[moderator: I posted on this subject yesterday, this is a reformulation
so that it's accepted as a valid DR submission]

[moderator's note: Forwarded to C++ Committee. -sdc]

The iterator constructor X(i,j) for containers as defined in 23.1.1 and
23.2.2 does only require that i and j be input iterators but
nothing is said about their associated value_type. There are three
sensible
options:

1. iterator's value_type is exactly X::value_type (modulo cv).
2. iterator's value_type is *implicitly* convertible to X::value_type.
3. iterator's value_type is *explicitly* convertible to X::value_type.

The issue has practical implications, and stdlib vendors have
taken divergent approaches to it: Dinkumware follows 2,
libstdc++ follows 3.

The same problem applies to the definition of insert(p,i,j) for
sequences and insert(i,j) for associative contianers, as well as
assign.

Joaqu   n M L   pez Mu   oz
Telef   nica, Investigaci   n y Desarrollo


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