[Bug c++/19808] miss a warning about uninitialized member usage in member initializer list in constructor

[anthony.brandon at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19808

Anthony Brandon <anthony.brandon at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |anthony.brandon at gmail dot com

--- Comment #24 from Anthony Brandon <anthony.brandon at gmail dot com> ---
Hi,

> It could be done specifically for uses in mem-initializers by walking the
> initializer in perform_mem_init to look for any references to members that
> haven't been marked yet.

I've been working on this using this approach.
At the moment I can detect and give a warning for something like:

struct S 
{ 
    int i, j; 
    S() : i(j), j(1) {} 
}; 

However it doesn't cover cases like i(j+1), and in the case of i(i) there would
currently be two warnings (due to -Winit-self).
Lastly, the warning is given like so:
a.cpp:8:2: warning: ‘S::i’ is initialized with uninitialized field ‘S::j’
[-Wuninitialized]
  S() : i(j), j(b) {}
  ^

So I have a couple of questions:
* How to get the right location for the mark. In other words:
  S() : i(j), j(b) {}
          ^
* Is there a function to traverse a tree structure looking for a particular
tree (or some other way to get things like i(j+1) to work)?

* Should this give a warning in the case of i(i)?