What context does make_links_data need?

I can’t get bpy.ops.make_links_data to work with context overrides. When I select objects manually, it works fine, but the following doesn’t:

bpy.ops.object.make_links_data({
    "active_object": source, 
    "object": source, 
    "selected_objects": [source, target]}, 
type='MODIFIERS')

I would expect the objects given "selected_objects" to have the same modifiers as the object in "active_object" or the one in "object". This does not seem to happen. (I can’t see anything happening at all.)

When I manually link the modifiers (which works), the line

bpy.ops.object.make_links_data(type='MODIFIERS')

appears in the scripting panel.

(This is in Blender 2.8.)