Goose  Diff

            {
                optional< UnificationContext > bestUC;
                optional< Term > bestSol;
                bool ambiguous = false;
                auto sig = GetFuncSig( callee );

                auto callPat = VEC( c.domain(), args.val(), HOLE( "_"_sid ) );
                for( auto&& [s, uc] : FullUnify( sig, callPat, c ) )
                {

                    if( !bestSol || uc.score() > bestUC->score() )
                    {
                        bestUC = uc;
                auto us = FindBestUnification( sig, callPat, c );
                        bestSol = s;
                        ambiguous = false;
                        continue;
                    }


                if( holds_alternative< NoUnification >( us ) )
                {
                    if( uc.score() < bestUC->score() )
                        continue;

                    // TODO display details
                    DiagnosticsManager::GetInstance().emitErrorMessage( loc,
                        "function arguments mismatch." );
                    return PoisonValue();
                    ambiguous = true;
                }

                if( ambiguous )
                if( holds_alternative< AmbiguousUnification >( us ) )
                {
                    // TODO display details
                    DiagnosticsManager::GetInstance().emitErrorMessage( loc,
                        "ambiguous function call." );
                    return PoisonValue();
                }

                if( !bestSol )
                {
                auto&& [s,uc] = get< UniSol >( us );

                    // TODO display details
                    DiagnosticsManager::GetInstance().emitErrorMessage( loc,
                        "function arguments mismatch." );
                    return PoisonValue();
                }

                return invoke( c, loc, callee, *bestSol, *bestUC );
                return invoke( c, loc, callee, s, uc );
            }

            Value invoke( const Context& c, uint32_t loc, const Value& callee, const Term& unifiedCallPat, UnificationContext& uc ) const final
            {
                auto newCallee = prepareFunc( c, 0, callee, unifiedCallPat, uc );
                if( newCallee.isPoison() )
                    return PoisonValue();