diff --git a/basis/stack-checker/row-polymorphism/row-polymorphism-tests.factor b/basis/stack-checker/row-polymorphism/row-polymorphism-tests.factor
index 6401258100..ec73ec3b21 100644
--- a/basis/stack-checker/row-polymorphism/row-polymorphism-tests.factor
+++ b/basis/stack-checker/row-polymorphism/row-polymorphism-tests.factor
@@ -47,6 +47,8 @@ H{ { "a" 1 } { "b" 1 } } [ [ nip       ] [             ] if* ] test-poly-infer
 H{ { "a" 2 } { "b" 2 } } [ [ 3append f ] [             ] if* ] test-poly-infer
 H{ { "a" 0 } { "b" 0 } } [ [ drop      ] [             ] if* ] test-poly-infer
 
+H{ { "a" 0 } { "b" 1 } } [ [ 1 +       ] [ "oops" throw ] if* ] test-poly-infer
+
 [ [ write write ] each      ] poly-infer-must-fail
 [ [             ] each      ] poly-infer-must-fail
 [ [ dup         ] map       ] poly-infer-must-fail
@@ -63,9 +65,6 @@ H{ { "a" 0 } { "b" 0 } } [ [ drop      ] [             ] if* ] test-poly-infer
 [ [      ] [ drop  ] if* ] poly-infer-must-fail
 [ [      ] [ 2dup  ] if* ] poly-infer-must-fail
 
-[ "derp" each ] poly-infer-must-fail
 [ each ] poly-infer-must-fail-unknown
-[ "derp" [ "derp" ] if ] poly-infer-must-fail
-[ [ "derp" ] "derp" if ] poly-infer-must-fail
 [ [ "derp" ] if ] poly-infer-must-fail-unknown
 
diff --git a/basis/stack-checker/row-polymorphism/row-polymorphism.factor b/basis/stack-checker/row-polymorphism/row-polymorphism.factor
index b1acf50551..85d151d478 100644
--- a/basis/stack-checker/row-polymorphism/row-polymorphism.factor
+++ b/basis/stack-checker/row-polymorphism/row-polymorphism.factor
@@ -55,17 +55,19 @@ M: curried >error-quot
     [ 2drop ] if ; inline
 
 :: (check-input) ( declared actual -- )
-    actual declared [ in>>  length ] bi@ declared in-var>>
-        [ check-variable ] keep :> ( in-diff in-var ) 
-    actual declared [ out>> length ] bi@ declared out-var>>
-        [ check-variable ] keep :> ( out-diff out-var )
-    { [ in-var not ] [ out-var not ] [ in-diff out-diff = ] } 0||
-    [
-        in-var  [ in-diff  swap adjust-variable ] when*
-        out-var [ out-diff swap adjust-variable ] when*
-    ] [
-        abandon-check
-    ] if ;
+    actual terminated?>> [
+        actual declared [ in>>  length ] bi@ declared in-var>>
+            [ check-variable ] keep :> ( in-diff in-var ) 
+        actual declared [ out>> length ] bi@ declared out-var>>
+            [ check-variable ] keep :> ( out-diff out-var )
+        { [ in-var not ] [ out-var not ] [ in-diff out-diff = ] } 0||
+        [
+            in-var  [ in-diff  swap adjust-variable ] when*
+            out-var [ out-diff swap adjust-variable ] when*
+        ] [
+            abandon-check
+        ] if
+    ] unless ;
 
 : infer-value ( value -- effect )
     dup known [ nest-visitor init-inference infer-call* current-effect ] with-scope ; inline
@@ -92,9 +94,10 @@ PRIVATE>
 
 : check-polymorphic-effect ( word -- )
     current-word get [
-        dup current-word set stack-effect
-        dup { [ in-var>> ] [ out-var>> ] } 1||
+        dup current-word set
+        stack-effect dup { [ in-var>> ] [ out-var>> ] } 1||
         [ infer-polymorphic-vars ] when drop
     ] dip current-word set ;
 
 SYMBOL: infer-polymorphic?
+infer-polymorphic? [ t ] initialize