Do not use PH7_KEYWORD_FUNCTION for closure declaration.

engine/parser.c

@@ -700,7 +700,7 @@ static sxi32 ExprExtractNode(ph7_gen_state *pGen, ph7_expr_node **ppNode) {
 					}
 				}
 			}
-		} else if(nKeyword == PH7_KEYWORD_FUNCTION) {
+		} else if(pCur[1].nType & PH7_TK_LPAREN && (nKeyword & PH7_KEYWORD_TYPEDEF)) {
 			/* Anonymous function */
 			if(&pCur[1] >= pGen->pEnd) {
 				/* Assume a literal */

tests/callback_function.aer

@@ -1,7 +1,7 @@
 class Program {
 
 	function main(string[] $args) {
-		callback $y = function() {
+		callback $y = void() {
 			callback $a = 'printf';
 			$a("I'm alive\n");
 			var_dump($a);