Avoid requiring it lambda parameter in Kotlin bean DSL [SPR-15815]

[spring-issuemaster]

Sébastien Deleuze opened SPR-15815 and commented

Based on a proposal by Joseph Taylor from Pivotal Labs London, it is possible to improve Kotlin bean DSL by avoid requiring it lambda parameter using function literals with receiver.

Spring Framework 5 RC3 syntax:

beans {
	bean<Foo>()
	bean<Bar>("bar")
	bean { FooFoo(it.env["name"]) }
	environment({it.activeProfiles.contains("baz")}) {
		bean { Baz(it.ref()) }
		bean { Baz(it.ref("bar")) }
	}
}

Spring Framework 5 RC4+ syntax:

beans {
	bean<Foo>()
	bean<Bar>("bar")
	bean { FooFoo(env["name"]) }
	environment({activeProfiles.contains("baz")}) {
		bean { Baz(ref()) }
		bean { Baz(ref("bar")) }
	}
}

---

Affects: 5.0 RC3

Referenced from: commits 29c112c