Function build_file_decl_index 

pub fn build_file_decl_index(
    indices: &[usize],
    parsed: &[ParsedFile],
) -> FileDeclIndex

Tree-relative, deliberately. This is an emit structure, not an index: record_name_ref compares these paths against ctx.source_path (emitter.rs), which is the file’s include-root-relative path. Keying it by identity_path (ADR 0198) makes path != &ctx.source_path always true for a split project, so a name declared in the same file is emitted as a sibling import of itself — the module then cannot load, and a workers runtime test hangs rather than fails. See ADR 0201 (E).