diff --git a/lappy/core/array.py b/lappy/core/array.py
index 8a20567b41a56134259acfe14ba68a00eee1ac74..3c9e95718130d6d80e13162b3523a731e7e277b7 100644
--- a/lappy/core/array.py
+++ b/lappy/core/array.py
@@ -644,7 +644,8 @@ class Array(LazyObjectBase):
                         raise ValueError(
                                 "cannot understand the return value "
                                 "of the precondition checker %s" % str(checker))
-            except Exception:  # noqa: W0703
+            except Exception as e:  # noqa: W0703
+                print(e)
                 failed_checks.append(checker)
 
         err_msgs = []
diff --git a/lappy/core/broadcast.py b/lappy/core/broadcast.py
index ae0012ffa073839cef8ff0f6c049c05da242446b..11e5fe48414b1e1e366fad1058e76ab22e805070 100644
--- a/lappy/core/broadcast.py
+++ b/lappy/core/broadcast.py
@@ -93,7 +93,7 @@ class BroadcastResult(object):
                 else:
                     # same name must have the same runtime values
                     # (may have different expressions)
-                    def check_name_valule_consistency(s, context):
+                    def check_name_valule_consistency(context, s):
                         s_val = evaluate(s.expr, context)
                         another_s_val = evaluate(
                             expr_map[var(s.name)], context)
@@ -128,7 +128,7 @@ class BroadcastResult(object):
                         # allow symbol == 1 or symbol == constant at runtime
                         assert isinstance(si, str)
 
-                        def check_broadcast_symbol_val(iaxis, si, context):
+                        def check_broadcast_symbol_val(context, iaxis, si):
                             si_val = evaluate(var(si), context)
                             return si_val in (bshape_pre[iaxis], 1)
 
@@ -150,7 +150,7 @@ class BroadcastResult(object):
                         # allow symbol == 1 or symbol == constant at runtime
                         assert isinstance(bshape_pre[iaxis], Expression)
 
-                        def check_broadcast_symbol_val(iaxis, context):
+                        def check_broadcast_symbol_val(context, iaxis):
                             lhs_val = evaluate(bshape_pre[iaxis], context)
                             return lhs_val in (bshape_pre[iaxis], 1)
 
@@ -167,7 +167,7 @@ class BroadcastResult(object):
                             assert isinstance(bshape_pre[iaxis], Expression)
                             assert isinstance(si, str)
 
-                            def check_broadcast_symbol_val(iaxis, si, context):
+                            def check_broadcast_symbol_val(context, iaxis, si):
                                 lhs_val = evaluate(bshape_pre[iaxis], context)
                                 si_val = evaluate(var(si), context)
                                 return (lhs_val == si_val) or (
diff --git a/lappy/core/ufuncs.py b/lappy/core/ufuncs.py
index 7fab3c2bac8a389bdcb31bd51e4285689ae7533b..1c8d3220b898d0ddb6a8c451e3bfee82b665c5c3 100644
--- a/lappy/core/ufuncs.py
+++ b/lappy/core/ufuncs.py
@@ -298,7 +298,7 @@ class BinaryOperation(UFunc):
             'bound_arguments': new_bound_arglist,
             'intermediaries': new_interm,
             'env': new_env,
-            'preconditions': a.preconditions + b.preconditions,
+            'preconditions': a.preconditions + b.preconditions + bres.preconditions,
             'ndim': bres.ndim, 'shape': bres._shape_exprs,
             'dtype': new_dtype,
             'is_integral': all([