Fix type inference

This fixes oss-fuzz #47920

Author: dstogov

Zend/Optimizer/zend_inference.c

@@ -3227,7 +3227,7 @@ static zend_always_inline int _zend_update_type_info(
 						tmp |= t1 & (MAY_BE_RC1|MAY_BE_RCN);
 					}
 					if (opline->op2_type == IS_UNUSED) {
-						if (t1 & (MAY_BE_UNDEF|MAY_BE_NULL)) {
+						if (t1 & (MAY_BE_UNDEF|MAY_BE_NULL|MAY_BE_FALSE)) {
 							key_type |= MAY_BE_ARRAY_PACKED;
 						}
 						if (t1 & MAY_BE_ARRAY) {

ext/opcache/tests/opt/inference_010.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Type inference 010: FRTCH_DIM_W
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+--FILE--
+<?php
+function foo() {
+    $x = false;
+    $x[] = &$y;
+}
+foo();
+?>
+DONE
+--EXPECTF--
+Deprecated: Automatic conversion of false to array is deprecated in %sinference_010.php on line 4
+DONE