diff --git a/core/inference/transforms/transforms-tests.factor b/core/inference/transforms/transforms-tests.factor
index 6dc5bcabcd..9a62a1faca 100644
--- a/core/inference/transforms/transforms-tests.factor
+++ b/core/inference/transforms/transforms-tests.factor
@@ -1,6 +1,6 @@
 IN: temporary
 USING: sequences inference.transforms tools.test math kernel
-quotations ;
+quotations tools.test.inference ;
 
 : compose-n-quot <repetition> >quotation ;
 : compose-n compose-n-quot call ;
@@ -18,3 +18,5 @@ quotations ;
 [ 268 ] [ 1 { 8 { 3 2 } } bitfield-quot call ] unit-test
 
 [ 512 ] [ 1 { { 1+ 8 } } bitfield-quot call ] unit-test
+
+\ construct-empty must-infer
diff --git a/core/inference/transforms/transforms.factor b/core/inference/transforms/transforms.factor
index 62c3129f3a..eabe4b8c2a 100755
--- a/core/inference/transforms/transforms.factor
+++ b/core/inference/transforms/transforms.factor
@@ -1,8 +1,8 @@
-! Copyright (C) 2007 Slava Pestov.
+! Copyright (C) 2007, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
 USING: arrays kernel words sequences generic math namespaces
 quotations assocs combinators math.bitfields inference.backend
-inference.dataflow inference.state tuples.private ;
+inference.dataflow inference.state tuples.private effects ;
 IN: inference.transforms
 
 : pop-literals ( n -- rstate seq )
@@ -61,11 +61,21 @@ M: pair (bitfield-quot) ( spec -- quot )
 
 \ set-slots [ <reversed> [get-slots] ] 1 define-transform
 
-: [construct] ( word quot -- newquot )
-    >r dup +inlined+ depends-on dup tuple-size r> 2curry ;
+\ construct-boa [
+    dup +inlined+ depends-on
+    dup tuple-size [ <tuple-boa> ] 2curry
+] 1 define-transform
 
-\ construct-boa
-[ [ <tuple-boa> ] [construct] ] 1 define-transform
+\ construct-empty [
+    1 ensure-values
+    peek-d value? [
+        pop-literal
+        dup +inlined+ depends-on
+        dup tuple-size [ <tuple> ] 2curry
+        swap infer-quot
+    ] [
+        \ construct-empty declared-infer
+    ] if
+] "infer" set-word-prop
 
-\ construct-empty
-[ [ <tuple> ] [construct] ] 1 define-transform
+\ construct-empty 1 1 <effect> "inferred-effect" set-word-prop