Occasional panic formatting

[dsherret]

I sometimes get an error that looks like this in the CLI:

[dprint-plugin-rustfmt]
error: expected item, found keyword `let`
 --> <stdin>:1:1
  |
1 | let result = dprint_core::formatting::format(|| {
  | ^^^ expected item

thread 'main' panicked at 'range start index 8 out of range for slice of length 0', src\format.rs:18:42
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: expected item, found keyword `let`
 --> <stdin>:3:1
  |
3 | let parent_process_id = ...; // parse this from the `--parent-pid` command line argument
  | ^^^ expected item

thread 'main' panicked at 'range start index 8 out of range for slice of length 0', src\format.rs:18:42
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: expected item, found keyword `let`
 --> <stdin>:1:1
  |
1 | let result = dprint_core::formatting::format(|| {
  | ^^^ expected item

thread 'main' panicked at 'range start index 8 out of range for slice of length 0', src\format.rs:18:42
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: expected item, found keyword `let`
 --> <stdin>:3:1
  |
3 | let parent_process_id = ...; // parse this from the `--parent-pid` command line argument
  | ^^^ expected item

thread 'main' panicked at 'range start index 8 out of range for slice of length 0', src\format.rs:18:42
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: expected one of `!` or `::`, found `(`
 --> <stdin>:1:30
  |
1 | handle_process_stdio_messages(MyPluginHandler::new())
  |                              ^ expected one of `!` or `::`

thread 'main' panicked at 'range start index 8 out of range for slice of length 0', src\format.rs:18:42
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

The error goes away when I run it again. It might have to do with the <stdin>:x:x thing.

[dsherret]

Fixed in #8 (or... should be fixed...)