Merge branch '5.1' into 5.2

* 5.1:
  CS: Apply ternary_to_null_coalescing fixer

Author: derrabus

ErrorHandler.php

@@ -665,7 +665,7 @@ public static function handleFatalError(array $error = null): void
         if ($error && $error['type'] &= \E_PARSE | \E_ERROR | \E_CORE_ERROR | \E_COMPILE_ERROR) {
             // Let's not throw anymore but keep logging
             $handler->throwAt(0, true);
-            $trace = isset($error['backtrace']) ? $error['backtrace'] : null;
+            $trace = $error['backtrace'] ?? null;
 
             if (0 === strpos($error['message'], 'Allowed memory') || 0 === strpos($error['message'], 'Out of memory')) {
                 $fatalError = new OutOfMemoryError($handler->levels[$error['type']].': '.$error['message'], 0, $error, 2, false, $trace);

Exception/FlattenException.php

@@ -300,11 +300,11 @@ public function setTrace($trace, $file, $line): self
             $this->trace[] = [
                 'namespace' => $namespace,
                 'short_class' => $class,
-                'class' => isset($entry['class']) ? $entry['class'] : '',
-                'type' => isset($entry['type']) ? $entry['type'] : '',
-                'function' => isset($entry['function']) ? $entry['function'] : null,
-                'file' => isset($entry['file']) ? $entry['file'] : null,
-                'line' => isset($entry['line']) ? $entry['line'] : null,
+                'class' => $entry['class'] ?? '',
+                'type' => $entry['type'] ?? '',
+                'function' => $entry['function'] ?? null,
+                'file' => $entry['file'] ?? null,
+                'line' => $entry['line'] ?? null,
                 'args' => isset($entry['args']) ? $this->flattenArgs($entry['args']) : [],
             ];
         }