How can I do a Func<object[],Expression<Func<T,bool>>> dynamic?

public static Expression<Func<TOut, bool>> CastParam<TIn, TOut>(this Expression<Func<TIn, bool>> inExpr) {
    if (inExpr.NodeType == ExpressionType.Lambda &&
        inExpr.Parameters.Count > 0) {

        var inP = inExpr.Parameters[0];
        var outP = Expression.Parameter(typeof(TOut), inP.Name);

        var outBody = inExpr.Body.ConvertAll(
            expr => (expr is ParameterExpression) ? outP : expr);                           
        return Expression.Lambda<Func<TOut,bool>>(
            outBody,
            new ParameterExpression[] { outP });
    }
    else {
        throw new NotSupportedException();
    }
}

class TInterface { public int IntVal; }
class TImplementation : TInterface { public int ImplVal; }

void Run ()
{
    Expression<Func<TInterface, bool>> intExpr = (i => i.IntVal == 42);
    Expression<Func<TImplementation, bool>> implExpr = intExpr.CastParam<TInterface, TImplementation> ();

    Console.WriteLine ("{0} --> {1}", intExpr, implExpr);

    var c = implExpr.Compile ();

    Console.WriteLine (c.Invoke (new TImplementation { IntVal = 41, ImplVal = 42 }));
    Console.WriteLine (c.Invoke (new TImplementation { IntVal = 42, ImplVal = 41 }));
}

False
True

public static Expression Rewrite(this Expression exp, Func<Expression, Expression> c) {
    Expression clone = null;
    switch (exp.NodeType) {
        case ExpressionType.Equal: {
            var x = exp as BinaryExpression;
            clone = Expression.Equal(Rewrite(x.Left,c), Rewrite(x.Right,c), x.IsLiftedToNull, x.Method);
            } break;
        case ExpressionType.MemberAccess: {
            var x = exp as MemberExpression;
            clone = Expression.MakeMemberAccess(Rewrite(x.Expression,c), x.Member);
            } break;
        case ExpressionType.Constant: {
            var x = exp as ConstantExpression;
            clone = Expression.Constant(x.Value);
            } break;
        case ExpressionType.Parameter: {
            var x = exp as ParameterExpression;
            clone = Expression.Parameter(x.Type, x.Name);
            } break;
        default:
            throw new NotImplementedException(exp.NodeType.ToString());
    }
    return c(clone);
}