813589 - Parallel Write Guard is insufficient

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Niko Matsakis [:nmatsakis]]

The current parallel write guard operation checks that the value was allocated by the current worker thread.  That's fine for |map()| but not for |reduce()| or |scan()|, since in those cases the return value is propagated between iterations.

Comment 1

[Niko Matsakis [:nmatsakis]]

Note: the current system cannot actually produce data races, it's just not the most intuitive.