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### 3416. The Throws: specification of `std::any` does not mention allocation

Section: 20.8.4 [any.class] Status: New Submitter: Thomas Köppe Opened: 2020-03-04 Last modified: 2020-04-04

Priority: 3

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Discussion:

Several of the function specifications in 20.8.4 [any.class] have Throws: elements, but those only mention "exceptions thrown by a constructor". It seems necessary for `std::any` to perform dynamic allocation in general, and so in general there should be a possibility of an exception raised by such dynamic allocation. (This may come from a user-provided `T::operator new`, as far as I can tell.)

We should revise the specifications to add relevant sources of exceptions.

The functions that should probably mention allocations are:

- `any(const any& other)`

- `template<class T> any(T&& value)`

- both `any(in_place_t<T>, …)` overloads

- `any& operator=(const any& rhs)`

- `template<class T> any& operator=(T&& rhs)`

- all `emplace` overloads

Proposed wording: None yet. Maybe insert something like "thrown by unspecified, internal bookkeeping logic" into each Throws: element, but perhaps something more specific is necessary.

[2020-04-04 Issue Prioritization]

Priority to 3 after reflector discussion.

Proposed resolution: