Rethink En Passant Evasion Capture
authorBM123499 <48841672+BM123499@users.noreply.github.com>
Fri, 8 Jan 2021 17:03:26 +0000 (14:03 -0300)
committerJoost VandeVondele <Joost.VandeVondele@gmail.com>
Mon, 11 Jan 2021 18:31:22 +0000 (19:31 +0100)
commit5f222f1d98c9b4cb07aa2303f085c2064e7ea77a
treede8134c7b922990e3d04b6f73d82db6e710700af
parent0266e702970640df693a8e572dd3cb9d227cdfc6
Rethink En Passant Evasion Capture

It now checks if it were a discovery attack instead of the attacking piece is the double-moved pawn.

As a side effect, certain illegal fens have different, and slightly more logical move generation.
There is no intend to maintain particular behavior for such non-reachable fens.

Passed STC:
LLR: 2.93 (-2.94,2.94) {-1.25,0.25}
Total: 47912 W: 4327 L: 4285 D: 39300
Ptnml(0-2): 144, 3312, 17012, 3334, 154
https://tests.stockfishchess.org/tests/view/5ff890946019e097de3ef0a5

closes https://github.com/official-stockfish/Stockfish/pull/3292

closes / fixes https://github.com/official-stockfish/Stockfish/issues/3270

No functional change
src/movegen.cpp