add asserts

stepmania/src/ScoreKeeperMAX2.cpp

@@ -35,7 +35,9 @@ ScoreKeeperMAX2::ScoreKeeperMAX2(
 	for( unsigned i=0; i<apSteps.size(); i++ )
 	{
 		Song* pSong = apSongs[i];
+		ASSERT( pSong );
 		Steps* pSteps = apSteps[i];
+		ASSERT( pSteps );
 		const AttackArray &aa = asModifiers[i];
 		NoteData ndTemp;
 		pSteps->GetNoteData( ndTemp );

stepmania/src/ScreenGameplay.cpp

@@ -739,8 +739,12 @@ void ScreenGameplay::InitSongQueues()
 		m_apSongsQueue.clear();
 		PlayerNumber pnMaster = GAMESTATE->m_MasterPlayerNumber;
 		Trail *pTrail = GAMESTATE->m_pCurTrail[pnMaster];
+		ASSERT( pTrail );
 		FOREACH_CONST( TrailEntry, pTrail->m_vEntries, e )
+		{
+			ASSERT( e->pSong );
 			m_apSongsQueue.push_back( e->pSong );
+		}
 
         FOREACH_EnabledPlayer(p)
 		{
@@ -751,6 +755,7 @@ void ScreenGameplay::InitSongQueues()
 			m_asModifiersQueue[p].clear();
 			FOREACH_CONST( TrailEntry, pTrail->m_vEntries, e )
 			{
+				ASSERT( e->pSteps );
 				m_vpStepsQueue[p].push_back( e->pSteps );
 				AttackArray a;
 				e->GetAttackArray( a );