[cfe-dev] Getting the FieldDecl of a template class from a MemberExpr

[Johannes Schaub (litb)]

Douglas Gregor wrote:

> 
> On May 27, 2011, at 10:02 AM, Adrien Chauve wrote:
> 
>> Hi,
>> 
>> Using a RecursiveASTVisitor, I've been trying to rename field names
>> against some conventions.
>> 
>> Let's say I would like to rename Foo::bar into Foo::m_bar in the
>> following code:
>> 
>> template<typename T>
>> struct Foo
>> {
>>     int bar;
>> };
>> 
>> int main()
>> {
>>     Foo<double> foo;
>>     foo.bar = 2;
>> 
>>     return 1;
>> }
>> 
>> 
>> In my custom visitor, I implement the following method:
>> 
>> bool VisitMemberExpr(MemberExpr* member)
>> {
>>     ValueDecl* v = member->getMemberDecl(); // FieldDecl or CXXMethodDecl
>>     ...
>> }
>> 
>> But the FieldDecl I get when visiting the statement corresponding to
>> "foo.bar=2;" is Foo<double>::bar, but not Foo::bar.
>> 
>> So my question is: is it possible to get the FieldDecl of Foo<T>::bar
>> from the FieldDecl of Foo<double>::bar ? at least when the struct is not
>> specialized? What happens when the struct is specialized?
> 
> For fields, this is a pain. You'll actually have to look at the type that
> owns the field (a ClassTemplateSpecializationDecl), check whether it was
> instantiated vs. specialized (using getSpecializationKind()) and, if it
> was instantiated, retrieve the class template from which is was
> instantiated (getSpecializedTemplate()).
> 

I was looking into the doxygen documentations, and I couldn't find how to 
proceed from that.

How to get the correct field decl of the class template that correspond to 
the field decl of the instantiated specialization? Can one just take the 
std::distance of the field decl iterator for the specialization, and with 
that, index into the field decl iterator of the class template?