[cfe-commits] [PATCH] RecursiveASTVisitor: fix type traversal for EnumDecl

[Manuel Klimek]

On Mon, Sep 3, 2012 at 12:53 PM, Philip Craig <philipjcraig at gmail.com> wrote:
> On Mon, Sep 3, 2012 at 8:14 PM, Manuel Klimek <klimek at google.com> wrote:
>> On Sat, Sep 1, 2012 at 7:41 AM, Philip Craig <philipjcraig at gmail.com> wrote:
>>> RecursiveASTVisitor was traversing D->getTypeForDecl() for EnumDecl,
>>> but shouldn't (same as for other TagDecl). It also wasn't traversing
>>> the C++11 integer type.
>>
>> Don't we still visit the type as part of the typeloc traversal after your patch?
>
> We still visit a type, but it's a different type. Previously it
> visited an EnumType (which is the type that is the result of this
> declaration, not part of it), but now it visits whatever type has been
> specified, if any (such as BuiltinType for int). Maybe I should have
> split this into separate patches?
>
>> Perhaps add a negative test for what we don't want to visit any more?
>
> I can if you think it's a good idea. I didn't for two reasons.
> - There's no end of things you could test for the absence of, is this
> important enough?

Yes, the potential for negative tests is unlimited. On the other hand,
having regression tests is in my opinion very useful and valuable - if
one person has made the error once, chances are, somebody else will
introduce the same error again (I've seen that happen many times).

> - Most of the other TypeDecl are already skipping this type, and have
> comments to that effect, but no tests. Should they have tests too?

Well, the RAV is definitely undertested. But I don't think the
asymmetry is too bad here - suddenly having to write tests for
everything costs a lot of effort, but introducing tests when fixing
bugs / implementing new features will already give lots of pay-out at
comparatively little effort.

> The way I'd prefer to test this is to visit everything, compare that
> against a whitelist of things we expected to visit, and fail the test
> if anything unexpected was visited, rather than having a blacklist of
> things not to visit. That seems like it will need a lot of test
> framework changes though.

I like tests that test very specific things. In my experience those
tend to be easier to maintain over the long run.

Cheers,
/Manuel