Is it meant to be guaranteed that same std::type_info::hash_code() values imply same types?
Cplusplus.com seems to claim so:
This function returns the same value for any two type_info objects that compare equal, and different values for distinct types that do not. [Emphasis mine]
Cppreference seems to claim otherwise:
Returns an unspecified value, which is identical for objects, referring to the same type. No other guarantees are given, in particular, the value can change between invocations of the same program. [Emphasis mine]
The relevant standards paragraphs are:
ยง p18.7.1 p7-8
size_t hash_code() const noexcept;
7 Returns: An unspecified value, except that within a single execution of the program, it shall return the same value for any two type_info objects which compare equal.
8 Remark: an implementation should return different values for two type_info objects which do not compare equal. [Emphasis mine]
What's the meaning of "should" supposed to be in the context above? If paragraph 8 is meant to be a requirement, then it seems impossible to fulfill unless the runtime does some kind of global uniquing over all symbol names in a program to ensure lack of hash collision, which seems to be a pretty big burden for the standard to foist upon implementations, especially for a function called hash_code(). (Itanium actually requires this, but it's explicitly an extra requirement above the standard.)
If "should" is not meant to be binding, then the remark se