My first commit of codes

vendor/psy/psysh/src/Psy/CodeCleaner/ValidFunctionNamePass.php

@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * This file is part of Psy Shell
+ *
+ * (c) 2012-2014 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Psy\CodeCleaner;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Stmt\Function_ as FunctionStmt;
+use Psy\Exception\FatalErrorException;
+
+/**
+ * Validate that function calls will succeed.
+ *
+ * This pass throws a FatalErrorException rather than letting PHP run
+ * headfirst into a real fatal error and die.
+ */
+class ValidFunctionNamePass extends NamespaceAwarePass
+{
+    /**
+     * Validate that function calls will succeed.
+     *
+     * @throws FatalErrorException if a function is redefined.
+     * @throws FatalErrorException if the function name is a string (not an expression) and is not defined.
+     *
+     * @param Node $node
+     */
+    public function leaveNode(Node $node)
+    {
+        if ($node instanceof FunctionStmt) {
+            $name = $this->getFullyQualifiedName($node->name);
+
+            if (function_exists($name) || isset($this->currentScope[strtolower($name)])) {
+                throw new FatalErrorException(sprintf('Cannot redeclare %s()', $name), 0, 1, null, $node->getLine());
+            }
+
+            $this->currentScope[strtolower($name)] = true;
+        } elseif ($node instanceof FuncCall) {
+            // if function name is an expression or a variable, give it a pass for now.
+            $name = $node->name;
+            if (!$name instanceof Expression && !$name instanceof Variable) {
+                $shortName = implode('\\', $name->parts);
+                $fullName  = $this->getFullyQualifiedName($name);
+                $inScope = isset($this->currentScope[strtolower($fullName)]);
+                if (!$inScope && !function_exists($shortName) && !function_exists($fullName)) {
+                    $message = sprintf('Call to undefined function %s()', $name);
+                    throw new FatalErrorException($message, 0, 1, null, $node->getLine());
+                }
+            }
+        }
+    }
+}