[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: Iafb11c42c1e99e70ed44b0835473a8c69e995b01
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/235780
Reviewed-by: Chloe Stefantsova <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/fasta/scope.dart

@@ -805,7 +805,7 @@ mixin ErroneousMemberBuilderMixin implements SourceMemberBuilder {
   }
 
   @override
-  LibraryBuilder get library {
+  SourceLibraryBuilder get library {
     throw new UnsupportedError('AmbiguousMemberBuilder.library');
   }
 

pkg/front_end/lib/src/fasta/source/source_class_builder.dart

@@ -2808,6 +2808,9 @@ class _RedirectingConstructorsFieldBuilder extends DillFieldBuilder
   _RedirectingConstructorsFieldBuilder(Field field, SourceClassBuilder parent)
       : super(field, parent);
 
+  @override
+  SourceLibraryBuilder get library => super.library as SourceLibraryBuilder;
+
   @override
   void buildOutlineExpressions(
       SourceLibraryBuilder library,

pkg/front_end/lib/src/fasta/source/source_constructor_builder.dart

@@ -129,9 +129,6 @@ class DeclaredSourceConstructorBuilder extends SourceFunctionBuilderImpl
         super(metadata, modifiers, returnType, name, typeVariables, formals,
             compilationUnit, charOffset, nativeMethodName);
 
-  @override
-  SourceLibraryBuilder get library => super.library as SourceLibraryBuilder;
-
   @override
   SourceClassBuilder get classBuilder =>
       super.classBuilder as SourceClassBuilder;
@@ -783,6 +780,9 @@ class SyntheticSourceConstructorBuilder extends DillConstructorBuilder
         _synthesizedFunctionNode = synthesizedFunctionNode,
         super(constructor, constructorTearOff, parent);
 
+  @override
+  SourceLibraryBuilder get library => super.library as SourceLibraryBuilder;
+
   // TODO(johnniwinther,cstefantsova): Rename [actualOrigin] to avoid the
   //  confusion with patches.
   MemberBuilder? get actualOrigin {

pkg/front_end/lib/src/fasta/source/source_factory_builder.dart

@@ -407,6 +407,11 @@ class RedirectingFactoryBuilder extends SourceFactoryBuilder {
       inferrer.helper = library.loader.createBodyBuilderForOutlineExpression(
           library, classBuilder, this, classBuilder!.scope, fileUri);
       Builder? targetBuilder = redirectionTarget.target;
+      if (targetBuilder is SourceMemberBuilder) {
+        // Ensure that target has been built.
+        targetBuilder.buildOutlineExpressions(targetBuilder.library,
+            classHierarchy, delayedActionPerformers, synthesizedFunctionNodes);
+      }
       if (targetBuilder is FunctionBuilder) {
         target = targetBuilder.member;
       } else if (targetBuilder is DillMemberBuilder) {
@@ -457,14 +462,34 @@ 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!,
-          library));
+    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!,
+            library));
+      }
     }
     if (isConst && isPatch) {
       _finishPatch();

pkg/front_end/lib/src/fasta/source/source_field_builder.dart

@@ -282,9 +282,6 @@ class SourceFieldBuilder extends SourceMemberBuilderImpl
     _typeEnsured = true;
   }
 
-  @override
-  SourceLibraryBuilder get library => super.library as SourceLibraryBuilder;
-
   @override
   Member get member => _fieldEncoding.field;
 

pkg/front_end/lib/src/fasta/source/source_member_builder.dart

@@ -25,6 +25,9 @@ import 'source_class_builder.dart';
 abstract class SourceMemberBuilder implements MemberBuilder {
   MemberDataForTesting? get dataForTesting;
 
+  @override
+  SourceLibraryBuilder get library;
+
   /// Builds the core AST structures for this member as needed for the outline.
   void buildMembers(
       SourceLibraryBuilder library, void Function(Member, BuiltMemberKind) f);
@@ -87,6 +90,9 @@ abstract class SourceMemberBuilderImpl extends MemberBuilderImpl
             retainDataForTesting ? new MemberDataForTesting() : null,
         super(parent, charOffset, fileUri);
 
+  @override
+  SourceLibraryBuilder get library => super.library as SourceLibraryBuilder;
+
   bool get isRedirectingGenerativeConstructor => false;
 
   @override

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
+}