From: Fabian Fichter <ianfab@users.noreply.github.com>
Date: Fri, 9 Nov 2018 21:43:31 +0000 (+0100)
Subject: Fix pseudo-legal move validation (resolves #12)
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=7f2056905e0808df42b7388e26d48ee16b0f0b72;p=fairystockfish.git

Fix pseudo-legal move validation (resolves #12)

For pieces which move and capture in different ways,
the pseudo-legal move validation needs to take into account
whether a move is a capture or not.

This fixes the pseudo-legal move validation for breakthrough and hoppelpoppel.

breakthrough
ELO: 372.25 +-109.6 (95%) LOS: 100.0%
Total: 100 W: 86 L: 7 D: 7

hoppelpoppel
ELO: 530.72 +-154.4 (95%) LOS: 100.0%
Total: 100 W: 92 L: 1 D: 7
---

diff --git a/src/position.cpp b/src/position.cpp
index e14ca16..ecf827c 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -843,7 +843,7 @@ bool Position::pseudo_legal(const Move m) const {
                && double_step_enabled()))
           return false;
   }
-  else if (!(attacks_from(us, type_of(pc), from) & to))
+  else if (!((capture(m) ? attacks_from(us, type_of(pc), from) : moves_from(us, type_of(pc), from)) & to))
       return false;
 
   // Evasions generator already takes care to avoid some kind of illegal moves