Add genType test.

Author: cristianoc

jscomp/gentype_tests/typescript-react-example/package-lock.json

@@ -15,6 +15,14 @@ export type fromPayload = { readonly x: number; readonly s: string };
 // tslint:disable-next-line:interface-over-type-literal
 export type toPayload = { readonly result: string };
 
+// tslint:disable-next-line:interface-over-type-literal
+export type settledResult<a> = 
+    { TAG: "fulfilled"; readonly value: a }
+  | { TAG: "rejected"; readonly reason: unknown };
+
+// tslint:disable-next-line:interface-over-type-literal
+export type settled = settledResult<string>;
+
 export const convert: (_1:Promise<fromPayload>) => Promise<toPayload> = TestPromiseBS.convert;
 
 export const barx: (_1:{ readonly x?: Promise<(undefined | string)> }, _2:void) => boolean = TestPromiseBS.barx;

jscomp/gentype_tests/typescript-react-example/src/Docstrings.bs.js

@@ -11,3 +11,11 @@ type fromPayload = {
 @genType let convert = Js.Promise.then_(({s}) => Js.Promise.resolve({result: s}))
 
 @genType let barx = (~x=Js.Promise.resolve(Some("a")), ()) => x == x
+
+@genType
+@tag("status")
+type settledResult<+'a> =
+  | @as("fulfilled") Fulfilled({value: 'a}) | @as("rejected") Rejected({reason: unknown})
+
+@genType
+type settled = settledResult<string>