Apply ExplicitNullableObjectInstanceRector

src/Codegen/TargetUnifier.php

@@ -671,7 +671,7 @@ private static function returnTypeBranches(
         ?\ReflectionType $type,
         \ReflectionClass $declaringClass,
     ): array {
-        if ($type === null) {
+        if (!$type instanceof \ReflectionType) {
             return [['mixed']];
         }
 

src/Codegen/TypeRenderer.php

@@ -33,7 +33,7 @@ private function __construct() {}
      */
     public static function parameterType(?\ReflectionType $type, ?\ReflectionClass $declaringClass = null): string
     {
-        if ($type === null) {
+        if (!$type instanceof \ReflectionType) {
             return '';
         }
 
@@ -83,7 +83,7 @@ public static function acceptsMatcher(?\ReflectionType $type): bool
      */
     public static function returnType(?\ReflectionType $type, ?\ReflectionClass $declaringClass = null): string
     {
-        return $type === null ? 'mixed' : self::resolveParent(self::render($type), $declaringClass);
+        return $type instanceof \ReflectionType ? self::resolveParent(self::render($type), $declaringClass) : 'mixed';
     }
 
     /**
@@ -150,7 +150,7 @@ private static function resolveParent(string $rendered, ?\ReflectionClass $decla
      */
     private static function resolveSelf(string $rendered, ?\ReflectionClass $declaringClass): string
     {
-        if ($declaringClass === null) {
+        if (!$declaringClass instanceof \ReflectionClass) {
             return $rendered;
         }
 

src/Defaults/DefaultFactories.php

@@ -66,7 +66,7 @@ public function valueFor(string $requested, ?RuntimeContext $owner = null): ?arr
         $owner ??= Runtime::current();
         $factory = $this->factoryFor($requested);
 
-        if ($factory === null) {
+        if (!$factory instanceof \Closure) {
             return null;
         }
 
@@ -79,7 +79,7 @@ public function valueFor(string $requested, ?RuntimeContext $owner = null): ?arr
 
         $valueOwner = is_object($value) ? Runtime::ownerOf($value) : null;
 
-        if ($valueOwner !== null && $valueOwner !== $owner) {
+        if ($valueOwner instanceof \Rasuvaeff\Understudy\Runtime\RuntimeContext && $valueOwner !== $owner) {
             throw ContextOwnershipViolation::forDouble();
         }
 

src/Defaults/TypeDefaultResolver.php

@@ -35,7 +35,7 @@ public static function forSignature(
         bool $nested = false,
         ?object $double = null,
     ): mixed {
-        if ($signature === null) {
+        if (!$signature instanceof \Rasuvaeff\Understudy\Codegen\MethodSignature) {
             return null;
         }
 

src/Expectation/ArgumentFormatter.php

@@ -59,7 +59,7 @@ private function __construct() {}
      */
     public static function scope(callable $render): mixed
     {
-        if (self::$aliases !== null) {
+        if (self::$aliases instanceof \SplObjectStorage) {
             return $render();
         }
 
@@ -82,7 +82,7 @@ public static function format(mixed $value, int $depth = 0): string
             return '…';
         }
 
-        if (self::$aliases === null) {
+        if (!self::$aliases instanceof \SplObjectStorage) {
             return self::scope(static fn(): string => self::format($value, $depth));
         }
 
@@ -224,7 +224,7 @@ private static function formatObject(object $value, int $depth): string
     private static function alias(object $value): int
     {
         $table = self::$aliases;
-        \assert($table !== null);
+        \assert($table instanceof \SplObjectStorage);
 
         // `contains()` is deprecated as of 8.5; `offsetExists()` is the same
         // lookup under the name the language kept.

src/Expectation/Expectation.php

@@ -168,7 +168,7 @@ public function hasCaptors(): bool
      */
     public function setGuard(callable $guard, string $description): void
     {
-        if ($this->guard !== null) {
+        if ($this->guard instanceof \Closure) {
             throw InvalidCallSpecification::guardAlreadyNarrowed($this->method, $this->guardDescription);
         }
 
@@ -189,7 +189,7 @@ public function setGuard(callable $guard, string $description): void
      */
     private function acceptsGuard(array $args): bool
     {
-        if ($this->guard === null) {
+        if (!$this->guard instanceof \Closure) {
             return true;
         }
 
@@ -349,7 +349,7 @@ public function matches(string $method, array $args): bool
      */
     public function matchesArguments(array $args): bool
     {
-        if ($this->tailMatcher !== null) {
+        if ($this->tailMatcher instanceof \Rasuvaeff\Understudy\Matcher\TailMatcher) {
             $fixed = $this->argumentCount - 1;
             /** @var int<0, max> $fixed */
 
@@ -517,7 +517,7 @@ public function describeAgainst(array $args): string
      */
     private function describeGuardAgainst(array $args): string
     {
-        if ($this->guard === null) {
+        if (!$this->guard instanceof \Closure) {
             return '';
         }
 
@@ -539,7 +539,7 @@ private function describeGuardAgainst(array $args): string
      */
     private function acceptsGuardDefensively(array $args): bool
     {
-        \assert($this->guard !== null);
+        \assert($this->guard instanceof \Closure);
 
         try {
             return ($this->guard)(...$args);

src/Invocation.php

@@ -181,7 +181,7 @@ public function recordOutcome(Outcome $outcome): void
      */
     public function recordReturned(mixed $value): void
     {
-        if ($this->returnedState !== null || $this->outcome !== null) {
+        if ($this->returnedState !== null || $this->outcome instanceof \Rasuvaeff\Understudy\Outcome) {
             return;
         }
 
@@ -201,7 +201,7 @@ public function recordReturned(mixed $value): void
      */
     public function recordDiscardedReturn(): void
     {
-        if ($this->returnedState !== null || $this->outcome !== null) {
+        if ($this->returnedState !== null || $this->outcome instanceof \Rasuvaeff\Understudy\Outcome) {
             return;
         }
 
@@ -226,7 +226,7 @@ public function isReturnDiscarded(): bool
      */
     public function recordThrown(\Throwable $thrown): void
     {
-        if ($this->returnedState !== null || $this->outcome !== null) {
+        if ($this->returnedState !== null || $this->outcome instanceof \Rasuvaeff\Understudy\Outcome) {
             return;
         }
 

src/Outcome.php

@@ -53,7 +53,7 @@ public function didThrow(): bool
     public function returned(string $method): mixed
     {
         if (!$this->returned) {
-            \assert($this->thrown !== null);
+            \assert($this->thrown instanceof \Throwable);
 
             throw OutcomeUnavailable::threwInstead($method, $this->thrown);
         }

src/Runtime/DoubleState.php

@@ -422,7 +422,7 @@ public function declaredExpectations(): array
      */
     public function settle(): void
     {
-        $remaining = static fn(Expectation $expectation): bool => $expectation->cardinality() === null;
+        $remaining = static fn(Expectation $expectation): bool => !$expectation->cardinality() instanceof \Rasuvaeff\Understudy\Cardinality;
 
         $this->expectations = array_values(array_filter($this->expectations, $remaining));
         $this->matchingExpectations = array_values(array_filter($this->matchingExpectations, $remaining));