Pattern: Unnecessary Object.collect() call
Issue: -
Some method calls to Object.collect(Closure) can be replaced with the spread operator. For instance, list.collect it.multiply(2) can be replaced by list*.multiply(2).
Examples of violations include:
assert [1, 2, 3].collect { it.multiply(2) }
assert [1, 2, 3].collect { x -> x.multiply(2) }
["1", "2", "3"].collect { it.bytes }The following code does not produce violations:
[1, 2, 3].collect { it * it } // OK, closure parameter is referenced twice
[1, 2, 3].mapMethod { it.multiply(5) } // OK, method call is not collect
[1, 2, 3].collect(5) // OK, collect parameter is not a closure
// OK, the closure is not a simple one line statement
[1, 2, 3].collect { println it; it.multiply(5) }
// OK, closure has too many arguments
[1, 2, 3].collect { a, b -> a.multiply(b) }
// OK, closure statement references parameter multiple times
[1, 2, 3].collect { it.multiply(it) }
// OK, it is referenced several times in the closure
[1, 2, 3].collect { it.multiply(2).multiply(it) }
["1", "2", "3"].collect { it.bytes.foo(it) }
// OK, chained methods are too complex to analyze at this point
[1, 2, 3].collect { it.multiply(2).multiply(4) }
// in general the above examples can be rewritten like this:
[1, 2, 3]*.multiply(2)
["1", "2", "3"]*.bytes