PolyPolyPoly.bpl(14,26): Error: invalid argument types ([]? and <a>[]C a) to binary operator ==
PolyPolyPoly.bpl(17,23): Error: invalid argument types ([]? and <a>[]C a) to binary operator ==
PolyPolyPoly.bpl(23,57): Error: invalid type for argument 1 in map select: b (expected: a)
3 type checking errors detected in PolyPolyPoly.bpl