7種類の@conventionのうち、.swiftで使えるのは3種類だけでした。

let thin: @convention(thin) () -> Int = { 1 } //let thick: @convention(thick) () -> Int = { 1 } // error: convention 'thick' not supported let block: @convention(block) () -> Int = { 1 } let c: @convention(c) () -> Int = { 1 } //let objc_method: @convention(objc_method) () -> Int = { 1 } // error: convention 'objc_method' not supported //let method: @convention(method) () -> Int = { 1 } // error: convention 'method' not supported //let witness_method: @convention(witness_method) () -> Int = { 1 } // error: convention 'witness_method' not supported