regresion test for dd7ff4e

t/pmc/namespace.t

@@ -55,7 +55,7 @@ Although NameSpace.'export_to'() is used in test_more.pir.
 
 .sub main :main
     .include 'test_more.pir'
-    plan(74)
+    plan(75)
 
     create_namespace_pmc()
     verify_namespace_type()
@@ -599,6 +599,22 @@ CODE
         .end
 CODE
 
+    errormsg = "can't handle argument of type"
+    description = "export_to() invalid 'what' type"
+    throws_substring(<<"CODE", errormsg, description)
+        .sub 'test' :main
+            .local pmc nsa, nsb, ar
+
+            # To trigger the condition we need something of an unexpected
+            # type which elements vtable function does not return 0
+            ar = new ['String']
+            ar = 'boo'
+            nsa = get_namespace
+            nsb = get_namespace ['Foo']
+            nsb.'export_to'(nsa, ar)
+        .end
+CODE
+
     errormsg = "exporting default object set not yet implemented"
     description = 'export_to() with null exports default object set !!!UNSPECIFIED!!!'
     throws_substring(<<'CODE', errormsg, description)