Fix #13828: Reference to static const behaves as self const

CLAUDE.md

@@ -307,6 +307,10 @@ This affects match expression exhaustiveness: `class-string<FinalA|FinalB>` matc
 
 `StaticType::transformStaticType()` is used when resolving method return types on a `StaticType` caller. It traverses the return type and transforms `StaticType`/`ThisType` instances via `changeBaseClass()`. Since `ThisType extends StaticType`, both are caught by the `$type instanceof StaticType` check. The critical invariant: when the **caller** is a `StaticType` (not `ThisType`) and the method's return type contains `ThisType`, the `ThisType` must be downgraded to a plain `StaticType`. This is because `$this` (the exact instance) cannot be guaranteed when calling on a `static` type (which could be any subclass instance). `ThisType::changeBaseClass()` returns a new `ThisType`, which preserves the `$this` semantics — so the downgrade must happen explicitly after `changeBaseClass()`. The `CallbackUnresolvedMethodPrototypeReflection` at line 91 also has special handling for `ThisType` return types intersected with `selfOutType`.
 
+### PHPDoc `static::CONST` resolution and ClassConstantAccessType
+
+PHPDoc types like `@return static::SOME_CONST` require late static binding semantics — the constant should resolve based on the caller's class, not the declaring class. `TypeNodeResolver::resolveConstTypeNode()` and `resolveArrayShapeOffsetType()` handle this by creating a `ClassConstantAccessType(StaticType, constantName)` when the keyword is `static` (not `self`). This type implements `LateResolvableType` and wraps a `StaticType` that gets replaced with the actual caller's `ObjectType` via `CalledOnTypeUnresolvedMethodPrototypeReflection::transformStaticType()` during method call resolution. The `getResult()` method then resolves the constant on the concrete type. For final classes, the `$isStatic` flag is cleared and the constant is resolved eagerly (same as `self`). The wildcard case (`static::CONST_*`) falls back to `getValueType()` from the class reflection.
+
 ### PHPDoc inheritance
 
 PHPDoc types (`@return`, `@param`, `@throws`, `@property`) are inherited through class hierarchies. Bugs arise when:

src/PhpDoc/TypeNodeResolver.php

@@ -58,6 +58,7 @@
 use PHPStan\Type\BenevolentUnionType;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\CallableType;
+use PHPStan\Type\ClassConstantAccessType;
 use PHPStan\Type\ClassStringType;
 use PHPStan\Type\ClosureType;
 use PHPStan\Type\ConditionalType;
@@ -1098,9 +1099,14 @@ private function resolveArrayShapeOffsetType(ArrayShapeItemNode $itemNode, NameS
 				throw new ShouldNotHappenException(); // global constant should get parsed as class name in IdentifierTypeNode
 			}
 
+			$isStatic = false;
 			if ($nameScope->getClassName() !== null) {
 				switch (strtolower($constExpr->className)) {
 					case 'static':
+						$className = $nameScope->getClassName();
+						$isStatic = true;
+						break;
+
 					case 'self':
 						$className = $nameScope->getClassName();
 						break;
@@ -1128,11 +1134,19 @@ private function resolveArrayShapeOffsetType(ArrayShapeItemNode $itemNode, NameS
 			}
 			$classReflection = $this->getReflectionProvider()->getClass($className);
 
+			if ($isStatic && $classReflection->isFinal()) {
+				$isStatic = false;
+			}
+
 			$constantName = $constExpr->name;
 			if (!$classReflection->hasConstant($constantName)) {
 				return new ErrorType();
 			}
 
+			if ($isStatic) {
+				return new ClassConstantAccessType(new StaticType($classReflection), $constantName);
+			}
+
 			$reflectionConstant = $classReflection->getNativeReflection()->getReflectionConstant($constantName);
 			if ($reflectionConstant === false) {
 				return new ErrorType();
@@ -1188,9 +1202,14 @@ private function resolveConstTypeNode(ConstTypeNode $typeNode, NameScope $nameSc
 				throw new ShouldNotHappenException(); // global constant should get parsed as class name in IdentifierTypeNode
 			}
 
+			$isStatic = false;
 			if ($nameScope->getClassName() !== null) {
 				switch (strtolower($constExpr->className)) {
 					case 'static':
+						$className = $nameScope->getClassName();
+						$isStatic = true;
+						break;
+
 					case 'self':
 						$className = $nameScope->getClassName();
 						break;
@@ -1219,6 +1238,10 @@ private function resolveConstTypeNode(ConstTypeNode $typeNode, NameScope $nameSc
 
 			$classReflection = $this->getReflectionProvider()->getClass($className);
 
+			if ($isStatic && $classReflection->isFinal()) {
+				$isStatic = false;
+			}
+
 			$constantName = $constExpr->name;
 			if (Strings::contains($constantName, '*')) {
 				// convert * into .*? and escape everything else so the constants can be matched against the pattern
@@ -1235,6 +1258,16 @@ private function resolveConstTypeNode(ConstTypeNode $typeNode, NameScope $nameSc
 						continue;
 					}
 
+					if ($isStatic) {
+						$constantReflection = $classReflection->getConstant($classConstantName);
+						if (!$constantReflection->isFinal() && !$constantReflection->hasPhpDocType() && !$constantReflection->hasNativeType()) {
+							$constantTypes[] = new MixedType();
+							continue;
+						}
+						$constantTypes[] = $constantReflection->getValueType();
+						continue;
+					}
+
 					$declaringClassName = $reflectionConstant->getDeclaringClass()->getName();
 					if (!$this->getReflectionProvider()->hasClass($declaringClassName)) {
 						continue;
@@ -1263,6 +1296,10 @@ private function resolveConstTypeNode(ConstTypeNode $typeNode, NameScope $nameSc
 				return new EnumCaseObjectType($classReflection->getName(), $constantName);
 			}
 
+			if ($isStatic) {
+				return new ClassConstantAccessType(new StaticType($classReflection), $constantName);
+			}
+
 			$reflectionConstant = $classReflection->getNativeReflection()->getReflectionConstant($constantName);
 			if ($reflectionConstant === false) {
 				return new ErrorType();

src/Type/ClassConstantAccessType.php

@@ -0,0 +1,95 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type;
+
+use PHPStan\PhpDocParser\Ast\ConstExpr\ConstFetchNode;
+use PHPStan\PhpDocParser\Ast\Type\ConstTypeNode;
+use PHPStan\PhpDocParser\Ast\Type\TypeNode;
+use PHPStan\Type\Generic\TemplateTypeVariance;
+use PHPStan\Type\Traits\LateResolvableTypeTrait;
+use PHPStan\Type\Traits\NonGeneralizableTypeTrait;
+
+final class ClassConstantAccessType implements CompoundType, LateResolvableType
+{
+
+	use LateResolvableTypeTrait;
+	use NonGeneralizableTypeTrait;
+
+	public function __construct(
+		private Type $type,
+		private string $constantName,
+	)
+	{
+	}
+
+	public function getReferencedClasses(): array
+	{
+		return $this->type->getReferencedClasses();
+	}
+
+	public function getReferencedTemplateTypes(TemplateTypeVariance $positionVariance): array
+	{
+		return $this->type->getReferencedTemplateTypes($positionVariance);
+	}
+
+	public function equals(Type $type): bool
+	{
+		return $type instanceof self
+			&& $this->type->equals($type->type)
+			&& $this->constantName === $type->constantName;
+	}
+
+	public function describe(VerbosityLevel $level): string
+	{
+		return $this->resolve()->describe($level);
+	}
+
+	public function isResolvable(): bool
+	{
+		return !TypeUtils::containsTemplateType($this->type);
+	}
+
+	protected function getResult(): Type
+	{
+		if ($this->type->hasConstant($this->constantName)->yes()) {
+			return $this->type->getConstant($this->constantName)->getValueType();
+		}
+
+		return new ErrorType();
+	}
+
+	/**
+	 * @param callable(Type): Type $cb
+	 */
+	public function traverse(callable $cb): Type
+	{
+		$type = $cb($this->type);
+
+		if ($this->type === $type) {
+			return $this;
+		}
+
+		return new self($type, $this->constantName);
+	}
+
+	public function traverseSimultaneously(Type $right, callable $cb): Type
+	{
+		if (!$right instanceof self) {
+			return $this;
+		}
+
+		$type = $cb($this->type, $right->type);
+
+		if ($this->type === $type) {
+			return $this;
+		}
+
+		return new self($type, $this->constantName);
+	}
+
+	public function toPhpDocNode(): TypeNode
+	{
+		return new ConstTypeNode(new ConstFetchNode('static', $this->constantName));
+	}
+
+}

tests/PHPStan/Analyser/nsrt/bug-13828.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Bug13828;
+
+use function PHPStan\Testing\assertType;
+
+class FooBar
+{
+	const FOO_BAR = 'foo';
+
+	/** @return static::FOO_BAR */
+	public function test(): string
+	{
+		return static::FOO_BAR;
+	}
+}
+
+class BarBaz extends FooBar
+{
+	const FOO_BAR = 'bar';
+}
+
+function test(FooBar $foo, BarBaz $bar): void
+{
+	assertType("'foo'", $foo->test());
+	assertType("'bar'", $bar->test());
+}
+
+final class FinalFoo
+{
+	const FOO_BAR = 'foo';
+
+	/** @return static::FOO_BAR */
+	public function test(): string
+	{
+		return static::FOO_BAR;
+	}
+}
+
+function testFinal(FinalFoo $foo): void
+{
+	assertType("'foo'", $foo->test());
+}