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Unrolled build for rust-lang#123049
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Rollup merge of rust-lang#123049 - compiler-errors:coroutine-closure-rcvr, r=oli-obk

In `ConstructCoroutineInClosureShim`, pass receiver by mut ref, not mut pointer

The receivers were compatible at codegen time, but did not necessarily have the same layouts due to niches, which was caught by miri.

Fixes rust-lang/miri#3400

r? oli-obk
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rust-timer authored Mar 27, 2024
2 parents 47ecded + 22bc5c5 commit 04dc2e4
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Showing 8 changed files with 81 additions and 21 deletions.
6 changes: 3 additions & 3 deletions compiler/rustc_mir_transform/src/shim.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1015,8 +1015,8 @@ fn build_construct_coroutine_by_move_shim<'tcx>(
bug!();
};

// We use `*mut Self` here because we only need to emit an ABI-compatible shim body,
// rather than match the signature exactly.
// We use `&mut Self` here because we only need to emit an ABI-compatible shim body,
// rather than match the signature exactly (which might take `&self` instead).
//
// The self type here is a coroutine-closure, not a coroutine, and we never read from
// it because it never has any captures, because this is only true in the Fn/FnMut
Expand All @@ -1025,7 +1025,7 @@ fn build_construct_coroutine_by_move_shim<'tcx>(
if receiver_by_ref {
// Triple-check that there's no captures here.
assert_eq!(args.as_coroutine_closure().tupled_upvars_ty(), tcx.types.unit);
self_ty = Ty::new_mut_ptr(tcx, self_ty);
self_ty = Ty::new_mut_ref(tcx, tcx.lifetimes.re_erased, self_ty);
}

let poly_sig = args.as_coroutine_closure().coroutine_closure_sig().map_bound(|sig| {
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8 changes: 6 additions & 2 deletions compiler/rustc_ty_utils/src/abi.rs
Original file line number Diff line number Diff line change
Expand Up @@ -125,8 +125,12 @@ fn fn_sig_for_fn_abi<'tcx>(
coroutine_kind = ty::ClosureKind::FnOnce;

// Implementations of `FnMut` and `Fn` for coroutine-closures
// still take their receiver by ref.
if receiver_by_ref { Ty::new_mut_ptr(tcx, coroutine_ty) } else { coroutine_ty }
// still take their receiver by (mut) ref.
if receiver_by_ref {
Ty::new_mut_ref(tcx, tcx.lifetimes.re_erased, coroutine_ty)
} else {
coroutine_ty
}
} else {
tcx.closure_env_ty(coroutine_ty, coroutine_kind, env_region)
};
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40 changes: 40 additions & 0 deletions src/tools/miri/tests/pass/async-closure-drop.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,40 @@
#![feature(async_closure, noop_waker, async_fn_traits)]

use std::future::Future;
use std::pin::pin;
use std::task::*;

pub fn block_on<T>(fut: impl Future<Output = T>) -> T {
let mut fut = pin!(fut);
let ctx = &mut Context::from_waker(Waker::noop());

loop {
match fut.as_mut().poll(ctx) {
Poll::Pending => {}
Poll::Ready(t) => break t,
}
}
}

async fn call_once(f: impl async FnOnce(DropMe)) {
f(DropMe("world")).await;
}

#[derive(Debug)]
struct DropMe(&'static str);

impl Drop for DropMe {
fn drop(&mut self) {
println!("{}", self.0);
}
}

pub fn main() {
block_on(async {
let b = DropMe("hello");
let async_closure = async move |a: DropMe| {
println!("{a:?} {b:?}");
};
call_once(async_closure).await;
});
}
3 changes: 3 additions & 0 deletions src/tools/miri/tests/pass/async-closure-drop.stdout
Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
DropMe("world") DropMe("hello")
world
hello
34 changes: 23 additions & 11 deletions src/tools/miri/tests/pass/async-closure.rs
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#![feature(async_closure, noop_waker, async_fn_traits)]

use std::future::Future;
use std::ops::{AsyncFnMut, AsyncFnOnce};
use std::pin::pin;
use std::task::*;

Expand All @@ -16,25 +17,36 @@ pub fn block_on<T>(fut: impl Future<Output = T>) -> T {
}
}

async fn call_once(f: impl async FnOnce(DropMe)) {
f(DropMe("world")).await;
async fn call_mut(f: &mut impl AsyncFnMut(i32)) {
f(0).await;
}

#[derive(Debug)]
struct DropMe(&'static str);
async fn call_once(f: impl AsyncFnOnce(i32)) {
f(1).await;
}

impl Drop for DropMe {
fn drop(&mut self) {
println!("{}", self.0);
}
async fn call_normal<F: Future<Output = ()>>(f: &impl Fn(i32) -> F) {
f(0).await;
}

async fn call_normal_once<F: Future<Output = ()>>(f: impl FnOnce(i32) -> F) {
f(1).await;
}

pub fn main() {
block_on(async {
let b = DropMe("hello");
let async_closure = async move |a: DropMe| {
println!("{a:?} {b:?}");
let b = 2i32;
let mut async_closure = async move |a: i32| {
println!("{a} {b}");
};
call_mut(&mut async_closure).await;
call_once(async_closure).await;

// No-capture closures implement `Fn`.
let async_closure = async move |a: i32| {
println!("{a}");
};
call_normal(&async_closure).await;
call_normal_once(async_closure).await;
});
}
7 changes: 4 additions & 3 deletions src/tools/miri/tests/pass/async-closure.stdout
Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
DropMe("world") DropMe("hello")
world
hello
0 2
1 2
0
1
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
// MIR for `main::{closure#0}::{closure#1}` 0 coroutine_closure_by_ref

fn main::{closure#0}::{closure#1}(_1: *mut {async closure@$DIR/async_closure_shims.rs:49:29: 49:48}, _2: i32) -> {async closure body@$DIR/async_closure_shims.rs:49:49: 51:10} {
fn main::{closure#0}::{closure#1}(_1: &mut {async closure@$DIR/async_closure_shims.rs:49:29: 49:48}, _2: i32) -> {async closure body@$DIR/async_closure_shims.rs:49:49: 51:10} {
let mut _0: {async closure body@$DIR/async_closure_shims.rs:49:49: 51:10};

bb0: {
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
// MIR for `main::{closure#0}::{closure#1}` 0 coroutine_closure_by_ref

fn main::{closure#0}::{closure#1}(_1: *mut {async closure@$DIR/async_closure_shims.rs:49:29: 49:48}, _2: i32) -> {async closure body@$DIR/async_closure_shims.rs:49:49: 51:10} {
fn main::{closure#0}::{closure#1}(_1: &mut {async closure@$DIR/async_closure_shims.rs:49:29: 49:48}, _2: i32) -> {async closure body@$DIR/async_closure_shims.rs:49:49: 51:10} {
let mut _0: {async closure body@$DIR/async_closure_shims.rs:49:49: 51:10};

bb0: {
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