Issue 9418 + 9458 - Invalid array operation should be rejected in glue layer

[Issue 9418](http://d.puremagic.com/issues/show_bug.cgi?id=9418) - Segmentation fault using only datetime and stdio
[Issue 9458](http://d.puremagic.com/issues/show_bug.cgi?id=9458) - ModExp generates invalid code against array operands

Essentially such invalid expressions should be detected in front end layer. (filed as [bug 9459](http://d.puremagic.com/issues/show_bug.cgi?id=9459))