Non-ArrayAccess object might be offset-accessible

Author: b1rdex

src/Type/ObjectType.php

@@ -589,7 +589,15 @@ private function isExtraOffsetAccessibleClass(): TrinaryLogic
 			}
 		}
 
-		return TrinaryLogic::createNo();
+		if ($classReflection->isInterface()) {
+			return TrinaryLogic::createMaybe();
+		}
+
+		if ($classReflection->isFinal()) {
+			return TrinaryLogic::createNo();
+		}
+
+		return TrinaryLogic::createMaybe();
 	}
 
 	public function isOffsetAccessible(): TrinaryLogic

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -1174,7 +1174,7 @@ public function dataArrayDestructuring(): array
 				'$intArrayForRewritingFirstElement[1]',
 			],
 			[
-				'*ERROR*',
+				'stdClass',
 				'$obj',
 			],
 			[

tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -230,4 +230,9 @@ public function testCoalesceAssign(): void
 		$this->analyse([__DIR__ . '/data/nonexistent-offset-coalesce-assign.php'], []);
 	}
 
+	public function testIntersection(): void
+	{
+		$this->analyse([__DIR__ . '/data/nonexistent-offset-intersection.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Arrays/data/nonexistent-offset-intersection.php

@@ -0,0 +1,21 @@
+<?php declare(strict_types = 1);
+
+class Foo
+{
+    /** @var \ArrayAccess<string, mixed> */
+    private $fooA;
+    /** @var \ArrayAccess<string, mixed>&iterable<mixed> */
+    private $fooB;
+    /** @var \ArrayAccess<string, mixed>&\Countable */
+    private $fooC;
+    /** @var \ArrayAccess<string, mixed>&\stdClass */
+    private $fooD;
+
+    public function test(): void
+    {
+        $a = $this->fooA['bar'];
+        $b = $this->fooB['bar'];
+        $c = $this->fooC['bar'];
+        $d = $this->fooD['bar'];
+    }
+}

tests/PHPStan/Type/ObjectTypeTest.php

@@ -437,13 +437,23 @@ public function dataHasOffsetValueType(): array
 			[
 				new ObjectType(\stdClass::class),
 				new IntegerType(),
+				TrinaryLogic::createMaybe(),
+			],
+			[
+				new ObjectType(\Generator::class),
+				new IntegerType(),
 				TrinaryLogic::createNo(),
 			],
 			[
 				new ObjectType(\ArrayAccess::class),
 				new IntegerType(),
 				TrinaryLogic::createMaybe(),
 			],
+			[
+				new ObjectType(\Countable::class),
+				new IntegerType(),
+				TrinaryLogic::createMaybe(),
+			],
 			[
 				new GenericObjectType(\ArrayAccess::class, [new IntegerType(), new MixedType()]),
 				new IntegerType(),