diff --git a/basis/compiler/tree/propagation/transforms/transforms.factor b/basis/compiler/tree/propagation/transforms/transforms.factor
index 3b387a2254..5dc417b8e7 100644
--- a/basis/compiler/tree/propagation/transforms/transforms.factor
+++ b/basis/compiler/tree/propagation/transforms/transforms.factor
@@ -178,7 +178,13 @@ ERROR: bad-partial-eval quot word ;
 
 \ instance? [
     dup classoid?
-    [ predicate-def ] [ drop f ] if
+    [
+        predicate-def
+        ! union{ and intersection{ have useless expansions, and recurse infinitely
+        dup { [ length 2 >= ] [ second \ instance? = ] } 1&& [
+            drop f
+        ] when
+    ] [ drop f ] if
 ] 1 define-partial-eval
 
 ! Shuffling
diff --git a/basis/prettyprint/prettyprint-tests.factor b/basis/prettyprint/prettyprint-tests.factor
index 49dcbab433..3df231db96 100644
--- a/basis/prettyprint/prettyprint-tests.factor
+++ b/basis/prettyprint/prettyprint-tests.factor
@@ -393,7 +393,6 @@ TUPLE: bob a b ;
 [ "maybe: bob\n" ] [ [  maybe: bob . ] with-string-writer ] unit-test
 [ "maybe: word\n" ] [ [  maybe: word . ] with-string-writer ] unit-test
 
-
 TUPLE: har a ;
 GENERIC: harhar ( obj -- obj )
 M: maybe: har harhar ;
@@ -408,12 +407,11 @@ M: integer harhar M\\ integer harhar drop ;\n"""
     [ \ harhar see-methods ] with-string-writer
 ] unit-test
 
-
 TUPLE: mo { a union{ float integer } } ;
 TUPLE: fo { a intersection{ fixnum integer } } ;
 
 [
-"""USING: classes.union math ;
+"""USING: math ;
 IN: prettyprint.tests
 TUPLE: mo { a union{ float integer } initial: 0 } ;
 """
@@ -422,7 +420,7 @@ TUPLE: mo { a union{ float integer } initial: 0 } ;
 ] unit-test
 
 [
-"""USING: classes.intersection math ;
+"""USING: math ;
 IN: prettyprint.tests
 TUPLE: fo { a intersection{ fixnum integer } initial: 0 } ;
 """