Created attachment 16101 [details]
Reproduction

#include <string>
void fn(std::string a = "");

The readability-redundant-string-init check tells me that the string 'a' has redundant string initialization. However, if I remove this, the code no longer compiles in the large picture, as I have callers of fn() without this string argument.

I've currently changed my code to: void fn(std::string a = std::string{});
This is most likely the better way of writing this code, however I still need to initialize a, hence the init is not redundant.

Note: clang-tidy has been build with rev264514.

PS: I've also noticed that this checker doesn't cover the init-list of a constructor, don't know if that is already worth logging a bug for.