3368: added downsides to "known problems" for get_unwrap lint r=flip1995 a=humean
As a beginner I found this lint to be confusing because I was not sure how the `Option` type disappeared as conceptually I know that my `.get()` and Index could fail. Initially I thought maybe the compiler or clippy was smart enough to understand that it was impossible for my `.get()` to fail in this particular case, but it was explained to me that using the Index syntax is just shorthand for directly unwrapping the value:
https://doc.rust-lang.org/src/std/collections/hash/map.rs.html#1547
For beginners or users trying to iterate quickly it seems common to litter your code with `unwrap` or `except` as placeholders for where some explicit error handling might need to take place. I think it should be warned that using Index is merely more concise, but doesn't at all reduce the risk of panics and might in fact cause you to miss handling them in a future refactor.
Co-authored-by: Michael Rutter <michael.john.rutter@gmail.com>
Co-authored-by: Michael Rutter <humean@users.noreply.github.com>
Methods like `Iterator::any` borrow the iterator mutably,
which is not allowed within a pattern guard and will fail to compile.
This commit prevents clippy from suggesting this type of change.
Closes#3069
