Relax constrain in connected_moves()
When testing if a piece is moving through the squares
vacated by a previous move there is no reason to require
the piece to be a slider, indeed we can have a double
pawn push like in this example:
r1q2rk1/2p1bppp/2Pp4/pN5b/Q1P1p3/4B2P/PP1R1PP1/1K5R w - - 3 18
Where black's move f5 is connected to previous move Be7 that
frees the path.
Or we can have a castle move:
r1bqkb1r/pppp1ppp/2n1pn2/1B6/4P3/2N2N2/PPPP1PPP/R1BQK2R b KQkq - 5 1
Where a previous move Bb5 allows the white to castle king side.
This time patch is mine ;-)
new bench: 5809010