$x . ' world', static fn (string $z): string => $z . '!!' ); static::assertSame('Hello world!!', $x('Hello')); } public function testItCombinesAFunctionThatDealWithDifferentTypes(): void { $x = Fun\after( static fn (string $x): int => Str\length($x), static fn (int $z): string => $z . '!' ); static::assertSame('5!', $x('Hello')); } }