Type Alias IndentResolverHandle 

pub type IndentResolverHandle = Arc<dyn IndentResolver + Send + Sync>;

IN.7: the same handle convention for the = operator’s per-line indent source. Owned + Send + Sync so it can cross the actor channel; the grammar side sees a bare &dyn IndentResolver.

Aliased Type

pub struct IndentResolverHandle { /* private fields */ }