Function find_method_implementations_from_workspace 

pub fn find_method_implementations_from_workspace(
    method_name: &str,
    declaring_class: &str,
    wi: &WorkspaceIndexData,
) -> Vec<Location>

Find all concrete implementations of a METHOD across the subtypes of its declaring class/interface.

When the cursor sits on a method name inside an interface or abstract class, this returns the same-named method in every class that extends or implements the declaring type. Uses the workspace aggregate’s subtypes_of reverse map for an O(subtypes) lookup instead of a full corpus walk.