Index: tests/parameters.test
===================================================================
diff -u -rda6586782390b02ed7660b56417c3db00d63d1c3 -r620972f9a159f83b824f229ab406331e6bd238de
--- tests/parameters.test	(.../parameters.test)	(revision da6586782390b02ed7660b56417c3db00d63d1c3)
+++ tests/parameters.test	(.../parameters.test)	(revision 620972f9a159f83b824f229ab406331e6bd238de)
@@ -1566,3 +1566,45 @@
   ? {::C::slot::x1 getParameterSpec} {-x1:alias hugo}
   ? {::C::slot::x2 getParameterSpec} {-x2:alias,substdefault {[self]}}
 }
+
+#
+# Test potential incfluence on parameters
+#
+Test case parameter-alias-default {
+  Class create C {
+    :attribute a1
+    :create c1 {
+      :attribute a2
+    }
+  }
+
+  Class create M {
+    :attribute b1:required
+  }
+  
+  c1 mixin M
+
+  ? {c1 info precedence} "::M ::C ::nx::Object"
+
+  ? {C info slots -closure} "::C::slot::a1 ::nx::Object::slot::volatile ::nx::Object::slot::noinit ::nx::Object::slot::mixin ::nx::Object::slot::__initcmd ::nx::Object::slot::class ::nx::Object::slot::filter"
+
+  ? {C eval :objectparameter} "{-superclass:alias,arg=::nsf::methods::class::superclass ::nx::Object} -object-mixin:alias,arg=::nsf::classes::nx::Object::mixin -mixin:alias -object-filter:alias,arg=::nsf::classes::nx::Object::filter -filter:alias -attributes:alias -volatile:alias,noarg -noinit:alias,arg=::nsf::methods::object::noinit,noarg -class:alias,arg=::nsf::methods::object::class __initcmd:initcmd,optional"
+
+  #
+  # invalidate object parameter and expect that the per-class mixin
+  # does not harm
+  #
+  ::nsf::invalidateobjectparameter C
+
+  c1 configure -a1 x
+
+  ? {c1 info precedence} "::M ::C ::nx::Object"
+
+  ? {C info slots -closure} "::C::slot::a1 ::nx::Object::slot::volatile ::nx::Object::slot::noinit ::nx::Object::slot::mixin ::nx::Object::slot::__initcmd ::nx::Object::slot::class ::nx::Object::slot::filter"
+
+  ? {C eval :objectparameter} "{-superclass:alias,arg=::nsf::methods::class::superclass ::nx::Object} -object-mixin:alias,arg=::nsf::classes::nx::Object::mixin -mixin:alias -object-filter:alias,arg=::nsf::classes::nx::Object::filter -filter:alias -attributes:alias -volatile:alias,noarg -noinit:alias,arg=::nsf::methods::object::noinit,noarg -class:alias,arg=::nsf::methods::object::class __initcmd:initcmd,optional"
+  
+  # should not require b1
+  ? {C create c2} ::c2
+ 
+}
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