Module error 

Cold-path error infrastructure.

Hosts the rssn_error! macro and the module-level error enums. Replaces the previous ad-hoc unwrap() / expect() / assert_eq! pattern with #[cold] #[inline(never)] constructors so that error handling stays off the hot path. Cold-path error infrastructure.

Provides the rssn_error! macro that generates, for every variant of an error enum, a cold_* constructor marked #[cold] #[inline(never)] #[track_caller]. The hot path branches into these constructors only on genuine failure, keeping the success path’s I-cache footprint minimal and letting the branch predictor assume success.

Each module-level error type below is the canonical failure surface for one subsystem. They are intentionally narrow — variants describe what went wrong, not where (the #[track_caller] attribute on the cold constructor captures the call site).

Enums

AstError

AST / projection-layer failures.

DagError

DAG arena / dedup / interning failures.

FfiError

FFI boundary failures.

JitError

JIT compilation pipeline failures.

ParallelError

Parallel evaluation / chunking failures.

ParserError

Parser surface failures (token / grammar level).

StorageError

Storage / cache / serialization failures.