[alies-dev]

Providers with only a native return type (iterable, array, Generator) get MixedReturnStatement, and their datasets are not checked.

Before

<?php
final class MyTestCase extends TestCase
{
    /** @psalm-pure */
    public static function provide(): iterable { // MixedReturnStatement: Providers must return iterable<array-key, array<array-key, mixed>>, possibly different iterable[pure]<mixed, mixed> provided
        yield 'one' => [1];
    }

    #[DataProvider('provide')]
    public function testSomething(int $i): void {
        $this->assertSame(1, $i);
    }
}

<?php
final class MyTestCase extends TestCase
{
    /** @psalm-pure */
    public static function provide(): array { // MixedReturnStatement: Providers must return iterable<array-key, array<array-key, mixed>>, possibly different array<array-key, mixed> provided
        return ['one' => ['x']];
    }

    #[DataProvider('provide')]
    public function testSomething(int $i): void { // no issue
        $this->assertSame(1, $i);
    }
}

After

    public static function provide(): iterable { // no issue

    public static function provide(): array { // no issue
    public function testSomething(int $i): void { // InvalidArgument: Argument 1 of NS\MyTestCase::testSomething expects int, 'x' provided by NS\MyTestCase::provide():(array{one: list{'x'}})

Datasets are checked against the type Psalm infers from the provider's body, one dataset at a time, for providers declared in the test class or in a trait it uses. Providers in a parent or external class, and providers using yield from, keep MixedReturnStatement, which now ends with ; add a @return type to NS\BaseTest::provide().

Fixes #269