Version 2.19.0-394.0.dev

Merge 29c3fea into dev

.github/workflows/no-response.yml

@@ -0,0 +1,33 @@
+# A workflow to close issues where the author hasn't responded to a request for
+# more information; see https://github.com/godofredoc/no-response for docs.
+
+name: No Response
+
+# Both `issue_comment` and `scheduled` event types are required.
+on:
+  issue_comment:
+    types: [created]
+  schedule:
+    # Schedule for five minutes after the hour, every hour
+    - cron: '5 * * * *'
+
+# All permissions not specified are set to 'none'.
+permissions:
+  issues: write
+
+jobs:
+  noResponse:
+    runs-on: ubuntu-latest
+    if: ${{ github.repository == 'dart-lang/sdk' }}
+    steps:
+      - uses: godofredoc/no-response@0ce2dc0e63e1c7d2b87752ceed091f6d32c9df09
+        with:
+          responseRequiredLabel: "needs-info"
+          responseRequiredColor: 4774bc
+          closeComment: >
+            Without additional information we're not able to resolve this
+            issue, so it will be closed at this time. You're still free to add
+            more info and respond to any questions above, though. We'll re-open
+            the case if you do. Thanks for your contribution!
+          daysUntilClose: 14
+          token: ${{ github.token }}

DEPS

@@ -150,7 +150,7 @@ vars = {
   "pool_rev": "1ea5b031cfda37786d305292cb8104dffb45d9ae",
   "protobuf_rev": "4af1cb3c4e116d02d3b3d005fd9d4995fbc4c564",
   "pub_rev": "6ac42d7644dedfcc500147ab47886eecab4b1b38", # manually rev'd
-  "pub_semver_rev": "5ac4c28f6d5f2ac737ed5443a3ffcb1d18e2b271",
+  "pub_semver_rev": "28159b8c5b96fc2709d0904389d7932880f68659", # b/258766867
   "root_certificates_rev": "692f6d6488af68e0121317a9c2c9eb393eb0ee50",
   "shelf_rev": "5fd2593d47120232054ebcc794f3a028d903f1f8",
   "source_map_stack_trace_rev": "8d8078fcc81c8f7936805cd277198493e0b7fc62",

OWNERS

@@ -1,6 +1,7 @@
 # Global approvers - only to be used as a last resort.
 [email protected] #{LAST_RESORT_SUGGESTION}
 [email protected] #{LAST_RESORT_SUGGESTION}
+[email protected] #{LAST_RESORT_SUGGESTION}
 [email protected] #{LAST_RESORT_SUGGESTION}
 [email protected] #{LAST_RESORT_SUGGESTION}
 [email protected] #{LAST_RESORT_SUGGESTION}

benchmarks/StringCompare/dart/LongStringCompare.dart

@@ -0,0 +1,46 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+//
+// Measure performance of string comparison.
+
+import 'package:benchmark_harness/benchmark_harness.dart';
+
+class LongStringCompare extends BenchmarkBase {
+  late String s, t;
+
+  String generateLongString() {
+    var s = "abcdefgh";
+    for (int i = 0; i < 20; i++) {
+      s = "$s ghijkl $s";
+    }
+    return s;
+  }
+
+  LongStringCompare() : super('LongStringCompare') {
+    s = generateLongString();
+    t = s;
+    // Difference in two strings goes in the middle.
+    s += "." + s;
+    t += "!" + t;
+  }
+
+  @override
+  void warmup() {
+    for (int i = 0; i < 4; i++) {
+      run();
+    }
+  }
+
+  @override
+  void run() {
+    bool b = true;
+    for (int i = 0; i < 5; i++) {
+      b &= (s == t);
+    }
+  }
+}
+
+void main() {
+  LongStringCompare().report();
+}

pkg/_fe_analyzer_shared/lib/src/type_inference/type_analyzer.dart

@@ -1064,12 +1064,12 @@ mixin TypeAnalyzer<
   ///
   /// Stack effect: none.
   Type analyzeVariablePattern(
-      Type matchedType,
-      MatchContext<Node, Expression, Pattern, Type, Variable> context,
-      Pattern node,
-      Variable? variable,
-      Type? declaredType,
-      {required bool isFinal}) {
+    Type matchedType,
+    MatchContext<Node, Expression, Pattern, Type, Variable> context,
+    Pattern node,
+    Variable? variable,
+    Type? declaredType,
+  ) {
     Type staticType =
         declaredType ?? variableTypeFromInitializerType(matchedType);
     Node? irrefutableContext = context.irrefutableContext;
@@ -1095,7 +1095,7 @@ mixin TypeAnalyzer<
         // TODO(paulberry): do we need to verify that all instances of a
         // variable are final or all are not final?
         flow?.initialize(variable, matchedType, context.getInitializer(node),
-            isFinal: context.isFinal || isFinal,
+            isFinal: context.isFinal || isVariableFinal(variable),
             isLate: context.isLate,
             isImplicitlyTyped: isImplicitlyTyped);
       }
@@ -1302,6 +1302,9 @@ mixin TypeAnalyzer<
   /// `default` clause.
   bool isSwitchExhaustive(Node node, Type expressionType);
 
+  /// Returns whether [node] is final.
+  bool isVariableFinal(Variable node);
+
   /// Queries whether [pattern] is a variable pattern.
   bool isVariablePattern(Node pattern);
 

pkg/_fe_analyzer_shared/test/mini_ast.dart

@@ -294,10 +294,9 @@ Statement while_(Expression condition, List<Statement> body) {
       location: location);
 }
 
-Pattern wildcard(
-        {String? type, String? expectInferredType, bool isFinal = false}) =>
+Pattern wildcard({String? type, String? expectInferredType}) =>
     _VariablePattern(type == null ? null : Type(type), null, expectInferredType,
-        isFinal: isFinal, location: computeLocation());
+        location: computeLocation());
 
 typedef SharedMatchContext
     = shared.MatchContext<Node, Expression, Pattern, Type, Var>;
@@ -1252,11 +1251,12 @@ abstract class TryStatement extends Statement implements TryBuilder {
 /// analysis testing.
 class Var extends Node implements Promotable {
   final String name;
+  final bool isFinal;
 
   /// The type of the variable, or `null` if it is not yet known.
   Type? _type;
 
-  Var(this.name) : super._(location: computeLocation());
+  Var(this.name, {this.isFinal = false}) : super._(location: computeLocation());
 
   /// Creates an L-value representing a reference to this variable.
   LValue get expr =>
@@ -1278,11 +1278,10 @@ class Var extends Node implements Promotable {
     _type = value;
   }
 
-  Pattern pattern(
-          {String? type, String? expectInferredType, bool isFinal = false}) =>
+  Pattern pattern({String? type, String? expectInferredType}) =>
       new _VariablePattern(
           type == null ? null : Type(type), this, expectInferredType,
-          isFinal: isFinal, location: computeLocation());
+          location: computeLocation());
 
   @override
   void preVisit(PreVisitor visitor) {}
@@ -3220,6 +3219,11 @@ class _MiniAstTypeAnalyzer
     return node.isExhaustive;
   }
 
+  @override
+  bool isVariableFinal(Var node) {
+    return node.isFinal;
+  }
+
   @override
   bool isVariablePattern(Node pattern) => pattern is _VariablePattern;
 
@@ -3925,10 +3929,8 @@ class _VariablePattern extends Pattern {
 
   final String? expectInferredType;
 
-  final bool isFinal;
-
   _VariablePattern(this.declaredType, this.variable, this.expectInferredType,
-      {this.isFinal = false, required super.location})
+      {required super.location})
       : super._();
 
   Type computeSchema(Harness h) =>
@@ -3949,8 +3951,7 @@ class _VariablePattern extends Pattern {
     SharedMatchContext context,
   ) {
     var staticType = h.typeAnalyzer.analyzeVariablePattern(
-        matchedType, context, this, variable, declaredType,
-        isFinal: isFinal);
+        matchedType, context, this, variable, declaredType);
     h.typeAnalyzer.handleVariablePattern(this,
         matchedType: matchedType, staticType: staticType);
   }

pkg/analysis_server/lib/src/services/correction/error_fix_status.yaml

@@ -1279,6 +1279,8 @@ HintCode.CAN_BE_NULL_AFTER_NULL_AWARE:
   status: hasFix
 HintCode.CAST_FROM_NULL_ALWAYS_FAILS:
   status: needsEvaluation
+HintCode.CAST_FROM_NULLABLE_ALWAYS_FAILS:
+  status: needsEvaluation
 HintCode.DEAD_CODE:
   status: hasFix
 HintCode.DEAD_CODE_CATCH_FOLLOWING_CATCH:

pkg/analysis_server/test/services/correction/name_suggestion_test.dart

@@ -18,8 +18,7 @@ void main() {
 class VariableNameSuggestionTest extends AbstractSingleUnitTest {
   Future<void> test_forExpression_cast() async {
     await resolveTestCode('''
-void f() {
-  var sortedNodes;
+void f(Object sortedNodes) {
   var res = sortedNodes as String;
 }
 ''');

pkg/analyzer/lib/src/dart/ast/ast.dart

@@ -13563,8 +13563,7 @@ class VariablePatternImpl extends DartPatternImpl implements VariablePattern {
     SharedMatchContext context,
   ) {
     resolverVisitor.analyzeVariablePattern(
-        matchedType, context, this, declaredElement, type?.typeOrThrow,
-        isFinal: keyword?.keyword == Keyword.FINAL);
+        matchedType, context, this, declaredElement, type?.typeOrThrow);
   }
 
   @override

pkg/analyzer/lib/src/dart/error/hint_codes.g.dart

@@ -66,6 +66,17 @@ class HintCode extends AnalyzerErrorCode {
     correctionMessage: "Replace the '.' with a '?.' in the invocation.",
   );
 
+  ///  Parameters:
+  ///  0: the name of the unassigned variable
+  static const HintCode CAST_FROM_NULLABLE_ALWAYS_FAILS = HintCode(
+    'CAST_FROM_NULLABLE_ALWAYS_FAILS',
+    "This cast will always throw an exception because the nullable local "
+        "variable '{0}' is not assigned.",
+    correctionMessage:
+        "Try giving it an initializer expression, or ensure that it's assigned "
+        "on every execution path.",
+  );
+
   ///  No parameters.
   static const HintCode CAST_FROM_NULL_ALWAYS_FAILS = HintCode(
     'CAST_FROM_NULL_ALWAYS_FAILS',

pkg/analyzer/lib/src/error/error_code_values.g.dart

@@ -545,6 +545,7 @@ const List<ErrorCode> errorCodeValues = [
   HintCode.BODY_MIGHT_COMPLETE_NORMALLY_CATCH_ERROR,
   HintCode.BODY_MIGHT_COMPLETE_NORMALLY_NULLABLE,
   HintCode.CAN_BE_NULL_AFTER_NULL_AWARE,
+  HintCode.CAST_FROM_NULLABLE_ALWAYS_FAILS,
   HintCode.CAST_FROM_NULL_ALWAYS_FAILS,
   HintCode.DEAD_CODE,
   HintCode.DEAD_CODE_CATCH_FOLLOWING_CATCH,

pkg/analyzer/lib/src/generated/resolver.dart

@@ -1067,6 +1067,11 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
   bool isSwitchExhaustive(AstNode node, DartType expressionType) =>
       switchExhaustiveness!.isExhaustive;
 
+  @override
+  bool isVariableFinal(PromotableElement element) {
+    return element.isFinal;
+  }
+
   @override
   bool isVariablePattern(AstNode pattern) => pattern is VariablePattern;
 
@@ -1570,6 +1575,24 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
     _insertImplicitCallReference(
         insertGenericFunctionInstantiation(node, contextType: contextType),
         contextType: contextType);
+
+    var expression = node.expression;
+    var staticType = node.staticType;
+    if (staticType != null && expression is SimpleIdentifier) {
+      var simpleIdentifier = expression as SimpleIdentifier;
+      var element = simpleIdentifier.staticElement;
+      if (element is PromotableElement &&
+          !expression.typeOrThrow.isDartCoreNull &&
+          typeSystem.isNullable(element.type) &&
+          typeSystem.isNonNullable(staticType) &&
+          flowAnalysis.isDefinitelyUnassigned(simpleIdentifier, element)) {
+        errorReporter.reportErrorForNode(
+          HintCode.CAST_FROM_NULLABLE_ALWAYS_FAILS,
+          simpleIdentifier,
+          [simpleIdentifier.name],
+        );
+      }
+    }
   }
 
   @override

pkg/analyzer/lib/src/workspace/blaze_watcher.dart

@@ -386,17 +386,20 @@ class BlazeSearchInfo {
 
 class BlazeWatcherError implements BlazeWatcherMessage {
   final String message;
+
   BlazeWatcherError(this.message);
 }
 
 class BlazeWatcherEvents implements BlazeWatcherMessage {
   final List<WatchEvent> events;
+
   BlazeWatcherEvents(this.events);
 }
 
 /// Sent by the watcher isolate to transfer the [SendPort] to the main isolate.
 class BlazeWatcherIsolateStarted implements BlazeWatcherMessage {
   final SendPort sendPort;
+
   BlazeWatcherIsolateStarted(this.sendPort);
 }
 
@@ -407,24 +410,28 @@ class BlazeWatcherShutdownIsolate implements BlazeWatcherMessage {}
 class BlazeWatcherStartWatching implements BlazeWatcherMessage {
   final String workspace;
   final BlazeSearchInfo info;
+
   BlazeWatcherStartWatching(this.workspace, this.info);
 }
 
 class BlazeWatcherStopWatching implements BlazeWatcherMessage {
   final String workspace;
   final String requestedPath;
+
   BlazeWatcherStopWatching(this.workspace, this.requestedPath);
 }
 
 class FileInfo {
   String path;
   _ModifiedInfo modified;
+
   FileInfo(this.path, this.modified);
 }
 
 /// Triggers polling every time something appears in the [stream].
 abstract class PollTrigger {
   Stream<Object> get stream;
+
   void cancel();
 }
 

pkg/analyzer/messages.yaml

@@ -19897,6 +19897,13 @@ HintCode:
     comment: |-
       No parameters.
     hasPublishedDocs: false
+  CAST_FROM_NULLABLE_ALWAYS_FAILS:
+    problemMessage: "This cast will always throw an exception because the nullable local variable '{0}' is not assigned."
+    correctionMessage: "Try giving it an initializer expression, or ensure that it's assigned on every execution path."
+    hasPublishedDocs: false
+    comment: |-
+      Parameters:
+      0: the name of the unassigned variable
   NULL_CHECK_ALWAYS_FAILS:
     problemMessage: "This null-check will always throw an exception because the expression will always evaluate to 'null'."
     comment: |-

pkg/analyzer/test/src/diagnostics/use_of_nullable_value_test.dart

@@ -361,12 +361,23 @@ m() {
     ]);
   }
 
-  test_as_nullable() async {
-    await assertNoErrorsInCode(r'''
-m() {
+  test_as_nullable_nonNullable() async {
+    await assertErrorsInCode(r'''
+void f() {
   num? x;
   x as int;
 }
+''', [
+      error(HintCode.CAST_FROM_NULLABLE_ALWAYS_FAILS, 23, 1),
+    ]);
+  }
+
+  test_as_nullable_nullable() async {
+    await assertNoErrorsInCode(r'''
+void f() {
+  num? x;
+  x as String?;
+}
 ''');
   }