functional programming - F# - Can I return a discriminated union from a function -

i have following types:

type goodresource = {     id:int;     field1:string }   type errorresource = {     statuscode:int;     description:string } 

i have following discriminated union:

type processingresult =      | of goodresource     | error of errorresource 

then want have function have return type of discriminated union processingresult:

let sampleprocessingfunction value =     match value     | "goodscenario" -> { id = 123; field1 = "field1data" }     | _ -> { statuscode = 456; description = "desc" } 

is trying possible. compiler giving out stating expects goodresource return type. missing or going wrong way?

as stands, sampleprocessingfunction returns 2 different types each branch.

to return same type, need create du (which did) specify case of du explicitly, this:

let sampleprocessingfunction value =     match value     | "goodscenario" -> { id = 123; field1 = "field1data" }     | _ -> error { statuscode = 456; description = "desc" } 

you might ask "why can't compiler figure out correct case automatically", happens if du has 2 cases of same type? example:

type goodorerror =      | of string     | error of string 

in example below, compiler cannot determine case mean:

let returngoodorerror value =     match value     | "goodscenario" -> "goodness"     | _ -> "badness" 

so again need use constructor case want:

let returngoodorerror value =     match value     | "goodscenario" -> "goodness"     | _ -> error "badness"