await of a void async function waits for it (#440)

tslang/lib/TypeScript/MLIRGenExpressions.cpp

@@ -492,7 +492,10 @@ namespace mlirgen
                     builder.create<mlir::async::YieldOp>(location, mlir::ValueRange{});
                 }
             });
-        EXIT_IF_FAILED_OR_NO_VALUE(result)
+        // a call to a void function succeeds with no value, and is awaited all the same: leaving
+        // here dropped the token, so nothing waited for the task and `await f()` went straight
+        // on (#440)
+        EXIT_IF_FAILED(result)
 
         // Registered only now, and only if the store above actually happened: an owned slot is
         // released at scope exit whatever is in it, and a slot nothing wrote holds whatever the

tslang/test/tester/CMakeLists.txt

@@ -351,6 +351,7 @@ tslang_add_test(NAME test-compile-00-array-literal-copy COMMAND test-runner "${P
 tslang_add_test(NAME test-compile-00-tuple-runtime-arrays COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00tuple_runtime_arrays.ts")
 tslang_add_test(NAME test-compile-00-record-to-class COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00record_to_class.ts")
 tslang_add_test(NAME test-compile-00-array-insert-functions COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_insert_functions.ts")
+tslang_add_test(NAME test-compile-00-await-void COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00await_void.ts")
 tslang_add_test(NAME test-compile-00-const-record-owned-fields COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00const_record_owned_fields.ts")
 tslang_add_test(NAME test-compile-00-array-length-valid COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_length_valid.ts")
 tslang_add_test(NAME test-compile-00-string-view-copy COMMAND test-runner "${PROJECT_SOURCE_DIR}/test/tester/tests/00string_view_copy.ts")
@@ -859,6 +860,7 @@ tslang_add_test(NAME test-jit-00-array-literal-copy COMMAND test-runner -jit "${
 tslang_add_test(NAME test-jit-00-tuple-runtime-arrays COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00tuple_runtime_arrays.ts")
 tslang_add_test(NAME test-jit-00-record-to-class COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00record_to_class.ts")
 tslang_add_test(NAME test-jit-00-array-insert-functions COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_insert_functions.ts")
+tslang_add_test(NAME test-jit-00-await-void COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00await_void.ts")
 tslang_add_test(NAME test-jit-00-const-record-owned-fields COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00const_record_owned_fields.ts")
 tslang_add_test(NAME test-jit-00-array-length-valid COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00array_length_valid.ts")
 tslang_add_test(NAME test-jit-00-string-view-copy COMMAND test-runner -jit "${PROJECT_SOURCE_DIR}/test/tester/tests/00string_view_copy.ts")
@@ -1696,6 +1698,7 @@ set(TSLANG_CORPUS
     00tuple_runtime_arrays.ts
     00record_to_class.ts
     00array_insert_functions.ts
+    00await_void.ts
     00const_record_owned_fields.ts
     00array_length_valid.ts
     00string_view_copy.ts

tslang/test/tester/tests/00await_void.ts

@@ -0,0 +1,26 @@
+// `await` of an async function that returns nothing runs it, and in order (#440): the await
+// left before its `async.await`, so nothing waited for the task and the awaiting function went
+// straight on.
+let log = "";
+async function step(s: string) { log += s; }
+async function twice() {
+    await step("b");
+    await step("c");
+}
+class C {
+    async run() { log += "m"; }
+}
+async function main() {
+    await step("a");
+    await twice();
+    for (let i = 0; i < 3; i++) {
+        await step("" + i);
+    }
+    const c = new C();
+    await c.run();
+    const g = async () => { log += "g"; };
+    await g();
+    print(log);
+    assert(log == "abc012mg", "in order");
+    print("done.");
+}