logan-5 marked 2 inline comments as done. logan-5 added a comment. Thanks for the feedback.
In D72282#1918253 <https://reviews.llvm.org/D72282#1918253>, @EricWF wrote: > - This check should suggest fixes. It knows what function is actually being > resolved, and it has enough information to create a minimally qualified name > that resolves it. True, though of course it will only be able to do so for the non-template version of the warning, since in the template version it only knows that the call _may_ be resolved through ADL. > - This check should ignore hidden friends, since their entire purpose is to > be called via ADL. > - This check should allow whitelisting namespaces that opt-out of ADL into > their namespace. This makes it much easier to roll out the clang-tidy > incrementally. I want to make absolutely sure I understand the last bullet. You'd like a whitelist of namespaces where, if a call is resolved by ADL to a function within any of those namespaces, the check doesn't fire? I like all these suggestions. I'll work on an updated patch. ================ Comment at: clang-tools-extra/clang-tidy/bugprone/UnintendedADLCheck.h:27 +class UnintendedADLCheck : public ClangTidyCheck { + const bool IgnoreOverloadedOperators; + const std::vector<std::string> AllowedIdentifiers; ---------------- Quuxplusone wrote: > EricWF wrote: > > I think we should always ignore operators. I don't see value in having a > > mode where every comparison triggers this warning. > > > I think there's value in that mode, for library writers (not libc++) who > really care about finding every unintentional ADL in their whole library. The > standard library is designed not-to-work with types like > [`Holder<Incomplete>`](https://quuxplusone.github.io/blog/2019/09/26/uglification-doesnt-stop-adl/), > but someone else's library might be designed to work even in that case, and > then they'd want to hear about ADL lookups for things like `operator,`. > Besides, it's just 1 extra line of code in the patch, isn't it? > > However, I now think I may not understand how this check works. I thought it > looked for unqualified calls (even in templates) that "may" use ADL, but now > that I look again at the tests, it seems to trigger only on concrete calls > (in concrete template instantiations) that "do" use ADL, which sounds still > useful but much less comprehensive than I had thought. > > I think it would catch > ``` > template<class T> void foo(T t) { t, 0; } > struct S { friend void operator,(S, int); }; > template void foo(S); > ``` > but not > ``` > template<class T> void foo(T t) { t, 0; } > struct S { friend void operator,(S, int); }; > template void foo(int); > ``` > or > ``` > template<class T> void foo(T t) { t, 0; } > ``` > is that right? @Quuxplusone your initial understanding was right; the check fires on both templates that "may" use ADL as well as concrete instantiations that "do." There are tests for both, but I see now that I failed to add tests for the "may" case for operators, which I'll do. ================ Comment at: clang-tools-extra/test/clang-tidy/checkers/bugprone-unintended-adl.cpp:202 +void macro_test(T t) { +#define MACRO(x) find_if(x, x, x) + ---------------- EricWF wrote: > Arguably this is *exactly* the kind of code we want to diagnose. > > The call in the macro either, > * Is a "customization point" and should be whitelisted. Or, > * It resolves the same in expansion (and can be qualified), Or, > * It is a bug. > > You mentioned false positives in things like `assert`. Can you provide > examples? Fair enough. Disabling the check for macros does seem short sighted on closer thought. When I run the check over LLVM in debug, `assert` expands to `(__builtin_expect(!(e), 0) ? __assert_rtn(__func__, __FILE__, __LINE__, #e) : (void)0)`. If the assert() is inside a function template, the check claims that `unqualified call to '__assert_rtn' may be resolved through ADL`. Inspecting the AST, this seems to be due to the fact that `__func__` has dependent type. I suppose `__func__` could be special cased to be ignored, or all uglified names, or something? Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D72282/new/ https://reviews.llvm.org/D72282 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
