Report non existent offset on non empty array

phpstan-baseline.neon

@@ -1746,13 +1746,13 @@ parameters:
 		-
 			rawMessage: 'Doing instanceof PHPStan\Type\Constant\ConstantArrayType is error-prone and deprecated. Use Type::getConstantArrays() instead.'
 			identifier: phpstanApi.instanceofType
-			count: 2
+			count: 1
 			path: src/Type/TypeUtils.php
 
 		-
 			rawMessage: Doing instanceof PHPStan\Type\IntersectionType is error-prone and deprecated.
 			identifier: phpstanApi.instanceofType
-			count: 3
+			count: 4
 			path: src/Type/TypeUtils.php
 
 		-

src/Internal/CombinationsHelper.php

@@ -2,14 +2,15 @@
 
 namespace PHPStan\Internal;
 
+use Traversable;
 use function array_pop;
 
 final class CombinationsHelper
 {
 
 	/**
 	 * @param array<iterable<mixed>> $arrays
-	 * @return iterable<list<mixed>>
+	 * @return Traversable<list<mixed>>
 	 */
 	public static function combinations(array $arrays): iterable
 	{

src/Type/Constant/ConstantArrayType.php

@@ -216,6 +216,8 @@ public function getAllArrays(): array
 		} else {
 			$optionalKeysCombinations = [
 				[],
+				array_slice($this->optionalKeys, 0, 1, true),
+				array_slice($this->optionalKeys, -1, 1, true),
 				$this->optionalKeys,
 			];
 		}

src/Type/TypeUtils.php

@@ -2,14 +2,18 @@
 
 namespace PHPStan\Type;
 
+use PHPStan\Internal\CombinationsHelper;
 use PHPStan\Type\Accessory\AccessoryType;
 use PHPStan\Type\Accessory\HasPropertyType;
 use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Generic\TemplateBenevolentUnionType;
 use PHPStan\Type\Generic\TemplateType;
 use PHPStan\Type\Generic\TemplateUnionType;
+use function array_filter;
+use function array_map;
 use function array_merge;
+use function iterator_to_array;
 
 /**
  * @api
@@ -133,17 +137,28 @@ public static function flattenTypes(Type $type): array
 			return $type->getAllArrays();
 		}
 
+		if ($type instanceof IntersectionType && $type->isConstantArray()->yes()) {
+			$newTypes = [];
+			foreach ($type->getTypes() as $innerType) {
+				$newTypes[] = self::flattenTypes($innerType);
+			}
+
+			return array_filter(
+				array_map(
+					static fn (array $types): Type => TypeCombinator::intersect(...$types),
+					iterator_to_array(CombinationsHelper::combinations($newTypes)),
+				),
+				static fn (Type $type): bool => !$type instanceof NeverType,
+			);
+		}
+
 		if ($type instanceof UnionType) {
 			$types = [];
 			foreach ($type->getTypes() as $innerType) {
-				if ($innerType instanceof ConstantArrayType) {
-					foreach ($innerType->getAllArrays() as $array) {
-						$types[] = $array;
-					}
-					continue;
+				$flattenTypes = self::flattenTypes($innerType);
+				foreach ($flattenTypes as $flattenType) {
+					$types[] = $flattenType;
 				}
-
-				$types[] = $innerType;
 			}
 
 			return $types;

tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -991,7 +991,7 @@ public function testBug7581(): void
 	public function testBug7903(): void
 	{
 		$errors = $this->runAnalyse(__DIR__ . '/data/bug-7903.php');
-		$this->assertCount(24, $errors);
+		$this->assertCount(39, $errors);
 	}
 
 	public function testBug7901(): void

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -385,11 +385,6 @@ public function testBug4747(): void
 		$this->analyse([__DIR__ . '/data/bug-4747.php'], []);
 	}
 
-	public function testBug6379(): void
-	{
-		$this->analyse([__DIR__ . '/data/bug-6379.php'], []);
-	}
-
 	#[RequiresPhp('>= 8.0')]
 	public function testBug4885(): void
 	{
@@ -929,13 +924,6 @@ public function testBug4809(): void
 		$this->analyse([__DIR__ . '/data/bug-4809.php'], []);
 	}
 
-	public function testBug11602(): void
-	{
-		$this->reportPossiblyNonexistentGeneralArrayOffset = true;
-
-		$this->analyse([__DIR__ . '/data/bug-11602.php'], []);
-	}
-
 	public function testBug12593(): void
 	{
 		$this->reportPossiblyNonexistentGeneralArrayOffset = true;
@@ -1116,6 +1104,28 @@ public function testPR4385Bis(): void
 		$this->analyse([__DIR__ . '/data/pr-4385-bis.php'], []);
 	}
 
+	public function testBug7143(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-7143.php'], [
+			[
+				"Offset 'foo' might not exist on non-empty-array{foo?: string, bar?: string}.",
+				12,
+			],
+			[
+				"Offset 'bar' might not exist on non-empty-array{foo?: string, bar?: string}.",
+				13,
+			],
+			[
+				"Offset 'foo' might not exist on non-empty-array{foo?: string, bar?: string, 1?: 1, 2?: 2, 3?: 3, 4?: 4, 5?: 5, 6?: 6, ...}.",
+				21,
+			],
+			[
+				"Offset 'bar' might not exist on non-empty-array{foo?: string, bar?: string, 1?: 1, 2?: 2, 3?: 3, 4?: 4, 5?: 5, 6?: 6, ...}.",
+				22,
+			],
+		]);
+	}
+
 	public function testBug12805(): void
 	{
 		$this->reportPossiblyNonexistentGeneralArrayOffset = true;

tests/PHPStan/Rules/Arrays/data/bug-7143.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Bug7143;
+
+class Foo
+{
+	/**
+	 * @param array{foo?: string, bar?: string}&non-empty-array $arr
+	 */
+	public function test(array $arr): void
+	{
+		echo $arr['foo'];
+		echo $arr['bar'];
+	}
+
+	/**
+	 * @param array{foo?: string, bar?: string, 1?:1, 2?:2, 3?:3, 4?:4, 5?:5, 6?:6, 7?:7, 8?:8, 9?:9}&non-empty-array $arr
+	 */
+	public function test2(array $arr): void
+	{
+		echo $arr['foo'];
+		echo $arr['bar'];
+	}
+}