@Override
    public Integer visit(FactoryExpression<?> expr, Void context) {
        int result = expr.getType().hashCode();
        return 31 * result + expr.getArgs().hashCode();
    }
{@code HashCodeVisitor} is used for hashCode generation in {@link Expression} implementations.

@author tiwe
querydsl-core/src/main/java/com/querydsl/core/types/HashCodeVisitor.java