Task() constructed in loop doesn't work (only the last task is created)

[swadey]

Defined outside of loops:

julia> t = Task(() -> produce(1))
julia> t2 = Task(() -> produce(2))
julia> consume(t)
1
julia> consume(t2)
2

Defined within a loop:

julia> x = {}
julia> for i = 1:10 push!(x, Task(() -> produce(i))) end
julia> x
10-element Any Array:
Task
Task
Task
Task
Task
Task
Task
Task
Task
Task
julia> consume(x[1])
10
julia> consume(x[2])
10
julia> consume(x[3])
10
julia> consume(x[4])
10
julia> consume(x[5])
...

[johnmyleswhite]

This is a dup of issues related to creating new bindings for each iteration of a for loop. I'm also hitting this since the changes to let mean that my Bloom filter code is now broken.

[JeffBezanson]

dup of #1571