calc unexpected v2.15.0.1 output

gistfile1.txt

    calc always evaluates terms from left to right
    ==============================================

    Calc has a definite order for evaluation of terms (adds in a
    sum, factors in a product, arguments for a function or a matrix,
    etc.).  This order is always from left to right. but skipping of
    terms may occur for ||, && and ? : .

    Consider, for example:

            A * B + C * D

    In calc above expression is evaluated in the following order:

            A
            B
            A * B
            C
            D
            C * D
            A * B + C * D

    This order of evaluation is significant if evaluation of a
    term changes a variable on which a later term depends.  For example:

            x++ * x++ + x++ * x++

    in calc returns the value:

            x * (x + 1) + (x + 2) * (x + 3)

    and increments x as if by x += 4.  Similarly, for functions f, g,
    the expression:

            f(x++, x++) + g(x++)

    evaluates to:

            f(x, x + 1) + g(x + 2)

    and increments x three times.

    In an other example, this expression:

        1<<8/2

    evaluates to 128, not 16, because <<8 is performed before the /2.