[cfe] Remove LibraryBuilder.nullableBuilder et al.

Change-Id: I36b2a8c25568d4df90a6a1b039d15519d244be96
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/371123
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

pkg/front_end/lib/src/fasta/builder/builder_mixins.dart

@@ -49,7 +49,7 @@ mixin DeclarationBuilderMixin implements IDeclarationBuilder {
       {required bool hasExplicitTypeArguments}) {
     return buildAliasedTypeWithBuiltArguments(
         library,
-        nullabilityBuilder.build(library),
+        nullabilityBuilder.build(),
         buildAliasedTypeArguments(library, arguments, hierarchy),
         typeUse,
         fileUri,

pkg/front_end/lib/src/fasta/builder/builtin_type_declaration_builder.dart

@@ -26,7 +26,7 @@ abstract class BuiltinTypeDeclarationBuilder extends TypeDeclarationBuilderImpl
       int charOffset,
       ClassHierarchyBase? hierarchy,
       {required bool hasExplicitTypeArguments}) {
-    return type.withDeclaredNullability(nullabilityBuilder.build(library));
+    return type.withDeclaredNullability(nullabilityBuilder.build());
   }
 
   @override

pkg/front_end/lib/src/fasta/builder/class_builder.dart

@@ -379,7 +379,7 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
     }
     return buildAliasedTypeWithBuiltArguments(
         library,
-        nullabilityBuilder.build(library),
+        nullabilityBuilder.build(),
         buildAliasedTypeArguments(library, arguments, hierarchy),
         typeUse,
         fileUri,

pkg/front_end/lib/src/fasta/builder/function_type_builder.dart

@@ -175,8 +175,8 @@ abstract class FunctionTypeBuilderImpl extends FunctionTypeBuilder {
         t.bound?.build(library, TypeUse.typeParameterBound);
       }
     }
-    return new FunctionType(positionalParameters, builtReturnType,
+    return new FunctionType(
-        nullabilityBuilder.build(library),
+        positionalParameters, builtReturnType, nullabilityBuilder.build(),
         namedParameters: namedParameters ?? const <NamedType>[],
         typeParameters: typeParameters ?? const <StructuralParameter>[],
         requiredParameterCount: requiredParameterCount);

pkg/front_end/lib/src/fasta/builder/future_or_type_declaration_builder.dart

@@ -33,7 +33,7 @@ class FutureOrTypeDeclarationBuilder extends BuiltinTypeDeclarationBuilder {
     return new FutureOrType(
         arguments!.single
             .buildAliased(library, TypeUse.typeArgument, hierarchy),
-        nullabilityBuilder.build(library));
+        nullabilityBuilder.build());
   }
 
   @override

pkg/front_end/lib/src/fasta/builder/library_builder.dart

@@ -5,17 +5,11 @@
 library fasta.library_builder;
 
 import 'package:_fe_analyzer_shared/src/messages/severity.dart' show Severity;
-
+import 'package:kernel/ast.dart' show Class, Library;
-import 'package:kernel/ast.dart' show Class, Library, Nullability;
 
 import '../combinator.dart' show CombinatorBuilder;
-
-import '../problems.dart' show internalProblem;
-
 import '../export.dart' show Export;
-
 import '../loader.dart' show Loader;
-
 import '../messages.dart'
     show
         FormattedMessage,
@@ -24,9 +18,8 @@ import '../messages.dart'
         templateInternalProblemConstructorNotFound,
         templateInternalProblemNotFoundIn,
         templateInternalProblemPrivateConstructorAccess;
-
+import '../problems.dart' show internalProblem;
 import '../scope.dart';
-
 import '../source/name_scheme.dart';
 import '../source/offset_map.dart';
 import '../source/source_class_builder.dart';
@@ -39,7 +32,6 @@ import 'inferable_type_builder.dart';
 import 'member_builder.dart';
 import 'modifier_builder.dart';
 import 'name_iterator.dart';
-import 'nullability_builder.dart';
 import 'prefix_builder.dart';
 import 'type_builder.dart';
 
@@ -268,17 +260,6 @@ abstract class LibraryBuilder implements Builder {
   void recordAccess(
       CompilationUnit accessor, int charOffset, int length, Uri fileUri);
 
-  Nullability get nullable;
-
-  Nullability nullableIfTrue(bool isNullable);
-
-  NullabilityBuilder get nullableBuilder;
-
-  NullabilityBuilder get nonNullableBuilder;
-
-  /// Unused in interface; left in on purpose.
-  NullabilityBuilder nullableBuilderIfTrue(bool isNullable);
-
   /// Returns `true` if [cls] is the 'Function' class defined in [coreLibrary].
   static bool isFunction(Class cls, LibraryBuilder coreLibrary) {
     return cls.name == 'Function' && _isCoreClass(cls, coreLibrary);
@@ -474,33 +455,6 @@ abstract class LibraryBuilderImpl extends ModifierBuilderImpl
   void recordAccess(
       CompilationUnit accessor, int charOffset, int length, Uri fileUri) {}
 
-  @override
-  Nullability get nullable {
-    return Nullability.nullable;
-  }
-
-  @override
-  Nullability nullableIfTrue(bool isNullable) {
-    return isNullable ? Nullability.nullable : Nullability.nonNullable;
-  }
-
-  @override
-  NullabilityBuilder get nullableBuilder {
-    return const NullabilityBuilder.nullable();
-  }
-
-  @override
-  NullabilityBuilder get nonNullableBuilder {
-    return const NullabilityBuilder.omitted();
-  }
-
-  @override
-  NullabilityBuilder nullableBuilderIfTrue(bool isNullable) {
-    return isNullable
-        ? const NullabilityBuilder.nullable()
-        : const NullabilityBuilder.omitted();
-  }
-
   @override
   StringBuffer printOn(StringBuffer buffer) {
     return buffer..write(isPart || isAugmenting ? fileUri : importUri);

pkg/front_end/lib/src/fasta/builder/never_type_declaration_builder.dart

@@ -34,7 +34,7 @@ class NeverTypeDeclarationBuilder extends BuiltinTypeDeclarationBuilder {
       int charOffset,
       ClassHierarchyBase? hierarchy,
       {required bool hasExplicitTypeArguments}) {
-    return type.withDeclaredNullability(nullabilityBuilder.build(library));
+    return type.withDeclaredNullability(nullabilityBuilder.build());
   }
 
   @override

pkg/front_end/lib/src/fasta/builder/nullability_builder.dart

@@ -4,8 +4,6 @@
 
 import 'package:kernel/ast.dart';
 
-import 'library_builder.dart';
-
 /// Represents the nullability modifiers encountered while parsing the types.
 ///
 /// The syntactic nullability needs to be interpreted, that is, built, into the
@@ -48,7 +46,7 @@ class NullabilityBuilder {
     }
   }
 
-  Nullability build(LibraryBuilder libraryBuilder) {
+  Nullability build() {
     switch (_syntacticNullability) {
       case SyntacticNullability.nullable:
         return Nullability.nullable;

pkg/front_end/lib/src/fasta/builder/record_type_builder.dart

@@ -256,8 +256,8 @@ abstract class RecordTypeBuilderImpl extends RecordTypeBuilder {
 
     // TODO(johnniwinther): Should we create an [InvalidType] if there is <= 1
     // entries?
-    return new RecordType(positionalEntries, namedEntries ?? [],
+    return new RecordType(
-        nullabilityBuilder.build(library));
+        positionalEntries, namedEntries ?? [], nullabilityBuilder.build());
   }
 
   @override

pkg/front_end/lib/src/fasta/builder/type_alias_builder.dart

@@ -182,7 +182,7 @@ abstract class TypeAliasBuilderImpl extends TypeDeclarationBuilderImpl
     DartType thisType = buildThisType();
     if (thisType is InvalidType) return thisType;
 
-    Nullability nullability = nullabilityBuilder.build(library);
+    Nullability nullability = nullabilityBuilder.build();
     return buildAliasedTypeWithBuiltArguments(
         library,
         nullability,
@@ -373,7 +373,7 @@ abstract class TypeAliasBuilderImpl extends TypeDeclarationBuilderImpl
             if (typeVariables != null)
               for (NominalVariableBuilder typeVariable in typeVariables!)
                 new NamedTypeBuilderImpl.fromTypeDeclarationBuilder(
-                    typeVariable, libraryBuilder.nonNullableBuilder,
+                    typeVariable, const NullabilityBuilder.omitted(),
                     arguments: const [],
                     fileUri: fileUri,
                     charOffset: charOffset,

pkg/front_end/lib/src/fasta/builder/type_variable_builder.dart

@@ -366,7 +366,7 @@ class NominalVariableBuilder extends TypeVariableBuilderBase {
         nullability = nullabilityFromParameterBound;
       }
     } else {
-      nullability = nullabilityBuilder.build(library);
+      nullability = nullabilityBuilder.build();
     }
     TypeParameterType type = buildAliasedTypeWithBuiltArguments(
         library, nullability, null, typeUse, fileUri, charOffset,
@@ -403,7 +403,7 @@ class NominalVariableBuilder extends TypeVariableBuilderBase {
     if (isAugmenting) return;
     DartType objectType = object.buildAliasedType(
         library,
-        library.nullableBuilder,
+        const NullabilityBuilder.nullable(),
         /* arguments = */ null,
         TypeUse.typeParameterBound,
         fileUri ?? missingUri,
@@ -705,7 +705,7 @@ class StructuralVariableBuilder extends TypeVariableBuilderBase {
             StructuralParameterType.computeNullabilityFromBound(parameter);
       }
     } else {
-      nullability = nullabilityBuilder.build(library);
+      nullability = nullabilityBuilder.build();
     }
     StructuralParameterType type = buildAliasedTypeWithBuiltArguments(
         library, nullability, null, typeUse, fileUri, charOffset,
@@ -753,7 +753,7 @@ class StructuralVariableBuilder extends TypeVariableBuilderBase {
     if (isAugmenting) return;
     DartType objectType = object.buildAliasedType(
         library,
-        library.nullableBuilder,
+        const NullabilityBuilder.nullable(),
         /* arguments = */ null,
         TypeUse.typeParameterBound,
         fileUri ?? missingUri,

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

@@ -5052,7 +5052,9 @@ class BodyBuilder extends StackListenerImpl
       if (prefix is ParserErrorGenerator) {
         // An error have already been issued.
         push(prefix.buildTypeWithResolvedArgumentsDoNotAddProblem(
-            libraryBuilder.nullableBuilderIfTrue(isMarkedAsNullable)));
+            isMarkedAsNullable
+                ? const NullabilityBuilder.nullable()
+                : const NullabilityBuilder.omitted()));
         return;
       } else if (prefix is Generator) {
         name = prefix.qualifiedLookup(suffix);
@@ -5065,7 +5067,9 @@ class BodyBuilder extends StackListenerImpl
             message, offset, lengthOfSpan(beginToken, suffix), uri);
         push(new NamedTypeBuilderImpl.forInvalidType(
             name,
-            libraryBuilder.nullableBuilderIfTrue(isMarkedAsNullable),
+            isMarkedAsNullable
+                ? const NullabilityBuilder.nullable()
+                : const NullabilityBuilder.omitted(),
             message.withLocation(
                 uri, offset, lengthOfSpan(beginToken, suffix))));
         return;
@@ -5080,7 +5084,10 @@ class BodyBuilder extends StackListenerImpl
         allowPotentiallyConstantType = inIsOrAsOperatorType;
       }
       result = name.buildTypeWithResolvedArguments(
-          libraryBuilder.nullableBuilderIfTrue(isMarkedAsNullable), arguments,
+          isMarkedAsNullable
+              ? const NullabilityBuilder.nullable()
+              : const NullabilityBuilder.omitted(),
+          arguments,
           allowPotentiallyConstantType: allowPotentiallyConstantType,
           performTypeCanonicalization: constantContext != ConstantContext.none);
     } else if (name is ProblemBuilder) {
@@ -5089,7 +5096,9 @@ class BodyBuilder extends StackListenerImpl
           name.message, name.charOffset, name.name.length, name.fileUri);
       result = new NamedTypeBuilderImpl.forInvalidType(
           name.name,
-          libraryBuilder.nullableBuilderIfTrue(isMarkedAsNullable),
+          isMarkedAsNullable
+              ? const NullabilityBuilder.nullable()
+              : const NullabilityBuilder.omitted(),
           name.message
               .withLocation(name.fileUri, name.charOffset, name.name.length));
     } else {
@@ -5178,8 +5187,8 @@ class BodyBuilder extends StackListenerImpl
       positionalFields,
       namedFields,
       questionMark != null
-          ? libraryBuilder.nullableBuilder
+          ? const NullabilityBuilder.nullable()
-          : libraryBuilder.nonNullableBuilder,
+          : const NullabilityBuilder.omitted(),
       uri,
       leftBracket.charOffset,
     ));
@@ -5235,7 +5244,9 @@ class BodyBuilder extends StackListenerImpl
         pop() as List<StructuralVariableBuilder>?;
     TypeBuilder type = formals.toFunctionType(
         returnType ?? const ImplicitTypeBuilder(),
-        libraryBuilder.nullableBuilderIfTrue(questionMark != null),
+        questionMark != null
+            ? const NullabilityBuilder.nullable()
+            : const NullabilityBuilder.omitted(),
         structuralVariableBuilders: typeVariables,
         hasFunctionFormalParameterSyntax: false);
     exitLocalScope();
@@ -5547,7 +5558,9 @@ class BodyBuilder extends StackListenerImpl
         pop() as List<StructuralVariableBuilder>?;
     TypeBuilder type = formals.toFunctionType(
         returnType ?? const ImplicitTypeBuilder(),
-        libraryBuilder.nullableBuilderIfTrue(question != null),
+        question != null
+            ? const NullabilityBuilder.nullable()
+            : const NullabilityBuilder.omitted(),
         structuralVariableBuilders: typeVariables,
         hasFunctionFormalParameterSyntax: true);
     exitLocalScope();
@@ -9297,7 +9310,7 @@ class BodyBuilder extends StackListenerImpl
       expression = new Let(
           new VariableDeclaration.forValue(argument,
               isFinal: true,
-              type: coreTypes.objectRawType(libraryBuilder.nullable)),
+              type: coreTypes.objectRawType(Nullability.nullable)),
           expression);
     }
     return expression;

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

@@ -3064,7 +3064,7 @@ class TypeUseGenerator extends AbstractReadOnlyAccessGenerator {
             offsetForToken(token),
             _helper.buildDartType(
                 buildTypeWithResolvedArguments(
-                    _helper.libraryBuilder.nonNullableBuilder, typeArguments,
+                    const NullabilityBuilder.omitted(), typeArguments,
                     allowPotentiallyConstantType: true,
                     performTypeCanonicalization: true),
                 TypeUse.typeLiteral,

pkg/front_end/lib/src/fasta/kernel/macro/identifiers.dart

@@ -118,7 +118,7 @@ class TypeBuilderIdentifier extends IdentifierImpl {
       NullabilityBuilder nullabilityBuilder, List<DartType> typeArguments) {
     return typeBuilder.declaration!.buildAliasedTypeWithBuiltArguments(
         libraryBuilder,
-        nullabilityBuilder.build(libraryBuilder),
+        nullabilityBuilder.build(),
         typeArguments,
         TypeUse.macroTypeArgument,
         // TODO(johnniwinther): How should handle malbounded types here? Should
@@ -180,7 +180,7 @@ class TypeDeclarationBuilderIdentifier extends IdentifierImpl {
       NullabilityBuilder nullabilityBuilder, List<DartType> typeArguments) {
     return typeDeclarationBuilder.buildAliasedTypeWithBuiltArguments(
         libraryBuilder,
-        nullabilityBuilder.build(libraryBuilder),
+        nullabilityBuilder.build(),
         // TODO(johnniwinther): How should handle malbounded types here? Should
         // we report an error on the annotation?
         typeArguments,

pkg/front_end/lib/src/fasta/source/outline_builder.dart

@@ -1327,8 +1327,7 @@ class OutlineBuilder extends StackListenerImpl {
 
       String classNameForErrors = identifier.name;
       if (supertype != null) {
-        if (supertype.nullabilityBuilder.build(libraryBuilder) ==
+        if (supertype.nullabilityBuilder.build() == Nullability.nullable) {
-            Nullability.nullable) {
           libraryBuilder.addProblem(
               templateNullableSuperclassError
                   .withArguments(supertype.fullNameForErrors),
@@ -1340,8 +1339,7 @@ class OutlineBuilder extends StackListenerImpl {
       if (mixinApplication != null) {
         List<TypeBuilder>? mixins = mixinApplication.mixins;
         for (TypeBuilder mixin in mixins) {
-          if (mixin.nullabilityBuilder.build(libraryBuilder) ==
+          if (mixin.nullabilityBuilder.build() == Nullability.nullable) {
-              Nullability.nullable) {
             libraryBuilder.addProblem(
                 templateNullableMixinError
                     .withArguments(mixin.fullNameForErrors),
@@ -1353,8 +1351,7 @@ class OutlineBuilder extends StackListenerImpl {
       }
       if (interfaces != null) {
         for (TypeBuilder interface in interfaces) {
-          if (interface.nullabilityBuilder.build(libraryBuilder) ==
+          if (interface.nullabilityBuilder.build() == Nullability.nullable) {
-              Nullability.nullable) {
             libraryBuilder.addProblem(
                 templateNullableInterfaceError
                     .withArguments(interface.fullNameForErrors),
@@ -1437,8 +1434,7 @@ class OutlineBuilder extends StackListenerImpl {
       String classNameForErrors = identifier.name;
       if (supertypeConstraints != null) {
         for (TypeBuilder supertype in supertypeConstraints) {
-          if (supertype.nullabilityBuilder.build(libraryBuilder) ==
+          if (supertype.nullabilityBuilder.build() == Nullability.nullable) {
-              Nullability.nullable) {
             libraryBuilder.addProblem(
                 templateNullableSuperclassError
                     .withArguments(supertype.fullNameForErrors),
@@ -1450,8 +1446,7 @@ class OutlineBuilder extends StackListenerImpl {
       }
       if (interfaces != null) {
         for (TypeBuilder interface in interfaces) {
-          if (interface.nullabilityBuilder.build(libraryBuilder) ==
+          if (interface.nullabilityBuilder.build() == Nullability.nullable) {
-              Nullability.nullable) {
             libraryBuilder.addProblem(
                 templateNullableInterfaceError
                     .withArguments(interface.fullNameForErrors),
@@ -2515,8 +2510,7 @@ class OutlineBuilder extends StackListenerImpl {
           mixinApplication as MixinApplicationBuilder;
       List<TypeBuilder> mixins = mixinApplicationBuilder.mixins;
       if (supertype is TypeBuilder && supertype is! MixinApplicationBuilder) {
-        if (supertype.nullabilityBuilder.build(libraryBuilder) ==
+        if (supertype.nullabilityBuilder.build() == Nullability.nullable) {
-            Nullability.nullable) {
           libraryBuilder.addProblem(
               templateNullableSuperclassError
                   .withArguments(supertype.fullNameForErrors),
@@ -2526,8 +2520,7 @@ class OutlineBuilder extends StackListenerImpl {
         }
       }
       for (TypeBuilder mixin in mixins) {
-        if (mixin.nullabilityBuilder.build(libraryBuilder) ==
+        if (mixin.nullabilityBuilder.build() == Nullability.nullable) {
-            Nullability.nullable) {
           libraryBuilder.addProblem(
               templateNullableMixinError.withArguments(mixin.fullNameForErrors),
               identifier.nameOffset,
@@ -2537,8 +2530,7 @@ class OutlineBuilder extends StackListenerImpl {
       }
       if (interfaces != null) {
         for (TypeBuilder interface in interfaces) {
-          if (interface.nullabilityBuilder.build(libraryBuilder) ==
+          if (interface.nullabilityBuilder.build() == Nullability.nullable) {
-              Nullability.nullable) {
             libraryBuilder.addProblem(
                 templateNullableInterfaceError
                     .withArguments(interface.fullNameForErrors),
@@ -2622,7 +2614,9 @@ class OutlineBuilder extends StackListenerImpl {
       Identifier identifier = name as Identifier;
       push(libraryBuilder.addNamedType(
           identifier.typeName,
-          libraryBuilder.nullableBuilderIfTrue(isMarkedAsNullable),
+          isMarkedAsNullable
+              ? const NullabilityBuilder.nullable()
+              : const NullabilityBuilder.omitted(),
           arguments,
           identifier.qualifierOffset,
           instanceTypeVariableAccess:
@@ -3059,8 +3053,7 @@ class OutlineBuilder extends StackListenerImpl {
       }
       if (interfaces != null) {
         for (TypeBuilder interface in interfaces) {
-          if (interface.nullabilityBuilder.build(libraryBuilder) ==
+          if (interface.nullabilityBuilder.build() == Nullability.nullable) {
-              Nullability.nullable) {
             libraryBuilder.addProblem(
                 templateNullableInterfaceError
                     .withArguments(interface.fullNameForErrors),
@@ -3150,8 +3143,8 @@ class OutlineBuilder extends StackListenerImpl {
       positionalFields,
       namedFields,
       questionMark != null
-          ? libraryBuilder.nullableBuilder
+          ? const NullabilityBuilder.nullable()
-          : libraryBuilder.nonNullableBuilder,
+          : const NullabilityBuilder.omitted(),
       uri,
       leftBracket.charOffset,
     ));
@@ -3208,7 +3201,9 @@ class OutlineBuilder extends StackListenerImpl {
         returnType ?? const ImplicitTypeBuilder(),
         typeVariables,
         formals,
-        libraryBuilder.nullableBuilderIfTrue(questionMark != null),
+        questionMark != null
+            ? const NullabilityBuilder.nullable()
+            : const NullabilityBuilder.omitted(),
         uri,
         functionToken.charOffset,
         hasFunctionFormalParameterSyntax: false));
@@ -3227,7 +3222,9 @@ class OutlineBuilder extends StackListenerImpl {
         returnType ?? const ImplicitTypeBuilder(),
         typeVariables,
         formals,
-        libraryBuilder.nullableBuilderIfTrue(question != null),
+        question != null
+            ? const NullabilityBuilder.nullable()
+            : const NullabilityBuilder.omitted(),
         uri,
         formalsOffset,
         hasFunctionFormalParameterSyntax: true));
@@ -3311,8 +3308,7 @@ class OutlineBuilder extends StackListenerImpl {
       identifier = name as Identifier;
       if (type is FunctionTypeBuilder &&
           !libraryFeatures.nonfunctionTypeAliases.isEnabled) {
-        if (type.nullabilityBuilder.build(libraryBuilder) ==
+        if (type.nullabilityBuilder.build() == Nullability.nullable) {
-            Nullability.nullable) {
           // The error is reported when the non-nullable experiment is enabled.
           // Otherwise, the attempt to use a nullable type will be reported
           // elsewhere.

pkg/front_end/lib/src/fasta/type_inference/inference_visitor.dart

@@ -2194,7 +2194,9 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         element.expression,
         new InterfaceType(
             coreTypes.iterableClass,
-            libraryBuilder.nullableIfTrue(element.isNullAware),
+            element.isNullAware
+                ? Nullability.nullable
+                : Nullability.nonNullable,
             <DartType>[inferredTypeArgument]),
         isVoidAllowed: true);
     element.expression = spreadResult.expression..parent = element;
@@ -2601,8 +2603,9 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       DartType? spreadType = inferredSpreadTypes[item.expression];
       if (spreadType is DynamicType) {
         Expression expression = ensureAssignable(
-            coreTypes.iterableRawType(
+            coreTypes.iterableRawType(item.isNullAware
-                libraryBuilder.nullableIfTrue(item.isNullAware)),
+                ? Nullability.nullable
+                : Nullability.nonNullable),
             spreadType,
             item.expression);
         item.expression = expression..parent = item;
@@ -3032,7 +3035,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         temp = _createVariable(
             value,
             typeSchemaEnvironment.iterableType(
-                elementType, libraryBuilder.nullable));
+                elementType, Nullability.nullable));
         body.add(temp);
         value = _createNullCheckedVariableGet(temp);
       }
@@ -3059,7 +3062,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         temp = _createVariable(
             value,
             typeSchemaEnvironment.iterableType(
-                const DynamicType(), libraryBuilder.nullable));
+                const DynamicType(), Nullability.nullable));
         body.add(temp);
         value = _createNullCheckedVariableGet(temp);
       }
@@ -3382,7 +3385,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         temp = _createVariable(
             value,
             typeSchemaEnvironment.mapType(
-                keyType, valueType, libraryBuilder.nullable));
+                keyType, valueType, Nullability.nullable));
         body.add(temp);
         value = _createNullCheckedVariableGet(temp);
       }
@@ -3408,7 +3411,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         temp = _createVariable(
             value,
             typeSchemaEnvironment.mapType(const DynamicType(),
-                const DynamicType(), libraryBuilder.nullable));
+                const DynamicType(), Nullability.nullable));
         body.add(temp);
         value = _createNullCheckedVariableGet(temp);
       }
@@ -3510,7 +3513,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
           VariableDeclaration temp = _createVariable(
               spreadExpression,
               typeSchemaEnvironment.iterableType(
-                  elementType, libraryBuilder.nullable));
+                  elementType, Nullability.nullable));
           parts.add(_createNullAwareGuard(element.fileOffset, temp,
               makeLiteral(element.fileOffset, []), iterableType));
         } else {
@@ -3584,7 +3587,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
         Expression spreadExpression = entry.expression;
         if (entry.isNullAware) {
           VariableDeclaration temp = _createVariable(spreadExpression,
-              collectionType.withDeclaredNullability(libraryBuilder.nullable));
+              collectionType.withDeclaredNullability(Nullability.nullable));
           parts.add(_createNullAwareGuard(entry.fileOffset, temp,
               makeLiteral(entry.fileOffset, []), collectionType));
         } else {
@@ -4045,11 +4048,11 @@ class InferenceVisitorImpl extends InferenceVisitorBase
 
     bool isMap = typeSchemaEnvironment.isSubtypeOf(
         spreadType,
-        coreTypes.mapRawType(libraryBuilder.nullable),
+        coreTypes.mapRawType(Nullability.nullable),
         SubtypeCheckMode.withNullabilities);
     bool isIterable = typeSchemaEnvironment.isSubtypeOf(
         spreadType,
-        coreTypes.iterableRawType(libraryBuilder.nullable),
+        coreTypes.iterableRawType(Nullability.nullable),
         SubtypeCheckMode.withNullabilities);
     if (isMap && !isIterable) {
       offsets.mapSpreadOffset = entry.fileOffset;
@@ -4530,8 +4533,9 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       DartType? spreadType = inferredSpreadTypes[entry.expression];
       if (spreadType is DynamicType) {
         Expression expression = ensureAssignable(
-            coreTypes
+            coreTypes.mapRawType(entry.isNullAware
-                .mapRawType(libraryBuilder.nullableIfTrue(entry.isNullAware)),
+                ? Nullability.nullable
+                : Nullability.nonNullable),
             spreadType,
             entry.expression);
         entry.expression = expression..parent = entry;
@@ -6072,7 +6076,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
     DartType rightType =
         operations.getNullableType(equalsTarget.getBinaryOperandType(this));
     DartType contextType =
-        rightType.withDeclaredNullability(libraryBuilder.nullable);
+        rightType.withDeclaredNullability(Nullability.nullable);
     rightResult = ensureAssignableResult(contextType, rightResult,
         errorTemplate: templateArgumentTypeNotAssignable,
         nullabilityErrorTemplate: templateArgumentTypeNotAssignableNullability,
@@ -8986,7 +8990,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
       CheckLibraryIsLoaded node, DartType typeContext) {
     // TODO(cstefantsova): Figure out the suitable nullability for that.
     return new ExpressionInferenceResult(
-        coreTypes.objectRawType(libraryBuilder.nullable), node);
+        coreTypes.objectRawType(Nullability.nullable), node);
   }
 
   ExpressionInferenceResult visitEquals(

pkg/front_end/lib/src/fasta/type_inference/inference_visitor_base.dart

@@ -2097,7 +2097,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
                   formalTypesFromContext[i]!);
           if (typeSchemaEnvironment.isSubtypeOf(inferredType, const NullType(),
               SubtypeCheckMode.withNullabilities)) {
-            inferredType = coreTypes.objectRawType(libraryBuilder.nullable);
+            inferredType = coreTypes.objectRawType(Nullability.nullable);
           }
         } else {
           inferredType = const DynamicType();
@@ -3381,7 +3381,7 @@ abstract class InferenceVisitorBase implements InferenceVisitor {
       // operator == always allows nullable arguments.
       functionType = new FunctionType([
         functionType.positionalParameters.single
-            .withDeclaredNullability(libraryBuilder.nullable)
+            .withDeclaredNullability(Nullability.nullable)
       ], functionType.returnType, functionType.declaredNullability);
     }
     InvocationInferenceResult result = inferInvocation(

pkg/front_end/test/coverage_suite_expected.dart

@@ -185,9 +185,9 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 17,
     missCount: 3,
   ),
-  // 80.85106382978722%.
+  // 79.7752808988764%.
   "package:front_end/src/fasta/builder/library_builder.dart": (
-    hitCount: 76,
+    hitCount: 71,
     missCount: 18,
   ),
   // 97.38562091503267%.
@@ -250,9 +250,9 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 151,
     missCount: 44,
   ),
-  // 78.99159663865547%.
+  // 78.8135593220339%.
   "package:front_end/src/fasta/builder/type_alias_builder.dart": (
-    hitCount: 188,
+    hitCount: 186,
     missCount: 50,
   ),
   // 77.77777777777779%.
@@ -265,9 +265,9 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 9,
     missCount: 1,
   ),
-  // 78.42227378190255%.
+  // 78.32167832167832%.
   "package:front_end/src/fasta/builder/type_variable_builder.dart": (
-    hitCount: 338,
+    hitCount: 336,
     missCount: 93,
   ),
   // 100.0%.
@@ -421,9 +421,9 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 0,
     missCount: 128,
   ),
-  // 91.26941617568292%.
+  // 91.24832214765101%.
   "package:front_end/src/fasta/kernel/body_builder.dart": (
-    hitCount: 6816,
+    hitCount: 6798,
     missCount: 652,
   ),
   // 70.40816326530613%.
@@ -471,9 +471,9 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 478,
     missCount: 163,
   ),
-  // 79.56411876184461%.
+  // 79.54473601011698%.
   "package:front_end/src/fasta/kernel/expression_generator.dart": (
-    hitCount: 2519,
+    hitCount: 2516,
     missCount: 647,
   ),
   // 100.0%.
@@ -589,7 +589,7 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
   // 0.0%.
   "package:front_end/src/fasta/kernel/macro/identifiers.dart": (
     hitCount: 0,
-    missCount: 134,
+    missCount: 132,
   ),
   // 0.0%.
   "package:front_end/src/fasta/kernel/macro/introspectors.dart": (
@@ -706,9 +706,9 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 118,
     missCount: 6,
   ),
-  // 91.45299145299145%.
+  // 91.38284776364382%.
   "package:front_end/src/fasta/source/outline_builder.dart": (
-    hitCount: 2247,
+    hitCount: 2227,
     missCount: 210,
   ),
   // 94.44444444444444%.
@@ -827,14 +827,14 @@ const Map<String, ({int hitCount, int missCount})> _expect = {
     hitCount: 166,
     missCount: 29,
   ),
-  // 90.25658807212206%.
+  // 90.25040575005796%.
   "package:front_end/src/fasta/type_inference/inference_visitor.dart": (
-    hitCount: 7809,
+    hitCount: 7785,
-    missCount: 843,
+    missCount: 841,
   ),
-  // 84.56303724928367%.
+  // 84.54088952654233%.
   "package:front_end/src/fasta/type_inference/inference_visitor_base.dart": (
-    hitCount: 2361,
+    hitCount: 2357,
     missCount: 431,
   ),
   // 80.26509572901325%.