1 files changed, 144 insertions, 0 deletions
diff --git a/src/test/ui/liveness/liveness-upvars.rs b/src/test/ui/liveness/liveness-upvars.rs
new file mode 100644
index 000000000..d446d57d3
--- /dev/null
+++ b/src/test/ui/liveness/liveness-upvars.rs
@@ -0,0 +1,144 @@
+// edition:2018
+// check-pass
+#![feature(generators)]
+#![warn(unused)]
+#![allow(unreachable_code)]
+
+pub fn unintentional_copy_one() {
+    let mut last = None;
+    let mut f = move |s| {
+        last = Some(s); //~  WARN value assigned to `last` is never read
+                        //~| WARN unused variable: `last`
+    };
+    f("a");
+    f("b");
+    f("c");
+    dbg!(last.unwrap());
+}
+
+pub fn unintentional_copy_two() {
+    let mut sum = 0;
+    (1..10).for_each(move |x| {
+        sum += x; //~ WARN unused variable: `sum`
+    });
+    dbg!(sum);
+}
+
+pub fn f() {
+    let mut c = 0;
+
+    // Captured by value, but variable is dead on entry.
+    let _ = move || {
+        c = 1; //~ WARN value captured by `c` is never read
+        println!("{}", c);
+    };
+    let _ = async move {
+        c = 1; //~ WARN value captured by `c` is never read
+        println!("{}", c);
+    };
+
+    // Read and written to, but never actually used.
+    let _ = move || {
+        c += 1; //~ WARN unused variable: `c`
+    };
+    let _ = async move {
+        c += 1; //~  WARN value assigned to `c` is never read
+                //~| WARN unused variable: `c`
+    };
+
+    let _ = move || {
+        println!("{}", c);
+        // Value is read by closure itself on later invocations.
+        c += 1;
+    };
+    let b = Box::new(42);
+    let _ = move || {
+        println!("{}", c);
+        // Never read because this is FnOnce closure.
+        c += 1; //~  WARN value assigned to `c` is never read
+        drop(b);
+    };
+    let _ = async move {
+        println!("{}", c);
+        // Never read because this is a generator.
+        c += 1; //~  WARN value assigned to `c` is never read
+    };
+}
+
+pub fn nested() {
+    let mut d = None;
+    let mut e = None;
+    let _ = || {
+        let _ = || {
+            d = Some("d1"); //~ WARN value assigned to `d` is never read
+            d = Some("d2");
+        };
+        let _ = move || {
+            e = Some("e1"); //~  WARN value assigned to `e` is never read
+                            //~| WARN unused variable: `e`
+            e = Some("e2"); //~  WARN value assigned to `e` is never read
+        };
+    };
+}
+
+pub fn g<T: Default>(mut v: T) {
+    let _ = |r| {
+        if r {
+            v = T::default(); //~ WARN value assigned to `v` is never read
+        } else {
+            drop(v);
+        }
+    };
+}
+
+pub fn h<T: Copy + Default + std::fmt::Debug>() {
+    let mut z = T::default();
+    let _ = move |b| {
+        loop {
+            if b {
+                z = T::default(); //~  WARN value assigned to `z` is never read
+                                  //~| WARN unused variable: `z`
+            } else {
+                return;
+            }
+        }
+        dbg!(z);
+    };
+}
+
+async fn yield_now() {
+    todo!();
+}
+
+pub fn async_generator() {
+    let mut state: u32 = 0;
+
+    let _ = async {
+        state = 1;
+        yield_now().await;
+        state = 2;
+        yield_now().await;
+        state = 3;
+    };
+
+    let _ = async move {
+        state = 4;  //~  WARN value assigned to `state` is never read
+                    //~| WARN unused variable: `state`
+        yield_now().await;
+        state = 5;  //~ WARN value assigned to `state` is never read
+    };
+}
+
+pub fn generator() {
+    let mut s: u32 = 0;
+    let _ = |_| {
+        s = 0;
+        yield ();
+        s = 1; //~ WARN value assigned to `s` is never read
+        yield (s = 2);
+        s = yield (); //~ WARN value assigned to `s` is never read
+        s = 3;
+    };
+}
+
+fn main() {}