Merge #2343

2343: implement assist invert_if r=matklad a=bravomikekilo

fix [issue 2219 invert if condition](https://github.com/rust-analyzer/rust-analyzer/issues/2219)
I put the assist cursor range to `if` of the if expression, because both condition and body will be replaced. Is there any way to replace them without cover the cursor position?
@matklad 

Co-authored-by: bravomikekilo <[email protected]>

1 files changed, 19 insertions, 0 deletions

diff --git a/docs/user/assists.md b/docs/user/assists.md
index 8da7578e2..6f4c30bee 100644
--- a/docs/user/assists.md
+++ b/docs/user/assists.md
@@ -329,6 +329,25 @@ fn main() {
 }
 ```
 
+## `invert_if`
+
+Apply invert_if
+This transforms if expressions of the form `if !x {A} else {B}` into `if x {B} else {A}`
+This also works with `!=`. This assist can only be applied with the cursor
+on `if`.
+
+```rust
+// BEFORE
+fn main() {
+    if┃ !y { A } else { B }
+}
+
+// AFTER
+fn main() {
+    if y { B } else { A }
+}
+```
+
 ## `make_raw_string`
 
 Adds `r#` to a plain string literal.