Suppress Swift compiler warning

Question

I'm using the Nimble assertion framework for unit testing in Swift (Xcode 6.3 beta). It works fine, but the compiler gives a warning for one of the lines in the Nimble source code:

public func expect<T>(expression: () -> T?, file: String = __FILE__, line: UInt = __LINE__) -> Expectation<T> {
    return Expectation(
        expression: Expression(
            expression: expression,
            location: SourceLocation(file: file, line: line),
            isClosure: true))
}

The warning is for the first line:

Closure parameter prior to parameters with default arguments will not be treated as a trailing closure

It's not a very serious issue, but I'd like to keep the number of compiler warnings low (zero) in my projects. Is there a way to remove this warning?

Answer 1

You can avoid the warning if the method signature will look like:

public func expect<T>(expression: (() -> T?), file: String = __FILE__, line: UInt = __LINE__) -> Expectation<T> 

added extra parenthesis around the first argument, tested with Swift 2.0 and Xcode 7.1

Another way of fixing it is to have all attributes with default value before the closure attribute as trailing closure is a quite convenient thing to have