[cfe] Remove Nullability.legacy

TEST=existing

Change-Id: Id924e4ef64ddabc1986cb885f558382ff139b481
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/436620
Reviewed-by: Mayank Patke <[email protected]>
Reviewed-by: Alexander Markov <[email protected]>
Commit-Queue: Chloe Stefantsova <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>
Reviewed-by: Nicholas Shahan <[email protected]>

Author: chloestefantsova

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

@@ -62,10 +62,6 @@ class DartTypeConverter extends ir.DartTypeVisitor<DartType> {
         return baseType;
       case ir.Nullability.nullable:
         return _dartTypes.nullableType(baseType);
-      case ir.Nullability.legacy:
-        throw UnsupportedError(
-          'Unexpected legacy nullability on $nullabilitySource',
-        );
       case ir.Nullability.undetermined:
         // Type parameters may have undetermined nullability since it is derived
         // from the intersection of the declared nullability with the

pkg/dart2bytecode/lib/bytecode_generator.dart

@@ -2100,8 +2100,9 @@ class BytecodeGenerator extends RecursiveVisitor {
       final targetTypeParameters = forwardingTarget.function!.typeParameters;
       assert(host.typeParameters.length == targetTypeParameters.length);
       for (int i = 0; i < targetTypeParameters.length; ++i) {
-        map[targetTypeParameters[i]] =
-            new TypeParameterType(host.typeParameters[i], Nullability.legacy);
+        map[targetTypeParameters[i]] = new TypeParameterType(
+            host.typeParameters[i],
+            host.typeParameters[i].computeNullabilityFromBound());
       }
     }
     return Substitution.fromMap(map);
@@ -2287,7 +2288,8 @@ class BytecodeGenerator extends RecursiveVisitor {
     final DartType bound = (forwardingTypeParameterBounds != null)
         ? forwardingTypeParameterBounds[typeParam]!
         : typeParam.bound;
-    final DartType type = new TypeParameterType(typeParam, Nullability.legacy);
+    final DartType type = new TypeParameterType(
+        typeParam, typeParam.computeNullabilityFromBound());
     _genPushInstantiatorAndFunctionTypeArguments([type, bound]);
     asm.emitPushConstant(cp.addType(type));
     asm.emitPushConstant(cp.addType(bound));

pkg/dart2bytecode/lib/object_table.dart

@@ -71,8 +71,6 @@ String objectKindToString(ObjectKind kind) =>
 
 String nullabilityToString(Nullability nullability) {
   switch (nullability) {
-    case Nullability.legacy:
-      return '*';
     case Nullability.nullable:
       return '?';
     case Nullability.undetermined:

pkg/dev_compiler/lib/src/kernel/future_or_normalizer.dart

@@ -43,17 +43,11 @@ class FutureOrNormalizer extends ReplacementVisitor {
         return typeArgument;
       case InterfaceType()
           when typeArgument.classNode == _coreTypes.objectClass:
-        // Normalize FutureOr of Object, Object?, Object*.
-        var nullable =
+        // Normalize FutureOr of Object, Object?.
+        var nullability =
             futureOr.nullability == Nullability.nullable ||
-            typeArgument.nullability == Nullability.nullable;
-        var legacy =
-            futureOr.nullability == Nullability.legacy ||
-            typeArgument.nullability == Nullability.legacy;
-        var nullability = nullable
+                typeArgument.nullability == Nullability.nullable
             ? Nullability.nullable
-            : legacy
-            ? Nullability.legacy
             : Nullability.nonNullable;
         return typeArgument.withDeclaredNullability(nullability);
       case NeverType() when typeArgument.nullability == Nullability.nonNullable:

pkg/dev_compiler/lib/src/kernel/type_recipe_generator.dart

@@ -587,8 +587,6 @@ class _TypeRecipeVisitor extends DartTypeVisitor<String> {
         return Recipe.wrapQuestionString;
       case Nullability.nonNullable:
         return '';
-      case Nullability.legacy:
-        throw UnsupportedError('Legacy nullability.');
     }
   }
 

pkg/dev_compiler/lib/src/kernel/type_table.dart

@@ -61,14 +61,9 @@ Set</* TypeParameter | StructuralParameter */ Object> freeTypeParameters(
 
 /// A name for a type made of JS identifier safe characters.
 ///
-/// 'L' and 'N' are appended to a type name to represent a legacy or nullable
-/// flavor of a type.
+/// 'N' is appended to a type name to represent a nullable flavor of a type.
 String _typeString(DartType type, {bool flat = false}) {
-  var nullability = type.declaredNullability == Nullability.legacy
-      ? 'L'
-      : type.declaredNullability == Nullability.nullable
-      ? 'N'
-      : '';
+  var nullability = type.declaredNullability == Nullability.nullable ? 'N' : '';
   switch (type) {
     case InterfaceType():
       var name = '${type.classNode.name}$nullability';

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

@@ -279,7 +279,6 @@ class ParsedType {
     if (type == ParsedTypeKind.Null) throw "No nullability on the null type";
     if (nullability == 0) return Nullability.nullable;
     if (nullability == 1) return Nullability.nonNullable;
-    if (nullability == 2) return Nullability.legacy;
     throw "Unknown nullability";
   }
 }

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

@@ -84,7 +84,6 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
   @override
   bool isNullClass = false;
 
-  InterfaceType? _legacyRawType;
   InterfaceType? _nullableRawType;
   InterfaceType? _nonNullableRawType;
   InterfaceType? _thisType;
@@ -105,12 +104,6 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
         getAsTypeArguments(cls.typeParameters, libraryBuilder.library));
   }
 
-  // Coverage-ignore(suite): Not run.
-  InterfaceType get legacyRawType {
-    return _legacyRawType ??= new InterfaceType(cls, Nullability.legacy,
-        new List<DartType>.filled(typeParametersCount, const DynamicType()));
-  }
-
   InterfaceType get nullableRawType {
     return _nullableRawType ??= new InterfaceType(cls, Nullability.nullable,
         new List<DartType>.filled(typeParametersCount, const DynamicType()));
@@ -125,9 +118,6 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
 
   InterfaceType rawType(Nullability nullability) {
     switch (nullability) {
-      case Nullability.legacy:
-        // Coverage-ignore(suite): Not run.
-        return legacyRawType;
       case Nullability.nullable:
         return nullableRawType;
       case Nullability.nonNullable:
@@ -243,7 +233,7 @@ abstract class ClassBuilderImpl extends DeclarationBuilderImpl
     if (arguments != null) {
       List<DartType> typeArguments =
           buildAliasedTypeArguments(library, arguments, /* hierarchy = */ null);
-      typeArguments = unaliasTypes(typeArguments, legacyEraseAliases: false)!;
+      typeArguments = unaliasTypes(typeArguments)!;
       return new Supertype(cls, typeArguments);
     } else {
       return new Supertype(

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

@@ -153,7 +153,7 @@ abstract class FunctionTypeBuilderImpl extends FunctionTypeBuilder {
   DartType _buildInternal(
       LibraryBuilder library, TypeUse typeUse, ClassHierarchyBase? hierarchy) {
     DartType aliasedType = buildAliased(library, typeUse, hierarchy);
-    return unalias(aliasedType, legacyEraseAliases: false);
+    return unalias(aliasedType);
   }
 
   @override

pkg/front_end/lib/src/builder/named_type_builder.dart

@@ -489,7 +489,7 @@ abstract class NamedTypeBuilderImpl extends NamedTypeBuilder {
             typeName.fullNameLength);
       }
     }
-    return unaliasing.unalias(aliasedType, legacyEraseAliases: false);
+    return unaliasing.unalias(aliasedType);
   }
 
   @override