Prevent issue with accessory-only IntersectionType

ondrejmirtes · ondrejmirtes · commit f2af15b571c3 · 2026-05-14T10:17:04.000+02:00
diff --git a/src/Analyser/MutatingScope.php b/src/Analyser/MutatingScope.php
@@ -63,7 +63,6 @@
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\Accessory\AccessoryArrayListType;
-use PHPStan\Type\Accessory\AccessoryType;
 use PHPStan\Type\Accessory\HasOffsetValueType;
 use PHPStan\Type\Accessory\NonEmptyArrayType;
 use PHPStan\Type\Accessory\OversizedArrayType;
@@ -3164,15 +3163,10 @@ public function addTypeToExpression(Expr $expr, Type $type): self
 			return $this->specifyExpressionType($expr, $newType, $newType, TrinaryLogic::createYes());
 		}
 
-		$newNativeType = TypeCombinator::intersect($type, $nativeType);
-		if ($newNativeType instanceof AccessoryType) {
-			$newNativeType = $nativeType;
-		}
-
 		return $this->specifyExpressionType(
 			$expr,
 			TypeCombinator::intersect($type, $originalExprType),
-			$newNativeType,
+			TypeCombinator::intersect($type, $nativeType),
 			TrinaryLogic::createYes(),
 		);
 	}
diff --git a/src/Type/Accessory/AccessoryArrayListType.php b/src/Type/Accessory/AccessoryArrayListType.php
@@ -7,6 +7,7 @@
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
+use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\CompoundType;
 use PHPStan\Type\Constant\ConstantFloatType;
@@ -549,6 +550,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new ArrayType(new MixedType(), new MixedType());
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('list');
diff --git a/src/Type/Accessory/AccessoryLiteralStringType.php b/src/Type/Accessory/AccessoryLiteralStringType.php
@@ -383,6 +383,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new StringType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('literal-string');
diff --git a/src/Type/Accessory/AccessoryLowercaseStringType.php b/src/Type/Accessory/AccessoryLowercaseStringType.php
@@ -388,6 +388,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new StringType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('lowercase-string');
diff --git a/src/Type/Accessory/AccessoryNonEmptyStringType.php b/src/Type/Accessory/AccessoryNonEmptyStringType.php
@@ -392,6 +392,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new StringType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('non-empty-string');
diff --git a/src/Type/Accessory/AccessoryNonFalsyStringType.php b/src/Type/Accessory/AccessoryNonFalsyStringType.php
@@ -389,6 +389,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new StringType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('non-falsy-string');
diff --git a/src/Type/Accessory/AccessoryNumericStringType.php b/src/Type/Accessory/AccessoryNumericStringType.php
@@ -373,7 +373,7 @@ public function generalize(GeneralizePrecision $precision): Type
 	public function tryRemove(Type $typeToRemove): ?Type
 	{
 		if ($typeToRemove instanceof ConstantStringType && $typeToRemove->getValue() === '0') {
-			return new IntersectionType([$this, new AccessoryNonFalsyStringType()]);
+			return new IntersectionType([new StringType(), $this, new AccessoryNonFalsyStringType()]);
 		}
 
 		return null;
@@ -392,6 +392,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new StringType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('numeric-string');
diff --git a/src/Type/Accessory/AccessoryType.php b/src/Type/Accessory/AccessoryType.php
@@ -55,4 +55,14 @@
 interface AccessoryType extends Type
 {
 
+	/**
+	 * Returns the base type this accessory refines.
+	 *
+	 * Used when an accessory would otherwise end up in an `IntersectionType`
+	 * without an explicit base type — the returned type provides that base.
+	 * For example `AccessoryNonEmptyStringType` returns `string`, array accessories
+	 * return `array`, and offset accessories return `array|ArrayAccess`.
+	 */
+	public function getDefaultBaseType(): Type;
+
 }
diff --git a/src/Type/Accessory/AccessoryUppercaseStringType.php b/src/Type/Accessory/AccessoryUppercaseStringType.php
@@ -388,6 +388,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new StringType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('uppercase-string');
diff --git a/src/Type/Accessory/HasMethodType.php b/src/Type/Accessory/HasMethodType.php
@@ -22,6 +22,7 @@
 use PHPStan\Type\IsSuperTypeOfResult;
 use PHPStan\Type\MixedType;
 use PHPStan\Type\ObjectType;
+use PHPStan\Type\ObjectWithoutClassType;
 use PHPStan\Type\StringType;
 use PHPStan\Type\Traits\MaybeCallableTypeTrait;
 use PHPStan\Type\Traits\MaybeIterableTypeTrait;
@@ -330,6 +331,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new ObjectWithoutClassType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode(''); // no PHPDoc representation
diff --git a/src/Type/Accessory/HasOffsetType.php b/src/Type/Accessory/HasOffsetType.php
@@ -2,11 +2,13 @@
 
 namespace PHPStan\Type\Accessory;
 
+use ArrayAccess;
 use PHPStan\Php\PhpVersion;
 use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
+use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\CompoundType;
 use PHPStan\Type\Constant\ConstantIntegerType;
@@ -17,6 +19,7 @@
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\IsSuperTypeOfResult;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\ObjectType;
 use PHPStan\Type\ObjectWithoutClassType;
 use PHPStan\Type\Traits\MaybeArrayTypeTrait;
 use PHPStan\Type\Traits\MaybeCallableTypeTrait;
@@ -449,6 +452,14 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new UnionType([
+			new ArrayType(new MixedType(), new MixedType()),
+			new ObjectType(ArrayAccess::class),
+		]);
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode(''); // no PHPDoc representation
diff --git a/src/Type/Accessory/HasOffsetValueType.php b/src/Type/Accessory/HasOffsetValueType.php
@@ -2,12 +2,14 @@
 
 namespace PHPStan\Type\Accessory;
 
+use ArrayAccess;
 use PHPStan\Php\PhpVersion;
 use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
+use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\CompoundType;
 use PHPStan\Type\Constant\ConstantIntegerType;
@@ -20,6 +22,7 @@
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\IsSuperTypeOfResult;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\ObjectType;
 use PHPStan\Type\ObjectWithoutClassType;
 use PHPStan\Type\StaticTypeFactory;
 use PHPStan\Type\StringType;
@@ -538,6 +541,14 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new UnionType([
+			new ArrayType(new MixedType(), new MixedType()),
+			new ObjectType(ArrayAccess::class),
+		]);
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode(''); // no PHPDoc representation
diff --git a/src/Type/Accessory/HasPropertyType.php b/src/Type/Accessory/HasPropertyType.php
@@ -15,6 +15,7 @@
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\IsSuperTypeOfResult;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\ObjectWithoutClassType;
 use PHPStan\Type\Traits\MaybeCallableTypeTrait;
 use PHPStan\Type\Traits\MaybeIterableTypeTrait;
 use PHPStan\Type\Traits\MaybeObjectTypeTrait;
@@ -308,6 +309,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new ObjectWithoutClassType();
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode(''); // no PHPDoc representation
diff --git a/src/Type/Accessory/NonEmptyArrayType.php b/src/Type/Accessory/NonEmptyArrayType.php
@@ -7,6 +7,7 @@
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
+use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\CompoundType;
 use PHPStan\Type\Constant\ConstantBooleanType;
@@ -532,6 +533,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new ArrayType(new MixedType(), new MixedType());
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode('non-empty-array');
diff --git a/src/Type/Accessory/OversizedArrayType.php b/src/Type/Accessory/OversizedArrayType.php
@@ -7,6 +7,7 @@
 use PHPStan\PhpDocParser\Ast\Type\TypeNode;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\AcceptsResult;
+use PHPStan\Type\ArrayType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\CompoundType;
 use PHPStan\Type\Constant\ConstantFloatType;
@@ -504,6 +505,11 @@ public function getFiniteTypes(): array
 		return [];
 	}
 
+	public function getDefaultBaseType(): Type
+	{
+		return new ArrayType(new MixedType(), new MixedType());
+	}
+
 	public function toPhpDocNode(): TypeNode
 	{
 		return new IdentifierTypeNode(''); // no PHPDoc representation
diff --git a/src/Type/TypeCombinator.php b/src/Type/TypeCombinator.php
@@ -1731,6 +1731,19 @@ public static function intersect(Type ...$types): Type
 			return $types[0];
 		}
 
+		$accessoryBaseTypes = [];
+		foreach ($types as $type) {
+			if (!$type instanceof AccessoryType) {
+				$accessoryBaseTypes = null;
+				break;
+			}
+			$accessoryBaseTypes[] = $type->getDefaultBaseType();
+		}
+		if ($accessoryBaseTypes !== null) {
+			// Accessory types never stand alone — supply the base type they refine.
+			return self::intersect(self::intersect(...$accessoryBaseTypes), ...$types);
+		}
+
 		return new IntersectionType($types);
 	}
 
diff --git a/tests/PHPStan/Type/Accessory/HasMethodTypeTest.php b/tests/PHPStan/Type/Accessory/HasMethodTypeTest.php
@@ -172,6 +172,7 @@ public static function dataIsSubTypeOf(): array
 			[
 				new HasMethodType('foo'),
 				new IntersectionType([
+					new ObjectWithoutClassType(),
 					new HasMethodType('foo'),
 					new HasMethodType('bar'),
 				]),
diff --git a/tests/PHPStan/Type/Accessory/HasPropertyTypeTest.php b/tests/PHPStan/Type/Accessory/HasPropertyTypeTest.php
@@ -138,6 +138,7 @@ public static function dataIsSubTypeOf(): array
 			[
 				new HasPropertyType('foo'),
 				new IntersectionType([
+					new ObjectWithoutClassType(),
 					new HasPropertyType('foo'),
 					new HasPropertyType('bar'),
 				]),
diff --git a/tests/PHPStan/Type/UnionTypeTest.php b/tests/PHPStan/Type/UnionTypeTest.php
@@ -129,7 +129,7 @@ public static function dataSelfCompare(): Iterator
 		yield [new HasPropertyType('foo')];
 		yield [IntegerRangeType::fromInterval(3, 10)];
 		yield [$integerType];
-		yield [new IntersectionType([new HasMethodType('Foo'), new HasPropertyType('bar')])];
+		yield [new IntersectionType([new ObjectWithoutClassType(), new HasMethodType('Foo'), new HasPropertyType('bar')])];
 		yield [new IterableType($integerType, $stringType)];
 		yield [$mixedType];
 		yield [new NeverType()];

Original file line number	Diff line number	Diff line change
`@@ -383,6 +383,11 @@ public function getFiniteTypes(): array`
`383`	`383`	`return [];`
`384`	`384`	`}`
`385`	`385`
	`386`	`+ public function getDefaultBaseType(): Type`
	`387`	`+ {`
	`388`	`+ return new StringType();`
	`389`	`+ }`
	`390`	`+`
`386`	`391`	`public function toPhpDocNode(): TypeNode`
`387`	`392`	`{`
`388`	`393`	`return new IdentifierTypeNode('literal-string');`
Original file line number	Diff line number	Diff line change
`@@ -388,6 +388,11 @@ public function getFiniteTypes(): array`
`388`	`388`	`return [];`
`389`	`389`	`}`
`390`	`390`
	`391`	`+ public function getDefaultBaseType(): Type`
	`392`	`+ {`
	`393`	`+ return new StringType();`
	`394`	`+ }`
	`395`	`+`
`391`	`396`	`public function toPhpDocNode(): TypeNode`
`392`	`397`	`{`
`393`	`398`	`return new IdentifierTypeNode('lowercase-string');`
Original file line number	Diff line number	Diff line change
`@@ -392,6 +392,11 @@ public function getFiniteTypes(): array`
`392`	`392`	`return [];`
`393`	`393`	`}`
`394`	`394`
	`395`	`+ public function getDefaultBaseType(): Type`
	`396`	`+ {`
	`397`	`+ return new StringType();`
	`398`	`+ }`
	`399`	`+`
`395`	`400`	`public function toPhpDocNode(): TypeNode`
`396`	`401`	`{`
`397`	`402`	`return new IdentifierTypeNode('non-empty-string');`
Original file line number	Diff line number	Diff line change
`@@ -389,6 +389,11 @@ public function getFiniteTypes(): array`
`389`	`389`	`return [];`
`390`	`390`	`}`
`391`	`391`
	`392`	`+ public function getDefaultBaseType(): Type`
	`393`	`+ {`
	`394`	`+ return new StringType();`
	`395`	`+ }`
	`396`	`+`
`392`	`397`	`public function toPhpDocNode(): TypeNode`
`393`	`398`	`{`
`394`	`399`	`return new IdentifierTypeNode('non-falsy-string');`
Original file line number	Diff line number	Diff line change
`@@ -373,7 +373,7 @@ public function generalize(GeneralizePrecision $precision): Type`
`373`	`373`	`public function tryRemove(Type $typeToRemove): ?Type`
`374`	`374`	`{`
`375`	`375`	`if ($typeToRemove instanceof ConstantStringType && $typeToRemove->getValue() === '0') {`
`376`		`- return new IntersectionType([$this, new AccessoryNonFalsyStringType()]);`
	`376`	`+ return new IntersectionType([new StringType(), $this, new AccessoryNonFalsyStringType()]);`
`377`	`377`	`}`
`378`	`378`
`379`	`379`	`return null;`
`@@ -392,6 +392,11 @@ public function getFiniteTypes(): array`
`392`	`392`	`return [];`
`393`	`393`	`}`
`394`	`394`
	`395`	`+ public function getDefaultBaseType(): Type`
	`396`	`+ {`
	`397`	`+ return new StringType();`
	`398`	`+ }`
	`399`	`+`
`395`	`400`	`public function toPhpDocNode(): TypeNode`
`396`	`401`	`{`
`397`	`402`	`return new IdentifierTypeNode('numeric-string');`
Original file line number	Diff line number	Diff line change
`@@ -55,4 +55,14 @@`
`55`	`55`	`interface AccessoryType extends Type`
`56`	`56`	`{`
`57`	`57`
	`58`	`+ /**`
	`59`	`+ * Returns the base type this accessory refines.`
	`60`	`+ *`
	`61`	+ * Used when an accessory would otherwise end up in an `IntersectionType`
	`62`	`+ * without an explicit base type — the returned type provides that base.`
	`63`	+ * For example `AccessoryNonEmptyStringType` returns `string`, array accessories
	`64`	+ * return `array`, and offset accessories return `array\|ArrayAccess`.
	`65`	`+ */`
	`66`	`+ public function getDefaultBaseType(): Type;`
	`67`	`+`
`58`	`68`	`}`