[cfe] Remove EvaluationMode.legacy

This is no longer valid. Since the SDK is agnostic we should default to weak mode.

Change-Id: Ia9fbf911e7ebb595c93a71afe3bb8de7495cebba
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149065
Reviewed-by: Jens Johansen <jensj@google.com>

pkg/_fe_analyzer_shared/lib/src/sdk/allowed_experiments.dart

@@ -27,7 +27,7 @@ class AllowedExperiments {
   /// are enabled for all files of this package.
   final Map<String, List<String>> packageExperiments;
 
-  AllowedExperiments({
+  const AllowedExperiments({
     @required this.sdkDefaultExperiments,
     @required this.sdkLibraryExperiments,
     @required this.packageExperiments,

pkg/compiler/lib/src/ir/constants.dart

@@ -21,16 +21,17 @@ class Dart2jsConstantEvaluator extends ir.ConstantEvaluator {
       ir.TypeEnvironment typeEnvironment, ReportErrorFunction reportError,
       {Map<String, String> environment: const {},
       bool enableTripleShift = false,
-      bool supportReevaluationForTesting: false})
+      bool supportReevaluationForTesting: false,
+      ir.EvaluationMode evaluationMode})
       : _supportReevaluationForTesting = supportReevaluationForTesting,
-        // TODO(johnniwinther,sigmund): Pass evaluation mode for nnbd
-        //  strong/weak mode.
+        assert(evaluationMode != null),
         super(
             const Dart2jsConstantsBackend(supportsUnevaluatedConstants: false),
             environment,
             typeEnvironment,
             new ErrorReporter(reportError),
-            enableTripleShift: enableTripleShift);
+            enableTripleShift: enableTripleShift,
+            evaluationMode: evaluationMode);
 
   @override
   ErrorReporter get errorReporter => super.errorReporter;

pkg/compiler/lib/src/js_model/element_map_impl.dart

@@ -2,6 +2,7 @@
 // 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.
 
+import 'package:front_end/src/api_prototype/constant_evaluator.dart' as ir;
 import 'package:front_end/src/api_unstable/dart2js.dart' as ir;
 
 import 'package:kernel/ast.dart' as ir;
@@ -1184,7 +1185,10 @@ class JsKernelToElementMap implements JsToElementMap, IrToElementMap {
     },
         environment: _environment.toMap(),
         enableTripleShift:
-            options.languageExperiments[ir.ExperimentalFlag.tripleShift]);
+            options.languageExperiments[ir.ExperimentalFlag.tripleShift],
+        evaluationMode: options.nullSafetyMode == NullSafetyMode.sound
+            ? ir.EvaluationMode.strong
+            : ir.EvaluationMode.weak);
   }
 
   @override

pkg/compiler/lib/src/kernel/element_map_impl.dart

@@ -4,6 +4,7 @@
 
 library dart2js.kernel.element_map;
 
+import 'package:front_end/src/api_prototype/constant_evaluator.dart' as ir;
 import 'package:front_end/src/api_unstable/dart2js.dart' as ir;
 import 'package:js_runtime/shared/embedded_names.dart';
 import 'package:kernel/ast.dart' as ir;
@@ -817,7 +818,10 @@ class KernelToElementMapImpl implements KernelToElementMap, IrToElementMap {
     },
         environment: _environment.toMap(),
         enableTripleShift:
-            options.languageExperiments[ir.ExperimentalFlag.tripleShift]);
+            options.languageExperiments[ir.ExperimentalFlag.tripleShift],
+        evaluationMode: options.nullSafetyMode == NullSafetyMode.sound
+            ? ir.EvaluationMode.strong
+            : ir.EvaluationMode.weak);
   }
 
   @override

pkg/compiler/test/model/cfe_constant_evaluation_test.dart

@@ -20,6 +20,8 @@ import 'package:compiler/src/ir/constants.dart';
 import 'package:compiler/src/ir/visitors.dart';
 import 'package:compiler/src/kernel/kernel_strategy.dart';
 import 'package:compiler/src/kernel/element_map_impl.dart';
+import 'package:compiler/src/options.dart';
+import 'package:front_end/src/api_prototype/constant_evaluator.dart' as ir;
 import 'package:front_end/src/api_unstable/dart2js.dart' as ir;
 import 'package:kernel/ast.dart' as ir;
 import 'package:kernel/type_environment.dart' as ir;
@@ -686,7 +688,13 @@ Future testData(TestData data) async {
             // the "real error message" is the first in the context.
             errors.add(context.first.code.name);
             reportLocatedMessage(elementMap.reporter, message, context);
-          }, environment: environment, supportReevaluationForTesting: true);
+          },
+                  environment: environment,
+                  supportReevaluationForTesting: true,
+                  evaluationMode:
+                      compiler.options.nullSafetyMode == NullSafetyMode.sound
+                          ? ir.EvaluationMode.strong
+                          : ir.EvaluationMode.weak);
           ir.Constant evaluatedConstant = evaluator.evaluate(
               new ir.StaticTypeContext(node, typeEnvironment), initializer);
 

pkg/front_end/lib/src/api_prototype/experimental_flags.dart

@@ -5,8 +5,9 @@
 // NOTE: THIS FILE IS GENERATED. DO NOT EDIT.
 //
 // Instead modify 'tools/experimental_features.yaml' and run
-// 'pkg/front_end/tool/fasta generate-experimental-flags' to update.
+// 'dart pkg/front_end/tool/fasta.dart generate-experimental-flags' to update.
 
+import 'package:_fe_analyzer_shared/src/sdk/allowed_experiments.dart';
 import 'package:kernel/kernel.dart' show Version;
 
 enum ExperimentalFlag {
@@ -78,3 +79,8 @@ const Map<ExperimentalFlag, bool> expiredExperimentalFlags = {
   ExperimentalFlag.tripleShift: false,
   ExperimentalFlag.variance: false,
 };
+
+const AllowedExperiments allowedExperiments =
+    const AllowedExperiments(sdkDefaultExperiments: [
+  "non-nullable",
+], sdkLibraryExperiments: {}, packageExperiments: {});

pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart

@@ -128,7 +128,6 @@ void transformLibraries(
 }
 
 enum EvaluationMode {
-  legacy,
   weak,
   agnostic,
   strong,
@@ -764,7 +763,7 @@ class ConstantEvaluator extends RecursiveVisitor<Constant> {
       {this.desugarSets = false,
       this.enableTripleShift = false,
       this.errorOnUnevaluatedConstant = false,
-      this.evaluationMode: EvaluationMode.legacy})
+      this.evaluationMode: EvaluationMode.weak})
       : numberSemantics = backend.numberSemantics,
         coreTypes = typeEnvironment.coreTypes,
         canonicalizationCache = <Constant, Constant>{},
@@ -799,7 +798,6 @@ class ConstantEvaluator extends RecursiveVisitor<Constant> {
 
   DartType convertType(DartType type) {
     switch (evaluationMode) {
-      case EvaluationMode.legacy:
       case EvaluationMode.strong:
       case EvaluationMode.agnostic:
         return type;
@@ -812,7 +810,6 @@ class ConstantEvaluator extends RecursiveVisitor<Constant> {
 
   List<DartType> convertTypes(List<DartType> types) {
     switch (evaluationMode) {
-      case EvaluationMode.legacy:
       case EvaluationMode.strong:
       case EvaluationMode.agnostic:
         return types;
@@ -2182,7 +2179,6 @@ class ConstantEvaluator extends RecursiveVisitor<Constant> {
         }
         return makeBoolConstant(strongResult);
       case EvaluationMode.weak:
-      case EvaluationMode.legacy:
         return makeBoolConstant(performIs(constant, strongMode: false));
     }
     throw new UnsupportedError("Unexpected evaluation mode $evaluationMode");
@@ -2327,7 +2323,6 @@ class ConstantEvaluator extends RecursiveVisitor<Constant> {
         result = strongResult;
         break;
       case EvaluationMode.weak:
-      case EvaluationMode.legacy:
         result =
             isSubtype(constant, type, SubtypeCheckMode.ignoringNullabilities);
         break;

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

@@ -1095,20 +1095,23 @@ class KernelTarget extends TargetImplementation {
     TypeEnvironment environment =
         new TypeEnvironment(loader.coreTypes, loader.hierarchy);
     constants.EvaluationMode evaluationMode;
-    if (enableNonNullable) {
-      switch (loader.nnbdMode) {
-        case NnbdMode.Weak:
-          evaluationMode = constants.EvaluationMode.weak;
-          break;
-        case NnbdMode.Strong:
-          evaluationMode = constants.EvaluationMode.strong;
-          break;
-        case NnbdMode.Agnostic:
-          evaluationMode = constants.EvaluationMode.agnostic;
-          break;
-      }
-    } else {
-      evaluationMode = constants.EvaluationMode.legacy;
+    // If nnbd is not enabled we will use weak evaluation mode. This is needed
+    // because the SDK might be agnostic and therefore needs to be weakened
+    // for legacy mode.
+    assert(
+        enableNonNullable || loader.nnbdMode == NnbdMode.Weak,
+        "Non-weak nnbd mode found without experiment enabled: "
+        "${loader.nnbdMode}.");
+    switch (loader.nnbdMode) {
+      case NnbdMode.Weak:
+        evaluationMode = constants.EvaluationMode.weak;
+        break;
+      case NnbdMode.Strong:
+        evaluationMode = constants.EvaluationMode.strong;
+        break;
+      case NnbdMode.Agnostic:
+        evaluationMode = constants.EvaluationMode.agnostic;
+        break;
     }
 
     constants.transformLibraries(

pkg/front_end/test/fasta/testing/suite.dart

@@ -617,7 +617,8 @@ class Outline extends Step<TestDescription, ComponentResult, FastaContext> {
     TestOptions testOptions = context.computeTestOptions(description);
     Map<ExperimentalFlag, bool> experimentalFlags =
         testOptions.computeExperimentalFlags(context.experimentalFlags);
-    NnbdMode nnbdMode = context.weak
+    NnbdMode nnbdMode = context.weak ||
+            !experimentalFlags[ExperimentalFlag.nonNullable]
         ? NnbdMode.Weak
         : (testOptions.nnbdAgnosticMode ? NnbdMode.Agnostic : NnbdMode.Strong);
     List<Uri> inputs = <Uri>[description.uri];

pkg/front_end/test/spell_checking_list_code.txt

@@ -1205,6 +1205,7 @@ watch
 watcher
 wb
 wc
+weakened
 weakener
 weird
 weren't

pkg/front_end/tool/_fasta/generate_experimental_flags.dart

@@ -7,6 +7,8 @@ import 'dart:io' show File, Platform;
 import 'package:_fe_analyzer_shared/src/scanner/characters.dart'
     show $A, $MINUS, $a, $z;
 
+import 'package:_fe_analyzer_shared/src/sdk/allowed_experiments.dart';
+
 import 'package:dart_style/dart_style.dart' show DartFormatter;
 
 import 'package:yaml/yaml.dart' show YamlMap, loadYaml;
@@ -33,6 +35,11 @@ Uri computeYamlFile() {
       .resolve("../../../../tools/experimental_features.yaml");
 }
 
+Uri computeAllowListFile() {
+  return Platform.script
+      .resolve("../../../../sdk_nnbd/lib/_internal/allowed_experiments.json");
+}
+
 String generateKernelFile() {
   Uri yamlFile = computeYamlFile();
   Map<dynamic, dynamic> yaml =
@@ -57,7 +64,7 @@ String generateKernelFile() {
 // NOTE: THIS FILE IS GENERATED. DO NOT EDIT.
 //
 // Instead modify 'tools/experimental_features.yaml' and run
-// 'pkg/front_end/tool/fasta generate-experimental-flags' to update.
+// 'dart pkg/front_end/tool/fasta.dart generate-experimental-flags' to update.
 
 import "ast.dart";
 
@@ -91,8 +98,9 @@ String generateCfeFile() {
 // NOTE: THIS FILE IS GENERATED. DO NOT EDIT.
 //
 // Instead modify 'tools/experimental_features.yaml' and run
-// 'pkg/front_end/tool/fasta generate-experimental-flags' to update.
+// 'dart pkg/front_end/tool/fasta.dart generate-experimental-flags' to update.
 
+import 'package:_fe_analyzer_shared/src/sdk/allowed_experiments.dart';
 import 'package:kernel/kernel.dart' show Version;
 ''');
 
@@ -164,7 +172,44 @@ const Map<ExperimentalFlag, bool> expiredExperimentalFlags = {
     bool expired = (features[key] as YamlMap)['expired'] == true;
     sb.writeln('  ExperimentalFlag.${keyToIdentifier(key)}: ${expired},');
   }
-  sb.writeln('};');
+  sb.write('''
+};
+  
+''');
+
+  Uri allowListFile = computeAllowListFile();
+  AllowedExperiments allowedExperiments = parseAllowedExperiments(
+      new File.fromUri(allowListFile).readAsStringSync());
+
+  sb.write('''
+const AllowedExperiments allowedExperiments = const AllowedExperiments(
+''');
+  sb.writeln('sdkDefaultExperiments: [');
+  for (String sdkDefaultExperiment
+      in allowedExperiments.sdkDefaultExperiments) {
+    sb.writeln('"$sdkDefaultExperiment",');
+  }
+  sb.writeln('],');
+  sb.writeln('sdkLibraryExperiments: {');
+  allowedExperiments.sdkLibraryExperiments
+      .forEach((String library, List<String> experiments) {
+    sb.writeln('"$library": [');
+    for (String experiment in experiments) {
+      sb.writeln('"$experiment",');
+    }
+    sb.writeln('],');
+  });
+  sb.writeln('},');
+  sb.writeln('packageExperiments: {');
+  allowedExperiments.packageExperiments
+      .forEach((String package, List<String> experiments) {
+    sb.writeln('"$package": [');
+    for (String experiment in experiments) {
+      sb.writeln('"$experiment",');
+    }
+    sb.writeln('],');
+  });
+  sb.writeln('});');
 
   return new DartFormatter().format("$sb");
 }

pkg/front_end/tool/_fasta/generate_experimental_flags_test.dart

@@ -37,7 +37,7 @@ The generated file
   ${generatedFile.path}
 
 is out of date. To regenerate the file, run
-  pkg/front_end/tool/fasta generate-experimental-flags
+  dart pkg/front_end/tool/fasta.dart generate-experimental-flags
 
 ------------------------
 """);

pkg/front_end/tool/smoke_test_quick.dart

@@ -26,6 +26,9 @@ main(List<String> args) async {
   futures.add(
       run("pkg/front_end/test/lint_suite.dart", ["--", "lint/front_end/..."]));
   futures.add(run("pkg/front_end/test/deps_test.dart", [], filter: false));
+  futures.add(run(
+      "pkg/front_end/tool/_fasta/generate_experimental_flags_test.dart", [],
+      filter: false));
   await Future.wait(futures);
   print("\n-----------------------\n");
   print("Done with exitcode $exitCode in ${stopwatch.elapsedMilliseconds} ms");

pkg/kernel/bin/transform.dart

@@ -100,12 +100,8 @@ Future<CompilerOutcome> runTransformation(List<String> arguments) async {
       break;
     case 'constants':
       final VmConstantsBackend backend = new VmConstantsBackend(coreTypes);
-      component = constants.transformComponent(
-          component,
-          backend,
-          defines,
-          const constants.SimpleErrorReporter(),
-          constants.EvaluationMode.legacy);
+      component = constants.transformComponent(component, backend, defines,
+          const constants.SimpleErrorReporter(), constants.EvaluationMode.weak);
       break;
     case 'empty':
       component = empty.transformComponent(component);

pkg/kernel/lib/default_language_version.dart

@@ -5,7 +5,7 @@
 // NOTE: THIS FILE IS GENERATED. DO NOT EDIT.
 //
 // Instead modify 'tools/experimental_features.yaml' and run
-// 'pkg/front_end/tool/fasta generate-experimental-flags' to update.
+// 'dart pkg/front_end/tool/fasta.dart generate-experimental-flags' to update.
 
 import "ast.dart";