undefinedAsDiscriminantWithUnknown(strictnullchecks=false).types

=== tests/cases/compiler/undefinedAsDiscriminantWithUnknown.ts ===
type S = 
>S : { type: 'string'; value: string; } | { type: 'number'; value: number; } | { type: 'unknown'; value: unknown; } | { value: undefined; }

| { type: 'string', value: string } 
>type : "string"
>value : string

| { type: 'number', value: number } 
>type : "number"
>value : number

| { type: 'unknown', value: unknown }
>type : "unknown"
>value : unknown

| { value: undefined };
>value : undefined

declare var s: S
>s : S

if (s.value !== undefined) {
>s.value !== undefined : boolean
>s.value : unknown
>s : S
>value : unknown
>undefined : undefined

  s;
>s : S
}
else {
  s;
>s : S
}