diff --git a/basis/tuple-arrays/tuple-arrays.factor b/basis/tuple-arrays/tuple-arrays.factor
index 35aa7ecdbd..8d8b3bfa16 100644
--- a/basis/tuple-arrays/tuple-arrays.factor
+++ b/basis/tuple-arrays/tuple-arrays.factor
@@ -1,8 +1,8 @@
 ! Copyright (C) 2009, 2010 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays classes.tuple classes.tuple.private
-combinators combinators.smart fry functors kernel macros math parser
-sequences sequences.private ;
+USING: accessors arrays classes classes.tuple
+classes.tuple.private combinators combinators.smart fry functors
+kernel macros math parser sequences sequences.private ;
 FROM: inverse => undo ;
 IN: tuple-arrays
 
diff --git a/extra/euler/operators/operators.factor b/extra/euler/operators/operators.factor
index f4847e1140..f2dea708d1 100644
--- a/extra/euler/operators/operators.factor
+++ b/extra/euler/operators/operators.factor
@@ -29,8 +29,10 @@ ERROR: edges-in-same-face ;
     [ dup opposite-edge>> assert-same-face ]
     bi ;
 
+ERROR: not-a-base-face face ;
+
 : assert-base-face ( face -- )
-    base-face check-instance drop ;
+    dup base-face? [ drop ] [ not-a-base-face ] if ;
 
 ERROR: has-rings face ;
 
diff --git a/extra/math/matrices/laplace/laplace.factor b/extra/math/matrices/laplace/laplace.factor
index 1d8f8468e7..932c5b2897 100644
--- a/extra/math/matrices/laplace/laplace.factor
+++ b/extra/math/matrices/laplace/laplace.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2013 Doug Coleman.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays fry kernel locals math math.matrices
-math.vectors sequences sequences.private ;
+USING: accessors arrays classes fry kernel locals math
+math.matrices math.vectors sequences sequences.private ;
 IN: math.matrices.laplace
 
 <PRIVATE