Fix disambiguation bug in move_to_san()

A pinned piece cannot move and so does not play any role
in SAN disambiguation.

Reported by Steven Edwards.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/move.cpp b/src/move.cpp
index 1a312cb..d079ee7 100644 (file)
--- a/src/move.cpp
+++ b/src/move.cpp
@@ -106,6 +106,10 @@ const string move_to_san(Position& pos, Move m) {
           {
               sq = pop_1st_bit(&attackers);
 
+              // Pinned pieces are not included in the possible sub-set
+              if (!pos.pl_move_is_legal(make_move(sq, to), pos.pinned_pieces()))
+                  continue;
+
               if (file_of(sq) == file_of(from))
                   ambiguousFile = true;