diff --git a/src/output/_messenger.php b/src/output/_messenger.php
index 43ef89a..44520b1 100644
--- a/src/output/_messenger.php
+++ b/src/output/_messenger.php
@@ -21,12 +21,12 @@ abstract class _messenger {
 
   static final function set_messenger_class(string $say_class, ?string $log_class=null) {
     if (!is_subclass_of($say_class, IMessenger::class)) {
-      throw ValueException::unexpected_class($say_class, IMessenger::class);
+      throw ValueException::invalid_class($say_class, IMessenger::class);
     }
     self::$say = new $say_class();
     if ($log_class !== null) {
       if (!is_subclass_of($log_class, IMessenger::class)) {
-        throw ValueException::unexpected_class($log_class, IMessenger::class);
+        throw ValueException::invalid_class($log_class, IMessenger::class);
       }
       self::$log = new $log_class();
     }
diff --git a/src/schema/ValueException.php b/src/schema/ValueException.php
deleted file mode 100644
index c210176..0000000
--- a/src/schema/ValueException.php
+++ /dev/null
@@ -1,20 +0,0 @@
-<?php
-namespace nur\sery\schema;
-
-use Exception;
-
-class ValueException extends Exception {
-  static final function invalid_kind(string $kind, $value, ?string $message=null): self {
-    $invalid_kind = var_export($value, true).": invalid $kind";
-    if ($message !== null) $invalid_kind .= ": $message";
-    return new static($invalid_kind);
-  }
-
-  static final function invalid_key($value, ?string $message=null): self {
-    return self::invalid_kind("key", $value, $message);
-  }
-
-  static final function invalid_value($value, ?string $message=null): self {
-    return self::invalid_kind("value", $value, $message);
-  }
-}
diff --git a/src/schema/_scalar/ScalarResult.php b/src/schema/_scalar/ScalarResult.php
index e5c5419..388a759 100644
--- a/src/schema/_scalar/ScalarResult.php
+++ b/src/schema/_scalar/ScalarResult.php
@@ -2,9 +2,9 @@
 namespace nur\sery\schema\_scalar;
 
 use nulib\cl;
+use nulib\ValueException;
 use nur\sery\schema\ref\ref_analyze;
 use nur\sery\schema\Result;
-use nur\sery\schema\ValueException;
 
 /**
  * Class ScalarResult: résultat de l'analyse ou de la normalisation d'une valeur
diff --git a/src/schema/_scalar/ScalarValue.php b/src/schema/_scalar/ScalarValue.php
index dcbbadb..4d880fb 100644
--- a/src/schema/_scalar/ScalarValue.php
+++ b/src/schema/_scalar/ScalarValue.php
@@ -1,12 +1,11 @@
 <?php
 namespace nur\sery\schema\_scalar;
 
+use nulib\ValueException;
 use nur\sery\schema\input\Input;
-use nur\sery\schema\ref\ref_analyze;
 use nur\sery\schema\Result;
 use nur\sery\schema\types\IType;
 use nur\sery\schema\Value;
-use nur\sery\schema\ValueException;
 
 class ScalarValue extends Value {
   function __construct(ScalarSchema $schema, &$dest=null, $key=null, bool $verifix=true) {
diff --git a/src/schema/types/tcallable.php b/src/schema/types/tcallable.php
index 6293b5a..c5a185c 100644
--- a/src/schema/types/tcallable.php
+++ b/src/schema/types/tcallable.php
@@ -1,11 +1,11 @@
 <?php
 namespace nur\sery\schema\types;
 
-use nur\sery\schema\ValueException;
+use nulib\ValueException;
 
 class tcallable implements IType {
   static function ensure_callable(&$callable): void {
-    if (!is_callable($callable)) throw ValueException::invalid_value($callable);
+    if (!is_callable($callable)) throw ValueException::unexpected_type($callable, "callable");
   }
 
   static function ensure_ncallable(&$callable): void {
diff --git a/src/sys/README.md b/src/sys/README.md
index 1c20a90..bcee0d0 100644
--- a/src/sys/README.md
+++ b/src/sys/README.md
@@ -2,6 +2,6 @@
 
 Ce package contient des services généraux spécifiques à PHP
 
-exemples: func, UserException
+exemples: func
 
 -*- coding: utf-8 mode: markdown -*- vim:sw=4:sts=4:et:ai:si:sta:fenc=utf-8:noeol:binary
\ No newline at end of file