[nnbd_migration] Add a description for type parameter instantiation

MichaelRFairhurst · commit-bot@chromium.org · commit c0bcfb7d0ce5 · 2020-02-28T23:26:22.000Z
Change-Id: Id8e3c4c98f3569b794e90d8a7a74d245f6f89504 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/137648 Reviewed-by: Janice Collins <jcollins@google.com> Reviewed-by: Paul Berry <paulberry@google.com>
diff --git a/pkg/analysis_server/lib/src/edit/nnbd_migration/info_builder.dart b/pkg/analysis_server/lib/src/edit/nnbd_migration/info_builder.dart
@@ -179,6 +179,9 @@ class InfoBuilder {
       return 'A length is specified in the "List()" constructor and the list '
           'items are initialized to null';
     }
+    if (origin.kind == EdgeOriginKind.typeParameterInstantiation) {
+      return 'This type parameter is instantiated with a nullable type';
+    }
 
     CompilationUnit unit = node.thisOrAncestorOfType<CompilationUnit>();
     int lineNumber = unit.lineInfo.getLocation(node.offset).lineNumber;
diff --git a/pkg/analysis_server/test/src/edit/nnbd_migration/info_builder_test.dart b/pkg/analysis_server/test/src/edit/nnbd_migration/info_builder_test.dart
@@ -280,6 +280,24 @@ int? f([num? a]) {
         details: ['The value of the expression is nullable']);
   }
 
+  Future<void> test_bound() async {
+    UnitInfo unit = await buildInfoForSingleTestFile('''
+class C<T extends Object> {}
+
+C<int/*?*/> c;
+''', migratedContent: '''
+class C<T extends Object?> {}
+
+C<int?/*?*/>? c;
+''');
+    List<RegionInfo> regions = unit.regions;
+    expect(regions, hasLength(3));
+    assertRegion(
+        region: regions[0],
+        offset: 24,
+        details: ['This type parameter is instantiated with a nullable type']);
+  }
+
   Future<void> test_discardCondition() async {
     UnitInfo unit = await buildInfoForSingleTestFile('''
 void g(int i) {

Original file line number	Diff line number	Diff line change
`@@ -179,6 +179,9 @@ class InfoBuilder {`
`179`	`179`	`return 'A length is specified in the "List()" constructor and the list '`
`180`	`180`	`'items are initialized to null';`
`181`	`181`	`}`
	`182`	`+ if (origin.kind == EdgeOriginKind.typeParameterInstantiation) {`
	`183`	`+ return 'This type parameter is instantiated with a nullable type';`
	`184`	`+ }`
`182`	`185`
`183`	`186`	`CompilationUnit unit = node.thisOrAncestorOfType<CompilationUnit>();`
`184`	`187`	`int lineNumber = unit.lineInfo.getLocation(node.offset).lineNumber;`