Function visible_source_files 

pub fn visible_source_files(
    root: &Path,
    extensions: &[&str],
    project_ignore_filename: &str,
) -> WalkReport

Discover visible source files selected by extension.

Hidden, Git-ignored, and project-ignored entries are omitted. Local and parent ignore files are honored without consulting user-specific excludes.

Traversal continues after entry failures and returns files and failures together in stable order.