Add non-regression tests for #11218

- DefinedVariableRuleTest: ensure no "Variable $test might not be defined"
  error in for loop where variable is always defined on first iteration
- NonexistentOffsetInArrayDimFetchRuleTest: ensure no "Offset 'test' does
  not exist" error when array offset is always set on first iteration

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -1277,4 +1277,11 @@ public function testBug14308(): void
 		$this->analyse([__DIR__ . '/data/bug-14308.php'], []);
 	}
 
+	public function testBug11218(): void
+	{
+		$this->reportPossiblyNonexistentConstantArrayOffset = true;
+
+		$this->analyse([__DIR__ . '/data/bug-11218.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Arrays/data/bug-11218.php

@@ -0,0 +1,18 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11218Array;
+
+function test(): void
+{
+	$level = 'test';
+
+	$test = [];
+
+	for ($i = 0 ; $i <= 3 ; $i++) {
+		if ($i === 0) {
+			$test[$level] = 'this is a';
+		} else {
+			$test[$level] .= ' test';
+		}
+	}
+}

tests/PHPStan/Rules/Variables/DefinedVariableRuleTest.php

@@ -1508,4 +1508,13 @@ public function testBug12597(): void
 		$this->analyse([__DIR__ . '/data/bug-12597.php'], []);
 	}
 
+	public function testBug11218(): void
+	{
+		$this->cliArgumentsVariablesRegistered = true;
+		$this->polluteScopeWithLoopInitialAssignments = false;
+		$this->checkMaybeUndefinedVariables = true;
+		$this->polluteScopeWithAlwaysIterableForeach = true;
+		$this->analyse([__DIR__ . '/data/bug-11218.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Variables/data/bug-11218.php

@@ -0,0 +1,16 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11218;
+
+function test(): void
+{
+	$level = 'test';
+
+	for ($i = 0 ; $i <= 3 ; $i++) {
+		if ($i === 0) {
+			$test[$level] = 'this is a';
+		} else {
+			$test[$level] .= ' test';
+		}
+	}
+}