Index: generic/nsf.c
===================================================================
diff -u -r764ac30a3ca9712d9fc59853b36759e1dd146114 -r4b9ddd1b06ce34fd352791fcae53ad91a79b43ce
--- generic/nsf.c	(.../nsf.c)	(revision 764ac30a3ca9712d9fc59853b36759e1dd146114)
+++ generic/nsf.c	(.../nsf.c)	(revision 4b9ddd1b06ce34fd352791fcae53ad91a79b43ce)
@@ -9403,14 +9403,9 @@
 	  cscPtr->flags, (cscPtr->flags & NSF_CSC_CALL_IS_NRE), pcPtr, result);*/
 
 #if defined(NSF_WITH_ASSERTIONS)
-  if (unlikely(opt && object->teardown && (opt->checkoptions & CHECK_POST))) {
-    int rc;
-    /*
-     * Even, when the returned result != TCL_OK, run assertion to report
-     * the highest possible method from the call-stack (e.g. "set" would not
-     * be very meaningful; however, do not flush a TCL_ERROR.
-     */
-    rc = AssertionCheck(interp, object, cscPtr->cl, data[2], CHECK_POST);
+  if (unlikely(opt && object->teardown && (opt->checkoptions & CHECK_POST)) 
+      && likely(result == TCL_OK)) {
+    int rc = AssertionCheck(interp, object, cscPtr->cl, data[2], CHECK_POST);
     if (rc != TCL_OK) {
       result = rc;
     }
@@ -9694,7 +9689,7 @@
   }
 
 #if defined(NSF_WITH_ASSERTIONS)
-  if (unlikely(object->opt != NULL)) {
+  if (unlikely(object->opt != NULL) && likely(result == TCL_OK)) {
     CheckOptions co = object->opt->checkoptions;
     if ((co & CHECK_INVAR)) {
       int rc = AssertionCheckInvars(interp, object, Tcl_GetCommandName(interp, cmd), co);
Index: library/xotcl/tests/testx.xotcl
===================================================================
diff -u -r35c0d6ecb3c83cc6d6b0dfe251ba1a0d9071dc30 -r4b9ddd1b06ce34fd352791fcae53ad91a79b43ce
--- library/xotcl/tests/testx.xotcl	(.../testx.xotcl)	(revision 35c0d6ecb3c83cc6d6b0dfe251ba1a0d9071dc30)
+++ library/xotcl/tests/testx.xotcl	(.../testx.xotcl)	(revision 4b9ddd1b06ce34fd352791fcae53ad91a79b43ce)
@@ -261,7 +261,7 @@
     a set x 1
     a check all
   }
-  ::errorCheck $err {assertion failed check: {$x == 1} in proc 'xTo2'} \
+  ::errorCheck $err {assertion failed check: {$x == 1} in proc 'set'} \
     "inheritance a xTo2"
 
   if {![catch {a yTo2} err]} {
@@ -280,7 +280,7 @@
     b set x 1
     b check all
   }
-  ::errorCheck $err {assertion failed check: {$x == 1} in proc 'xTo2'} \
+  ::errorCheck $err {assertion failed check: {$x == 1} in proc 'set'} \
     "inheritance b xTo2"
 
   if {![catch {b yTo2} err]} {
Index: tests/methods.test
===================================================================
diff -u -r764ac30a3ca9712d9fc59853b36759e1dd146114 -r4b9ddd1b06ce34fd352791fcae53ad91a79b43ce
--- tests/methods.test	(.../methods.test)	(revision 764ac30a3ca9712d9fc59853b36759e1dd146114)
+++ tests/methods.test	(.../methods.test)	(revision 4b9ddd1b06ce34fd352791fcae53ad91a79b43ce)
@@ -1090,17 +1090,29 @@
     :public method foo {} {
       :configure -xxx 1
     }
+    :public method bar {} {
+      :configure -xxx 1
+    } -postcondition {{1 == 0}}
     :create e1
   }
 
   # base case
   ? {catch {e1 foo} errMsg} 1
   ? {string match "invalid non-positional*" $errMsg} 1
 
+  ? {catch {e1 bar} errMsg} 1
+  ? {string match "invalid non-positional*" $errMsg} 1
+
+
   # turn on assertion checking
   nsf::method::assertion e1 check all
 
-  # still report error
+  # still report error when invariant would not return error
   ? {catch {e1 foo} errMsg} 1
   ? {string match "invalid non-positional*" $errMsg} 1
+
+  # still report error when postcondition would not return error
+  ? {catch {e1 bar} errMsg} 1
+  ? {string match "invalid non-positional*" $errMsg} 1
+
 }