Implement task to infer instance members

pkg/analyzer/test/src/task/dart_test.dart

Index: pkg/analyzer/test/src/task/dart_test.dart
diff --git a/pkg/analyzer/test/src/task/dart_test.dart b/pkg/analyzer/test/src/task/dart_test.dart
index f2184611aa7391ae1f7d6e6448fee7e7daabb6eb..6e0bb485ab9f1829ceb3bf7767c556ea1d915001 100644
--- a/pkg/analyzer/test/src/task/dart_test.dart
+++ b/pkg/analyzer/test/src/task/dart_test.dart
@@ -47,6 +47,7 @@ main() {
   runReflectiveTests(GatherUsedImportedElementsTaskTest);
   runReflectiveTests(GatherUsedLocalElementsTaskTest);
   runReflectiveTests(GenerateHintsTaskTest);
+  runReflectiveTests(InferInstanceMembersInUnitTaskTest);
   runReflectiveTests(InferStaticVariableTypesInUnitTaskTest);
   runReflectiveTests(InferStaticVariableTypeTaskTest);
   runReflectiveTests(LibraryErrorsReadyTaskTest);
@@ -2034,6 +2035,40 @@ f(A a) {
 }
 
 @reflectiveTest
+class InferInstanceMembersInUnitTaskTest extends _AbstractDartTaskTest {
+  void test_perform() {
+    enableStrongMode();
+    AnalysisTarget source = newSource(
+        '/test.dart',
+        '''
+class A {
+  X f;
+  Y m(Z x) {}
+}
+class B extends A {
+  var f;
+  m(x) {}
+}
+class X {}
+class Y {}
+class Z {}
+''');
+    computeResult(new LibrarySpecificUnit(source, source),
+        RESOLVED_UNIT7); //  new isInstanceOf<InferInstanceMembersInUnitTask>()
+    CompilationUnit unit = outputs[RESOLVED_UNIT7];
+    VariableDeclaration field = getFieldInClass(unit, 'B', 'f');
+    MethodDeclaration method = getMethodInClass(unit, 'B', 'm');
+    DartType typeX = getClass(unit, 'X').element.type;
+    DartType typeY = getClass(unit, 'Y').element.type;
+    DartType typeZ = getClass(unit, 'Z').element.type;
+
+    expect(field.element.type, typeX);
+    expect(method.element.returnType, typeY);
+    expect(method.element.parameters[0].type, typeZ);
+  }
+}
+
+@reflectiveTest
 class InferStaticVariableTypesInUnitTaskTest extends _AbstractDartTaskTest {
   void test_perform() {
     enableStrongMode();
@@ -3020,6 +3055,27 @@ class _AbstractDartTaskTest extends AbstractContextTest {
   }
 
   /**
+   * Return the declaration of the method with the given [methodName] in the
+   * class with the given [className] in the given compilation [unit].
+   */
+  MethodDeclaration getMethodInClass(
+      CompilationUnit unit, String className, String methodName) {
+    ClassDeclaration unitMember = getClass(unit, className);
+    if (unitMember == null) {

[Paul Berry, 2015/08/31 20:39:24]

Nit: since this is test code, I don't think it's necessary to program
defensively.  Consider just changing this to "expect(unitMember, isNotNull)". 
This will have the advantage that if unitMember ever is null, the unit test
stack trace will give slightly more information about the cause of the problem.

[Brian Wilkerson, 2015/08/31 21:23:34]

Based on the next comment, I just put a call to 'fail' in 'getClass' if no class
is found.

+      return null;
+    }
+    NodeList<ClassMember> classMembers = unitMember.members;
+    for (ClassMember classMember in classMembers) {
+      if (classMember is MethodDeclaration) {
+        if (classMember.name.name == methodName) {
+          return classMember;
+        }
+      }
+    }
+    return null;

[Paul Berry, 2015/08/31 20:39:24]

Similarly, consider changing this to something like "fail('No method named
$methodName found');"

[Brian Wilkerson, 2015/08/31 21:23:34]

I added the file (but can't remove the return without producing a hint).

+  }
+
+  /**
    * Return the declaration of the top-level variable with the given
    * [variableName] in the given compilation [unit].
    */