extern crate rayon;

use std::rc::Rc;

fn main() {
    rayon::join(|| Rc::new(22), || ()); //~ ERROR E0277
    rayon::join(|| (), || Rc::new(23)); //~ ERROR E0277
}

extern crate rayon;

use std::rc::Rc;

fn main() {
    rayon::join(|| Rc::new(22), || Rc::new(23));
    //~^ ERROR E0277
    //~| ERROR E0277
}

--- 
+++ 
@@ -3,6 +3,7 @@
 use std::rc::Rc;
 
 fn main() {
-    rayon::join(|| Rc::new(22), || ()); //~ ERROR E0277
-    rayon::join(|| (), || Rc::new(23)); //~ ERROR E0277
+    rayon::join(|| Rc::new(22), || Rc::new(23));
+    //~^ ERROR E0277
+    //~| ERROR E0277
 }
Split up the test of join returning Rc

It seems that current rustc is now only reporting one error for `Rc`
returned in both `join` arguments.  We can split our test into two lines
to explicitly check the failure in each argument position.
