Flycheck provides the functionality needed to run
cargo check or
another compatible command (f.x. clippy) in a background thread and provide
LSP diagnostics based on the output of the command.
A diagnostic message generated by rustc
The error code associated to this diagnostic.
A section of the source code associated with a Diagnostic
Macro expansion information associated with a diagnostic.
Flycheck wraps the shared state and communication machinery used for
cargo check (or other compatible command) and providing
diagnostics based on the output.
The spawned thread is shut down when this struct is dropped.