Add test case motivating prior commit

Author: weswigham

tests/baselines/reference/propTypeValidatorInference.js

@@ -0,0 +1,121 @@
+//// [tests/cases/compiler/propTypeValidatorInference.ts] ////
+
+//// [index.d.ts]
+export const nominalTypeHack: unique symbol;
+
+export type IsOptional<T> = undefined | null extends T ? true : undefined extends T ? true : null extends T ? true : false;
+
+export type RequiredKeys<V> = { [K in keyof V]-?: Exclude<V[K], undefined> extends Validator<infer T> ? IsOptional<T> extends true ? never : K : never }[keyof V];
+export type OptionalKeys<V> = Exclude<keyof V, RequiredKeys<V>>;
+export type InferPropsInner<V> = { [K in keyof V]-?: InferType<V[K]>; };
+
+export interface Validator<T> {
+    (props: object, propName: string, componentName: string, location: string, propFullName: string): Error | null;
+    [nominalTypeHack]?: T;
+}
+
+export interface Requireable<T> extends Validator<T | undefined | null> {
+    isRequired: Validator<NonNullable<T>>;
+}
+
+export type ValidationMap<T> = { [K in keyof T]?: Validator<T[K]> };
+
+export type InferType<V> = V extends Validator<infer T> ? T : any;
+export type InferProps<V> =
+    & InferPropsInner<Pick<V, RequiredKeys<V>>>
+    & Partial<InferPropsInner<Pick<V, OptionalKeys<V>>>>;
+
+export const any: Requireable<any>;
+export const array: Requireable<any[]>;
+export const bool: Requireable<boolean>;
+export const string: Requireable<string>;
+export const number: Requireable<number>;
+export function shape<P extends ValidationMap<any>>(type: P): Requireable<InferProps<P>>;
+export function oneOfType<T extends Validator<any>>(types: T[]): Requireable<NonNullable<InferType<T>>>;
+
+
+//// [file.ts]
+import * as PropTypes from "prop-types";
+interface Props {
+    any?: any;
+    array: string[];
+    bool: boolean;
+    shape: {
+        foo: string;
+        bar?: boolean;
+        baz?: any
+    };
+    oneOfType: string | boolean | {
+        foo?: string;
+        bar: number;
+    };
+}
+
+type PropTypesMap = PropTypes.ValidationMap<Props>;
+
+const innerProps = {
+    foo: PropTypes.string.isRequired,
+    bar: PropTypes.bool,
+    baz: PropTypes.any
+};
+
+const arrayOfTypes = [PropTypes.string, PropTypes.bool, PropTypes.shape({
+    foo: PropTypes.string,
+    bar: PropTypes.number.isRequired
+})];
+
+// TS checking
+const propTypes: PropTypesMap = {
+    any: PropTypes.any,
+    array: PropTypes.array.isRequired,
+    bool: PropTypes.bool.isRequired,
+    shape: PropTypes.shape(innerProps).isRequired,
+    oneOfType: PropTypes.oneOfType(arrayOfTypes).isRequired,
+};
+
+// JS checking
+const propTypesWithoutAnnotation = {
+    any: PropTypes.any,
+    array: PropTypes.array.isRequired,
+    bool: PropTypes.bool.isRequired,
+    shape: PropTypes.shape(innerProps).isRequired,
+    oneOfType: PropTypes.oneOfType(arrayOfTypes).isRequired,
+};
+
+type ExtractedProps = PropTypes.InferProps<typeof propTypes>;
+
+type ExtractedPropsWithoutAnnotation = PropTypes.InferProps<typeof propTypesWithoutAnnotation>;
+
+type ExtractPropsMatch = ExtractedProps extends ExtractedPropsWithoutAnnotation ? true : false;
+const x: true = (null as any as ExtractPropsMatch);
+
+//// [file.js]
+"use strict";
+exports.__esModule = true;
+var PropTypes = require("prop-types");
+var innerProps = {
+    foo: PropTypes.string.isRequired,
+    bar: PropTypes.bool,
+    baz: PropTypes.any
+};
+var arrayOfTypes = [PropTypes.string, PropTypes.bool, PropTypes.shape({
+        foo: PropTypes.string,
+        bar: PropTypes.number.isRequired
+    })];
+// TS checking
+var propTypes = {
+    any: PropTypes.any,
+    array: PropTypes.array.isRequired,
+    bool: PropTypes.bool.isRequired,
+    shape: PropTypes.shape(innerProps).isRequired,
+    oneOfType: PropTypes.oneOfType(arrayOfTypes).isRequired
+};
+// JS checking
+var propTypesWithoutAnnotation = {
+    any: PropTypes.any,
+    array: PropTypes.array.isRequired,
+    bool: PropTypes.bool.isRequired,
+    shape: PropTypes.shape(innerProps).isRequired,
+    oneOfType: PropTypes.oneOfType(arrayOfTypes).isRequired
+};
+var x = null;