot be used in patterns
--> $DIR/non-structural-match-types.rs:12:9
|
LL | const { || {} } => {}
| ^^^^^^^^^^^^^^^
error: `{async block@$DIR/non-structural-match-types.rs:15:17: 15:25}` cannot be used in patterns
--> $DIR/non-structural-match-types.rs:15:9
|
LL | const { async {} } => {}
| ^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors

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@ -1,4 +1,7 @@
// edition:2021
// revisions: mir thir
// [thir]compile-flags: -Z thir-unsafeck
#![allow(incomplete_features)]
#![allow(unreachable_code)]
#![feature(const_async_blocks)]

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@ -1,14 +0,0 @@
error: `{closure@$DIR/non-structural-match-types.rs:9:17: 9:19}` cannot be used in patterns
--> $DIR/non-structural-match-types.rs:9:9
|
LL | const { || {} } => {}
| ^^^^^^^^^^^^^^^
error: `{async block@$DIR/non-structural-match-types.rs:12:17: 12:25}` cannot be used in patterns
--> $DIR/non-structural-match-types.rs:12:9
|
LL | const { async {} } => {}
| ^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors

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@ -0,0 +1,14 @@
error: `{closure@$DIR/non-structural-match-types.rs:12:17: 12:19}` cannot be used in patterns
--> $DIR/non-structural-match-types.rs:12:9
|
LL | const { || {} } => {}
| ^^^^^^^^^^^^^^^
error: `{async block@$DIR/non-structural-match-types.rs:15:17: 15:25}` cannot be used in patterns
--> $DIR/non-structural-match-types.rs:15:9
|
LL | const { async {} } => {}
| ^^^^^^^^^^^^^^^^^^
error: aborting due to 2 previous errors