From f23dd7a7b2682b6521b2be91dbf90655a9a22709 Mon Sep 17 00:00:00 2001
From: Ron Buckton <ron.buckton@microsoft.com>
Date: Tue, 14 Feb 2023 11:16:12 -0500
Subject: [PATCH] Fix crash in getAwaitedType (#52752)

---
 src/compiler/checker.ts                            | 2 +-
 tests/baselines/reference/awaitedTypeCrash.js      | 7 +++++++
 tests/baselines/reference/awaitedTypeCrash.symbols | 9 +++++++++
 tests/baselines/reference/awaitedTypeCrash.types   | 5 +++++
 tests/cases/compiler/awaitedTypeCrash.ts           | 4 ++++
 5 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/awaitedTypeCrash.js
 create mode 100644 tests/baselines/reference/awaitedTypeCrash.symbols
 create mode 100644 tests/baselines/reference/awaitedTypeCrash.types
 create mode 100644 tests/cases/compiler/awaitedTypeCrash.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 0a2d154b449..d4da8647a6f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -39028,7 +39028,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             }
         }
 
-        Debug.assert(getPromisedTypeOfPromise(type) === undefined, "type provided should not be a non-generic 'promise'-like.");
+        Debug.assert(isAwaitedTypeInstantiation(type) || getPromisedTypeOfPromise(type) === undefined, "type provided should not be a non-generic 'promise'-like.");
         return type;
     }
 
diff --git a/tests/baselines/reference/awaitedTypeCrash.js b/tests/baselines/reference/awaitedTypeCrash.js
new file mode 100644
index 00000000000..9cefb23cd49
--- /dev/null
+++ b/tests/baselines/reference/awaitedTypeCrash.js
@@ -0,0 +1,7 @@
+//// [awaitedTypeCrash.ts]
+// https://github.com/microsoft/TypeScript/issues/51984
+async function* f<T extends Promise<never>>(): AsyncGenerator<T, void, void> { }
+
+//// [awaitedTypeCrash.js]
+// https://github.com/microsoft/TypeScript/issues/51984
+async function* f() { }
diff --git a/tests/baselines/reference/awaitedTypeCrash.symbols b/tests/baselines/reference/awaitedTypeCrash.symbols
new file mode 100644
index 00000000000..024b6d90efb
--- /dev/null
+++ b/tests/baselines/reference/awaitedTypeCrash.symbols
@@ -0,0 +1,9 @@
+=== tests/cases/compiler/awaitedTypeCrash.ts ===
+// https://github.com/microsoft/TypeScript/issues/51984
+async function* f<T extends Promise<never>>(): AsyncGenerator<T, void, void> { }
+>f : Symbol(f, Decl(awaitedTypeCrash.ts, 0, 0))
+>T : Symbol(T, Decl(awaitedTypeCrash.ts, 1, 18))
+>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --), Decl(lib.es2015.iterable.d.ts, --, --), Decl(lib.es2015.promise.d.ts, --, --), Decl(lib.es2015.symbol.wellknown.d.ts, --, --), Decl(lib.es2018.promise.d.ts, --, --))
+>AsyncGenerator : Symbol(AsyncGenerator, Decl(lib.es2018.asyncgenerator.d.ts, --, --))
+>T : Symbol(T, Decl(awaitedTypeCrash.ts, 1, 18))
+
diff --git a/tests/baselines/reference/awaitedTypeCrash.types b/tests/baselines/reference/awaitedTypeCrash.types
new file mode 100644
index 00000000000..010ac8795ec
--- /dev/null
+++ b/tests/baselines/reference/awaitedTypeCrash.types
@@ -0,0 +1,5 @@
+=== tests/cases/compiler/awaitedTypeCrash.ts ===
+// https://github.com/microsoft/TypeScript/issues/51984
+async function* f<T extends Promise<never>>(): AsyncGenerator<T, void, void> { }
+>f : <T extends Promise<never>>() => AsyncGenerator<T, void, void>
+
diff --git a/tests/cases/compiler/awaitedTypeCrash.ts b/tests/cases/compiler/awaitedTypeCrash.ts
new file mode 100644
index 00000000000..b90f3236321
--- /dev/null
+++ b/tests/cases/compiler/awaitedTypeCrash.ts
@@ -0,0 +1,4 @@
+// @target: esnext
+
+// https://github.com/microsoft/TypeScript/issues/51984
+async function* f<T extends Promise<never>>(): AsyncGenerator<T, void, void> { }
\ No newline at end of file