diff --git a/coverage/collector.py b/coverage/collector.py
index 2f8c17520..ca7f5d94b 100644
--- a/coverage/collector.py
+++ b/coverage/collector.py
@@ -456,7 +456,7 @@ def mapped_file_dict(self, d: Mapping[str, T]) -> Dict[str, T]:
             assert isinstance(runtime_err, Exception)
             raise runtime_err
 
-        return {self.cached_mapped_file(k): v for k, v in items}
+        return {self.cached_mapped_file(k): v for k, v in items if v}
 
     def plugin_was_disabled(self, plugin: CoveragePlugin) -> None:
         """Record that `plugin` was disabled during the run."""