hasDirectiveContext property
Whether message already names which module failed to load which target.
DFUB13. loadModule recurses, so every frame on the way out could prepend
its own "Failed to load ..." prefix to the same underlying error. Only the
innermost frame knows the file that actually contains the bad directive,
so wrapDirectiveError sets this when it adds context and consults it to
stay silent on every outer frame.
It lives on the base class rather than on one subtype because the two
module loaders report a missing module with different exception types —
the filesystem loader raises SourceCodeD4rtException, the bundle loader
raises RuntimeD4rtException — and both need the same once-only rule.
Implementation
bool hasDirectiveContext = false;