laravel/framework · error · BindingResolutionException

Unresolvable dependency resolving [$parameter] in class {$pa

Error message

Unresolvable dependency resolving [$parameter] in class {$parameter->getDeclaringClass()->getName()}

What it means

Thrown by Container::unresolvablePrimitive during dependency resolution when a constructor parameter is a primitive (non-class) type with no default value, no contextual binding for '$name', is not nullable, and is not variadic. The container cannot fabricate an int/string/bool so it errors, naming the parameter and declaring class.

Source

Thrown at src/Illuminate/Container/Container.php:1450

        } else {
            $message = "Target [$concrete] is not instantiable.";
        }

        throw new BindingResolutionException($message);
    }

    /**
     * Throw an exception for an unresolvable primitive.
     *
     * @return void
     *
     * @throws \Illuminate\Contracts\Container\BindingResolutionException
     */
    protected function unresolvablePrimitive(ReflectionParameter $parameter)
    {
        $message = "Unresolvable dependency resolving [$parameter] in class {$parameter->getDeclaringClass()->getName()}";

        throw new BindingResolutionException($message);
    }

    /**
     * Register a new before resolving callback for all types.
     *
     * @param  \Closure|string  $abstract
     * @return void
     */
    public function beforeResolving($abstract, ?Closure $callback = null)
    {
        if (is_string($abstract)) {
            $abstract = $this->getAlias($abstract);
        }

        if ($abstract instanceof Closure && is_null($callback)) {
            $this->globalBeforeResolvingCallbacks[] = $abstract;
        } else {
            $this->beforeResolvingCallbacks[$abstract][] = $callback;

View on GitHub (pinned to bd6b5437e6)

Solutions

1. Pass the parameter when resolving: app()->make(Service::class, ['timeout' => 30]).
2. Register a contextual binding for the primitive: $this->app->when(Service::class)->needs('$timeout')->give(30).
3. Give the parameter a default value (int $timeout = 60), make it nullable (?int $timeout = null), or make it variadic.
4. Bind the whole class with a Closure that supplies the primitive.

Example fix

// before
class HttpClient { public function __construct(public int $timeout) {} }
app()->make(HttpClient::class);

// after
app()->bind(HttpClient::class, fn () => new HttpClient(config('http.timeout', 30)));

$r = new \ReflectionMethod($class, '__construct');
foreach ($r->getParameters() as $p) {
    if ($p->hasType() && $p->getType()->isBuiltin() && ! $p->isDefaultValueAvailable()
        && ! $p->isVariadic() && ! $p->allowsNull()
        && ! array_key_exists($p->getName(), $params)) {
        throw new \InvalidArgumentException("Primitive \${$p->getName()} required");
    }
}

function primitivesHaveDefaultsOrFail(string $class): bool
{
    foreach ((new \ReflectionMethod($class, '__construct'))->getParameters() as $p) {
        if ($p->getType()?->isBuiltin() && ! $p->isDefaultValueAvailable() && ! $p->allowsNull()) return false;
    }
    return true;
}

use Illuminate\Contracts\Container\BindingResolutionException;
try {
    app()->make(Service::class);
} catch (BindingResolutionException $e) {
    if (str_contains($e->getMessage(), 'Unresolvable dependency')) {
        app()->bind(Service::class, fn () => new Service(default: 30));
    }
    throw $e;
}

When it happens

Trigger: A class __construct(public int $timeout) resolved via app()->make() without supplying ['timeout' => 30]; any primitive scalar required by a constructor that the container is asked to auto-resolve.

Common situations: Adding a new required scalar config parameter to a service constructor; switching a value object to container-resolved without passing parameters; missing config values that used to be injected via service provider.

Related errors

• Unable to resolve dependency [{$parameter}] in class {$param
• [{$abstract}] is aliased to itself.
• Target [$concrete] is not instantiable while building [$prev
• Circular alias reference for [{$abstract}].
• The environment property must be set and cannot be empty.

AI-assisted analysis of laravel/framework@bd6b5437e6 (2026-08-06). Data as JSON: /data/errors/aaa3556d3589fa68.json. Report an issue: GitHub.