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Thomas Mang · Guest

Greetings,

I start this thread after a discussion in comp.lang.c++.moderated.

Given this program:

void foo(int);
void foo(int const &);

int main()
{
int i(0);
foo (i);
}

Comeau and GCC 3.3.1 complain ambiguity (BCC 5.5.1 picks the first, but that
must be wrong).

Calling the first is lvalue transformation with rank of exact match, calling
the second is identity conversion with rank of exact match.

13.3.3.2/3 says:

Standard conversion sequence S1 is a better conversion sequence than
standard conversion sequence S2 if
- S1 is a proper subsequence of S2 (comparing the conversion sequences in
the canonical form defined by 13.3.3.1.1, excluding any Lvalue
Transformation; the identity conversion sequence is considered to be a
subsequence of any non-identity conversion sequence) or.....

My reading of this bullet is that it pretty much clearly says the second foo
should be called - because of the part "the identity conversion sequence is
considered to be a subsequence of any non-identity conversion sequence" -
independet of the fact that the non-identiy conversion sequence consists of
only an Lvalue-Transformation, since there is no word such a sequence will
become "graded up" to identity conversion; it still remains officially
non-identity conversion.

My questions:

1) is my reading wrong and the 2 compilers are correct?

If yes, what part did I read wrong?

2) If my reading is correct, was this intended behavior and the compilers
are broken, or is it a defect?

Thomas

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Mikael Kilpeläinen · Guest

Thomas Mang wrote:

Thomas Mang · Guest

"Mikael Kilpeläinen" <belz (AT) kolumbus (DOT) fi> schrieb im Newsbeitrag
news:ctnl52$e1i$1 (AT) phys-news1 (DOT) kolumbus.fi...