diff --git a/lib/ClassBuilder.js b/lib/ClassBuilder.js
index 4d5430c..50d19a1 100644
--- a/lib/ClassBuilder.js
+++ b/lib/ClassBuilder.js
@@ -447,22 +447,6 @@ exports.prototype.build = function extend( _, __ )
         }
     }
 
-    // we transparently handle extending errors in a sane manner, which is
-    // traditionally a huge mess (you're welcome)
-    if ( this._ector && this._ector.isError( base ) )
-    {
-        // declare public properties (otherwise, they'll be confined to the
-        // private visibility object in ES5+ environments)
-        props.message = '';
-        props.stack   = '';
-
-        // user-provided constructor
-        var ector_own = props.__construct;
-
-        // everything else is handled by the constructor
-        props.__construct = this._ector.createCtor( base, cname, ector_own );
-    }
-
     // increment class identifier
     this._classId++;
 
@@ -508,6 +492,24 @@ exports.prototype.build = function extend( _, __ )
         }
     }
 
+    // we transparently handle extending errors in a sane manner, which is
+    // traditionally a huge mess (you're welcome)
+    if ( this._ector && this._ector.isError( base ) )
+    {
+        // declare public properties (otherwise, they'll be confined to the
+        // private visibility object in ES5+ environments)
+        props.message = '';
+        props.stack   = '';
+
+        // user-provided constructor
+        var ector_own = members[ 'public' ].__construct;
+
+        // everything else is handled by the constructor
+        members[ 'public' ].__construct = this._ector.createCtor(
+            base, cname, ector_own
+        );
+    }
+
     // reference to the parent prototype (for more experienced users)
     prototype.___$$parent$$ = base.prototype;
 
diff --git a/test/ClassBuilder/ErrorExtendTest.js b/test/ClassBuilder/ErrorExtendTest.js
index 5bd6007..647d552 100644
--- a/test/ClassBuilder/ErrorExtendTest.js
+++ b/test/ClassBuilder/ErrorExtendTest.js
@@ -38,6 +38,8 @@ require( 'common' ).testCase(
             RangeError,
             URIError,
         ];
+
+        this.ctors = [ '__construct', 'constructor' ];
     },
 
 
@@ -164,7 +166,7 @@ require( 'common' ).testCase(
      * implementation.  However, a user can provide a method to be invoked
      * after the generated constructor.
      */
-    'Can override generated constructor': function()
+    '@each(ctors) Can override generated constructor': function( ctor )
     {
         var called_gen = false,
             called_own = false;
@@ -178,12 +180,13 @@ require( 'common' ).testCase(
             };
         };
 
-        var result = this.builder.build( {}, {
-            __construct: function()
-            {
-                called_own = true;
-            },
-        } )();
+        var dfn = {};
+        dfn[ ctor ] = function()
+        {
+            called_own = true;
+        };
+
+        var result = this.builder.build( {}, dfn )();
 
         this.assertOk( called_gen );
         this.assertOk( called_own );