Make ParsedLibraryResult.units non-nullable.

Change-Id: I49ee1c8881c8c49f64404363c8e94e931e2968c3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/206562
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analyzer/CHANGELOG.md

@@ -1,5 +1,6 @@
 ## 2.1.0
 * Changed `AnalysisResult.path` to be non-nullable.
+* Changed `ParsedLibraryResult.units` to be non-nullable.
 
 ## 2.0.0
 * Removed deprecated `Scope.lookup2()`.

pkg/analyzer/lib/dart/analysis/results.dart

@@ -162,9 +162,7 @@ class NotPathOfUriResult
 abstract class ParsedLibraryResult
     implements SomeParsedLibraryResult, AnalysisResult {
   /// The parsed units of the library.
-  ///
-  /// TODO(migration): should not be null, probably empty list
-  List<ParsedUnitResult>? get units;
+  List<ParsedUnitResult> get units;
 
   /// Return the declaration of the [element], or `null` if the [element]
   /// is synthetic. Throw [ArgumentError] if the [element] is not defined in

pkg/analyzer/lib/src/dart/analysis/results.dart

@@ -76,7 +76,7 @@ class LibraryElementResultImpl implements LibraryElementResult {
 class ParsedLibraryResultImpl extends AnalysisResultImpl
     implements ParsedLibraryResult {
   @override
-  final List<ParsedUnitResult>? units;
+  final List<ParsedUnitResult> units;
 
   ParsedLibraryResultImpl(
       AnalysisSession session, String path, Uri uri, this.units)
@@ -101,7 +101,7 @@ class ParsedLibraryResultImpl extends AnalysisResultImpl
     }
 
     var elementPath = element.source!.fullName;
-    var unitResult = units!.firstWhere(
+    var unitResult = units.firstWhere(
       (r) => r.path == elementPath,
       orElse: () {
         var elementStr = element.getDisplayString(withNullability: true);

pkg/analyzer/test/src/dart/analysis/driver_test.dart

@@ -1403,10 +1403,10 @@ class B {}
     var result = driver.getParsedLibrary2(testFile);
     result as ParsedLibraryResult;
     expect(result.units, hasLength(1));
-    expect(result.units![0].path, testFile);
-    expect(result.units![0].content, content);
-    expect(result.units![0].unit, isNotNull);
-    expect(result.units![0].errors, isEmpty);
+    expect(result.units[0].path, testFile);
+    expect(result.units[0].content, content);
+    expect(result.units[0].unit, isNotNull);
+    expect(result.units[0].errors, isEmpty);
   }
 
   test_getParsedLibrary2_invalidPath_notAbsolute() async {
@@ -1429,9 +1429,9 @@ class B {}
     result as ParsedLibraryResult;
     expect(result.uri, uri);
     expect(result.units, hasLength(1));
-    expect(result.units![0].uri, uri);
-    expect(result.units![0].path, testFile);
-    expect(result.units![0].content, content);
+    expect(result.units[0].uri, uri);
+    expect(result.units[0].path, testFile);
+    expect(result.units[0].content, content);
   }
 
   test_getParsedLibraryByUri2_notLibrary() async {

pkg/analyzer/test/src/dart/analysis/session_test.dart

@@ -233,7 +233,7 @@ class B {}
 
     expect(parsedLibrary.units, hasLength(1));
     {
-      var parsedUnit = parsedLibrary.units![0];
+      var parsedUnit = parsedLibrary.units[0];
       expect(parsedUnit.session, session);
       expect(parsedUnit.path, testPath);
       expect(parsedUnit.uri, Uri.parse('package:test/test.dart'));
@@ -288,21 +288,21 @@ class C3 {}
     expect(parsedLibrary.units, hasLength(3));
 
     {
-      var aUnit = parsedLibrary.units![0];
+      var aUnit = parsedLibrary.units[0];
       expect(aUnit.path, a);
       expect(aUnit.uri, Uri.parse('package:test/a.dart'));
       expect(aUnit.unit.declarations, hasLength(1));
     }
 
     {
-      var bUnit = parsedLibrary.units![1];
+      var bUnit = parsedLibrary.units[1];
       expect(bUnit.path, b);
       expect(bUnit.uri, Uri.parse('package:test/b.dart'));
       expect(bUnit.unit.declarations, hasLength(2));
     }
 
     {
-      var cUnit = parsedLibrary.units![2];
+      var cUnit = parsedLibrary.units[2];
       expect(cUnit.path, c);
       expect(cUnit.uri, Uri.parse('package:test/c.dart'));
       expect(cUnit.unit.declarations, hasLength(3));
@@ -378,15 +378,15 @@ part 'c.dart';
 
     expect(parsedLibrary.units, hasLength(3));
     expect(
-      parsedLibrary.units![0].path,
+      parsedLibrary.units[0].path,
       convertPath('/home/test/lib/test.dart'),
     );
     expect(
-      parsedLibrary.units![1].path,
+      parsedLibrary.units[1].path,
       convertPath('/home/test/lib/a.dart'),
     );
     expect(
-      parsedLibrary.units![2].path,
+      parsedLibrary.units[2].path,
       convertPath('/home/test/lib/c.dart'),
     );
   }