This is mostly straight-forward, but some things are worth noting:
1. Yes, this is necessary. The noexcept operator looks for noexcept tagging,
not at the contents of the function to determine whether to return true.
The more conditionally-noexcept functions are used, the more important it
becomes that low-level classes are correctly marked noexcept. In that, it
is like constexpr.
2. The functions that actually call into the model (data(), flags(), sibling(),
...) can throw (bad_alloc, if nothing else).
Consequently, they're not marked nothrow. They're the only ones.
Change-Id: Id0413212b0f1c049a339480ee449a53c3ca9fea0
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
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