pub type BuiltinComponentMap = fn(&str) -> Option<&'static [u8]>;Expand description
Resolves a built-in rule name to its component’s embedded source map.
A third hook rather than a third element of BuiltinComponent, because it answers a
different kind of question and almost every caller has no use for it: what a map buys is where
a thrown rule error is reported, and nothing else. A violation’s position never passes
through JavaScript at all, so a build that wired this to nothing would produce identical
violations and a worse stack.
That is also its risk, and the reason crates/lanekeep-rules/tests/source_maps.rs asserts the
wiring end to end rather than trusting it: a caller that sets RuleRoot::with_builtin_components
and forgets this one gets rules that work and diagnostics that name entry.js, with nothing
anywhere going red.
None is the ordinary answer. Every component built from Rust is one — a panicking rule traps,
and a trap reaches the host with no stack to remap.