Re: new foo::foo() erroneous, ugly, or OK?

From:
"kanze" <kanze@gabi-soft.fr>
Newsgroups:
comp.lang.c++.moderated
Date:
27 Jun 2006 07:27:18 -0400
Message-ID:
<1151323097.168104.293500@r2g2000cwb.googlegroups.com>
usenet@schweikhardt.net wrote:

gcc accepts the following code, while
FlexeLint 8.00u reports an error:


I'll bet that there are lots of cases where FlexLint reports
errors, but g++ accepts the code. The two tools are designed
for different purposes.

$ cat foo.cpp
class foo {
public:
     foo() { }
};

int main (void)
{
     foo *myfoo = new foo::foo();
     delete myfoo;
     return 0;
}

---snip---

FlexeLint for C/C++ (Unix) Vers. 8.00u, Copyright
Gimpel Software 1985-2006

--- Module: foo.cpp (C++)

         foo *myfoo = new foo::foo();
foo.cpp 8 Error 1018: Expected a type after 'new'
[...]


Well, the error message is odd: you do have a type after new.
But the way you've written the type is strange enough to be
worthy of provoking a comment.

I'm not a C++ expert, so my question to the resident AI is: Is
this in fact an error, or does the C++ standard allow this
syntactically/semantically?


It's clearly legal C++. As would be "new foo::foo::foo:foo()".
The name of a class is inserted into the scope of the class, so
when you write foo::foo, the compiler looks in the class foo,
and finds the class foo. Ad infinitum. In this case, however,
we are dealing with a side effect of class name injection.

Of course the remedy is to remove the "foo::", but
nevertheless, isn't FlexeLint too picky or misleading here?


Given the target for FlexeLint, I wouldn't say too picky, but
the actual message is misleading.

Where on the scale from "erroneous--ugly--unusual--perfectly fine"
is this construct?


Ugly and unusual. Unusual enough to be misleading, in fact.

--
James Kanze GABI Software
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