Fix for WordPress Plugin error "Fatal error: Cannot declare class ArithmeticError". See below for instructions.

polyfill-php70.diff

commit c79529943b7aa11ac328b1de6ac10173da35b453
Author: Julien Deniau <julien.deniau@gmail.com>
Date:   Wed Sep 5 14:38:59 2018 +0200

    add test to prevent lint from failing

diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/ArithmeticError.php b/vendor/symfony/polyfill-php70/Resources/stubs/ArithmeticError.php
index 6819124..4c981d0 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/ArithmeticError.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/ArithmeticError.php
@@ -1,5 +1,7 @@
 <?php

-class ArithmeticError extends Error
-{
+if (PHP_VERSION_ID < 70000) {
+    class ArithmeticError extends Error
+    {
+    }
 }
diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/AssertionError.php b/vendor/symfony/polyfill-php70/Resources/stubs/AssertionError.php
index acb1250..8d58081 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/AssertionError.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/AssertionError.php
@@ -1,5 +1,7 @@
 <?php

-class AssertionError extends Error
-{
+if (PHP_VERSION_ID < 70000) {
+    class AssertionError extends Error
+    {
+    }
 }
diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/DivisionByZeroError.php b/vendor/symfony/polyfill-php70/Resources/stubs/DivisionByZeroError.php
index c99278b..d009d06 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/DivisionByZeroError.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/DivisionByZeroError.php
@@ -1,5 +1,7 @@
 <?php

-class DivisionByZeroError extends Error
-{
+if (PHP_VERSION_ID < 70000) {
+    class DivisionByZeroError extends Error
+    {
+    }
 }
diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/Error.php b/vendor/symfony/polyfill-php70/Resources/stubs/Error.php
index 405847f..702d40b 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/Error.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/Error.php
@@ -1,5 +1,7 @@
 <?php

-class Error extends Exception
-{
+if (PHP_VERSION_ID < 70000) {
+    class Error extends Exception
+    {
+    }
 }
diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/ParseError.php b/vendor/symfony/polyfill-php70/Resources/stubs/ParseError.php
index 2dd447d..b321576 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/ParseError.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/ParseError.php
@@ -1,5 +1,7 @@
 <?php

-class ParseError extends Error
-{
+if (PHP_VERSION_ID < 70000) {
+    class ParseError extends Error
+    {
+    }
 }
diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/SessionUpdateTimestampHandlerInterface.php b/vendor/symfony/polyfill-php70/Resources/stubs/SessionUpdateTimestampHandlerInterface.php
index 0cc02c8..3a26fb8 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/SessionUpdateTimestampHandlerInterface.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/SessionUpdateTimestampHandlerInterface.php
@@ -1,23 +1,25 @@
 <?php

-interface SessionUpdateTimestampHandlerInterface
-{
-    /**
-     * Checks if a session identifier already exists or not.
-     *
-     * @param string $key
-     *
-     * @return bool
-     */
-    public function validateId($key);
+if (PHP_VERSION_ID < 70000) {
+    interface SessionUpdateTimestampHandlerInterface
+    {
+        /**
+         * Checks if a session identifier already exists or not.
+         *
+         * @param string $key
+         *
+         * @return bool
+         */
+        public function validateId($key);

-    /**
-     * Updates the timestamp of a session when its data didn't change.
-     *
-     * @param string $key
-     * @param string $val
-     *
-     * @return bool
-     */
-    public function updateTimestamp($key, $val);
+        /**
+         * Updates the timestamp of a session when its data didn't change.
+         *
+         * @param string $key
+         * @param string $val
+         *
+         * @return bool
+         */
+        public function updateTimestamp($key, $val);
+    }
 }
diff --git a/vendor/symfony/polyfill-php70/Resources/stubs/TypeError.php b/vendor/symfony/polyfill-php70/Resources/stubs/TypeError.php
index 2bed1b4..027495f 100644
--- a/vendor/symfony/polyfill-php70/Resources/stubs/TypeError.php
+++ b/vendor/symfony/polyfill-php70/Resources/stubs/TypeError.php
@@ -1,5 +1,7 @@
 <?php

-class TypeError extends Error
-{
+if (PHP_VERSION_ID < 70000) {
+    class TypeError extends Error
+    {
+    }
 }

To fix the WordPress Plugin error to SVN with symfony/polyfill-php70 (see symfony/polyfill#276), apply this patch as follows:

# go to your wordpress plugin SVN directory. Here we use "trunk" but this can be applied anywhere
cd /path/to/your/wordpress_plugin/trunk

# curl this patch file. You can also just copy/paste the contents into a file
curl https://gist.github.com/bshaffer/904b596beecdfbb0a39cb3cd07728720/raw > polyfill-php70.diff

# apply the patch
patch -p1 < polyfill-php70.diff