std::extents<IndexType,Extents...>::index-cast
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                    |   template< class OtherIndexType > static constexpr auto /*index-cast*/( OtherIndexType&& i ) noexcept;  | 
 (since C++23)  (exposition only*)  | 
|
Casts the index i of type OtherIndexType into a certain integral type. 
It is equivalent to:
-  return i;, if 
OtherIndexTypeis an integral type other than bool and - return static_cast<index_type>(i); otherwise.
 
Parameters
| i | - | the index to be cast | 
Return value
Cast index.
Notes
A call to this function will always return an integral type other than bool. Integer-class types can use the static_cast branch without loss of precision because this function's call sites are already constrained on the convertibility of OtherIndexType to index_type.