diff options
Diffstat (limited to '')
| -rw-r--r-- | src/tools/clippy/src/docs/get_unwrap.txt | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/tools/clippy/src/docs/get_unwrap.txt b/src/tools/clippy/src/docs/get_unwrap.txt new file mode 100644 index 000000000..8defc2224 --- /dev/null +++ b/src/tools/clippy/src/docs/get_unwrap.txt @@ -0,0 +1,30 @@ +### What it does +Checks for use of `.get().unwrap()` (or +`.get_mut().unwrap`) on a standard library type which implements `Index` + +### Why is this bad? +Using the Index trait (`[]`) is more clear and more +concise. + +### Known problems +Not a replacement for error handling: Using either +`.unwrap()` or the Index trait (`[]`) carries the risk of causing a `panic` +if the value being accessed is `None`. If the use of `.get().unwrap()` is a +temporary placeholder for dealing with the `Option` type, then this does +not mitigate the need for error handling. If there is a chance that `.get()` +will be `None` in your program, then it is advisable that the `None` case +is handled in a future refactor instead of using `.unwrap()` or the Index +trait. + +### Example +``` +let mut some_vec = vec![0, 1, 2, 3]; +let last = some_vec.get(3).unwrap(); +*some_vec.get_mut(0).unwrap() = 1; +``` +The correct use would be: +``` +let mut some_vec = vec![0, 1, 2, 3]; +let last = some_vec[3]; +some_vec[0] = 1; +```
\ No newline at end of file |