[PATCH] D79895: Add a new warning to warn when passing uninitialized variables as const reference parameters to a function

Tue Jun 23 06:21:52 PDT 2020

hans added a comment.

In D79895#2107604 <https://reviews.llvm.org/D79895#2107604>, @nick wrote:

> This diagnostic bring headaches because frequently `-Wunused-variable` suppression is done via no-op pseudo-consuming function like `boost::ignore_unused` <https://www.boost.org/doc/libs/1_73_0/libs/core/doc/html/core/ignore_unused.html>.

I haven't seen boost::ignore_unused before. In my experience, the idiomatic way of ignoring an unused variable in C/C++ is to cast it to void, as Arthur said.

> Particularly, it fires in Boost here https://github.com/boostorg/concept_check/blob/e69c81326d5a4359ac53f9c6fe53fc2baf24df50/include/boost/concept_check.hpp#L135-L141.
>  Is it possible to make the diagnostic not fire for empty body consuming functions?

The combination of having an uninitialized variable and explicitly marking it unused like this seems to me like it would be unusual.

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https://reviews.llvm.org/D79895