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delay_span_bug if const-checking an async function

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This errors during AST lowering. Any errors we emit here are just noise.
This commit is contained in:
Dylan MacKenzie 2020-09-29 19:13:25 -07:00
parent 25c7753eee
commit c38aca0502
5 changed files with 38 additions and 61 deletions
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19
compiler/rustc_mir/src/transform/check_consts/validation.rs
View file

@ -1,8 +1,8 @@
//! The `Visitor` responsible for actually checking a `mir::Body` for invalid operations.
use rustc_errors::struct_span_err;
use rustc_hir::{self as hir, LangItem};
use rustc_hir::{def_id::DefId, HirId};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::{self as hir, HirId, LangItem};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::*;
@ -204,6 +204,13 @@ impl Validator<'mir, 'tcx> {
pub fn check_body(&mut self) {
let ConstCx { tcx, body, def_id, .. } = *self.ccx;
// `async` functions cannot be `const fn`. This is checked during AST lowering, so there's
// no need to emit duplicate errors here.
if is_async_fn(tcx, def_id) || body.generator_kind.is_some() {
tcx.sess.delay_span_bug(body.span, "`async` functions cannot be `const fn`");
return;
}
// The local type and predicate checks are not free and only relevant for `const fn`s.
if self.const_kind() == hir::ConstContext::ConstFn {
// Prevent const trait methods from being annotated as `stable`.
@ -877,3 +884,11 @@ fn place_as_reborrow(
fn is_int_bool_or_char(ty: Ty<'_>) -> bool {
ty.is_bool() || ty.is_integral() || ty.is_char()
}
fn is_async_fn(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
let hir_map = tcx.hir();
let hir_id = hir_map.local_def_id_to_hir_id(def_id);
hir_map
.fn_sig_by_hir_id(hir_id)
.map_or(false, |sig| sig.header.asyncness == hir::IsAsync::Async)
}

1
src/test/ui/async-await/no-const-async.rs
View file

@ -3,4 +3,3 @@
pub const async fn x() {}
//~^ ERROR functions cannot be both `const` and `async`
//~| ERROR `impl Trait` in const fn is unstable

12
src/test/ui/async-await/no-const-async.stderr
View file

@ -7,15 +7,5 @@ LL | pub const async fn x() {}
| | `async` because of this
| `const` because of this
error[E0723]: `impl Trait` in const fn is unstable
--> $DIR/no-const-async.rs:4:24
|
LL | pub const async fn x() {}
| ^
|
= note: see issue #57563 <https://github.com/rust-lang/rust/issues/57563> for more information
= help: add `#![feature(const_fn)]` to the crate attributes to enable
error: aborting due to previous error
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0723`.

3
src/test/ui/parser/fn-header-semantic-fail.rs
View file

@ -12,7 +12,6 @@ fn main() {
extern "C" fn ff4() {} // OK.
const async unsafe extern "C" fn ff5() {} // OK.
//~^ ERROR functions cannot be both `const` and `async`
//~| ERROR `from_generator` is not yet stable as a const fn
trait X {
async fn ft1(); //~ ERROR functions in traits cannot be declared `async`
@ -35,7 +34,6 @@ fn main() {
const async unsafe extern "C" fn ft5() {}
//~^ ERROR functions in traits cannot be declared `async`
//~| ERROR functions in traits cannot be declared const
//~| ERROR `from_generator` is not yet stable as a const fn
//~| ERROR method `ft5` has an incompatible type for trait
//~| ERROR functions cannot be both `const` and `async`
}
@ -47,7 +45,6 @@ fn main() {
extern "C" fn fi4() {} // OK.
const async unsafe extern "C" fn fi5() {}
//~^ ERROR functions cannot be both `const` and `async`
//~| ERROR `from_generator` is not yet stable as a const fn
}
extern {

64
src/test/ui/parser/fn-header-semantic-fail.stderr
View file

@ -8,7 +8,7 @@ LL | const async unsafe extern "C" fn ff5() {} // OK.
| `const` because of this
error[E0706]: functions in traits cannot be declared `async`
--> $DIR/fn-header-semantic-fail.rs:18:9
--> $DIR/fn-header-semantic-fail.rs:17:9
|
LL | async fn ft1();
| -----^^^^^^^^^^
@ -19,19 +19,19 @@ LL | async fn ft1();
= note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
error[E0379]: functions in traits cannot be declared const
--> $DIR/fn-header-semantic-fail.rs:20:9
--> $DIR/fn-header-semantic-fail.rs:19:9
|
LL | const fn ft3();
| ^^^^^ functions in traits cannot be const
error[E0379]: functions in traits cannot be declared const
--> $DIR/fn-header-semantic-fail.rs:22:9
--> $DIR/fn-header-semantic-fail.rs:21:9
|
LL | const async unsafe extern "C" fn ft5();
| ^^^^^ functions in traits cannot be const
error[E0706]: functions in traits cannot be declared `async`
--> $DIR/fn-header-semantic-fail.rs:22:9
--> $DIR/fn-header-semantic-fail.rs:21:9
|
LL | const async unsafe extern "C" fn ft5();
| ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -42,7 +42,7 @@ LL | const async unsafe extern "C" fn ft5();
= note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
error: functions cannot be both `const` and `async`
--> $DIR/fn-header-semantic-fail.rs:22:9
--> $DIR/fn-header-semantic-fail.rs:21:9
|
LL | const async unsafe extern "C" fn ft5();
| ^^^^^-^^^^^----------------------------
@ -51,7 +51,7 @@ LL | const async unsafe extern "C" fn ft5();
| `const` because of this
error[E0706]: functions in traits cannot be declared `async`
--> $DIR/fn-header-semantic-fail.rs:30:9
--> $DIR/fn-header-semantic-fail.rs:29:9
|
LL | async fn ft1() {}
| -----^^^^^^^^^^^^
@ -62,19 +62,19 @@ LL | async fn ft1() {}
= note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
error[E0379]: functions in traits cannot be declared const
--> $DIR/fn-header-semantic-fail.rs:33:9
--> $DIR/fn-header-semantic-fail.rs:32:9
|
LL | const fn ft3() {}
| ^^^^^ functions in traits cannot be const
error[E0379]: functions in traits cannot be declared const
--> $DIR/fn-header-semantic-fail.rs:35:9
--> $DIR/fn-header-semantic-fail.rs:34:9
|
LL | const async unsafe extern "C" fn ft5() {}
| ^^^^^ functions in traits cannot be const
error[E0706]: functions in traits cannot be declared `async`
--> $DIR/fn-header-semantic-fail.rs:35:9
--> $DIR/fn-header-semantic-fail.rs:34:9
|
LL | const async unsafe extern "C" fn ft5() {}
| ^^^^^^-----^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -85,7 +85,7 @@ LL | const async unsafe extern "C" fn ft5() {}
= note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
error: functions cannot be both `const` and `async`
--> $DIR/fn-header-semantic-fail.rs:35:9
--> $DIR/fn-header-semantic-fail.rs:34:9
|
LL | const async unsafe extern "C" fn ft5() {}
| ^^^^^-^^^^^------------------------------
@ -94,7 +94,7 @@ LL | const async unsafe extern "C" fn ft5() {}
| `const` because of this
error: functions cannot be both `const` and `async`
--> $DIR/fn-header-semantic-fail.rs:48:9
--> $DIR/fn-header-semantic-fail.rs:46:9
|
LL | const async unsafe extern "C" fn fi5() {}
| ^^^^^-^^^^^------------------------------
@ -103,7 +103,7 @@ LL | const async unsafe extern "C" fn fi5() {}
| `const` because of this
error: functions in `extern` blocks cannot have qualifiers
--> $DIR/fn-header-semantic-fail.rs:54:18
--> $DIR/fn-header-semantic-fail.rs:51:18
|
LL | extern {
| ------ in this `extern` block
@ -113,7 +113,7 @@ LL | async fn fe1();
| help: remove the qualifiers: `fn`
error: functions in `extern` blocks cannot have qualifiers
--> $DIR/fn-header-semantic-fail.rs:55:19
--> $DIR/fn-header-semantic-fail.rs:52:19
|
LL | extern {
| ------ in this `extern` block
@ -124,7 +124,7 @@ LL | unsafe fn fe2();
| help: remove the qualifiers: `fn`
error: functions in `extern` blocks cannot have qualifiers
--> $DIR/fn-header-semantic-fail.rs:56:18
--> $DIR/fn-header-semantic-fail.rs:53:18
|
LL | extern {
| ------ in this `extern` block
@ -135,7 +135,7 @@ LL | const fn fe3();
| help: remove the qualifiers: `fn`
error: functions in `extern` blocks cannot have qualifiers
--> $DIR/fn-header-semantic-fail.rs:57:23
--> $DIR/fn-header-semantic-fail.rs:54:23
|
LL | extern {
| ------ in this `extern` block
@ -146,7 +146,7 @@ LL | extern "C" fn fe4();
| help: remove the qualifiers: `fn`
error: functions in `extern` blocks cannot have qualifiers
--> $DIR/fn-header-semantic-fail.rs:58:42
--> $DIR/fn-header-semantic-fail.rs:55:42
|
LL | extern {
| ------ in this `extern` block
@ -157,7 +157,7 @@ LL | const async unsafe extern "C" fn fe5();
| help: remove the qualifiers: `fn`
error: functions cannot be both `const` and `async`
--> $DIR/fn-header-semantic-fail.rs:58:9
--> $DIR/fn-header-semantic-fail.rs:55:9
|
LL | const async unsafe extern "C" fn fe5();
| ^^^^^-^^^^^----------------------------
@ -165,16 +165,8 @@ LL | const async unsafe extern "C" fn fe5();
| | `async` because of this
| `const` because of this
error: `from_generator` is not yet stable as a const fn
--> $DIR/fn-header-semantic-fail.rs:13:44
|
LL | const async unsafe extern "C" fn ff5() {} // OK.
| ^^
|
= help: add `#![feature(gen_future)]` to the crate attributes to enable
error[E0053]: method `ft1` has an incompatible type for trait
--> $DIR/fn-header-semantic-fail.rs:30:24
--> $DIR/fn-header-semantic-fail.rs:29:24
|
LL | async fn ft1();
| - type in trait
@ -189,7 +181,7 @@ LL | async fn ft1() {}
found fn pointer `fn() -> impl Future`
error[E0053]: method `ft5` has an incompatible type for trait
--> $DIR/fn-header-semantic-fail.rs:35:48
--> $DIR/fn-header-semantic-fail.rs:34:48
|
LL | const async unsafe extern "C" fn ft5();
| - type in trait
@ -203,23 +195,7 @@ LL | const async unsafe extern "C" fn ft5() {}
= note: expected fn pointer `unsafe extern "C" fn()`
found fn pointer `unsafe extern "C" fn() -> impl Future`
error: `from_generator` is not yet stable as a const fn
--> $DIR/fn-header-semantic-fail.rs:35:48
|
LL | const async unsafe extern "C" fn ft5() {}
| ^^
|
= help: add `#![feature(gen_future)]` to the crate attributes to enable
error: `from_generator` is not yet stable as a const fn
--> $DIR/fn-header-semantic-fail.rs:48:48
|
LL | const async unsafe extern "C" fn fi5() {}
| ^^
|
= help: add `#![feature(gen_future)]` to the crate attributes to enable
error: aborting due to 23 previous errors
error: aborting due to 20 previous errors
Some errors have detailed explanations: E0053, E0379, E0706.
For more information about an error, try `rustc --explain E0053`.