Merge branch 'PHP-7.0'

Zend/tests/generators/yield_from_by_reference.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Yield from by reference is not supported
+--FILE--
+<?php
+
+function &gen() {
+    yield from [];
+}
+
+?>
+--EXPECTF--
+Fatal error: Cannot use "yield from" inside a by-reference generator in %s on line %d

Zend/zend_compile.c

@@ -6616,6 +6616,11 @@ void zend_compile_yield_from(znode *result, zend_ast *ast) /* {{{ */
 
 	zend_mark_function_as_generator();
 
+	if (CG(active_op_array)->fn_flags & ZEND_ACC_RETURN_REFERENCE) {
+		zend_error_noreturn(E_COMPILE_ERROR,
+			"Cannot use \"yield from\" inside a by-reference generator");
+	}
+
 	zend_compile_expr(&expr_node, expr_ast);
 	zend_emit_op_tmp(result, ZEND_YIELD_FROM, &expr_node, NULL);
 }