Migration: add support for creating instances without supplying type arguments.

stereotype441 · commit-bot@chromium.org · commit e9fdeb2db80e · 2019-08-28T22:12:51.000Z
Should address ~622 exceptions whose stack trace contains the line: new DecoratedType.<anonymous closure> (package:nnbd_migration/src/decorated_type.dart:64:16) Change-Id: I01951abf28b7c474ca31eb2d2878caaf3c3b9073 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/114744 Reviewed-by: Dan Rubel <danrubel@google.com> Commit-Queue: Paul Berry <paulberry@google.com>
diff --git a/pkg/nnbd_migration/lib/src/edge_builder.dart b/pkg/nnbd_migration/lib/src/edge_builder.dart
@@ -758,7 +758,15 @@ class EdgeBuilder extends GeneralizingAstVisitor<DecoratedType>
           .map((t) => _variables.decoratedTypeAnnotation(source, t))
           .toList();
     } else {
-      decoratedTypeArguments = const [];
+      var staticType = node.staticType;
+      if (staticType is InterfaceType) {
+        decoratedTypeArguments = staticType.typeArguments
+            .map((t) => DecoratedType.forImplicitType(_typeProvider, t, _graph))
+            .toList();
+      } else {
+        // Note: this could happen if the code being migrated has errors.
+        decoratedTypeArguments = const [];
+      }
     }
     var createdType = DecoratedType(node.staticType, _graph.never,
         typeArguments: decoratedTypeArguments);
@@ -1666,6 +1674,9 @@ class EdgeBuilder extends GeneralizingAstVisitor<DecoratedType>
                   DecoratedType.forImplicitType(_typeProvider, argType, _graph))
               .toList();
           calleeType = calleeType.instantiate(argumentTypes);
+        } else if (constructorTypeParameters != null) {
+          // No need to instantiate; caller has already substituted in the
+          // correct type arguments.
         } else {
           assert(
               false,
diff --git a/pkg/nnbd_migration/test/edge_builder_test.dart b/pkg/nnbd_migration/test/edge_builder_test.dart
@@ -1969,6 +1969,23 @@ C<Object> f() => C<dynamic>();
         hard: false);
   }
 
+  test_instanceCreation_generic_inferredParameterType() async {
+    await analyze('''
+class C<T> {
+  C(List<T> x);
+}
+C<int> f(List<int> x) => C(x);
+''');
+    var edge = assertEdge(anyNode, decoratedTypeAnnotation('int> f').node,
+        hard: false);
+    var inferredTypeArgument = edge.primarySource;
+    assertEdge(
+        decoratedTypeAnnotation('int> x').node,
+        substitutionNode(
+            inferredTypeArgument, decoratedTypeAnnotation('T> x').node),
+        hard: false);
+  }
+
   test_instanceCreation_generic_parameter() async {
     await analyze('''
 class C<T> {
