user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Auto merge of #11387 - y21:issue11371, r=blyxyas

Browse source 
[`unnecessary_unwrap`]: lint on `.as_ref().unwrap()`

Closes #11371

This turned out to be a little more code than I originally thought, because the lint also makes sure to not lint if the user tries to mutate the option:
```rs
if option.is_some() {
  option = None;
  option.unwrap(); // don't lint here
}
```
... which means that even if we taught this lint to recognize `.as_mut()`, it would *still* not lint because that would count as a mutation. So we need to allow `.as_mut()` calls but reject other kinds of mutations.
Unfortunately it doesn't look like this is possible with `is_potentially_mutated` (seeing what kind of mutation happened).
This replaces it with a custom little visitor that does basically what it did before, but also allows `.as_mut()`.

changelog: [`unnecessary_unwrap`]: lint on `.as_ref().unwrap()`
This commit is contained in:
bors 2023-08-28 20:29:42 +00:00
commit b97eaab558
4 changed files with 235 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

51
tests/ui/checked_unwrap/simple_conditionals.rs
View file

@ -128,6 +128,57 @@ fn main() {
assert!(x.is_ok(), "{:?}", x.unwrap_err());
}
fn issue11371() {
let option = Some(());
if option.is_some() {
option.as_ref().unwrap();
//~^ ERROR: called `unwrap` on `option` after checking its variant with `is_some`
} else {
option.as_ref().unwrap();
//~^ ERROR: this call to `unwrap()` will always panic
}
let result = Ok::<(), ()>(());
if result.is_ok() {
result.as_ref().unwrap();
//~^ ERROR: called `unwrap` on `result` after checking its variant with `is_ok`
} else {
result.as_ref().unwrap();
//~^ ERROR: this call to `unwrap()` will always panic
}
let mut option = Some(());
if option.is_some() {
option.as_mut().unwrap();
//~^ ERROR: called `unwrap` on `option` after checking its variant with `is_some`
} else {
option.as_mut().unwrap();
//~^ ERROR: this call to `unwrap()` will always panic
}
let mut result = Ok::<(), ()>(());
if result.is_ok() {
result.as_mut().unwrap();
//~^ ERROR: called `unwrap` on `result` after checking its variant with `is_ok`
} else {
result.as_mut().unwrap();
//~^ ERROR: this call to `unwrap()` will always panic
}
// This should not lint. Statics are, at the time of writing, not linted on anyway,
// but if at some point they are supported by this lint, it should correctly see that
// `X` is being mutated and not suggest `if let Some(..) = X {}`
static mut X: Option<i32> = Some(123);
unsafe {
if X.is_some() {
X = None;
X.unwrap();
}
}
}
fn check_expect() {
let x = Some(());
if x.is_some() {

70
tests/ui/checked_unwrap/simple_conditionals.stderr
View file

@ -168,5 +168,73 @@ LL | if x.is_err() {
LL | x.unwrap_err();
| ^^^^^^^^^^^^^^
error: aborting due to 17 previous errors
error: called `unwrap` on `option` after checking its variant with `is_some`
--> $DIR/simple_conditionals.rs:135:9
|
LL | if option.is_some() {
| ------------------- help: try: `if let Some(..) = &option`
LL | option.as_ref().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: this call to `unwrap()` will always panic
--> $DIR/simple_conditionals.rs:138:9
|
LL | if option.is_some() {
| ---------------- because of this check
...
LL | option.as_ref().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: called `unwrap` on `result` after checking its variant with `is_ok`
--> $DIR/simple_conditionals.rs:145:9
|
LL | if result.is_ok() {
| ----------------- help: try: `if let Ok(..) = &result`
LL | result.as_ref().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: this call to `unwrap()` will always panic
--> $DIR/simple_conditionals.rs:148:9
|
LL | if result.is_ok() {
| -------------- because of this check
...
LL | result.as_ref().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: called `unwrap` on `option` after checking its variant with `is_some`
--> $DIR/simple_conditionals.rs:154:9
|
LL | if option.is_some() {
| ------------------- help: try: `if let Some(..) = &mut option`
LL | option.as_mut().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: this call to `unwrap()` will always panic
--> $DIR/simple_conditionals.rs:157:9
|
LL | if option.is_some() {
| ---------------- because of this check
...
LL | option.as_mut().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: called `unwrap` on `result` after checking its variant with `is_ok`
--> $DIR/simple_conditionals.rs:163:9
|
LL | if result.is_ok() {
| ----------------- help: try: `if let Ok(..) = &mut result`
LL | result.as_mut().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: this call to `unwrap()` will always panic
--> $DIR/simple_conditionals.rs:166:9
|
LL | if result.is_ok() {
| -------------- because of this check
...
LL | result.as_mut().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 25 previous errors