Automatic Rustup

README.md

@@ -505,6 +505,8 @@ binaries, and as such worth documenting:
 * `MIRI_LOCAL_CRATES` is set by `cargo-miri` to tell the Miri driver which
   crates should be given special treatment in diagnostics, in addition to the
   crate currently being compiled.
+* `MIRI_ORIG_RUSTDOC` is set and read by different phases of `cargo-miri` to remember the
+  value of `RUSTDOC` from before it was overwritten.
 * `MIRI_VERBOSE` when set to any value tells the various `cargo-miri` phases to
   perform verbose logging.
 * `MIRI_HOST_SYSROOT` is set by bootstrap to tell `cargo-miri` which sysroot to use for *host*

cargo-miri/src/phases.rs

@@ -211,6 +211,9 @@ pub fn phase_cargo_miri(mut args: impl Iterator<Item = String>) {
     cmd.env("MIRI_BE_RUSTC", "target"); // we better remember to *unset* this in the other phases!
 
     // Set rustdoc to us as well, so we can run doctests.
+    if let Some(orig_rustdoc) = env::var_os("RUSTDOC") {
+        cmd.env("MIRI_ORIG_RUSTDOC", orig_rustdoc);
+    }
     cmd.env("RUSTDOC", &cargo_miri_path);
 
     cmd.env("MIRI_LOCAL_CRATES", local_crates(&metadata));
@@ -581,9 +584,10 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
     let verbose = std::env::var("MIRI_VERBOSE")
         .map_or(0, |verbose| verbose.parse().expect("verbosity flag must be an integer"));
 
-    // phase_cargo_miri sets the RUSTDOC env var to ourselves, so we can't use that here;
-    // just default to a straight-forward invocation for now:
-    let mut cmd = Command::new("rustdoc");
+    // phase_cargo_miri sets the RUSTDOC env var to ourselves, and puts a backup
+    // of the old value into MIRI_ORIG_RUSTDOC. So that's what we have to invoke now.
+    let rustdoc = env::var("MIRI_ORIG_RUSTDOC").unwrap_or("rustdoc".to_string());
+    let mut cmd = Command::new(rustdoc);
 
     while let Some(arg) = args.next() {
         if arg == "--extern" {

rust-version

@@ -1 +1 @@
-b13a71a2e77f4625d1a2b8a5b9488414686ebca9
+760e567af5398a0d8c512f904e551e1f38e00d79

src/shims/panic.rs

@@ -256,8 +256,16 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             }
 
             _ => {
-                // Forward everything else to `panic` lang item.
-                this.start_panic(msg.description(), unwind)?;
+                // Call the lang item associated with this message.
+                let fn_item = this.tcx.require_lang_item(msg.panic_function(), None);
+                let instance = ty::Instance::mono(this.tcx.tcx, fn_item);
+                this.call_function(
+                    instance,
+                    Abi::Rust,
+                    &[],
+                    None,
+                    StackPopCleanup::Goto { ret: None, unwind },
+                )?;
             }
         }
         Ok(())

tests/pass/async-closure-drop.rs

@@ -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;
+    });
+}

tests/pass/async-closure-drop.stdout

@@ -0,0 +1,3 @@
+DropMe("world") DropMe("hello")
+world
+hello

tests/pass/async-closure.rs

@@ -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::*;
 
@@ -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;
     });
 }

tests/pass/async-closure.stdout

@@ -1,3 +1,4 @@
-DropMe("world") DropMe("hello")
-world
-hello
+0 2
+1 2
+0
+1