x, y = 1, 2, 3 does not fail

[twolodzko]

In Julia 1.5.1 (and earlier) the following code does not fail with error

julia> x, y = 1, 2, 3
(1, 2, 3)
julia> x, y
(1, 2)

I would expect this to fail, so that it prevents me from writing buggy code. Silently dropping values in assignments can lead to some ugly and hard to trace bugs.

[thofma]

Dup of #37132