Swift Dictionary Initialization of custom type gives: '>' is not a postfix unary operator error -

i trying initialise empty dictionary custom type in swift getting '>' not postfix unary operator error

struct prims {     var msset = [vertex<int> : double]() // lines gives error } 

i tried way; still getting same error

struct prims {   var msset: [vertex<int> : double]     init() {     self.msset = [vertex<int> : double]()    } } 

i have defined vertex in separate file

import foundation  public struct vertex<t: hashable> {     var data: t }  extension vertex: hashable {     public var hashvalue: int {         return "\(data)".hashvalue     }      static public func ==(lhs: vertex, rhs: vertex) -> bool {         return lhs.data == rhs.data     } }  extension vertex: customstringconvertible {     public var description: string {         return "\(data)"     } } 

i looking why happening. know using var msset = dictionary<vertex<int>, double>() work.

while can't tell why swift compiler emits error, can make compile this:

struct prims {     var msset = dictionary<vertex<int>, double>() } 

or this:

struct prims {     typealias v = vertex<int>     var msset = [v : double]() }