Initial support for sealed classes

PiperOrigin-RevId: 400303125

27 files changed, 229 insertions, 8 deletions

diff --git a/java/com/google/turbine/binder/CanonicalTypeBinder.java b/java/com/google/turbine/binder/CanonicalTypeBinder.java
index cbdc025..944563f 100644
--- a/java/com/google/turbine/binder/CanonicalTypeBinder.java
+++ b/java/com/google/turbine/binder/CanonicalTypeBinder.java
@@ -67,6 +67,7 @@ public final class CanonicalTypeBinder {
     ImmutableList<FieldInfo> fields = fields(base.source(), env, sym, base.fields());
     return new SourceTypeBoundClass(
         interfaceTypes.build(),
+        base.permits(),
         superClassType,
         typParamTypes,
         base.access(),
diff --git a/java/com/google/turbine/binder/CompUnitPreprocessor.java b/java/com/google/turbine/binder/CompUnitPreprocessor.java
index 3323938..0e9f4e5 100644
--- a/java/com/google/turbine/binder/CompUnitPreprocessor.java
+++ b/java/com/google/turbine/binder/CompUnitPreprocessor.java
@@ -225,6 +225,7 @@ public final class CompUnitPreprocessor {
         ImmutableList.of(),
         ImmutableList.of(),
         ImmutableList.of(),
+        ImmutableList.of(),
         TurbineTyKind.INTERFACE,
         /* javadoc= */ null);
   }
diff --git a/java/com/google/turbine/binder/ConstBinder.java b/java/com/google/turbine/binder/ConstBinder.java
index 232370c..3ba059f 100644
--- a/java/com/google/turbine/binder/ConstBinder.java
+++ b/java/com/google/turbine/binder/ConstBinder.java
@@ -110,6 +110,7 @@ public class ConstBinder {
     ImmutableList<MethodInfo> methods = bindMethods(base.methods());
     return new SourceTypeBoundClass(
         bindTypes(base.interfaceTypes()),
+        base.permits(),
         base.superClassType() != null ? bindType(base.superClassType()) : null,
         bindTypeParameters(base.typeParameterTypes()),
         base.access(),
diff --git a/java/com/google/turbine/binder/DisambiguateTypeAnnotations.java b/java/com/google/turbine/binder/DisambiguateTypeAnnotations.java
index 4929962..65c1021 100644
--- a/java/com/google/turbine/binder/DisambiguateTypeAnnotations.java
+++ b/java/com/google/turbine/binder/DisambiguateTypeAnnotations.java
@@ -71,6 +71,7 @@ public final class DisambiguateTypeAnnotations {
       SourceTypeBoundClass base, Env<ClassSymbol, TypeBoundClass> env) {
     return new SourceTypeBoundClass(
         base.interfaceTypes(),
+        base.permits(),
         base.superClassType(),
         base.typeParameterTypes(),
         base.access(),
diff --git a/java/com/google/turbine/binder/TypeBinder.java b/java/com/google/turbine/binder/TypeBinder.java
index f4b4849..ccc0ad3 100644
--- a/java/com/google/turbine/binder/TypeBinder.java
+++ b/java/com/google/turbine/binder/TypeBinder.java
@@ -229,6 +229,15 @@ public class TypeBinder {
       interfaceTypes.add(bindClassTy(bindingScope, i));
     }
 
+    ImmutableList.Builder<ClassSymbol> permits = ImmutableList.builder();
+    for (Tree.ClassTy i : base.decl().permits()) {
+      Type type = bindClassTy(bindingScope, i);
+      if (!type.tyKind().equals(Type.TyKind.CLASS_TY)) {
+        throw new AssertionError(type.tyKind());
+      }
+      permits.add(((Type.ClassTy) type).sym());
+    }
+
     CompoundScope scope =
         base.scope()
             .toScope(Resolve.resolveFunction(env, owner))
@@ -251,6 +260,7 @@ public class TypeBinder {
 
     return new SourceTypeBoundClass(
         interfaceTypes.build(),
+        permits.build(),
         superClassType,
         typeParameterTypes,
         base.access(),
diff --git a/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java b/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java
index fb3ee27..5e9817e 100644
--- a/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java
+++ b/java/com/google/turbine/binder/bound/SourceTypeBoundClass.java
@@ -44,6 +44,7 @@ public class SourceTypeBoundClass implements TypeBoundClass {
   private final ImmutableMap<TyVarSymbol, TyVarInfo> typeParameterTypes;
   private final @Nullable Type superClassType;
   private final ImmutableList<Type> interfaceTypes;
+  private final ImmutableList<ClassSymbol> permits;
   private final ImmutableList<RecordComponentInfo> components;
   private final ImmutableList<MethodInfo> methods;
   private final ImmutableList<FieldInfo> fields;
@@ -57,6 +58,7 @@ public class SourceTypeBoundClass implements TypeBoundClass {
 
   public SourceTypeBoundClass(
       ImmutableList<Type> interfaceTypes,
+      ImmutableList<ClassSymbol> permits,
       @Nullable Type superClassType,
       ImmutableMap<TyVarSymbol, TyVarInfo> typeParameterTypes,
       int access,
@@ -75,6 +77,7 @@ public class SourceTypeBoundClass implements TypeBoundClass {
       SourceFile source,
       Tree.TyDecl decl) {
     this.interfaceTypes = interfaceTypes;
+    this.permits = permits;
     this.superClassType = superClassType;
     this.typeParameterTypes = typeParameterTypes;
     this.access = access;
@@ -117,6 +120,11 @@ public class SourceTypeBoundClass implements TypeBoundClass {
   }
 
   @Override
+  public ImmutableList<ClassSymbol> permits() {
+    return permits;
+  }
+
+  @Override
   public int access() {
     return access;
   }
diff --git a/java/com/google/turbine/binder/bound/TypeBoundClass.java b/java/com/google/turbine/binder/bound/TypeBoundClass.java
index cc28901..8321bde 100644
--- a/java/com/google/turbine/binder/bound/TypeBoundClass.java
+++ b/java/com/google/turbine/binder/bound/TypeBoundClass.java
@@ -18,6 +18,7 @@ package com.google.turbine.binder.bound;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.turbine.binder.sym.ClassSymbol;
 import com.google.turbine.binder.sym.FieldSymbol;
 import com.google.turbine.binder.sym.MethodSymbol;
 import com.google.turbine.binder.sym.ParamSymbol;
@@ -43,6 +44,9 @@ public interface TypeBoundClass extends HeaderBoundClass {
   /** Implemented interface types. */
   ImmutableList<Type> interfaceTypes();
 
+  /** The permitted direct subclasses. */
+  ImmutableList<ClassSymbol> permits();
+
   ImmutableMap<TyVarSymbol, TyVarInfo> typeParameterTypes();
 
   /** Declared fields. */
diff --git a/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java b/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java
index 516a027..9be2dd1 100644
--- a/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java
+++ b/java/com/google/turbine/binder/bytecode/BytecodeBoundClass.java
@@ -306,6 +306,11 @@ public class BytecodeBoundClass implements TypeBoundClass {
     return interfaceTypes.get();
   }
 
+  @Override
+  public ImmutableList<ClassSymbol> permits() {
+    return ImmutableList.of();
+  }
+
   private final Supplier<ImmutableMap<TyVarSymbol, TyVarInfo>> typeParameterTypes =
       Suppliers.memoize(
           new Supplier<ImmutableMap<TyVarSymbol, TyVarInfo>>() {
diff --git a/java/com/google/turbine/bytecode/Attribute.java b/java/com/google/turbine/bytecode/Attribute.java
index 581de3d..ad6ffc1 100644
--- a/java/com/google/turbine/bytecode/Attribute.java
+++ b/java/com/google/turbine/bytecode/Attribute.java
@@ -45,7 +45,8 @@ interface Attribute {
     NEST_HOST("NestHost"),
     NEST_MEMBERS("NestMembers"),
     RECORD("Record"),
-    TURBINE_TRANSITIVE_JAR("TurbineTransitiveJar");
+    TURBINE_TRANSITIVE_JAR("TurbineTransitiveJar"),
+    PERMITTED_SUBCLASSES("PermittedSubclasses");
 
     private final String signature;
 
@@ -396,6 +397,20 @@ interface Attribute {
     }
   }
 
+  /** A JVMS §4.7.31 PermittedSubclasses attribute. */
+  class PermittedSubclasses implements Attribute {
+    final List<String> permits;
+
+    public PermittedSubclasses(List<String> permits) {
+      this.permits = permits;
+    }
+
+    @Override
+    public Kind kind() {
+      return Kind.PERMITTED_SUBCLASSES;
+    }
+  }
+
   /** A custom attribute for recording the original jar of repackaged transitive classes. */
   class TurbineTransitiveJar implements Attribute {
 
diff --git a/java/com/google/turbine/bytecode/AttributeWriter.java b/java/com/google/turbine/bytecode/AttributeWriter.java
index ed7b2ab..6aac19a 100644
--- a/java/com/google/turbine/bytecode/AttributeWriter.java
+++ b/java/com/google/turbine/bytecode/AttributeWriter.java
@@ -95,6 +95,9 @@ public class AttributeWriter {
       case RECORD:
         writeRecord(output, (Attribute.Record) attribute);
         break;
+      case PERMITTED_SUBCLASSES:
+        writePermittedSubclasses(output, (Attribute.PermittedSubclasses) attribute);
+        break;
       case TURBINE_TRANSITIVE_JAR:
         writeTurbineTransitiveJar(output, (Attribute.TurbineTransitiveJar) attribute);
         break;
@@ -318,6 +321,16 @@ public class AttributeWriter {
     output.write(data);
   }
 
+  private void writePermittedSubclasses(
+      ByteArrayDataOutput output, Attribute.PermittedSubclasses attribute) {
+    output.writeShort(pool.utf8(attribute.kind().signature()));
+    output.writeInt(2 + attribute.permits.size() * 2);
+    output.writeShort(attribute.permits.size());
+    for (String permits : attribute.permits) {
+      output.writeShort(pool.classInfo(permits));
+    }
+  }
+
   private void writeTurbineTransitiveJar(
       ByteArrayDataOutput output, TurbineTransitiveJar attribute) {
     output.writeShort(pool.utf8(attribute.kind().signature()));
diff --git a/java/com/google/turbine/bytecode/ClassFile.java b/java/com/google/turbine/bytecode/ClassFile.java
index 124e03c..820f17d 100644
--- a/java/com/google/turbine/bytecode/ClassFile.java
+++ b/java/com/google/turbine/bytecode/ClassFile.java
@@ -37,6 +37,7 @@ public class ClassFile {
   private final @Nullable String signature;
   private final @Nullable String superClass;
   private final List<String> interfaces;
+  private final List<String> permits;
   private final List<MethodInfo> methods;
   private final List<FieldInfo> fields;
   private final List<AnnotationInfo> annotations;
@@ -55,6 +56,7 @@ public class ClassFile {
       @Nullable String signature,
       @Nullable String superClass,
       List<String> interfaces,
+      List<String> permits,
       List<MethodInfo> methods,
       List<FieldInfo> fields,
       List<AnnotationInfo> annotations,
@@ -71,6 +73,7 @@ public class ClassFile {
     this.signature = signature;
     this.superClass = superClass;
     this.interfaces = interfaces;
+    this.permits = permits;
     this.methods = methods;
     this.fields = fields;
     this.annotations = annotations;
@@ -113,6 +116,11 @@ public class ClassFile {
     return interfaces;
   }
 
+  /** The permitted direct subclasses. */
+  public List<String> permits() {
+    return permits;
+  }
+
   /** Methods declared by this class or interfaces type. */
   public List<MethodInfo> methods() {
     return methods;
diff --git a/java/com/google/turbine/bytecode/ClassReader.java b/java/com/google/turbine/bytecode/ClassReader.java
index b429032..0f08fc3 100644
--- a/java/com/google/turbine/bytecode/ClassReader.java
+++ b/java/com/google/turbine/bytecode/ClassReader.java
@@ -143,6 +143,7 @@ public class ClassReader {
         signature,
         superClass,
         interfaces,
+        /* permits= */ ImmutableList.of(),
         methodinfos,
         fieldinfos,
         annotations.build(),
diff --git a/java/com/google/turbine/bytecode/LowerAttributes.java b/java/com/google/turbine/bytecode/LowerAttributes.java
index 54937fc..8952dff 100644
--- a/java/com/google/turbine/bytecode/LowerAttributes.java
+++ b/java/com/google/turbine/bytecode/LowerAttributes.java
@@ -54,6 +54,9 @@ public final class LowerAttributes {
     if (classfile.record() != null) {
       attributes.add(recordAttribute(classfile.record()));
     }
+    if (!classfile.permits().isEmpty()) {
+      attributes.add(new Attribute.PermittedSubclasses(classfile.permits()));
+    }
     if (classfile.transitiveJar() != null) {
       attributes.add(new Attribute.TurbineTransitiveJar(classfile.transitiveJar()));
     }
diff --git a/java/com/google/turbine/deps/Transitive.java b/java/com/google/turbine/deps/Transitive.java
index 62d15c3..fa3d475 100644
--- a/java/com/google/turbine/deps/Transitive.java
+++ b/java/com/google/turbine/deps/Transitive.java
@@ -95,6 +95,7 @@ public final class Transitive {
         cf.signature(),
         cf.superName(),
         cf.interfaces(),
+        cf.permits(),
         // drop methods, except for annotations where we need to resolve key/value information
         (cf.access() & TurbineFlag.ACC_ANNOTATION) == TurbineFlag.ACC_ANNOTATION
             ? cf.methods()
diff --git a/java/com/google/turbine/lower/Lower.java b/java/com/google/turbine/lower/Lower.java
index 0f3eb24..ff7e13c 100644
--- a/java/com/google/turbine/lower/Lower.java
+++ b/java/com/google/turbine/lower/Lower.java
@@ -192,6 +192,7 @@ public class Lower {
             /* signature= */ null,
             /* superClass= */ null,
             /* interfaces= */ ImmutableList.of(),
+            /* permits= */ ImmutableList.of(),
             /* methods= */ ImmutableList.of(),
             /* fields= */ ImmutableList.of(),
             annotations,
@@ -259,6 +260,10 @@ public class Lower {
     for (ClassSymbol i : info.interfaces()) {
       interfaces.add(sig.descriptor(i));
     }
+    List<String> permits = new ArrayList<>();
+    for (ClassSymbol i : info.permits()) {
+      permits.add(sig.descriptor(i));
+    }
 
     ClassFile.RecordInfo record = null;
     if (info.kind().equals(TurbineTyKind.RECORD)) {
@@ -310,6 +315,7 @@ public class Lower {
             signature,
             superName,
             interfaces,
+            permits,
             methods,
             fields.build(),
             annotations,
diff --git a/java/com/google/turbine/model/TurbineFlag.java b/java/com/google/turbine/model/TurbineFlag.java
index c138d46..6e8d64b 100644
--- a/java/com/google/turbine/model/TurbineFlag.java
+++ b/java/com/google/turbine/model/TurbineFlag.java
@@ -55,5 +55,8 @@ public final class TurbineFlag {
   /** Synthetic constructors (e.g. of inner classes and enums). */
   public static final int ACC_SYNTH_CTOR = 1 << 18;
 
+  public static final int ACC_SEALED = 1 << 19;
+  public static final int ACC_NON_SEALED = 1 << 20;
+
   private TurbineFlag() {}
 }
diff --git a/java/com/google/turbine/parse/Parser.java b/java/com/google/turbine/parse/Parser.java
index 06b3db6..ed8958e 100644
--- a/java/com/google/turbine/parse/Parser.java
+++ b/java/com/google/turbine/parse/Parser.java
@@ -17,8 +17,10 @@
 package com.google.turbine.parse;
 
 import static com.google.turbine.parse.Token.COMMA;
+import static com.google.turbine.parse.Token.IDENT;
 import static com.google.turbine.parse.Token.INTERFACE;
 import static com.google.turbine.parse.Token.LPAREN;
+import static com.google.turbine.parse.Token.MINUS;
 import static com.google.turbine.parse.Token.RPAREN;
 import static com.google.turbine.parse.Token.SEMI;
 import static com.google.turbine.tree.TurbineModifier.PROTECTED;
@@ -187,12 +189,25 @@ public class Parser {
           {
             Ident ident = ident();
             if (ident.value().equals("record")) {
-              ident = eatIdent();
+              next();
               decls.add(recordDeclaration(access, annos.build()));
               access = EnumSet.noneOf(TurbineModifier.class);
               annos = ImmutableList.builder();
               break;
             }
+            if (ident.value().equals("sealed")) {
+              next();
+              access.add(TurbineModifier.SEALED);
+              break;
+            }
+            if (ident.value().equals("non")) {
+              int start = position;
+              next();
+              eatNonSealed(start);
+              next();
+              access.add(TurbineModifier.NON_SEALED);
+              break;
+            }
             if (access.isEmpty()
                 && (ident.value().equals("module") || ident.value().equals("open"))) {
               boolean open = false;
@@ -216,6 +231,22 @@ public class Parser {
     }
   }
 
+  // Handle the hypenated pseudo-keyword 'non-sealed'.
+  //
+  // This will need to be updated to handle other hyphenated keywords if when/they are introduced.
+  private void eatNonSealed(int start) {
+    eat(Token.MINUS);
+    if (token != IDENT) {
+      throw error(token);
+    }
+    if (!ident().value().equals("sealed")) {
+      throw error(token);
+    }
+    if (position != start + "non-".length()) {
+      throw error(token);
+    }
+  }
+
   private void next() {
     token = lexer.next();
     position = lexer.position();
@@ -255,6 +286,7 @@ public class Parser {
         typarams,
         Optional.<ClassTy>empty(),
         interfaces.build(),
+        /* permits= */ ImmutableList.of(),
         members,
         formals.build(),
         TurbineTyKind.RECORD,
@@ -279,6 +311,15 @@ public class Parser {
         interfaces.add(classty());
       } while (maybe(Token.COMMA));
     }
+    ImmutableList.Builder<ClassTy> permits = ImmutableList.builder();
+    if (token == Token.IDENT) {
+      if (ident().value().equals("permits")) {
+        eat(Token.IDENT);
+        do {
+          permits.add(classty());
+        } while (maybe(Token.COMMA));
+      }
+    }
     eat(Token.LBRACE);
     ImmutableList<Tree> members = classMembers();
     eat(Token.RBRACE);
@@ -290,6 +331,7 @@ public class Parser {
         typarams,
         Optional.<ClassTy>empty(),
         interfaces.build(),
+        permits.build(),
         members,
         ImmutableList.of(),
         TurbineTyKind.INTERFACE,
@@ -312,6 +354,7 @@ public class Parser {
         ImmutableList.<TyParam>of(),
         Optional.<ClassTy>empty(),
         ImmutableList.<ClassTy>of(),
+        ImmutableList.of(),
         members,
         ImmutableList.of(),
         TurbineTyKind.ANNOTATION,
@@ -342,6 +385,7 @@ public class Parser {
         ImmutableList.<TyParam>of(),
         Optional.<ClassTy>empty(),
         interfaces.build(),
+        ImmutableList.of(),
         members,
         ImmutableList.of(),
         TurbineTyKind.ENUM,
@@ -569,6 +613,15 @@ public class Parser {
         interfaces.add(classty());
       } while (maybe(Token.COMMA));
     }
+    ImmutableList.Builder<ClassTy> permits = ImmutableList.builder();
+    if (token == Token.IDENT) {
+      if (ident().value().equals("permits")) {
+        eat(Token.IDENT);
+        do {
+          permits.add(classty());
+        } while (maybe(Token.COMMA));
+      }
+    }
     switch (token) {
       case LBRACE:
         next();
@@ -588,6 +641,7 @@ public class Parser {
         tyParams,
         Optional.ofNullable(xtnds),
         interfaces.build(),
+        permits.build(),
         members,
         ImmutableList.of(),
         TurbineTyKind.CLASS,
@@ -665,8 +719,22 @@ public class Parser {
 
         case IDENT:
           Ident ident = ident();
+          if (ident.value().equals("non")) {
+            int pos = position;
+            next();
+            if (token != MINUS) {
+              acc.addAll(member(access, annos.build(), ImmutableList.of(), pos, ident));
+              access = EnumSet.noneOf(TurbineModifier.class);
+              annos = ImmutableList.builder();
+            } else {
+              eatNonSealed(pos);
+              next();
+              access.add(TurbineModifier.NON_SEALED);
+            }
+            break;
+          }
           if (ident.value().equals("record")) {
-            eat(Token.IDENT);
+            eat(IDENT);
             acc.add(recordDeclaration(access, annos.build()));
             access = EnumSet.noneOf(TurbineModifier.class);
             annos = ImmutableList.builder();
@@ -758,13 +826,13 @@ public class Parser {
       case IDENT:
         int pos = position;
         Ident ident = eatIdent();
-        return classMemberIdent(access, annos, typaram, pos, ident);
+        return member(access, annos, typaram, pos, ident);
       default:
         throw error(token);
     }
   }
 
-  private ImmutableList<Tree> classMemberIdent(
+  private ImmutableList<Tree> member(
       EnumSet<TurbineModifier> access,
       ImmutableList<Anno> annos,
       ImmutableList<TyParam> typaram,
@@ -820,6 +888,7 @@ public class Parser {
                 ImmutableList.<Type>of(),
                 ImmutableList.of());
         break;
+
       default:
         throw error(token);
     }
diff --git a/java/com/google/turbine/tree/Pretty.java b/java/com/google/turbine/tree/Pretty.java
index 84b4ab5..788ab58 100644
--- a/java/com/google/turbine/tree/Pretty.java
+++ b/java/com/google/turbine/tree/Pretty.java
@@ -459,6 +459,17 @@ public class Pretty implements Tree.Visitor<@Nullable Void, @Nullable Void> {
         first = false;
       }
     }
+    if (!tyDecl.permits().isEmpty()) {
+      append(" permits ");
+      boolean first = true;
+      for (Tree.ClassTy t : tyDecl.permits()) {
+        if (!first) {
+          append(", ");
+        }
+        t.accept(this, null);
+        first = false;
+      }
+    }
     append(" {").append('\n');
     indent++;
     switch (tyDecl.tykind()) {
@@ -522,6 +533,8 @@ public class Pretty implements Tree.Visitor<@Nullable Void, @Nullable Void> {
         case TRANSIENT:
         case DEFAULT:
         case TRANSITIVE:
+        case SEALED:
+        case NON_SEALED:
           append(mod.toString()).append(' ');
           break;
         case ACC_SUPER:
diff --git a/java/com/google/turbine/tree/Tree.java b/java/com/google/turbine/tree/Tree.java
index ce32628..f7917b9 100644
--- a/java/com/google/turbine/tree/Tree.java
+++ b/java/com/google/turbine/tree/Tree.java
@@ -934,6 +934,7 @@ public abstract class Tree {
     private final ImmutableList<TyParam> typarams;
     private final Optional<ClassTy> xtnds;
     private final ImmutableList<ClassTy> impls;
+    private final ImmutableList<ClassTy> permits;
     private final ImmutableList<Tree> members;
     private final ImmutableList<VarDecl> components;
     private final TurbineTyKind tykind;
@@ -947,6 +948,7 @@ public abstract class Tree {
         ImmutableList<TyParam> typarams,
         Optional<ClassTy> xtnds,
         ImmutableList<ClassTy> impls,
+        ImmutableList<ClassTy> permits,
         ImmutableList<Tree> members,
         ImmutableList<VarDecl> components,
         TurbineTyKind tykind,
@@ -958,6 +960,7 @@ public abstract class Tree {
       this.typarams = typarams;
       this.xtnds = xtnds;
       this.impls = impls;
+      this.permits = permits;
       this.members = members;
       this.components = components;
       this.tykind = tykind;
@@ -999,6 +1002,10 @@ public abstract class Tree {
       return impls;
     }
 
+    public ImmutableList<ClassTy> permits() {
+      return permits;
+    }
+
     public ImmutableList<Tree> members() {
       return members;
     }
diff --git a/java/com/google/turbine/tree/TurbineModifier.java b/java/com/google/turbine/tree/TurbineModifier.java
index 35dc11c..e5153b9 100644
--- a/java/com/google/turbine/tree/TurbineModifier.java
+++ b/java/com/google/turbine/tree/TurbineModifier.java
@@ -45,7 +45,9 @@ public enum TurbineModifier {
   ACC_SYNTHETIC(TurbineFlag.ACC_SYNTHETIC),
   ACC_BRIDGE(TurbineFlag.ACC_BRIDGE),
   DEFAULT(TurbineFlag.ACC_DEFAULT),
-  TRANSITIVE(TurbineFlag.ACC_TRANSITIVE);
+  TRANSITIVE(TurbineFlag.ACC_TRANSITIVE),
+  SEALED(TurbineFlag.ACC_SEALED),
+  NON_SEALED(TurbineFlag.ACC_NON_SEALED);
 
   private final int flag;
 
@@ -59,6 +61,6 @@ public enum TurbineModifier {
 
   @Override
   public String toString() {
-    return name().toLowerCase(ENGLISH);
+    return name().replace('_', '-').toLowerCase(ENGLISH);
   }
 }
diff --git a/javatests/com/google/turbine/bytecode/ClassWriterTest.java b/javatests/com/google/turbine/bytecode/ClassWriterTest.java
index 4ca5e36..a6f9234 100644
--- a/javatests/com/google/turbine/bytecode/ClassWriterTest.java
+++ b/javatests/com/google/turbine/bytecode/ClassWriterTest.java
@@ -186,6 +186,7 @@ public class ClassWriterTest {
             /* signature= */ null,
             /* superClass= */ "java/lang/Record",
             /* interfaces= */ ImmutableList.of(),
+            /* permits= */ ImmutableList.of(),
             /* methods= */ ImmutableList.of(),
             /* fields= */ ImmutableList.of(),
             /* annotations= */ ImmutableList.of(),
@@ -240,6 +241,7 @@ public class ClassWriterTest {
             /* signature= */ null,
             /* superClass= */ null,
             /* interfaces= */ ImmutableList.of(),
+            /* permits= */ ImmutableList.of(),
             /* methods= */ ImmutableList.of(),
             /* fields= */ ImmutableList.of(),
             /* annotations= */ ImmutableList.of(),
diff --git a/javatests/com/google/turbine/lower/LowerIntegrationTest.java b/javatests/com/google/turbine/lower/LowerIntegrationTest.java
index 9e16075..db73ec0 100644
--- a/javatests/com/google/turbine/lower/LowerIntegrationTest.java
+++ b/javatests/com/google/turbine/lower/LowerIntegrationTest.java
@@ -44,7 +44,9 @@ import org.junit.runners.Parameterized.Parameters;
 public class LowerIntegrationTest {
 
   private static final ImmutableMap<String, Integer> SOURCE_VERSION =
-      ImmutableMap.of("record.test", 16);
+      ImmutableMap.of(
+          "record.test", 16,
+          "sealed.test", 17);
 
   @Parameters(name = "{index}: {0}")
   public static Iterable<Object[]> parameters() {
@@ -60,6 +62,7 @@ public class LowerIntegrationTest {
       "B8148131.test",
       "abstractenum.test",
       "access1.test",
+      "ambiguous_identifier.test",
       "anno_const_coerce.test",
       "anno_const_scope.test",
       "anno_nested.test",
@@ -264,6 +267,7 @@ public class LowerIntegrationTest {
       "record.test",
       "rek.test",
       "samepkg.test",
+      "sealed.test",
       "self.test",
       "semi.test",
       // https://bugs.openjdk.java.net/browse/JDK-8054064 ?
diff --git a/javatests/com/google/turbine/lower/LowerTest.java b/javatests/com/google/turbine/lower/LowerTest.java
index e560321..c679228 100644
--- a/javatests/com/google/turbine/lower/LowerTest.java
+++ b/javatests/com/google/turbine/lower/LowerTest.java
@@ -185,6 +185,7 @@ public class LowerTest {
     SourceTypeBoundClass c =
         new SourceTypeBoundClass(
             interfaceTypes,
+            ImmutableList.of(),
             xtnds,
             tps,
             access,
@@ -206,6 +207,7 @@ public class LowerTest {
     SourceTypeBoundClass i =
         new SourceTypeBoundClass(
             ImmutableList.of(),
+            ImmutableList.of(),
             Type.ClassTy.OBJECT,
             ImmutableMap.of(),
             TurbineFlag.ACC_STATIC | TurbineFlag.ACC_PROTECTED,
diff --git a/javatests/com/google/turbine/lower/testdata/ambiguous_identifier.test b/javatests/com/google/turbine/lower/testdata/ambiguous_identifier.test
new file mode 100644
index 0000000..d7bbc54
--- /dev/null
+++ b/javatests/com/google/turbine/lower/testdata/ambiguous_identifier.test
@@ -0,0 +1,14 @@
+=== Test.java ===
+class Test {
+  static final int non = 42;
+  static final int sealed = 1;
+  // here 'non-sealed' is a binary expression subtracting two identifiers,
+  // not a contextual hyphenated keyword
+  static final int x = non-sealed;
+}
+
+// handle backtracking when we see 'non', but it isn't part of a contextualy
+// hyphenated keyword 'non-sealed'
+class non {
+  non self;
+}
diff --git a/javatests/com/google/turbine/lower/testdata/sealed.test b/javatests/com/google/turbine/lower/testdata/sealed.test
new file mode 100644
index 0000000..0bac7b1
--- /dev/null
+++ b/javatests/com/google/turbine/lower/testdata/sealed.test
@@ -0,0 +1,11 @@
+=== Sealed.java ===
+
+sealed class Sealed permits Sealed.Foo, Sealed.Bar {
+  static final class Foo extends Sealed {}
+  static final class Bar extends Sealed {}
+}
+
+sealed interface ISealed permits ISealed.Foo, ISealed.Bar {
+  static final class Foo implements ISealed {}
+  static non-sealed class Bar implements ISealed {}
+}
diff --git a/javatests/com/google/turbine/parse/ParserIntegrationTest.java b/javatests/com/google/turbine/parse/ParserIntegrationTest.java
index ade6bf0..2f37a84 100644
--- a/javatests/com/google/turbine/parse/ParserIntegrationTest.java
+++ b/javatests/com/google/turbine/parse/ParserIntegrationTest.java
@@ -76,6 +76,7 @@ public class ParserIntegrationTest {
       "type_annotations.input",
       "module-info.input",
       "record.input",
+      "sealed.input",
     };
     return Iterables.transform(
         Arrays.asList(tests),
diff --git a/javatests/com/google/turbine/parse/testdata/sealed.input b/javatests/com/google/turbine/parse/testdata/sealed.input
new file mode 100644
index 0000000..5a277b8
--- /dev/null
+++ b/javatests/com/google/turbine/parse/testdata/sealed.input
@@ -0,0 +1,15 @@
+sealed class Sealed permits Sealed.Foo, Sealed.Bar {
+  static final class Foo extends Sealed {
+  }
+
+  static final class Bar extends Sealed {
+  }
+}
+
+sealed interface ISealed permits ISealed.Foo, ISealed.Bar {
+  static final class Foo implements ISealed {
+  }
+
+  static non-sealed class Bar implements ISealed {
+  }
+}