It seems that a vector will check if the move constructor is labeled as noexcept before deciding on whether to move or copy elements when reallocating. Is the default move c
I think the answer is 15.4/14 (Exception specifications):
An inheriting constructor (12.9) and an implicitly declared special member function (Clause 12) have an exception-specification. If
fis an inheriting constructor or an implicitly declared default constructor, copy constructor, move constructor, destructor, copy assignment operator, or move assignment operator, its implicit exception-specification specifies the type-idTif and only ifTis allowed by the exception-specification of a function directly invoked byf’s implicit definition;fallows all exceptions if any function it directly invokes allows all exceptions, andfhas the exception-specificationnoexcept(true)if every function it directly invokes allows no exceptions.
Basically, it Does What You Think, and the implicitly-declared move constructor is noexcept whenever it can be.