Function scan_file 

pub fn scan_file(
    graph: RubyGraphSource<'_>,
    ruby: &dyn RubySource,
    support: &dyn BoundedDefinitionLookup,
    file: &ProjectFile,
    input: &FileEdgeScanInput<'_>,
) -> PerFileEdges

One file’s caller -> callee edges, for the whole-workspace inverted pass.

The pass’s fan-out – build_edge_output plus parse_and_collect, the shared cross-language driver – stays in brokk-bifrost-analysis and calls this per file, so the Ruby half is a pure function of a parsed file and the two sources.