From 0c5293991c97ce8271d7dc6697db764d35e88b6e Mon Sep 17 00:00:00 2001
From: Mike Gerwitz <mike@mikegerwitz.com>
Date: Wed, 18 May 2011 20:51:02 -0400
Subject: [PATCH] Disallowed use of final keyword with properties

---
 lib/member_builder.js            | 10 ++++++++++
 test/test-class_builder-final.js | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/lib/member_builder.js b/lib/member_builder.js
index e83cda2..f4ea3b6 100644
--- a/lib/member_builder.js
+++ b/lib/member_builder.js
@@ -208,6 +208,16 @@ exports.buildProp = function( members, meta, name, value, keywords, base )
         );
     }
 
+    // nor do final properties, because of late static binding (const should be
+    // used instead; read up on the rationale in the documentation)
+    if ( keywords[ 'final' ] )
+    {
+        throw TypeError(
+            "Property '" + name + "' cannot be declared as final; consider " +
+            "const"
+        );
+    }
+
     getMemberVisibility( members, keywords )[ name ] = value;
 };
 
diff --git a/test/test-class_builder-final.js b/test/test-class_builder-final.js
index 1d90c19..3550031 100644
--- a/test/test-class_builder-final.js
+++ b/test/test-class_builder-final.js
@@ -61,3 +61,35 @@ var common    = require( './common' ),
     assert.fail( 'Should not be able to override final methods' );
 } )();
 
+
+/**
+ * Due to our static implementation (late static binding), the use of 'final'
+ * with properties doesn't make much sense. We have to deal with different
+ * problems than languages like Java that truly bind members statically. Consult
+ * the documentation for rationale.
+ *
+ * See also const keyword.
+ */
+( function testFinalKeywordCannotBeUsedWithProperties()
+{
+    try
+    {
+        // attempt to define a 'final' property (should fail)
+        builder.build(
+        {
+            'final public foo': 'bar',
+        } );
+    }
+    catch ( e )
+    {
+        assert.ok(
+            e.message.search( 'foo' ) !== -1,
+            "Final property error message contains name of method"
+        );
+
+        return;
+    }
+
+    assert.fail( "Should not be able to use final keyword with properties" );
+} )();
+