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This guideline prohibits publishing a reference to a partially initialized member object instance before initialization completes while CON16TSM01-J. Do not let the (this) reference escape during object construction prohibits the this reference of the current object from escaping.
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Consequently, the reference to the helper field should not be published before class Foo's constructor has finished its initialization (see CON16TSM01-J. Do not let the (this) reference escape during object construction).
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