[cfe] Update test expectation for language/unsorted/flatten_test/12

+ use the inferred return type in error reporting when no return type is
declared. This turned up in this particular case where we report an
error between the returned value and the inferred return type.

Closes #42546

Change-Id: I48da24047f2e92ca91a514dfcb43c2ba6f65ee46
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/153610
Reviewed-by: Erik Ernst <eernst@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

pkg/front_end/lib/src/fasta/type_inference/closure_context.dart

@@ -484,8 +484,8 @@ class _AsyncClosureContext implements ClosureContext {
           // flatten(S) is neither void, dynamic, Null.
           statement.expression = inferrer.helper.wrapInProblem(
               new NullLiteral()..fileOffset = statement.fileOffset,
-              templateInvalidReturnAsync.withArguments(expressionType,
-                  _declaredReturnType, inferrer.isNonNullableByDefault),
+              templateInvalidReturnAsync.withArguments(
+                  expressionType, returnType, inferrer.isNonNullableByDefault),
               statement.expression.fileOffset,
               noLength)
             ..parent = statement;
@@ -496,8 +496,8 @@ class _AsyncClosureContext implements ClosureContext {
           // nor dynamic, and flatten(S) is void.
           statement.expression = inferrer.helper.wrapInProblem(
               new NullLiteral()..fileOffset = statement.fileOffset,
-              templateInvalidReturnAsync.withArguments(expressionType,
-                  _declaredReturnType, inferrer.isNonNullableByDefault),
+              templateInvalidReturnAsync.withArguments(
+                  expressionType, returnType, inferrer.isNonNullableByDefault),
               statement.expression.fileOffset,
               noLength)
             ..parent = statement;
@@ -513,7 +513,7 @@ class _AsyncClosureContext implements ClosureContext {
               futureValueType, expressionType, statement.expression,
               fileOffset: statement.expression.fileOffset,
               runtimeCheckedType: _returnContext,
-              declaredContextType: _declaredReturnType,
+              declaredContextType: returnType,
               isVoidAllowed: false,
               errorTemplate: templateInvalidReturnAsync)
             ..parent = statement;

pkg/front_end/test/spell_checking_list_tests.txt

@@ -160,6 +160,7 @@ discovering
 dispatcher
 dispose
 dist
+divergent
 doctype
 doesnt
 dog

pkg/front_end/testcases/nnbd/issue42546.dart

@@ -0,0 +1,17 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Based on tests/language/unsorted/flatten_test/12
+
+import 'dart:async';
+
+class Divergent<T> implements Future<Divergent<Divergent<T>>> {
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+test() async {
+  Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+}
+
+main() {}

pkg/front_end/testcases/nnbd/issue42546.dart.outline.expect

@@ -0,0 +1,31 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+import "dart:async" as asy;
+
+import "dart:async";
+
+class Divergent<T extends core::Object? = dynamic> extends core::Object implements asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>> {
+  synthetic constructor •() → self::Divergent<self::Divergent::T%>
+    ;
+  method noSuchMethod(core::Invocation invocation) → dynamic
+    ;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ catchError(core::Function onError, {(core::Object) →? core::bool test = #C1}) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#catchError, 0, const <core::Type*>[], core::List::unmodifiable<dynamic>(<dynamic>[onError]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#test: test}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ whenComplete(() → FutureOr<void>action) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#whenComplete, 0, const <core::Type*>[], core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(const <core::Symbol*, dynamic>{}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ timeout(core::Duration timeLimit, {generic-covariant-impl () →? FutureOr<self::Divergent<self::Divergent<self::Divergent::T%>>>onTimeout = #C1}) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#timeout, 0, const <core::Type*>[], core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#onTimeout: onTimeout}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ then<R extends core::Object? = dynamic>((self::Divergent<self::Divergent<self::Divergent::T%>>) → FutureOr<self::Divergent::then::R%>onValue, {core::Function? onError = #C1}) → asy::Future<self::Divergent::then::R%>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#then, 0, core::List::unmodifiable<core::Type*>(<core::Type*>[self::Divergent::then::R%]), core::List::unmodifiable<dynamic>(<dynamic>[onValue]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#onError: onError}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent::then::R%>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ asStream() → asy::Stream<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#asStream, 0, const <core::Type*>[], const <dynamic>[], core::Map::unmodifiable<core::Symbol*, dynamic>(const <core::Symbol*, dynamic>{}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Stream<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+}
+static method test() → dynamic async 
+  ;
+static method main() → dynamic
+  ;
+
+constants  {
+  #C1 = null
+}

pkg/front_end/testcases/nnbd/issue42546.dart.strong.expect

@@ -0,0 +1,66 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/issue42546.dart:14:58: Error: A value of type 'Divergent<int>' can't be returned from an async function with return type 'Future<Divergent<Divergent<Divergent<int>>>>'.
+//  - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+//  - 'Future' is from 'dart:async'.
+//   Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+//                                                          ^
+//
+// pkg/front_end/testcases/nnbd/issue42546.dart:14:75: Error: A value of type 'Future<Divergent<Divergent<Divergent<int>>>>' can't be assigned to a variable of type 'Future<Divergent<Divergent<int>>>'.
+//  - 'Future' is from 'dart:async'.
+//  - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+//   Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+//                                                                           ^
+//
+import self as self;
+import "dart:core" as core;
+import "dart:async" as asy;
+
+import "dart:async";
+
+class Divergent<T extends core::Object? = dynamic> extends core::Object implements asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>> {
+  synthetic constructor •() → self::Divergent<self::Divergent::T%>
+    : super core::Object::•()
+    ;
+  method noSuchMethod(core::Invocation invocation) → dynamic
+    return super.{core::Object::noSuchMethod}(invocation);
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ catchError(core::Function onError, {(core::Object) →? core::bool test = #C1}) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C2, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[onError]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C4: test}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ whenComplete(() → FutureOr<void>action) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C5, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C7))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ timeout(core::Duration timeLimit, {generic-covariant-impl () →? FutureOr<self::Divergent<self::Divergent<self::Divergent::T%>>>onTimeout = #C1}) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C8, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C9: onTimeout}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ then<R extends core::Object? = dynamic>((self::Divergent<self::Divergent<self::Divergent::T%>>) → FutureOr<self::Divergent::then::R%>onValue, {core::Function? onError = #C1}) → asy::Future<self::Divergent::then::R%>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C10, 0, core::List::unmodifiable<core::Type*>(<core::Type*>[self::Divergent::then::R%]), core::List::unmodifiable<dynamic>(<dynamic>[onValue]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C11: onError}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent::then::R%>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ asStream() → asy::Stream<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C12, 0, #C3, #C6, core::Map::unmodifiable<core::Symbol*, dynamic>(#C7))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Stream<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+}
+static method test() → dynamic async {
+  asy::Future<self::Divergent<self::Divergent<core::int>>> x = let final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/nnbd/issue42546.dart:14:75: Error: A value of type 'Future<Divergent<Divergent<Divergent<int>>>>' can't be assigned to a variable of type 'Future<Divergent<Divergent<int>>>'.
+ - 'Future' is from 'dart:async'.
+ - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+  Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+                                                                          ^" in (() → asy::Future<self::Divergent<self::Divergent<self::Divergent<core::int>>>> async => let final<BottomType> #t2 = invalid-expression "pkg/front_end/testcases/nnbd/issue42546.dart:14:58: Error: A value of type 'Divergent<int>' can't be returned from an async function with return type 'Future<Divergent<Divergent<Divergent<int>>>>'.
+ - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+ - 'Future' is from 'dart:async'.
+  Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+                                                         ^" in new self::Divergent::•<core::int>() as{TypeError,ForNonNullableByDefault} self::Divergent<self::Divergent<self::Divergent<core::int>>>).call() as{TypeError,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<core::int>>>;
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = null
+  #C2 = #catchError
+  #C3 = <core::Type*>[]
+  #C4 = #test
+  #C5 = #whenComplete
+  #C6 = <dynamic>[]
+  #C7 = core::_ImmutableMap<core::Symbol*, dynamic> {_kvPairs:#C6}
+  #C8 = #timeout
+  #C9 = #onTimeout
+  #C10 = #then
+  #C11 = #onError
+  #C12 = #asStream
+}

pkg/front_end/testcases/nnbd/issue42546.dart.textual_outline.expect

@@ -0,0 +1,8 @@
+import 'dart:async';
+
+class Divergent<T> implements Future<Divergent<Divergent<T>>> {
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+test() async {}
+main() {}

pkg/front_end/testcases/nnbd/issue42546.dart.textual_outline_modelled.expect

@@ -0,0 +1,8 @@
+import 'dart:async';
+
+class Divergent<T> implements Future<Divergent<Divergent<T>>> {
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+main() {}
+test() async {}

pkg/front_end/testcases/nnbd/issue42546.dart.weak.expect

@@ -0,0 +1,66 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/issue42546.dart:14:58: Error: A value of type 'Divergent<int>' can't be returned from an async function with return type 'Future<Divergent<Divergent<Divergent<int>>>>'.
+//  - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+//  - 'Future' is from 'dart:async'.
+//   Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+//                                                          ^
+//
+// pkg/front_end/testcases/nnbd/issue42546.dart:14:75: Error: A value of type 'Future<Divergent<Divergent<Divergent<int>>>>' can't be assigned to a variable of type 'Future<Divergent<Divergent<int>>>'.
+//  - 'Future' is from 'dart:async'.
+//  - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+//   Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+//                                                                           ^
+//
+import self as self;
+import "dart:core" as core;
+import "dart:async" as asy;
+
+import "dart:async";
+
+class Divergent<T extends core::Object? = dynamic> extends core::Object implements asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>> {
+  synthetic constructor •() → self::Divergent<self::Divergent::T%>
+    : super core::Object::•()
+    ;
+  method noSuchMethod(core::Invocation invocation) → dynamic
+    return super.{core::Object::noSuchMethod}(invocation);
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ catchError(core::Function onError, {(core::Object) →? core::bool test = #C1}) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C2, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[onError]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C4: test}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ whenComplete(() → FutureOr<void>action) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C5, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C7))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ timeout(core::Duration timeLimit, {generic-covariant-impl () →? FutureOr<self::Divergent<self::Divergent<self::Divergent::T%>>>onTimeout = #C1}) → asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C8, 0, #C3, core::List::unmodifiable<dynamic>(<dynamic>[timeLimit]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C9: onTimeout}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ then<R extends core::Object? = dynamic>((self::Divergent<self::Divergent<self::Divergent::T%>>) → FutureOr<self::Divergent::then::R%>onValue, {core::Function? onError = #C1}) → asy::Future<self::Divergent::then::R%>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C10, 0, core::List::unmodifiable<core::Type*>(<core::Type*>[self::Divergent::then::R%]), core::List::unmodifiable<dynamic>(<dynamic>[onValue]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C11: onError}))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Future<self::Divergent::then::R%>;
+  no-such-method-forwarder method /* from org-dartlang-sdk:///sdk/lib/async/future.dart */ asStream() → asy::Stream<self::Divergent<self::Divergent<self::Divergent::T%>>>
+    return this.{self::Divergent::noSuchMethod}(new core::_InvocationMirror::_withType(#C12, 0, #C3, #C6, core::Map::unmodifiable<core::Symbol*, dynamic>(#C7))) as{TypeError,ForDynamic,ForNonNullableByDefault} asy::Stream<self::Divergent<self::Divergent<self::Divergent::T%>>>;
+}
+static method test() → dynamic async {
+  asy::Future<self::Divergent<self::Divergent<core::int>>> x = let final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/nnbd/issue42546.dart:14:75: Error: A value of type 'Future<Divergent<Divergent<Divergent<int>>>>' can't be assigned to a variable of type 'Future<Divergent<Divergent<int>>>'.
+ - 'Future' is from 'dart:async'.
+ - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+  Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+                                                                          ^" in (() → asy::Future<self::Divergent<self::Divergent<self::Divergent<core::int>>>> async => let final<BottomType> #t2 = invalid-expression "pkg/front_end/testcases/nnbd/issue42546.dart:14:58: Error: A value of type 'Divergent<int>' can't be returned from an async function with return type 'Future<Divergent<Divergent<Divergent<int>>>>'.
+ - 'Divergent' is from 'pkg/front_end/testcases/nnbd/issue42546.dart'.
+ - 'Future' is from 'dart:async'.
+  Future<Divergent<Divergent<int>>> x = (() async => new Divergent<int>())();
+                                                         ^" in new self::Divergent::•<core::int>() as{TypeError,ForNonNullableByDefault} self::Divergent<self::Divergent<self::Divergent<core::int>>>).call() as{TypeError,ForNonNullableByDefault} asy::Future<self::Divergent<self::Divergent<core::int>>>;
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = null
+  #C2 = #catchError
+  #C3 = <core::Type*>[]
+  #C4 = #test
+  #C5 = #whenComplete
+  #C6 = <dynamic>[]
+  #C7 = core::_ImmutableMap<core::Symbol*, dynamic> {_kvPairs:#C6}
+  #C8 = #timeout
+  #C9 = #onTimeout
+  #C10 = #then
+  #C11 = #onError
+  #C12 = #asStream
+}

pkg/front_end/testcases/strong.status

@@ -172,6 +172,7 @@ instantiate_to_bound/non_simple_generic_function_in_bound_regress: RuntimeError
 late_lowering/covariant_late_field: TypeCheckError
 nnbd/covariant_late_field: TypeCheckError
 nnbd/issue41180: RuntimeError # Strong mode runtime checking fails due to mixed strong mode.
+nnbd/issue42546: TypeCheckError
 nnbd/nullable_object_access: TypeCheckError
 nnbd/nullable_receiver: TypeCheckError
 nnbd/potentially_nullable_access: TypeCheckError

pkg/front_end/testcases/text_serialization.status

@@ -170,6 +170,7 @@ instantiate_to_bound/non_simple_generic_function_in_bound_regress: RuntimeError
 late_lowering/covariant_late_field: TypeCheckError
 nnbd/covariant_late_field: TypeCheckError
 nnbd/issue41180: RuntimeError
+nnbd/issue42546: TypeCheckError
 nnbd/nullable_object_access: TypeCheckError
 nnbd/nullable_receiver: TypeCheckError
 nnbd/potentially_nullable_access: TypeCheckError