Introduced NodeConnectingVisitor to be able to look around the current node in rules

Author: ondrejmirtes

conf/config.neon

@@ -274,10 +274,14 @@ services:
 		class: PhpParser\NodeTraverser
 		setup:
 			- addVisitor(@PhpParser\NodeVisitor\NameResolver)
+			- addVisitor(@PhpParser\NodeVisitor\NodeConnectingVisitor)
 
 	-
 		class: PhpParser\NodeVisitor\NameResolver
 
+	-
+		class: PhpParser\NodeVisitor\NodeConnectingVisitor
+
 	-
 		class: PhpParser\Parser\Php7
 

tests/PHPStan/Rules/NodeConnectingRule.php

@@ -0,0 +1,31 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+
+/**
+ * @implements Rule<Node\Stmt\Echo_>
+ */
+class NodeConnectingRule implements Rule
+{
+
+	public function getNodeType(): string
+	{
+		return Node\Stmt\Echo_::class;
+	}
+
+	public function processNode(Node $node, Scope $scope): array
+	{
+		return [
+			sprintf(
+				'Parent: %s, previous: %s, next: %s',
+				get_class($node->getAttribute('parent')),
+				get_class($node->getAttribute('previous')),
+				get_class($node->getAttribute('next')),
+			),
+		];
+	}
+
+}

tests/PHPStan/Rules/NodeConnectingRuleTest.php

@@ -0,0 +1,28 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Rules;
+
+use PHPStan\Testing\RuleTestCase;
+
+/**
+ * @extends RuleTestCase<NodeConnectingRule>
+ */
+class NodeConnectingRuleTest extends RuleTestCase
+{
+
+	protected function getRule(): Rule
+	{
+		return new NodeConnectingRule();
+	}
+
+	public function testRule(): void
+	{
+		$this->analyse([__DIR__ . '/data/node-connecting.php'], [
+			[
+				'Parent: PhpParser\Node\Stmt\If_, previous: PhpParser\Node\Stmt\Switch_, next: PhpParser\Node\Stmt\Foreach_',
+				11,
+			],
+		]);
+	}
+
+}

tests/PHPStan/Rules/data/node-connecting.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace NodeConnecting;
+
+function foobar(): void
+{
+	if (rand(0, 1)) {
+		switch ('foo') {
+			default: 'bar';
+		}
+		echo 'test';
+		foreach ([] as $val) {
+
+		}
+	}
+}