11. The source-location side table

Source locations live in a separate document, written next to the IR when asked (compile --source-map) and never inside it:

interface SourceMap {
  irRevision: number;
  locations: Record<string, { file: string; line: number; column: number; endLine: number; endColumn: number }>;
}

Keys are "<layer>#<pointer>", the serialised form of an Origin. file is relative to the workspace root, with forward slashes. Every pass, lint and the CLI turn an origin into file:line:col through this table, so diagnostics stay located after the IR is built (FR-1). A pack origin maps to the pack’s own file inside its package or bundle. Its file is .packs/<name>@<version>/<path inside the pack>, the path the bundle vendors it under, wherever the package manager installed the pack. A core origin has no entry, and the key pattern refuses one: a core declaration has no file, so a diagnostic about it is located at the binding or use that pulled it in (section 6).