[cfe-dev] type-punning warnings for CXXTypeidExpr::child_begin()/child_end()

[Sebastian Redl]

Eli Friedman wrote:
> On Wed, Dec 3, 2008 at 1:28 PM, Ted Kremenek <kremenek at apple.com> wrote:
>   
>> In ExprCXX.cpp I see:
>>
>> Stmt::child_iterator CXXTypeidExpr::child_begin() {
>>   return isTypeOperand() ? child_iterator() : (Stmt**)&Operand;
>> }
>>
>> The expression '(Stmt**)&Operand' leads to type-punning warnings
>> during a Release build.  This looks like a real issue to me.  Is this
>> safe, or do we need to fix it?  The same warning appears in child_end().
>>     
>
> It looks like a real issue to me too.  I guess the simplest solution
> is to change "void *Operand;" to "union {void* Operand; Stmt*
> OperandExpr;};", and change child_begin to use OperandExpr.  It isn't
> pretty, but I think it has the intended semantics.
>
> I guess it's worth noting that SizeOfAlignOfExpr has the same issue.
>   
My code, both of it. I suppose I can go with the union.

Sebastian