Function trace_class_member 

pub fn trace_class_member(
    graph: &RetainedModuleGraph,
    root: &Path,
    file_path: &str,
    member_name: &str,
) -> Option<ClassMemberTrace>

Trace a class / enum / store member (the --trace FILE:MEMBER fallback when MEMBER is not a top-level export). See issue #1744.