[nnbd_migration] Fix TypeParameterType asInstanceOf where valid.

Change-Id: I033b378d0e87ead2bacad27d71a0c696904d8e15 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/128985 Commit-Queue: Mike Fairhurst <mfairhurst@google.com> Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
filmil · Dec 20, 2019 · 4681868 · 4681868
1 parent 4dd9734
commit 4681868
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diff --git a/pkg/nnbd_migration/lib/src/decorated_class_hierarchy.dart b/pkg/nnbd_migration/lib/src/decorated_class_hierarchy.dart
@@ -28,9 +28,10 @@ class DecoratedClassHierarchy {
 
   /// Retrieves a [DecoratedType] describing how [type] implements [superclass].
   ///
-  /// If [type] is not an interface type, or it does not implement [superclass],
-  /// raises an exception.
+  /// If the [type] is a [TypeParameterType], it will be resolved against its
+  /// bound.
   DecoratedType asInstanceOf(DecoratedType type, ClassElement superclass) {
+    type = _getInterfaceType(type);
     var typeType = type.type as InterfaceType;
     var class_ = typeType.element;
     if (class_ == superclass) return type;
@@ -104,4 +105,19 @@ class DecoratedClassHierarchy {
     }
     return decorations;
   }
+
+  DecoratedType _getInterfaceType(DecoratedType type) {
+    var typeType = type.type;
+    if (typeType is InterfaceType) {
+      return type;
+    }
+
+    if (typeType is TypeParameterType) {
+      final innerType = _getInterfaceType(
+          _variables.decoratedTypeParameterBound(typeType.element));
+      return type.substitute({typeType.element: innerType});
+    }
+
+    throw ArgumentError('$type is an unexpected type');
+  }
 }
diff --git a/pkg/nnbd_migration/test/edge_builder_test.dart b/pkg/nnbd_migration/test/edge_builder_test.dart
@@ -2138,6 +2138,38 @@ void f(List<int> l) {
         hard: false);
   }
 
+  test_for_each_on_type_parameter_type() async {
+    await analyze('''
+void f<T extends List<int>>(T l) {
+  for (int i in l) {}
+}
+''');
+    // TODO(mfairhurst): fix this: https://github.com/dart-lang/sdk/issues/39852
+    //assertEdge(decoratedTypeAnnotation('List<int>').node, never, hard: true);
+    assertEdge(decoratedTypeAnnotation('T l').node, never, hard: true);
+    assertEdge(
+        substitutionNode(
+            decoratedTypeAnnotation('int>').node, inSet(pointsToNever)),
+        decoratedTypeAnnotation('int i').node,
+        hard: false);
+  }
+
+  test_for_each_on_type_parameter_type_bound_bound() async {
+    await analyze('''
+void f<T extends R, R extends List<int>>(T l) {
+  for (int i in l) {}
+}
+''');
+    // TODO(mfairhurst): fix this: https://github.com/dart-lang/sdk/issues/39852
+    //assertEdge(decoratedTypeAnnotation('List<int>').node, never, hard: true);
+    assertEdge(decoratedTypeAnnotation('T l').node, never, hard: true);
+    assertEdge(
+        substitutionNode(
+            decoratedTypeAnnotation('int>').node, inSet(pointsToNever)),
+        decoratedTypeAnnotation('int i').node,
+        hard: false);
+  }
+
   test_for_each_with_declaration() async {
     await analyze('''
 void f(List<int> l) {
@@ -5670,6 +5702,77 @@ void f(C<int> c) {}
         hard: true);
   }
 
+  test_type_parameter_method_call_bound() async {
+    await analyze('''
+class Foo {
+  void bar(int x) {}
+}
+
+void f<T extends Foo>(T t) {
+  t.bar(null);
+}
+''');
+    assertEdge(decoratedTypeAnnotation('T t').node, never, hard: true);
+    // TODO(mfairhurst): fix this: https://github.com/dart-lang/sdk/issues/39852
+    //assertEdge(decoratedTypeAnnotation('Foo>').node, never, hard: true);
+    assertEdge(inSet(alwaysPlus), decoratedTypeAnnotation('int x').node,
+        hard: false);
+  }
+
+  test_type_parameter_method_call_bound_bound() async {
+    await analyze('''
+class Foo {
+  void bar(int x) {}
+}
+
+void f<T extends R, R extends Foo>(T t) {
+  t.bar(null);
+}
+''');
+    assertEdge(decoratedTypeAnnotation('T t').node, never, hard: true);
+    // TODO(mfairhurst): fix this: https://github.com/dart-lang/sdk/issues/39852
+    //assertEdge(decoratedTypeAnnotation('Foo>').node, never, hard: true);
+    assertEdge(inSet(alwaysPlus), decoratedTypeAnnotation('int x').node,
+        hard: false);
+  }
+
+  test_type_parameter_method_call_bound_generic() async {
+    await analyze('''
+class Foo<T> {
+  void bar(int x) {}
+}
+
+void f<T extends Foo<dynamic>>(T t) {
+  t.bar(null);
+}
+''');
+    assertEdge(decoratedTypeAnnotation('T t').node, never, hard: true);
+    // TODO(mfairhurst): fix this: https://github.com/dart-lang/sdk/issues/39852
+    //assertEdge(decoratedTypeAnnotation('Foo>').node, never, hard: true);
+    assertEdge(inSet(alwaysPlus), decoratedTypeAnnotation('int x').node,
+        hard: false);
+  }
+
+  test_type_parameter_method_call_bound_generic_complex() async {
+    await analyze('''
+class Foo<T> {
+  void bar(T x) {}
+}
+
+void f<R extends Object, T extends Foo<R>>(T t) {
+  t.bar(null);
+}
+''');
+    assertEdge(decoratedTypeAnnotation('T t').node, never, hard: true);
+    // TODO(mfairhurst): fix this: https://github.com/dart-lang/sdk/issues/39852
+    //assertEdge(decoratedTypeAnnotation('Foo>').node, never, hard: true);
+    assertEdge(
+        inSet(alwaysPlus),
+        substitutionNode(decoratedTypeAnnotation('R>').node,
+            decoratedTypeAnnotation('T x').node),
+        hard: false);
+  }
+
   test_type_parameterized_migrated_bound_class() async {
     await analyze('''
 import 'dart:math';