[1 of 3] Compiling SafeLang10_A     ( SafeLang10_A.hs, SafeLang10_A.o )
[2 of 3] Compiling SafeLang10_B     ( SafeLang10_B.hs, SafeLang10_B.o )
[3 of 3] Compiling Main             ( SafeLang10.hs, SafeLang10.o )

SafeLang10.hs:8:13:
    Unsafe overlapping instances for Pos [Int]
      arising from a use of ‘res’
    The matching instance is:
      instance [overlapping] [safe] Pos [Int]
        -- Defined at SafeLang10_B.hs:13:30
    It is compiled in a Safe module and as such can only
    overlap instances from the same module, however it
    overlaps the following instances from different modules:
      instance Pos [a] -- Defined at SafeLang10_A.hs:13:10
    In the expression: res [(1 :: Int)]
    In an equation for ‘r’: r = res [(1 :: Int)]
    In the expression:
      do { let r = res ...;
           putStrLn $ "Result: " ++ show r;
           putStrLn $ "Result: " ++ show function }