x = return 1
    ^~~~~~~~ unexpected void value expression
x = return, 1
    ^~~~~~ unexpected void value expression
x = 1, return
       ^~~~~~ unexpected void value expression
x, y = return
       ^~~~~~ unexpected void value expression
x = begin return ensure end
          ^~~~~~ unexpected void value expression
x = begin ensure return end
                 ^~~~~~ unexpected void value expression
x = begin return ensure return end
          ^~~~~~ unexpected void value expression
x = begin return; rescue; return end
          ^~~~~~ unexpected void value expression
x = begin return; rescue; return; else return end
          ^~~~~~ unexpected void value expression
x = begin; return; rescue; retry; end
           ^~~~~~ unexpected void value expression