Decorators

• JS/TS already sorta kinda has decorators, sometimes

• extended placement

• decorators on expressions

• newtypes as decorators

• incl. union newtypes

• queryable

• @if static gating

• @allow, @warn, @deny, @forbid, and @expect tune diagnostics lexically; conditional forms may use static metadata and carry a reason

• @unsafe marks an unsafe operation, while @safe exposes a checked API whose implementation contains unsafe operations

• @derive synthesizes compiler-known interfaces such as Copy, SharedSafe, Clone, Default, comparison, formatting, hashing, and serialization capabilities