user-defined conversion

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struct X {
//implicit conversion
operator int() const { return 7; }
// explicit conversion
explicit operator int*() const { return nullptr; }
// Error: array operator not allowed in conversion-type-id
// operator int(*)[3]() const { return nullptr; }
using arr_t = int[3];
operator arr_t*() const { return nullptr; } // OK if done through typedef
// operator arr_t () const; // Error: conversion to array not allowed in any case
};
int main()
{
X x;
int n = static_cast<int>(x); // OK: sets n to 7
int m = x; // OK: sets m to 7
int* p = static_cast<int*>(x); // OK: sets p to null
// int* q = x; // Error: no implicit conversion
int (*pa)[3] = x; // OK
}
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