[Haskell-beginners] Multiple declarations of value constructor

Hi, -- tests.hs data MyType1 = Value1 | Value2 data MyType2 = Value1 | Value2 Prelude> :l tests [1 of 1] Compiling Main ( tests.hs, interpreted ) tests.hs:3:16: Multiple declarations of `Main.Value1' Declared at: tests.hs:1:16 tests.hs:3:16 tests.hs:3:25: Multiple declarations of `Main.Value2' Declared at: tests.hs:1:25 tests.hs:3:25 Failed, modules loaded: none. If so, how are numbers defined? I can use 1 :: Int or 1 :: Integer. Why not Value1 :: MyType1 and Value1 :: MyType2? Emanuel