Error highlights the full identifier but warning only highlights the first character in C++

Using clang-tidy from LLVM 9.0.0

I've noticed that in C++ code I can write something like `undeclaredVar = 1;` and ALE would report the missing declaration by highlighting the whole identifier `undeclaredVar` in red.

Shouldn't this be easy to implement for warnings too? When I write `int unusedVar;` I would expect ALE to highlight `unusedVar` just as it would for an error but it highlights just the first character `u`.

Maybe some configuration option I'm missing?