generics - F# 类型函数和 [] 属性

Question

这两个 F# 类型的函数有什么区别:

let defaultInstance1<'a when 'a:(new: unit->'a)> = new 'a()

[<GeneralizableValue>]
let defaultInstance2<'a when 'a:(new: unit->'a)> = new 'a()

Answer 1

let defaultInstance1<'a when 'a:(new: unit->'a)> = new 'a()

[<GeneralizableValue>]
let defaultInstance2<'a when 'a:(new: unit->'a)> = new 'a()

let x1 = defaultInstance1 // value restriction
let x2 = defaultInstance2