Fix splat and multiple assignments

Case1: From variable

Code:

    a = [1, 2, 3, 4, 5]
    b, c, *d = a

    p [a, b, c, d]

Before:

    [[1, 2, 3, 4, 5], 1, 2, []]

After:

    [[1, 2, 3, 4, 5], 1, 2, [3, 4, 5]]

Ruby:

    [[1, 2, 3, 4, 5], 1, 2, [3, 4, 5]]

Case2: From variables

Code:

    a = [1, 2, 3]
    b = [4, 5, 6, 7]
    c, d, *e, f, g = *a, *b

    p [a, b, c, d, e, f, g]

Before:

    [[1, 2, 3], [4, 5, 6, 7], 1, 2, [], 6, 7]

After:

    [[1, 2, 3], [4, 5, 6, 7], 1, 2, [3, 4, 5], 6, 7]

Ruby:

    [[1, 2, 3], [4, 5, 6, 7], 1, 2, [3, 4, 5], 6, 7]

Case 3: "for"

Code:

    a = [1, 2, 3, 4, 5, 6, 7]
    for b, c, *d, e, f in [a] do
      p [a, b, c, d, e, f]
    end

Before:

    [[1, 2, 3, 4, 5, 6, 7], 1, 2, [], nil, nil]

After:

    [[1, 2, 3, 4, 5, 6, 7], 1, 2, [3, 4, 5], 6, 7]

Ruby:

    [[1, 2, 3, 4, 5, 6, 7], 1, 2, [3, 4, 5], 6, 7]
Merge pull request #2684 from kou/fix-splat-and-multiple-assignments

Fix splat and multiple assignments