Valentin David <valentin.david@gmail.com> writes: | Hi, | | I did not understand some behaviors of Gcc. Gcc accepts this: | | -->8-- | class A {}; | class B {}; | A B; | -->8-- | | I found nothing in the standard that says it is not valid. Ok. In fact the C++ standard says it is valid, see 3.3/4 | According to the standard this one is valid, and Gcc accepts it: | | -->8-- | typedef int T; | typedef int T; | -->8-- Indeed. | It does not accept this one: | | -->8-- | typedef int T; | T T; | -->8-- | | That is ok, T is a typedef-name. and because of 3.3/4 | But on this one, it fails: | -->8-- | class A {}; | typedef A T; | T T; | -->8-- | | But normally, T is class-name. Yes, but that is only half of the story. The other half is 3.3/4 since T is also a typedef-name. | And the same on this one: | | -->8-- | typedef class {} A; | A A; | -->8-- | | But here, A is not only a class-name, it is *THE* real name of the class. Same reason. | I do not understand why Gcc does not accept these two last examples. I | did not find it in the standard. If someone find it somewhere... See 3.3/4. -- Gaby