wtf, ocaml record types

gistfile1.txt

➜  ~  ocaml
        OCaml version 4.00.0

# type record1 = { x : int; y : int };;
type record1 = { x : int; y : int; }
# { x = 10; y = 20 };;
- : record1 = {x = 10; y = 20}
# type record2 = { x : int };;
type record2 = { x : int; }
# { x = 10; y = 20 };;
Error: The record field label y belongs to the type record1
       but is mixed here with labels of type record2
# { x = 10 };;
- : record2 = {x = 10}
# let a r = r.x;;
val a : record2 -> int = <fun>