diff --git a/lib/spack/spack/modules.py b/lib/spack/spack/modules.py
index 7303844229c..f5bf2138456 100644
--- a/lib/spack/spack/modules.py
+++ b/lib/spack/spack/modules.py
@@ -165,7 +165,7 @@ def write(self):
         # Let the extendee modify their extensions before asking for package-specific modifications
         for extendee in self.pkg.extendees:
             extendee_spec = self.spec[extendee]
-            extendee_spec.package.modify_module(self.pkg, extendee_spec, self.spec)
+            extendee_spec.package.modify_module(self.pkg.module, extendee_spec, self.spec)
 
         # Package-specific environment modifications
         self.spec.package.setup_environment(env)