With this patch, in these examples
```rust
fn main() {
"⊞$0";
}
```
```rust
struct S {
д$0 u8
}
```
entering ':' character in `$0` places shouldn't cause panics.
With this patch, in these examples
```rust
fn main() {
"⊞$0";
}
```
```rust
struct S {
д$0 u8
}
```
entering ':' character in `$0` places shouldn't cause panics.