Null Safety preview: Fix description for uninitialized field

Fixes flutter#40773

Change-Id: I7639364820785f5a877917afbbb62ab9c09eff00
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/138781
Reviewed-by: Mike Fairhurst <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

pkg/analysis_server/lib/src/edit/nnbd_migration/info_builder.dart

@@ -173,16 +173,6 @@ class InfoBuilder {
       return 'The value of the expression is nullable';
     }
 
-    // Text indicating the type of nullable value found.
-    String nullableValue;
-    if (node is NullLiteral) {
-      nullableValue = "an explicit 'null'";
-    } else if (origin.kind == EdgeOriginKind.dynamicAssignment) {
-      nullableValue = 'a dynamic value, which is nullable';
-    } else {
-      nullableValue = 'a nullable value';
-    }
-
     if (origin.kind == EdgeOriginKind.listLengthConstructor) {
       return 'A length is specified in the "List()" constructor and the list '
           'items are initialized to null';
@@ -205,6 +195,16 @@ class InfoBuilder {
           '$lineNumber, which implicitly returns null.';
     }
 
+    // Text indicating the type of nullable value found.
+    String nullableValue;
+    if (node is NullLiteral) {
+      nullableValue = "an explicit 'null'";
+    } else if (origin.kind == EdgeOriginKind.dynamicAssignment) {
+      nullableValue = 'a dynamic value, which is nullable';
+    } else {
+      nullableValue = 'a nullable value';
+    }
+
     /// If the [node] is inside the return expression for a function body,
     /// return the function body. Otherwise return `null`.
     FunctionBody findFunctionBody() {
@@ -263,16 +263,19 @@ class InfoBuilder {
         return 'This field is initialized to $nullableValue';
       }
       return 'This variable is initialized to $nullableValue';
-    } else if (node is ConstructorDeclaration &&
-        origin.kind == EdgeOriginKind.fieldNotInitialized) {
-      String constructorName =
-          node.declaredElement.enclosingElement.displayName;
-      if (node.declaredElement.displayName.isNotEmpty) {
-        constructorName =
-            '$constructorName.${node.declaredElement.displayName}';
+    } else if (origin.kind == EdgeOriginKind.fieldNotInitialized) {
+      if (node is ConstructorDeclaration) {
+        String constructorName =
+            node.declaredElement.enclosingElement.displayName;
+        if (node.declaredElement.displayName.isNotEmpty) {
+          constructorName =
+              '$constructorName.${node.declaredElement.displayName}';
+        }
+        return "The constructor '$constructorName' does not initialize this "
+            'field in its initializer list';
+      } else {
+        return 'This field is not initialized';
       }
-      return "The constructor '$constructorName' does not initialize this "
-          'field in its initializer list';
     }
 
     String enclosingMemberDescription = buildEnclosingMemberDescription(node);

pkg/analysis_server/test/src/edit/nnbd_migration/info_builder_test.dart

@@ -1344,7 +1344,6 @@ class B extends A {
         details: ['A nullable value is assigned']);
   }
 
-  @FailingTest(issue: 'https://dartbug.com/40773')
   Future<void> test_parameter_fromOverriddenField_explicit() async {
     UnitInfo unit = await buildInfoForSingleTestFile('''
 class A {
@@ -1366,8 +1365,7 @@ void f(A a) => a.m = null;
     List<RegionInfo> regions = unit.fixRegions;
     expect(regions, hasLength(2));
     assertRegion(region: regions[0], offset: 15, details: [
-      // TODO(mfairhurst): Implement something similar to this error message
-      'No initializer is given',
+      'This field is not initialized',
       "An explicit 'null' is assigned in the function 'f'",
     ]);
     assertRegion(region: regions[1], offset: 61, details: [
@@ -1823,7 +1821,6 @@ class C {
     assertDetail(detail: region.details[2], offset: 70, length: 3);
   }
 
-  @FailingTest(issue: 'https://dartbug.com/40773')
   Future<void> test_uninitializedMember() async {
     UnitInfo unit = await buildInfoForSingleTestFile('''
 class C {
@@ -1837,10 +1834,11 @@ class C {
     List<RegionInfo> regions = unit.fixRegions;
     expect(regions, hasLength(1));
     expect(regions[0].details, isNotEmpty);
-    // disabled so that it won't interfere with @FailingTest annotation.
-    //assertRegion(region: regions[0], offset: 15, length: 1, details: [
-    //  'This field is not initialized and is therefore made nullable'
-    //]);
+    assertRegion(
+        region: regions[0],
+        offset: 15,
+        length: 1,
+        details: ['This field is not initialized']);
   }
 
   Future<void> test_uninitializedVariable_notLate_uninitializedUse() async {