Make class constants fully dereferencable

Zend/tests/varSyntax/class_constant_static_deref.phpt

@@ -0,0 +1,27 @@
+--TEST--
+Class constants can be used as a class name
+--FILE--
+<?php
+
+class Test {
+    const NAME = 'Test2';
+}
+
+class Test2 {
+    const FOO = 42;
+    public static $foo = 42;
+
+    public static function foo() {
+        return 42;
+    }
+}
+
+var_dump(Test::NAME::FOO);
+var_dump(Test::NAME::$foo);
+var_dump(Test::NAME::foo());
+
+?>
+--EXPECT--
+int(42)
+int(42)
+int(42)

Zend/zend_language_parser.y

@@ -1150,12 +1150,12 @@ fully_dereferencable:
 		variable				{ $$ = $1; }
 	|	'(' expr ')'			{ $$ = $2; }
 	|	dereferencable_scalar	{ $$ = $1; }
+	|	class_constant			{ $$ = $1; }
 ;
 
 array_object_dereferencable:
 		fully_dereferencable	{ $$ = $1; }
 	|	constant				{ $$ = $1; }
-	|	class_constant			{ $$ = $1; }
 ;
 
 callable_expr: