1196966 - Add explicit operator bool for mozilla::Variant

Status: RESOLVED WONTFIX

(Core :: MFBT, defect)

Description

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

It turns out that it is useful to be able to convert to bool; who would have thought??

Comment 1

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: Add an 'explicit operator bool' to mozilla::Variant

Comment 2

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=a9a0296a387d

Comment 3

[Jeff Walden [:Waldo]]

I think we're going to go with WONTFIX here, in favor of matching more visibly and more explicitly.  Conversion to bool, notwithstanding the |explicit| qualifier here, is not nearly as visible and clear as just matching the normal way.  And it doesn't seem great to me to add an operator bool just because every embedded type supports it -- not when those types might support it with semantically different meanings (although this is probably less common than moderately-consistent types being unioned).  Better to be clear about the exact meaning being tested, using the existing matching infrastructure.