1 files changed, 42 insertions, 0 deletions
diff --git a/tests/ui/nll/closure-requirements/escape-argument.rs b/tests/ui/nll/closure-requirements/escape-argument.rs
new file mode 100644
index 000000000..066cd4360
--- /dev/null
+++ b/tests/ui/nll/closure-requirements/escape-argument.rs
@@ -0,0 +1,42 @@
+// Test closure that:
+//
+// - takes an argument `y`
+// - stores `y` into another, longer-lived spot
+//
+// but is invoked with a spot that doesn't live long
+// enough to store `y`.
+//
+// The error is reported in the caller: invoking the closure links the
+// lifetime of the variable that is given as `y` (via subtyping) and
+// thus forces the corresponding borrow to live too long. This is
+// basically checking that the MIR type checker correctly enforces the
+// closure signature.
+
+// compile-flags:-Zverbose
+
+#![feature(rustc_attrs)]
+
+#[rustc_regions]
+fn test() {
+    let x = 44;
+    let mut p = &x;
+
+    {
+        let y = 22;
+        let mut closure = expect_sig(|p, y| *p = y);
+        closure(&mut p, &y);
+        //~^ ERROR `y` does not live long enough [E0597]
+    }
+
+    deref(p);
+}
+
+fn expect_sig<F>(f: F) -> F
+    where F: for<'a, 'b> FnMut(&'a mut &'b i32, &'b i32)
+{
+    f
+}
+
+fn deref(_p: &i32) { }
+
+fn main() { }