It is now mandatory to list all possible class-types that can be
inferred by the mapper. This change is a step towards the library being
able to deliver powerful new features such as compiling a mapper for
better performance.
BREAKING CHANGE: the existing calls to `MapperBuilder::infer` that could
return several class-names must now add a signature to the callback. The
callbacks that require no parameter and always return the same
class-name can remain unchanged.
For instance:
```php
$builder = (new \CuyZ\Valinor\MapperBuilder())
// Can remain unchanged
->infer(SomeInterface::class, fn () => SomeImplementation::class);
```
```php
$builder = (new \CuyZ\Valinor\MapperBuilder())
->infer(
SomeInterface::class,
fn (string $type) => match($type) {
'first' => ImplementationA::class,
'second' => ImplementationB::class,
default => throw new DomainException("Unhandled `$type`.")
}
)
// …should be modified with:
->infer(
SomeInterface::class,
/** @return class-string<ImplementationA|ImplementationB> */
fn (string $type) => match($type) {
'first' => ImplementationA::class,
'second' => ImplementationB::class,
default => throw new DomainException("Unhandled `$type`.")
}
);
```
