Widen empty ConstantArrayType to array when resolving dynamic constant types

src/Analyser/ConstantResolver.php

@@ -13,6 +13,8 @@
 use PHPStan\Reflection\ReflectionProvider\ReflectionProviderProvider;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
+use PHPStan\Type\ArrayType;
+use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantFloatType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
@@ -424,7 +426,7 @@ public function resolveConstantType(string $constantName, Type $constantType): T
 				return $constantType;
 			}
 			if (in_array($constantName, $this->dynamicConstantNames, true)) {
-				return $constantType->generalize(GeneralizePrecision::lessSpecific());
+				return $this->generalizeDynamicConstantType($constantType);
 			}
 		}
 
@@ -459,13 +461,23 @@ public function resolveClassConstantType(string $className, string $constantName
 			}
 
 			if ($constantType->isConstantValue()->yes()) {
-				return $constantType->generalize(GeneralizePrecision::lessSpecific());
+				return $this->generalizeDynamicConstantType($constantType);
 			}
 		}
 
 		return $constantType;
 	}
 
+	private function generalizeDynamicConstantType(Type $constantType): Type
+	{
+		$generalized = $constantType->generalize(GeneralizePrecision::lessSpecific());
+		if ($generalized->equals(new ConstantArrayType([], []))) {
+			return new ArrayType(new MixedType(), new MixedType());
+		}
+
+		return $generalized;
+	}
+
 	private function createInteger(?int $min, ?int $max): Type
 	{
 		if ($min !== null && $min === $max) {

tests/PHPStan/Analyser/Bug8526IntegrationTest.php

@@ -0,0 +1,53 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser;
+
+use PHPStan\Testing\PHPStanTestCase;
+use PHPUnit\Framework\Attributes\CoversNothing;
+use function array_merge;
+use function array_unique;
+
+#[CoversNothing]
+class Bug8526IntegrationTest extends PHPStanTestCase
+{
+
+	public function testBug8526(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-8526.php');
+		$this->assertNoErrors($errors);
+	}
+
+	/**
+	 * @return list<Error>
+	 */
+	private function runAnalyse(string $file): array
+	{
+		$file = $this->getFileHelper()->normalizePath($file);
+
+		$analyser = self::getContainer()->getByType(Analyser::class);
+		$finalizer = self::getContainer()->getByType(AnalyserResultFinalizer::class);
+		$errors = $finalizer->finalize(
+			$analyser->analyse([$file], null, null, true),
+			false,
+			true,
+		)->getErrors();
+		foreach ($errors as $error) {
+			$this->assertSame($file, $error->getFilePath());
+		}
+
+		return $errors;
+	}
+
+	public static function getAdditionalConfigFiles(): array
+	{
+		return array_unique(
+			array_merge(
+				parent::getAdditionalConfigFiles(),
+				[
+					__DIR__ . '/bug-8526.neon',
+				],
+			),
+		);
+	}
+
+}

tests/PHPStan/Analyser/bug-8526.neon

@@ -0,0 +1,7 @@
+includes:
+	- ../../../conf/bleedingEdge.neon
+
+parameters:
+	dynamicConstantNames:
+		- FOO
+		- DYNAMICARRAY

tests/PHPStan/Analyser/data/bug-8526.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Bug8526;
+
+define('FOO', true);
+define('DYNAMICARRAY', []);
+
+function doFoo(): void
+{
+	if (isset(DYNAMICARRAY['MyKey'])) {
+		echo 'has key';
+	}
+	if (FOO) {
+		echo 'foo';
+	}
+}

tests/PHPStan/Analyser/data/dynamic-constant.php

@@ -7,6 +7,7 @@
 define('GLOBAL_PURE_CONSTANT', 123);
 define('GLOBAL_DYNAMIC_CONSTANT', false);
 define('GLOBAL_DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES', null);
+define('GLOBAL_DYNAMIC_EMPTY_ARRAY', []);
 
 class DynamicConstantClass
 {
@@ -22,6 +23,8 @@ class DynamicConstantClass
 
 	/** @var int */
 	const DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT = null;
+
+	const DYNAMIC_EMPTY_ARRAY_NO_PHPDOC = [];
 }
 
 class NoDynamicConstantClass
@@ -41,5 +44,7 @@ private function rip()
 		assertType('string|null', DynamicConstantClass::DYNAMIC_NULL_WITH_PHPDOC_CONSTANT);
 		assertType('list<string>', DynamicConstantClass::DYNAMIC_EMPTY_ARRAY_WITH_PHPDOC_CONSTANT);
 		assertType('int', DynamicConstantClass::DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT);
+		assertType('array', DynamicConstantClass::DYNAMIC_EMPTY_ARRAY_NO_PHPDOC);
+		assertType('array', GLOBAL_DYNAMIC_EMPTY_ARRAY);
 	}
 }

tests/PHPStan/Analyser/dynamic-constants.neon

@@ -7,6 +7,8 @@ parameters:
 		- DynamicConstants\DynamicConstantClass::DYNAMIC_NULL_WITH_PHPDOC_CONSTANT
 		- DynamicConstants\DynamicConstantClass::DYNAMIC_EMPTY_ARRAY_WITH_PHPDOC_CONSTANT
 		- DynamicConstants\DynamicConstantClass::DYNAMIC_INCOMPATIBLE_PHPDOC_CONSTANT
+		- DynamicConstants\DynamicConstantClass::DYNAMIC_EMPTY_ARRAY_NO_PHPDOC
 		- GLOBAL_DYNAMIC_CONSTANT
+		- GLOBAL_DYNAMIC_EMPTY_ARRAY
 		DynamicConstants\DynamicConstantClass::DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES_IN_CLASS: 'string|null'
 		GLOBAL_DYNAMIC_CONSTANT_WITH_EXPLICIT_TYPES: 'string|null'