Add tests for Awaited<null> and Awaited<undefined> (#52960)

Author: rbuckton

tests/baselines/reference/awaitedType.errors.txt

@@ -1,5 +1,5 @@
-tests/cases/compiler/awaitedType.ts(18,12): error TS2589: Type instantiation is excessively deep and possibly infinite.
 tests/cases/compiler/awaitedType.ts(22,12): error TS2589: Type instantiation is excessively deep and possibly infinite.
+tests/cases/compiler/awaitedType.ts(26,12): error TS2589: Type instantiation is excessively deep and possibly infinite.
 
 
 ==== tests/cases/compiler/awaitedType.ts (2 errors) ====
@@ -19,6 +19,10 @@ tests/cases/compiler/awaitedType.ts(22,12): error TS2589: Type instantiation is
     type T14 = _Expect<Awaited<Promise<Promise<number>> | string | undefined>, /*expected*/ string | number | undefined>; // otherwise just prints T14 in types tests, which isn't very helpful
     type T15 = _Expect<Awaited<Promise<Promise<number>> | string | null | undefined>, /*expected*/ string | number | null | undefined>; // otherwise just prints T15 in types tests, which isn't very helpful
 
+    type TUndefined = Awaited<undefined>;
+    type TNull = Awaited<null>;
+    type TNullOrUndefined = Awaited<null | undefined>;
+    
     interface BadPromise { then(cb: (value: BadPromise) => void): void; }
     type T16 = Awaited<BadPromise>; // error
                ~~~~~~~~~~~~~~~~~~~

tests/baselines/reference/awaitedType.js

@@ -15,6 +15,10 @@ type T13 = _Expect<Awaited<Promise<Promise<number>> | string | null>, /*expected
 type T14 = _Expect<Awaited<Promise<Promise<number>> | string | undefined>, /*expected*/ string | number | undefined>; // otherwise just prints T14 in types tests, which isn't very helpful
 type T15 = _Expect<Awaited<Promise<Promise<number>> | string | null | undefined>, /*expected*/ string | number | null | undefined>; // otherwise just prints T15 in types tests, which isn't very helpful
 
+type TUndefined = Awaited<undefined>;
+type TNull = Awaited<null>;
+type TNullOrUndefined = Awaited<null | undefined>;
+
 interface BadPromise { then(cb: (value: BadPromise) => void): void; }
 type T16 = Awaited<BadPromise>; // error
 

tests/baselines/reference/awaitedType.symbols

@@ -54,6 +54,17 @@ type T15 = _Expect<Awaited<Promise<Promise<number>> | string | null | undefined>
 >null : null
 >null : null
 
+type TUndefined = Awaited<undefined>;
+>TUndefined : undefined
+
+type TNull = Awaited<null>;
+>TNull : null
+>null : null
+
+type TNullOrUndefined = Awaited<null | undefined>;
+>TNullOrUndefined : null
+>null : null
+
 interface BadPromise { then(cb: (value: BadPromise) => void): void; }
 >then : (cb: (value: BadPromise) => void) => void
 >cb : (value: BadPromise) => void

tests/baselines/reference/awaitedType.types

@@ -1,5 +1,5 @@
-tests/cases/compiler/awaitedTypeStrictNull.ts(18,12): error TS2589: Type instantiation is excessively deep and possibly infinite.
 tests/cases/compiler/awaitedTypeStrictNull.ts(22,12): error TS2589: Type instantiation is excessively deep and possibly infinite.
+tests/cases/compiler/awaitedTypeStrictNull.ts(26,12): error TS2589: Type instantiation is excessively deep and possibly infinite.
 
 
 ==== tests/cases/compiler/awaitedTypeStrictNull.ts (2 errors) ====
@@ -19,6 +19,10 @@ tests/cases/compiler/awaitedTypeStrictNull.ts(22,12): error TS2589: Type instant
     type T14 = _Expect<Awaited<Promise<Promise<number>> | string | undefined>, /*expected*/ string | number | undefined>; // otherwise just prints T14 in types tests, which isn't very helpful
     type T15 = _Expect<Awaited<Promise<Promise<number>> | string | null | undefined>, /*expected*/ string | number | null | undefined>; // otherwise just prints T15 in types tests, which isn't very helpful
 
+    type TUndefined = Awaited<undefined>;
+    type TNull = Awaited<null>;
+    type TNullOrUndefined = Awaited<null | undefined>;
+    
     interface BadPromise { then(cb: (value: BadPromise) => void): void; }
     type T16 = Awaited<BadPromise>; // error
                ~~~~~~~~~~~~~~~~~~~

tests/baselines/reference/awaitedTypeStrictNull.errors.txt

@@ -15,6 +15,10 @@ type T13 = _Expect<Awaited<Promise<Promise<number>> | string | null>, /*expected
 type T14 = _Expect<Awaited<Promise<Promise<number>> | string | undefined>, /*expected*/ string | number | undefined>; // otherwise just prints T14 in types tests, which isn't very helpful
 type T15 = _Expect<Awaited<Promise<Promise<number>> | string | null | undefined>, /*expected*/ string | number | null | undefined>; // otherwise just prints T15 in types tests, which isn't very helpful
 
+type TUndefined = Awaited<undefined>;
+type TNull = Awaited<null>;
+type TNullOrUndefined = Awaited<null | undefined>;
+
 interface BadPromise { then(cb: (value: BadPromise) => void): void; }
 type T16 = Awaited<BadPromise>; // error