[cp][cfe] Use effective target in redirecting factory tear off lowering

The tear-off lowering for a redirecting factory called the
immediate target (even when this was also a redirecting factory)
instead of the effective target. This caused problem in backends
that don't support redirecting factories directly.

Closes #47916

Change-Id: I708c59dae9d210e0eb6dab4d01c6a044f6b2fd00

Author: johnniwinther

pkg/front_end/lib/src/fasta/builder/factory_builder.dart

@@ -396,6 +396,14 @@ class RedirectingFactoryBuilder extends SourceFactoryBuilder {
       inferrer.helper = library.loader.createBodyBuilderForOutlineExpression(
           library, classBuilder, this, classBuilder!.scope, fileUri);
       Builder? targetBuilder = redirectionTarget.target;
+      if (targetBuilder is MemberBuilder) {
+        // Ensure that target has been built.
+        targetBuilder.buildOutlineExpressions(
+            targetBuilder.library as SourceLibraryBuilder,
+            coreTypes,
+            delayedActionPerformers,
+            synthesizedFunctionNodes);
+      }
       if (targetBuilder is FunctionBuilder) {
         target = targetBuilder.member;
       } else if (targetBuilder is DillMemberBuilder) {
@@ -446,13 +454,33 @@ class RedirectingFactoryBuilder extends SourceFactoryBuilder {
           new RedirectingFactoryBody(target, typeArguments, function);
       function.body!.parent = function;
     }
-    if (_factoryTearOff != null &&
-        (target is Constructor || target is Procedure && target.isFactory)) {
-      synthesizedFunctionNodes.add(buildRedirectingFactoryTearOffBody(
-          _factoryTearOff!,
-          target!,
-          typeArguments ?? [],
-          _tearOffTypeParameters!));
+    if (_factoryTearOff != null) {
+      Set<Procedure> seenTargets = {};
+      while (target is Procedure && target.isRedirectingFactory) {
+        if (!seenTargets.add(target)) {
+          // Cyclic dependency.
+          target = null;
+          break;
+        }
+        RedirectingFactoryBody body =
+            target.function.body as RedirectingFactoryBody;
+        if (typeArguments != null) {
+          Substitution substitution = Substitution.fromPairs(
+              target.function.typeParameters, typeArguments);
+          typeArguments =
+              body.typeArguments?.map(substitution.substituteType).toList();
+        } else {
+          typeArguments = body.typeArguments;
+        }
+        target = body.target;
+      }
+      if (target is Constructor || target is Procedure && target.isFactory) {
+        synthesizedFunctionNodes.add(buildRedirectingFactoryTearOffBody(
+            _factoryTearOff!,
+            target!,
+            typeArguments ?? [],
+            _tearOffTypeParameters!));
+      }
     }
     if (isConst && isPatch) {
       _finishPatch();

pkg/front_end/testcases/dart2js/issue47916.dart

@@ -0,0 +1,19 @@
+// Copyright (c) 2022, 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.
+
+abstract class A {
+  const factory A() = B;
+}
+
+abstract class B implements A {
+  const factory B() = C;
+}
+
+class C implements B {
+  const C();
+}
+
+main() {
+  A.new;
+}

pkg/front_end/testcases/dart2js/issue47916.dart.strong.expect

@@ -0,0 +1,34 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[#C1]/*isLegacy*/;
+  static factory •() → self::A
+    return self::B::•();
+  static method _#new#tearOff() → self::A
+    return new self::C::•();
+}
+abstract class B extends core::Object implements self::A {
+  static final field dynamic _redirecting# = <dynamic>[#C2]/*isLegacy*/;
+  static factory •() → self::B
+    return new self::C::•();
+  static method _#new#tearOff() → self::B
+    return new self::C::•();
+}
+class C extends core::Object implements self::B /*hasConstConstructor*/  {
+  const constructor •() → self::C
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff() → self::C
+    return new self::C::•();
+}
+static method main() → dynamic {
+  #C3;
+}
+
+constants  {
+  #C1 = constructor-tearoff self::A::•
+  #C2 = constructor-tearoff self::B::•
+  #C3 = static-tearoff self::A::_#new#tearOff
+}

pkg/front_end/testcases/dart2js/issue47916.dart.strong.transformed.expect

@@ -0,0 +1,34 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[#C1]/*isLegacy*/;
+  static factory •() → self::A
+    return self::B::•();
+  static method _#new#tearOff() → self::A
+    return new self::C::•();
+}
+abstract class B extends core::Object implements self::A {
+  static final field dynamic _redirecting# = <dynamic>[#C2]/*isLegacy*/;
+  static factory •() → self::B
+    return new self::C::•();
+  static method _#new#tearOff() → self::B
+    return new self::C::•();
+}
+class C extends core::Object implements self::B /*hasConstConstructor*/  {
+  const constructor •() → self::C
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff() → self::C
+    return new self::C::•();
+}
+static method main() → dynamic {
+  #C3;
+}
+
+constants  {
+  #C1 = constructor-tearoff self::A::•
+  #C2 = constructor-tearoff self::B::•
+  #C3 = static-tearoff self::A::_#new#tearOff
+}

pkg/front_end/testcases/dart2js/issue47916.dart.textual_outline.expect

@@ -0,0 +1,13 @@
+abstract class A {
+  const factory A() = B;
+}
+
+abstract class B implements A {
+  const factory B() = C;
+}
+
+class C implements B {
+  const C();
+}
+
+main() {}

pkg/front_end/testcases/dart2js/issue47916.dart.textual_outline_modelled.expect

@@ -0,0 +1,13 @@
+abstract class A {
+  const factory A() = B;
+}
+
+abstract class B implements A {
+  const factory B() = C;
+}
+
+class C implements B {
+  const C();
+}
+
+main() {}

pkg/front_end/testcases/dart2js/issue47916.dart.weak.expect

@@ -0,0 +1,34 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[#C1]/*isLegacy*/;
+  static factory •() → self::A
+    return self::B::•();
+  static method _#new#tearOff() → self::A
+    return new self::C::•();
+}
+abstract class B extends core::Object implements self::A {
+  static final field dynamic _redirecting# = <dynamic>[#C2]/*isLegacy*/;
+  static factory •() → self::B
+    return new self::C::•();
+  static method _#new#tearOff() → self::B
+    return new self::C::•();
+}
+class C extends core::Object implements self::B /*hasConstConstructor*/  {
+  const constructor •() → self::C
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff() → self::C
+    return new self::C::•();
+}
+static method main() → dynamic {
+  #C3;
+}
+
+constants  {
+  #C1 = constructor-tearoff self::A::•
+  #C2 = constructor-tearoff self::B::•
+  #C3 = static-tearoff self::A::_#new#tearOff
+}

pkg/front_end/testcases/dart2js/issue47916.dart.weak.modular.expect

@@ -0,0 +1,34 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[#C1]/*isLegacy*/;
+  static factory •() → self::A
+    return self::B::•();
+  static method _#new#tearOff() → self::A
+    return new self::C::•();
+}
+abstract class B extends core::Object implements self::A {
+  static final field dynamic _redirecting# = <dynamic>[#C2]/*isLegacy*/;
+  static factory •() → self::B
+    return new self::C::•();
+  static method _#new#tearOff() → self::B
+    return new self::C::•();
+}
+class C extends core::Object implements self::B /*hasConstConstructor*/  {
+  const constructor •() → self::C
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff() → self::C
+    return new self::C::•();
+}
+static method main() → dynamic {
+  #C3;
+}
+
+constants  {
+  #C1 = constructor-tearoff self::A::•
+  #C2 = constructor-tearoff self::B::•
+  #C3 = static-tearoff self::A::_#new#tearOff
+}

pkg/front_end/testcases/dart2js/issue47916.dart.weak.outline.expect

@@ -0,0 +1,33 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[self::A::•]/*isLegacy*/;
+  static factory •() → self::A
+    return self::B::•();
+  static method _#new#tearOff() → self::A
+    return new self::C::•();
+}
+abstract class B extends core::Object implements self::A {
+  static final field dynamic _redirecting# = <dynamic>[self::B::•]/*isLegacy*/;
+  static factory •() → self::B
+    return new self::C::•();
+  static method _#new#tearOff() → self::B
+    return new self::C::•();
+}
+class C extends core::Object implements self::B /*hasConstConstructor*/  {
+  const constructor •() → self::C
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff() → self::C
+    return new self::C::•();
+}
+static method main() → dynamic
+  ;
+
+
+Extra constant evaluation status:
+Evaluated: ConstructorTearOff @ org-dartlang-testcase:///issue47916.dart:5:16 -> ConstructorTearOffConstant(A.)
+Evaluated: ConstructorTearOff @ org-dartlang-testcase:///issue47916.dart:9:16 -> ConstructorTearOffConstant(B.)
+Extra constant evaluation: evaluated: 9, effectively constant: 2

pkg/front_end/testcases/dart2js/issue47916.dart.weak.transformed.expect

@@ -0,0 +1,34 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[#C1]/*isLegacy*/;
+  static factory •() → self::A
+    return self::B::•();
+  static method _#new#tearOff() → self::A
+    return new self::C::•();
+}
+abstract class B extends core::Object implements self::A {
+  static final field dynamic _redirecting# = <dynamic>[#C2]/*isLegacy*/;
+  static factory •() → self::B
+    return new self::C::•();
+  static method _#new#tearOff() → self::B
+    return new self::C::•();
+}
+class C extends core::Object implements self::B /*hasConstConstructor*/  {
+  const constructor •() → self::C
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff() → self::C
+    return new self::C::•();
+}
+static method main() → dynamic {
+  #C3;
+}
+
+constants  {
+  #C1 = constructor-tearoff self::A::•
+  #C2 = constructor-tearoff self::B::•
+  #C3 = static-tearoff self::A::_#new#tearOff
+}

pkg/front_end/testcases/dart2js/issue47916b.dart

@@ -0,0 +1,21 @@
+// Copyright (c) 2022, 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.
+
+abstract class A<T> {
+  const factory A() = B;
+}
+
+abstract class B<S, T> implements A<T> {
+  const factory B() = C;
+}
+
+class C<T, S, U> implements B<S, T> {
+  const C();
+}
+
+main() {
+  A<int>.new;
+  B<String, double>.new;
+  C<bool, num, void>.new;
+}

pkg/front_end/testcases/dart2js/issue47916b.dart.strong.expect

@@ -0,0 +1,41 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+abstract class A<T extends core::Object? = dynamic> extends core::Object {
+  static final field dynamic _redirecting# = <dynamic>[#C1]/*isLegacy*/;
+  static factory •<T extends core::Object? = dynamic>() → self::A<self::A::•::T%>
+    return self::B::•<dynamic, self::A::•::T%>();
+  static method _#new#tearOff<T extends core::Object? = dynamic>() → self::A<self::A::_#new#tearOff::T%>
+    return new self::C::•<self::A::_#new#tearOff::T%, dynamic, dynamic>();
+}
+abstract class B<S extends core::Object? = dynamic, T extends core::Object? = dynamic> extends core::Object implements self::A<self::B::T%> {
+  static final field dynamic _redirecting# = <dynamic>[#C2]/*isLegacy*/;
+  static factory •<S extends core::Object? = dynamic, T extends core::Object? = dynamic>() → self::B<self::B::•::S%, self::B::•::T%>
+    return new self::C::•<self::B::•::T%, self::B::•::S%, dynamic>();
+  static method _#new#tearOff<S extends core::Object? = dynamic, T extends core::Object? = dynamic>() → self::B<self::B::_#new#tearOff::S%, self::B::_#new#tearOff::T%>
+    return new self::C::•<self::B::_#new#tearOff::T%, self::B::_#new#tearOff::S%, dynamic>();
+}
+class C<T extends core::Object? = dynamic, S extends core::Object? = dynamic, U extends core::Object? = dynamic> extends core::Object implements self::B<self::C::S%, self::C::T%> /*hasConstConstructor*/  {
+  const constructor •() → self::C<self::C::T%, self::C::S%, self::C::U%>
+    : super core::Object::•()
+    ;
+  static method _#new#tearOff<T extends core::Object? = dynamic, S extends core::Object? = dynamic, U extends core::Object? = dynamic>() → self::C<self::C::_#new#tearOff::T%, self::C::_#new#tearOff::S%, self::C::_#new#tearOff::U%>
+    return new self::C::•<self::C::_#new#tearOff::T%, self::C::_#new#tearOff::S%, self::C::_#new#tearOff::U%>();
+}
+static method main() → dynamic {
+  #C4;
+  #C6;
+  #C8;
+}
+
+constants  {
+  #C1 = constructor-tearoff self::A::•
+  #C2 = constructor-tearoff self::B::•
+  #C3 = static-tearoff self::A::_#new#tearOff
+  #C4 = instantiation #C3 <core::int>
+  #C5 = static-tearoff self::B::_#new#tearOff
+  #C6 = instantiation #C5 <core::String, core::double>
+  #C7 = static-tearoff self::C::_#new#tearOff
+  #C8 = instantiation #C7 <core::bool, core::num, void>
+}