Merge pull request #536 from RalfJung/self-referential-generator

test self-referential generator

Author: RalfJung

tests/run-pass-fullmir/async-fn.rs

@@ -0,0 +1,35 @@
+#![feature(
+    async_await,
+    await_macro,
+    futures_api,
+    pin,
+)]
+
+use std::{future::Future, pin::Pin, task::Poll};
+
+// See if we can run a basic `async fn`
+pub async fn foo(x: &u32, y: u32) -> u32 {
+    let y = &y;
+    let z = 9;
+    let z = &z;
+    let y = await!(async { *y + *z });
+    let a = 10;
+    let a = &a;
+    *x + y + *a
+}
+
+fn main() {
+    use std::{sync::Arc, task::{Wake, local_waker}};
+
+    struct NoWake;
+    impl Wake for NoWake {
+        fn wake(_arc_self: &Arc<Self>) {
+            panic!();
+        }
+    }
+
+    let lw = unsafe { local_waker(Arc::new(NoWake)) };
+    let x = 5;
+    let mut fut = foo(&x, 7);
+    assert_eq!(unsafe { Pin::new_unchecked(&mut fut) }.poll(&lw), Poll::Ready(31));
+}

tests/run-pass/generator_control_flow.rs renamed to tests/run-pass/generator.rs

@@ -13,11 +13,11 @@
 use std::ops::{GeneratorState, Generator};
 
 fn finish<T>(mut amt: usize, mut t: T) -> T::Return
-    where T: Generator<Yield = ()>
+    where T: Generator<Yield = usize>
 {
     loop {
         match unsafe { t.resume() } {
-            GeneratorState::Yielded(()) => amt -= 1,
+            GeneratorState::Yielded(y) => amt -= y,
             GeneratorState::Complete(ret) => {
                 assert_eq!(amt, 0);
                 return ret
@@ -28,38 +28,50 @@ fn finish<T>(mut amt: usize, mut t: T) -> T::Return
 }
 
 fn main() {
-    finish(1, || yield);
+    finish(1, || yield 1);
     finish(3, || {
         let mut x = 0;
-        yield;
+        yield 1;
         x += 1;
-        yield;
+        yield 1;
         x += 1;
-        yield;
+        yield 1;
         assert_eq!(x, 2);
     });
-    finish(8, || {
-        for _ in 0..8 {
-            yield;
+    finish(7*8/2, || {
+        for i in 0..8 {
+            yield i;
         }
     });
     finish(1, || {
         if true {
-            yield;
+            yield 1;
         } else {
         }
     });
     finish(1, || {
         if false {
         } else {
-            yield;
+            yield 1;
         }
     });
     finish(2, || {
-        if { yield; false } {
-            yield;
+        if { yield 1; false } {
+            yield 1;
             panic!()
         }
-        yield
+        yield 1;
     });
+    // also test a self-referential generator
+    assert_eq!(
+        finish(5, || {
+            let mut x = Box::new(5);
+            let y = &mut *x;
+            *y = 5;
+            yield *y;
+            *y = 10;
+            *x
+        }),
+        10
+    );
 }