Add unit test and fix USING:

core/optimizer/control/control.factor

@@ -145,9 +145,6 @@ M: #call-label detect-loops*
 : clone-node ( node -- newnode )
     clone dup [ clone ] modify-values ;
 
-: detach-node-successor ( node -- successor )
-    dup node-successor #terminate rot set-node-successor ;
-
 ! BEFORE
 !
 !         #if ----> #merge ----> B ----> #return/#values
@@ -261,6 +258,9 @@ M: #dispatch optimize-node*
         ] if
     ] when ;
 
+: detach-node-successor ( node -- successor )
+    dup node-successor #terminate rot set-node-successor ;
+
 : lift-loop-tail? ( #label -- tail/f )
     dup node-successor node-successor [
         dup node-param swap node-child find-final-if dup [

core/optimizer/optimizer-tests.factor

@@ -301,3 +301,15 @@ TUPLE: silly-tuple a b ;
 [ t ] [ \ array \ nth-unsafe should-inline? ] unit-test
 [ t ] [ \ growable \ nth-unsafe should-inline? ] unit-test
 [ t ] [ \ sbuf \ set-nth-unsafe should-inline? ] unit-test
+
+! Regression
+: lift-throw-tail-regression
+    dup integer? [ "an integer" ] [
+        dup string? [ "a string" ] [
+            "error" throw
+        ] if
+    ] if ;
+
+[ t ] [ \ lift-throw-tail-regression compiled? ] unit-test
+[ 3 "an integer" ] [ 3 lift-throw-tail-regression ] unit-test
+[ "hi" "a string" ] [ "hi" lift-throw-tail-regression ] unit-test