Prohibiting trait getters/setters

lib/Trait.js

@@ -99,6 +99,7 @@ Trait.extend = function( dfn )
     dfn.___$$parser$$ = {
         each:     _parseMember,
         property: _parseProps,
+        getset:   _parseGetSet,
     };
 
     // give the abstract trait class a distinctive name for debugging
@@ -208,6 +209,28 @@ function _parseProps( name, value, keywords, h )
 }
 
 
+/**
+ * Immediately throws an exception, as getters/setters are unsupported
+ *
+ * This is a temporary restriction; they will be supported in future
+ * releases.
+ *
+ * @param  {string}   name      property name
+ * @param  {*}        value     property value
+ * @param  {Object}   keywords  property keywords
+ * @param  {Function} h         original handler that we replaced
+ *
+ * @return  {undefined}
+ */
+function _parseGetSet( name, value, keywords, h )
+{
+    throw Error(
+        "Cannot define property `" + name + "'; getters/setters are " +
+        "currently unsupported"
+    );
+}
+
+
 /**
  * Implement one or more interfaces
  *

test/Trait/DefinitionTest.js

@@ -28,6 +28,10 @@ require( 'common' ).testCase(
         this.Interface     = this.require( 'interface' );
         this.AbstractClass = this.require( 'class_abstract' );
 
+        this.hasGetSet = !(
+            this.require( 'util' ).definePropertyFallback()
+        );
+
         // means of creating anonymous traits
         this.ctor = [
             this.Sut.extend,
@@ -413,4 +417,38 @@ require( 'common' ).testCase(
             Sut( { 'static foo': function() {} } );
         } );
     },
+
+
+    /**
+     * For the same reasons as static members (described immediately above),
+     * getters/setters are unsupported until future versions.
+     *
+     * Note that we use defineProperty instead of the short-hand object
+     * literal notation to avoid syntax errors in pre-ES5 environments.
+     */
+    'Trait getters and setters are prohibited': function()
+    {
+        // perform these tests only when getters/setters are supported by
+        // our environment
+        if ( !( this.hasGetSet ) )
+        {
+            return;
+        }
+
+        var Sut = this.Sut;
+
+        this.assertThrows( function()
+        {
+            var dfn = {};
+            Object.defineProperty( dfn, 'foo',
+            {
+                get: function() {},
+                set: function() {},
+
+                enumerable: true,
+            } );
+
+            Sut( dfn );
+        } );
+    },
 } );