[Issue 15624] opApply with @safe and @system variants can't be used with foreach syntax

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=15624

--- Comment #1 from Walter Bright <bugzilla at digitalmars.com> ---
The foreach delegate is correctly constructed and its @safe-ty is correctly
inferred. The overloading of opApply() is correct.

The trouble is that the opApply() is selected by inferApplyArgTypes() before
the foreach delegate is constructed.

--