Enforce that abstract members are implemented

This adds a check that abstract members must be implemented.
If any members lack an implementation, an error is thrown describing
the missing members.

Also: we have a bug in `pkl:base`; class `Set` does not implement all
members of class `Collection`.

.github/workflows/__lockfile__.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: nothing
     steps:
     - name: EnricoMi/publish-unit-test-result-action@v2
-      uses: EnricoMi/publish-unit-test-result-action@d0a4676d0e0b938bc201470d88276b7c74c712b3 # v2
+      uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
     - name: actions/checkout@v6
       uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
     - name: actions/create-github-app-token@v2

.github/workflows/build.yml

@@ -949,7 +949,7 @@ jobs:
         pattern: test-results-xml-*
     - name: Publish test results
       if: '!cancelled()'
-      uses: EnricoMi/publish-unit-test-result-action@d0a4676d0e0b938bc201470d88276b7c74c712b3 # v2
+      uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
       with:
         comment_mode: 'off'
         files: test-results-xml-*/**/*.xml

.github/workflows/main.yml

@@ -1018,7 +1018,7 @@ jobs:
         pattern: test-results-xml-*
     - name: Publish test results
       if: '!cancelled()'
-      uses: EnricoMi/publish-unit-test-result-action@d0a4676d0e0b938bc201470d88276b7c74c712b3 # v2
+      uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
       with:
         comment_mode: 'off'
         files: test-results-xml-*/**/*.xml

.github/workflows/release-branch.yml

@@ -947,7 +947,7 @@ jobs:
         pattern: test-results-xml-*
     - name: Publish test results
       if: '!cancelled()'
-      uses: EnricoMi/publish-unit-test-result-action@d0a4676d0e0b938bc201470d88276b7c74c712b3 # v2
+      uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
       with:
         comment_mode: 'off'
         files: test-results-xml-*/**/*.xml

.github/workflows/release.yml

@@ -1043,7 +1043,7 @@ jobs:
         pattern: test-results-xml-*
     - name: Publish test results
       if: '!cancelled()'
-      uses: EnricoMi/publish-unit-test-result-action@d0a4676d0e0b938bc201470d88276b7c74c712b3 # v2
+      uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
       with:
         comment_mode: 'off'
         files: test-results-xml-*/**/*.xml

.github/workflows/test_report.yml

@@ -25,7 +25,7 @@ jobs:
         name_is_regexp: true
         run_id: ${{ github.event.workflow_run.id }}
     - name: Publish test results
-      uses: EnricoMi/publish-unit-test-result-action@d0a4676d0e0b938bc201470d88276b7c74c712b3 # v2
+      uses: EnricoMi/publish-unit-test-result-action@c950f6fb443cb5af20a377fd0dfaa78838901040 # v2
       with:
         commit: ${{ github.event.workflow_run.head_sha }}
         comment_mode: 'off'

build-logic/src/main/kotlin/InstallGraalVm.kt

@@ -13,13 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import java.nio.file.AtomicMoveNotSupportedException
 import java.nio.file.Files
-import java.nio.file.Path
 import java.nio.file.Paths
 import java.nio.file.StandardCopyOption
 import java.util.*
-import java.util.zip.ZipInputStream
 import javax.inject.Inject
 import kotlin.io.path.createDirectories
 import org.gradle.api.DefaultTask
@@ -44,14 +41,19 @@ constructor(
   @TaskAction
   @Suppress("unused")
   fun run() {
-    // minimize chance of corruption by extract-to-random-dir-and-publish
+    // minimize chance of corruption by extract-to-random-dir-and-flip-symlink
     val distroDir = Paths.get(graalVm.get().homeDir, UUID.randomUUID().toString())
     try {
       distroDir.createDirectories()
       println("Extracting ${graalVm.get().downloadFile} into $distroDir")
-      val os = org.gradle.internal.os.OperatingSystem.current()
-      if (os.isWindows) extractZip(distroDir) else extractTarGz(distroDir)
+      // faster and more reliable than Gradle's `copy { from tarTree() }`
+      execOperations.exec {
+        workingDir = distroDir.toFile()
+        executable = "tar"
+        args("--strip-components=1", "-xzf", graalVm.get().downloadFile)
+      }
 
+      val os = org.gradle.internal.os.OperatingSystem.current()
       val distroBinDir =
         if (os.isMacOsX) distroDir.resolve("Contents/Home/bin") else distroDir.resolve("bin")
 
@@ -68,7 +70,17 @@ constructor(
         }
       }
 
-      publishInstallDir(distroDir, os)
+      println("Creating symlink ${graalVm.get().installDir} for $distroDir")
+      val tempLink = Paths.get(graalVm.get().homeDir, UUID.randomUUID().toString())
+      Files.createSymbolicLink(tempLink, distroDir)
+      try {
+        Files.move(tempLink, graalVm.get().installDir.toPath(), StandardCopyOption.ATOMIC_MOVE)
+      } catch (e: Exception) {
+        try {
+          fileOperations.delete(tempLink.toFile())
+        } catch (ignored: Exception) {}
+        throw e
+      }
     } catch (e: Exception) {
       try {
         fileOperations.delete(distroDir)
@@ -76,75 +88,4 @@ constructor(
       throw e
     }
   }
-
-  private fun extractTarGz(distroDir: Path) {
-    // faster and more reliable than Gradle's `copy { from tarTree() }`
-    execOperations.exec {
-      workingDir = distroDir.toFile()
-      executable = "tar"
-      args("--strip-components=1", "-xzf", graalVm.get().downloadFile)
-    }
-  }
-
-  private fun extractZip(distroDir: Path) {
-    val targetDir = distroDir.toAbsolutePath().normalize()
-    ZipInputStream(graalVm.get().downloadFile.inputStream().buffered()).use { zipInput ->
-      var entry = zipInput.nextEntry
-      while (entry != null) {
-        try {
-          val strippedPath = stripFirstPathComponent(entry.name)
-          if (strippedPath != null) {
-            val target = targetDir.resolve(strippedPath).normalize()
-            require(target.startsWith(targetDir)) {
-              "GraalVM archive entry escapes destination directory: ${entry.name}"
-            }
-            if (entry.isDirectory) {
-              target.createDirectories()
-            } else {
-              target.parent?.createDirectories()
-              Files.copy(zipInput, target)
-            }
-          }
-        } finally {
-          zipInput.closeEntry()
-        }
-        entry = zipInput.nextEntry
-      }
-    }
-  }
-
-  private fun stripFirstPathComponent(path: String): String? {
-    val normalizedPath = path.replace('\\', '/').trimStart('/')
-    val separatorIndex = normalizedPath.indexOf('/')
-    if (separatorIndex == -1) return null
-    return normalizedPath.substring(separatorIndex + 1).takeIf { it.isNotEmpty() }
-  }
-
-  private fun publishInstallDir(distroDir: Path, os: org.gradle.internal.os.OperatingSystem) {
-    if (os.isWindows) {
-      println("Installing ${graalVm.get().installDir} from $distroDir")
-      moveAtomicallyOrRegularly(distroDir, graalVm.get().installDir.toPath())
-      return
-    }
-
-    println("Creating symlink ${graalVm.get().installDir} for $distroDir")
-    val tempLink = Paths.get(graalVm.get().homeDir, UUID.randomUUID().toString())
-    Files.createSymbolicLink(tempLink, distroDir)
-    try {
-      moveAtomicallyOrRegularly(tempLink, graalVm.get().installDir.toPath())
-    } catch (e: Exception) {
-      try {
-        fileOperations.delete(tempLink.toFile())
-      } catch (ignored: Exception) {}
-      throw e
-    }
-  }
-
-  private fun moveAtomicallyOrRegularly(source: Path, target: Path) {
-    try {
-      Files.move(source, target, StandardCopyOption.ATOMIC_MOVE)
-    } catch (e: AtomicMoveNotSupportedException) {
-      Files.move(source, target)
-    }
-  }
 }

docs/modules/ROOT/partials/component-attributes.adoc

@@ -69,7 +69,6 @@ endif::[]
 
 :uri-stdlib-baseModule: {uri-pkl-stdlib-docs}/base
 :uri-stdlib-CommandModule: {uri-pkl-stdlib-docs}/Command
-:uri-stdlib-refModule: {uri-pkl-stdlib-docs}/ref
 :uri-stdlib-analyzeModule: {uri-pkl-stdlib-docs}/analyze
 :uri-stdlib-jsonnetModule: {uri-pkl-stdlib-docs}/jsonnet
 :uri-stdlib-reflectModule: {uri-pkl-stdlib-docs}/reflect
@@ -161,8 +160,6 @@ endif::[]
 :uri-stdlib-Command-CountedFlag: {uri-stdlib-CommandModule}/CountedFlag
 :uri-stdlib-Command-Argument: {uri-stdlib-CommandModule}/Argument
 :uri-stdlib-Command-Import: {uri-stdlib-CommandModule}/Import
-:uri-stdlib-ref-Reference: {uri-stdlib-baseModule}/Reference
-:uri-stdlib-ref-Access: {uri-stdlib-baseModule}/Access
 
 :uri-messagepack: https://msgpack.org/index.html
 :uri-messagepack-spec: https://github.com/msgpack/msgpack/blob/master/spec.md

docs/modules/bindings-specification/pages/binary-encoding.adoc

@@ -187,15 +187,7 @@ The array's length is the number of slots that are filled. For example, xref:{ur
 |
 |
 |
-
-|link:{uri-stdlib-ref-Reference}[Reference]
-|`0x20`
-|`<value>` (Typed)
-|Domain
-|`<value>`
-|Data
-|link:{uri-messagepack-array}[array]
-|Array of link:{uri-stdlib-ref-Access}[`pkl.ref#Access`] values
+|===
 
 [[type-name-encoding]]
 [NOTE]

gradle/libs.versions.toml

@@ -5,7 +5,7 @@ checksumPlugin = "1.4.0"
 clikt = "5.0.3"
 commonMark = "0.28.0"
 downloadTaskPlugin = "5.7.0"
-errorProne = "2.50.0"
+errorProne = "2.49.0"
 errorPronePlugin = "5.1.0"
 geantyref = "2.0.1"
 #noinspection UnusedVersionCatalogEntry
@@ -54,7 +54,7 @@ ktfmt = "0.62"
 log4j = "2.17.1"
 msgpack = "0.9.12"
 nexusPublishPlugin = "2.0.0"
-nullaway = "0.13.6"
+nullaway = "0.13.4"
 nullawayPlugin = "3.0.0"
 nuValidator = "26.5.29"
 paguro = "3.10.3"

pkl-core/src/main/java/org/pkl/core/PClass.java

@@ -27,7 +27,6 @@ public final class PClass extends Member implements Value {
   private final List<TypeParameter> typeParameters;
   private final Map<String, Property> properties;
   private final Map<String, Method> methods;
-  private final @Nullable PClass moduleClass;
 
   private @Nullable PType supertype;
   private @Nullable PClass superclass;
@@ -43,14 +42,12 @@ public final class PClass extends Member implements Value {
       PClassInfo<?> classInfo,
       List<TypeParameter> typeParameters,
       Map<String, Property> properties,
-      Map<String, Method> methods,
-      @Nullable PClass moduleClass) {
+      Map<String, Method> methods) {
     super(docComment, sourceLocation, modifiers, annotations, classInfo.getSimpleName());
     this.classInfo = classInfo;
     this.typeParameters = typeParameters;
     this.properties = properties;
     this.methods = methods;
-    this.moduleClass = moduleClass;
   }
 
   public void initSupertype(PType supertype, PClass superclass) {
@@ -60,7 +57,7 @@ public final class PClass extends Member implements Value {
 
   /**
    * Returns the name of the module that this class is declared in. Note that a module name is not
-   * guaranteed to be unique, especially if it is not declared but inferred from the module URI.
+   * guaranteed to be unique, especially if it not declared but inferred from the module URI.
    */
   public String getModuleName() {
     return classInfo.getModuleName();
@@ -122,11 +119,6 @@ public final class PClass extends Member implements Value {
     return allMethods;
   }
 
-  /** Returns the class's containing module's class, or this class if it is a module class. */
-  public PClass getModuleClass() {
-    return moduleClass != null ? moduleClass : this;
-  }
-
   @Override
   public void accept(ValueVisitor visitor) {
     visitor.visitClass(this);
@@ -146,10 +138,6 @@ public final class PClass extends Member implements Value {
     return getDisplayName();
   }
 
-  public boolean isSubclassOf(PClass other) {
-    return this == other || getSuperclass() != null && getSuperclass().isSubclassOf(other);
-  }
-
   public abstract static class ClassMember extends Member {
     @Serial private static final long serialVersionUID = 0L;
 

pkl-core/src/main/java/org/pkl/core/PClassInfo.java

@@ -39,7 +39,6 @@ public final class PClassInfo<T> implements Serializable {
   public static final URI pklSemverUri = URI.create("pkl:semver");
   public static final URI pklSettingsUri = URI.create("pkl:settings");
   public static final URI pklProjectUri = URI.create("pkl:Project");
-  public static final URI pklRefUri = URI.create("pkl:ref");
 
   public static final PClassInfo<Void> Any = pklBaseClassInfo("Any", Void.class);
   public static final PClassInfo<PNull> Null = pklBaseClassInfo("Null", PNull.class);
@@ -83,11 +82,9 @@ public final class PClassInfo<T> implements Serializable {
   public static final PClassInfo<PObject> Version =
       new PClassInfo<>("pkl.semver", "Version", PObject.class, pklSemverUri);
   public static final PClassInfo<PObject> Project =
-      new PClassInfo<>("pkl.Project", MODULE_CLASS_NAME, PObject.class, pklProjectUri);
+      new PClassInfo<>("pkl.Project", "ModuleClass", PObject.class, pklProjectUri);
   public static final PClassInfo<PObject> Settings =
-      new PClassInfo<>("pkl.settings", MODULE_CLASS_NAME, PObject.class, pklSettingsUri);
-  public static final PClassInfo<Reference> Reference =
-      new PClassInfo<>("pkl.ref", "Reference", Reference.class, pklRefUri);
+      new PClassInfo<>("pkl.settings", "ModuleClass", PObject.class, pklSettingsUri);
 
   public static final PClassInfo<Object> Unavailable =
       new PClassInfo<>("unavailable", "unavailable", Object.class, URI.create("pkl:unavailable"));

pkl-core/src/main/java/org/pkl/core/PType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,6 @@ package org.pkl.core;
 import java.io.Serial;
 import java.io.Serializable;
 import java.util.*;
-import java.util.stream.Collectors;
 
 /** A Pkl type as used in type annotations. */
 public abstract class PType implements Serializable {
@@ -28,33 +27,18 @@ public abstract class PType implements Serializable {
   public static final PType UNKNOWN =
       new PType() {
         @Serial private static final long serialVersionUID = 0L;
-
-        @Override
-        public String toString() {
-          return "unknown";
-        }
       };
 
   /** The bottom type. */
   public static final PType NOTHING =
       new PType() {
         @Serial private static final long serialVersionUID = 0L;
-
-        @Override
-        public String toString() {
-          return "nothing";
-        }
       };
 
   /** The type of the enclosing module. */
   public static final PType MODULE =
       new PType() {
         @Serial private static final long serialVersionUID = 0L;
-
-        @Override
-        public String toString() {
-          return "module";
-        }
       };
 
   private PType() {}
@@ -75,22 +59,6 @@ public abstract class PType implements Serializable {
     public String getLiteral() {
       return literal;
     }
-
-    @Override
-    public String toString() {
-      return ValueFormatter.basic().formatStringValue(literal, "");
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof StringLiteral that && literal.equals(that.literal);
-    }
-
-    @Override
-    public int hashCode() {
-      return literal.hashCode();
-    }
   }
 
   public static final class Class extends PType {
@@ -124,31 +92,6 @@ public abstract class PType implements Serializable {
     public List<PType> getTypeArguments() {
       return typeArguments;
     }
-
-    @Override
-    public String toString() {
-      var result = pClass.getDisplayName();
-      if (!typeArguments.isEmpty()) {
-        result +=
-            "<"
-                + typeArguments.stream().map(Object::toString).collect(Collectors.joining(", "))
-                + ">";
-      }
-      return result;
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof Class that
-          && pClass.equals(that.pClass)
-          && typeArguments.equals(that.typeArguments);
-    }
-
-    @Override
-    public int hashCode() {
-      return 31 * pClass.hashCode() + typeArguments.hashCode();
-    }
   }
 
   public static final class Nullable extends PType {
@@ -163,24 +106,6 @@ public abstract class PType implements Serializable {
     public PType getBaseType() {
       return baseType;
     }
-
-    @Override
-    public String toString() {
-      return baseType instanceof Function || baseType instanceof Union
-          ? "(" + baseType + ")?"
-          : baseType + "?";
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof Nullable that && baseType.equals(that.baseType);
-    }
-
-    @Override
-    public int hashCode() {
-      return baseType.hashCode();
-    }
   }
 
   public static final class Constrained extends PType {
@@ -201,29 +126,6 @@ public abstract class PType implements Serializable {
     public List<String> getConstraints() {
       return constraints;
     }
-
-    @Override
-    public String toString() {
-      return (baseType instanceof Function || baseType instanceof Union
-              ? "(" + baseType + ")"
-              : baseType)
-          + "("
-          + String.join(", ", constraints)
-          + ")";
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof Constrained that
-          && baseType.equals(that.baseType)
-          && constraints.equals(that.constraints);
-    }
-
-    @Override
-    public int hashCode() {
-      return 31 * baseType.hashCode() + constraints.hashCode();
-    }
   }
 
   public static final class Alias extends PType {
@@ -259,31 +161,6 @@ public abstract class PType implements Serializable {
     public PType getAliasedType() {
       return aliasedType;
     }
-
-    @Override
-    public String toString() {
-      var result = typeAlias.getDisplayName();
-      if (!typeArguments.isEmpty()) {
-        result +=
-            "<"
-                + typeArguments.stream().map(Object::toString).collect(Collectors.joining(", "))
-                + ">";
-      }
-      return result;
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof Alias that
-          && typeAlias.equals(that.typeAlias)
-          && typeArguments.equals(that.typeArguments);
-    }
-
-    @Override
-    public int hashCode() {
-      return 31 * typeAlias.hashCode() + typeArguments.hashCode();
-    }
   }
 
   public static final class Function extends PType {
@@ -304,27 +181,6 @@ public abstract class PType implements Serializable {
     public PType getReturnType() {
       return returnType;
     }
-
-    @Override
-    public String toString() {
-      return "("
-          + parameterTypes.stream().map(Object::toString).collect(Collectors.joining(", "))
-          + ") -> "
-          + returnType;
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof Function that
-          && parameterTypes.equals(that.parameterTypes)
-          && returnType.equals(that.returnType);
-    }
-
-    @Override
-    public int hashCode() {
-      return 31 * parameterTypes.hashCode() + returnType.hashCode();
-    }
   }
 
   public static final class Union extends PType {
@@ -339,22 +195,6 @@ public abstract class PType implements Serializable {
     public List<PType> getElementTypes() {
       return elementTypes;
     }
-
-    @Override
-    public String toString() {
-      return elementTypes.stream().map(Object::toString).collect(Collectors.joining(" | "));
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof Union that && elementTypes.equals(that.elementTypes);
-    }
-
-    @Override
-    public int hashCode() {
-      return elementTypes.hashCode();
-    }
   }
 
   public static final class TypeVariable extends PType {
@@ -373,21 +213,5 @@ public abstract class PType implements Serializable {
     public TypeParameter getTypeParameter() {
       return typeParameter;
     }
-
-    @Override
-    public String toString() {
-      return typeParameter.getName();
-    }
-
-    @Override
-    public boolean equals(@org.jspecify.annotations.Nullable Object obj) {
-      if (obj == this) return true;
-      return obj instanceof TypeVariable that && typeParameter.equals(that.typeParameter);
-    }
-
-    @Override
-    public int hashCode() {
-      return typeParameter.hashCode();
-    }
   }
 }

pkl-core/src/main/java/org/pkl/core/PropertiesRenderer.java

@@ -177,13 +177,6 @@ final class PropertiesRenderer implements ValueRenderer {
               "Values of type `Regex` cannot be rendered as Properties. Value: %s", value));
     }
 
-    @Override
-    public String convertReference(Reference value) {
-      throw new RendererException(
-          String.format(
-              "Values of type `Reference` cannot be rendered as Properties. Value: %s", value));
-    }
-
     private void doVisitMap(@Nullable String keyPrefix, Map<?, ?> map) {
       for (Map.Entry<?, ?> entry : map.entrySet()) {
         doVisitKeyAndValue(keyPrefix, entry.getKey(), entry.getValue());

pkl-core/src/main/java/org/pkl/core/Reference.java

@@ -1,101 +0,0 @@
-/*
- * Copyright © 2026 Apple Inc. and the Pkl project authors. All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.pkl.core;
-
-import java.io.Serial;
-import java.util.List;
-
-public class Reference implements Value {
-  @Serial private static final long serialVersionUID = 0L;
-
-  private final Composite domain;
-  private final Object data;
-  private final List<Composite> path;
-  private final PType referentType;
-
-  /** Constructs a reference. */
-  public Reference(Composite domain, Object data, List<Composite> path, PType referentType) {
-    this.domain = domain;
-    this.data = data;
-    this.path = path;
-    this.referentType = referentType;
-  }
-
-  /** Returns the domain object of this reference. */
-  public Composite getDomain() {
-    return domain;
-  }
-
-  /** Returns the data object of this reference. */
-  public Object getData() {
-    return data;
-  }
-
-  /**
-   * Returns the access path of this reference.
-   *
-   * <p>All elements are exported {@code pkl.ref#Access} instances.
-   */
-  public List<Composite> getPath() {
-    return path;
-  }
-
-  /** Returns the referent type of this reference. */
-  public PType getReferentType() {
-    return referentType;
-  }
-
-  @Override
-  public void accept(ValueVisitor visitor) {
-    visitor.visitReference(this);
-  }
-
-  @Override
-  public <T> T accept(ValueConverter<T> converter) {
-    return converter.convertReference(this);
-  }
-
-  @Override
-  public final boolean equals(Object o) {
-    if (!(o instanceof Reference reference)) {
-      return false;
-    }
-
-    return domain.equals(reference.domain)
-        && data.equals(reference.data)
-        && path.equals(reference.path)
-        && referentType.equals(reference.referentType);
-  }
-
-  @Override
-  public PClassInfo<?> getClassInfo() {
-    return PClassInfo.Reference;
-  }
-
-  @Override
-  public int hashCode() {
-    int result = domain.hashCode();
-    result = 31 * result + data.hashCode();
-    result = 31 * result + path.hashCode();
-    result = 31 * result + referentType.hashCode();
-    return result;
-  }
-
-  @Override
-  public String toString() {
-    return super.toString();
-  }
-}

pkl-core/src/main/java/org/pkl/core/TypeAlias.java

@@ -28,7 +28,6 @@ public final class TypeAlias extends Member implements Value {
   private final String moduleName;
   private final String qualifiedName;
   private final List<TypeParameter> typeParameters;
-  private final PClass moduleClass;
 
   @LateInit private PType aliasedType;
 
@@ -40,13 +39,11 @@ public final class TypeAlias extends Member implements Value {
       String simpleName,
       String moduleName,
       String qualifiedName,
-      List<TypeParameter> typeParameters,
-      PClass moduleClass) {
+      List<TypeParameter> typeParameters) {
     super(docComment, sourceLocation, modifiers, annotations, simpleName);
     this.moduleName = moduleName;
     this.qualifiedName = qualifiedName;
     this.typeParameters = typeParameters;
-    this.moduleClass = moduleClass;
   }
 
   public void initAliasedType(PType type) {
@@ -82,10 +79,6 @@ public final class TypeAlias extends Member implements Value {
     return typeParameters;
   }
 
-  public PClass getModuleClass() {
-    return moduleClass;
-  }
-
   /** Returns the type that this type alias stands for. */
   public PType getAliasedType() {
     //noinspection ConstantValue

pkl-core/src/main/java/org/pkl/core/ValueConverter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,8 +57,6 @@ public interface ValueConverter<T> {
 
   T convertRegex(Pattern value);
 
-  T convertReference(Reference value);
-
   default T convert(Object value) {
     if (value instanceof Value v) {
       return (v.accept(this));

pkl-core/src/main/java/org/pkl/core/ValueVisitor.java

@@ -93,10 +93,6 @@ public interface ValueVisitor {
     visitDefault(value);
   }
 
-  default void visitReference(Reference value) {
-    visitDefault(value);
-  }
-
   default void visit(Object value) {
     if (value instanceof Value v) {
       v.accept(this);

pkl-core/src/main/java/org/pkl/core/ast/builder/AstBuilder.java

@@ -1476,6 +1476,8 @@ public class AstBuilder extends AbstractAstBuilder<Object> {
     var scope = (ModuleScope) symbolTable.getCurrentScope();
     scope.setModifiers(modifiers);
 
+    checkAbstractMembersAllowed(modifiers, mod.getProperties(), mod.getMethods());
+
     // visit imports first so that we already have the object member name available
     var imports = mod.getImports();
     var importMembers = new ObjectMember[imports.size()];
@@ -1720,6 +1722,7 @@ public class AstBuilder extends AbstractAstBuilder<Object> {
           List<ClassProperty> properties = bodyNode != null ? bodyNode.getProperties() : List.of();
           List<ClassMethod> methods = bodyNode != null ? bodyNode.getMethods() : List.of();
           registerClassScopeNames(scope, properties, methods);
+          checkAbstractMembersAllowed(modifiers, properties, methods);
 
           var supertypeCtx = clazz.getSuperClass();
 
@@ -1810,6 +1813,30 @@ public class AstBuilder extends AbstractAstBuilder<Object> {
     };
   }
 
+  private void checkAbstractMembersAllowed(
+      int enclosingModifiers, List<ClassProperty> properties, List<ClassMethod> methods) {
+    if (VmModifier.isAbstract(enclosingModifiers)) {
+      return;
+    }
+    for (var property : properties) {
+      checkMemberNotAbstract(property.getModifiers());
+    }
+    for (var method : methods) {
+      checkMemberNotAbstract(method.getModifiers());
+    }
+  }
+
+  private void checkMemberNotAbstract(List<Modifier> modifiers) {
+    for (var modifier : modifiers) {
+      if (modifier.getValue() == ModifierValue.ABSTRACT) {
+        throw exceptionBuilder()
+            .evalError("abstractMemberInNonAbstractClass")
+            .withSourceSection(createSourceSection(modifier.span()))
+            .build();
+      }
+    }
+  }
+
   private UnresolvedPropertyNode[] doVisitClassProperties(
       List<ClassProperty> propertyContexts, Set<String> propertyNames) {
     var propertyNodes = new UnresolvedPropertyNode[propertyContexts.size()];

pkl-core/src/main/java/org/pkl/core/ast/expression/binary/SubscriptNode.java

@@ -100,20 +100,6 @@ public abstract class SubscriptNode extends BinaryExpressionNode {
     return readMember(dynamic, key, callNode);
   }
 
-  @Specialization
-  protected VmReference eval(VmReference reference, Object key) {
-    var result = reference.withSubscriptAccess(key);
-    if (result != null) return result;
-
-    CompilerDirectives.transferToInterpreter();
-    throw exceptionBuilder()
-        .evalError(
-            "operatorNotDefined2", getShortName(), reference.exportType(), VmUtils.getClass(key))
-        .withProgramValue("Left operand", reference)
-        .withProgramValue("Right operand", key)
-        .build();
-  }
-
   @Specialization
   protected long eval(VmBytes receiver, long index) {
     if (index < 0 || index >= receiver.getLength()) {

pkl-core/src/main/java/org/pkl/core/ast/expression/member/ReadPropertyNode.java

@@ -61,18 +61,6 @@ public abstract class ReadPropertyNode extends ExpressionNode {
     this(sourceSection, propertyName, MemberLookupMode.EXPLICIT_RECEIVER, false);
   }
 
-  @Specialization
-  protected VmReference evalReference(VmReference receiver) {
-    assert lookupMode == MemberLookupMode.EXPLICIT_RECEIVER;
-    var result = receiver.withPropertyAccess(propertyName);
-    if (result != null) return result;
-
-    CompilerDirectives.transferToInterpreter();
-    throw exceptionBuilder()
-        .evalError("cannotFindPropertyInReference", propertyName, receiver.exportType())
-        .build();
-  }
-
   // This method effectively covers `VmObject receiver` but is implemented in a more
   // efficient way. See:
   // https://www.graalvm.org/22.0/graalvm-as-a-platform/language-implementation-framework/TruffleLibraries/#strategy-2-java-interfaces

pkl-core/src/main/java/org/pkl/core/ast/internal/ToStringNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,6 @@ import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
-import com.oracle.truffle.api.nodes.DirectCallNode;
 import com.oracle.truffle.api.source.SourceSection;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.MemberLookupMode;
@@ -63,16 +62,8 @@ public abstract class ToStringNode extends UnaryExpressionNode {
       VmTyped value,
       @Cached(value = "createInvokeNode()", neverDefault = true)
           InvokeMethodVirtualNode invokeNode) {
-    return (String) invokeNode.executeWith(frame, value, value.getVmClass());
-  }
 
-  @Specialization
-  protected String evalReference(
-      VirtualFrame frame,
-      VmReference value,
-      @Cached(value = "createReferenceCallNode(value)", neverDefault = true)
-          DirectCallNode callNode) {
-    return (String) callNode.call(value, value.getVmClass().getPrototype());
+    return (String) invokeNode.executeWith(frame, value, value.getVmClass());
   }
 
   @Fallback
@@ -83,6 +74,7 @@ public abstract class ToStringNode extends UnaryExpressionNode {
   }
 
   protected InvokeMethodVirtualNode createInvokeNode() {
+    //noinspection ConstantConditions
     return InvokeMethodVirtualNodeGen.create(
         sourceSection,
         Identifier.TO_STRING,
@@ -91,10 +83,4 @@ public abstract class ToStringNode extends UnaryExpressionNode {
         null,
         null);
   }
-
-  protected DirectCallNode createReferenceCallNode(VmReference reference) {
-    var toStringMethod = reference.getVmClass().getDeclaredMethod(Identifier.TO_STRING);
-    assert toStringMethod != null;
-    return DirectCallNode.create(toStringMethod.getCallTarget());
-  }
 }

pkl-core/src/main/java/org/pkl/core/ast/member/ClassProperty.java

@@ -24,7 +24,7 @@ import org.pkl.core.ast.VmModifier;
 import org.pkl.core.runtime.*;
 
 public final class ClassProperty extends ClassMember {
-  private final @Nullable PropertyTypeNode typeNode;
+  private @Nullable PropertyTypeNode typeNode;
   private final ObjectMember initializer;
 
   public ClassProperty(
@@ -64,6 +64,11 @@ public final class ClassProperty extends ClassMember {
     return VmModifier.getMirrors(mods, false);
   }
 
+  public void lateInitTypeNodeAndModifiers(@Nullable PropertyTypeNode typeNode, int modifiers) {
+    this.typeNode = typeNode;
+    this.modifiers = modifiers;
+  }
+
   public @Nullable PropertyTypeNode getTypeNode() {
     return typeNode;
   }

pkl-core/src/main/java/org/pkl/core/ast/member/Member.java

@@ -25,7 +25,7 @@ public abstract class Member {
 
   protected final SourceSection headerSection;
 
-  protected final int modifiers;
+  protected int modifiers;
 
   protected final @Nullable Identifier name;
 

pkl-core/src/main/java/org/pkl/core/ast/type/TypeNode.java

@@ -2127,125 +2127,6 @@ public abstract class TypeNode extends PklNode {
     }
   }
 
-  public abstract static class ReferenceTypeNode extends ObjectSlotTypeNode {
-    @Child private TypeNode domainTypeNode;
-    @Child private TypeNode referentTypeNode;
-    @Child private ExpressionNode getModuleNode;
-
-    public ReferenceTypeNode(
-        SourceSection sourceSection, TypeNode domainTypeNode, TypeNode referentTypeNode) {
-      super(sourceSection);
-      this.domainTypeNode = domainTypeNode;
-      this.referentTypeNode = referentTypeNode;
-      this.getModuleNode = new GetModuleNode(sourceSection);
-      validateTypeArguments(sourceSection);
-    }
-
-    @Specialization
-    protected Object eval(VirtualFrame frame, VmReference value) {
-      if (domainTypeNode.isNoopTypeCheck() && referentTypeNode.isNoopTypeCheck()) {
-        return value;
-      }
-
-      try {
-        domainTypeNode.execute(frame, value.getDomain());
-      } catch (VmTypeMismatchException e) {
-        CompilerDirectives.transferToInterpreter();
-        throw new VmTypeMismatchException.Reference(
-            sourceSection,
-            value,
-            TypeNode.export(domainTypeNode),
-            TypeNode.export(referentTypeNode));
-      }
-
-      var module = (VmTyped) getModuleNode.executeGeneric(frame);
-      return doEval(value, module);
-    }
-
-    @TruffleBoundary
-    private Object doEval(VmReference value, VmTyped module) {
-      var referentType = TypeNode.export(referentTypeNode);
-      if (value.referentTypeIsSubtypeOf(referentType, module.getVmClass().export())) {
-        return value;
-      }
-
-      throw new VmTypeMismatchException.Reference(
-          sourceSection, value, TypeNode.export(domainTypeNode), referentType);
-    }
-
-    public void validateTypeArguments(@Nullable SourceSection aliasSourceSection) {
-      // constraints may not be used in Reference type annotation referents
-      // walk the type and throw if any part of the referent is constrained
-
-      // TODO improve error message when this type node and/or referent constraint are behind type
-      // aliases
-      referentTypeNode.acceptTypeNode(
-          true,
-          (typeNode) -> {
-            if (typeNode instanceof ConstrainedTypeNode) {
-              CompilerDirectives.transferToInterpreter();
-              var err =
-                  exceptionBuilder().evalError("invalidReferenceTypeAnnotationWithConstraint");
-              if (aliasSourceSection != null) {
-                err.withSourceSection(aliasSourceSection);
-              }
-              throw err.build();
-            }
-            return true;
-          });
-    }
-
-    @Fallback
-    protected Object fallback(Object value) {
-      throw typeMismatch(value, RefModule.getReferenceClass());
-    }
-
-    @Override
-    protected boolean acceptTypeNode(boolean visitTypeArguments, TypeNodeConsumer consumer) {
-      if (visitTypeArguments)
-        return consumer.accept(this)
-            && consumer.accept(domainTypeNode)
-            && consumer.accept(referentTypeNode);
-      return consumer.accept(this);
-    }
-
-    @Override
-    public VmClass getVmClass() {
-      return RefModule.getReferenceClass();
-    }
-
-    @Override
-    public VmList getTypeArgumentMirrors() {
-      return VmList.of(domainTypeNode.getMirror(), referentTypeNode.getMirror());
-    }
-
-    @Override
-    protected boolean doIsEquivalentTo(TypeNode other) {
-      if (!(other instanceof ReferenceTypeNode referenceTypeNode)) {
-        return false;
-      }
-      return referentTypeNode.isEquivalentTo(referenceTypeNode.referentTypeNode);
-    }
-
-    @Override
-    public boolean isNoopTypeCheck() {
-      return domainTypeNode.isNoopTypeCheck() && referentTypeNode.isNoopTypeCheck();
-    }
-
-    @Override
-    protected PType doExport() {
-      return new PType.Class(
-          RefModule.getReferenceClass().export(),
-          domainTypeNode.doExport(),
-          referentTypeNode.doExport());
-    }
-
-    @Override
-    protected boolean isParametric() {
-      return true;
-    }
-  }
-
   public static final class PairTypeNode extends ObjectSlotTypeNode {
     @Child private TypeNode firstTypeNode;
     @Child private TypeNode secondTypeNode;
@@ -2703,7 +2584,7 @@ public abstract class TypeNode extends PklNode {
 
       this.typeAlias = typeAlias;
       this.typeArgumentNodes = typeArgumentNodes;
-      aliasedTypeNode = typeAlias.instantiate(typeArgumentNodes, sourceSection);
+      aliasedTypeNode = typeAlias.instantiate(typeArgumentNodes);
     }
 
     public TypeNode getAliasedTypeNode() {

pkl-core/src/main/java/org/pkl/core/ast/type/UnresolvedTypeNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -287,13 +287,6 @@ public abstract class UnresolvedTypeNode extends PklNode {
           return new VarArgsTypeNode(sourceSection, typeArgumentNodes[0].execute(frame));
         }
 
-        if (clazz.isReferenceClass()) {
-          return ReferenceTypeNodeGen.create(
-              sourceSection,
-              typeArgumentNodes[0].execute(frame),
-              typeArgumentNodes[1].execute(frame));
-        }
-
         throw exceptionBuilder()
             .evalError("notAParameterizableClass", clazz.getDisplayName())
             .withSourceSection(typeArgumentNodes[0].sourceSection)

pkl-core/src/main/java/org/pkl/core/ast/type/VmTypeMismatchException.java

@@ -23,7 +23,6 @@ import com.oracle.truffle.api.source.SourceSection;
 import java.util.*;
 import java.util.stream.Collectors;
 import org.jspecify.annotations.Nullable;
-import org.pkl.core.PType;
 import org.pkl.core.StackFrame;
 import org.pkl.core.ValueFormatter;
 import org.pkl.core.ast.type.TypeNode.UnionTypeNode;
@@ -334,44 +333,4 @@ public abstract class VmTypeMismatchException extends ControlFlowException {
       return false;
     }
   }
-
-  public static final class Reference extends VmTypeMismatchException {
-
-    private final PType expectedDomainType;
-    private final PType expectedReferentType;
-
-    public Reference(
-        SourceSection sourceSection,
-        VmReference actualValue,
-        PType expectedDomainType,
-        PType expectedReferentType) {
-      super(sourceSection, actualValue);
-      this.expectedDomainType = expectedDomainType;
-      this.expectedReferentType = expectedReferentType;
-    }
-
-    @Override
-    public void buildMessage(
-        AnsiStringBuilder builder, String indent, boolean withPowerAssertions) {
-      builder
-          .append(
-              ErrorMessages.createIndented(
-                  "typeMismatch",
-                  indent,
-                  new PType.Class(
-                      RefModule.getReferenceClass().export(),
-                      expectedDomainType,
-                      expectedReferentType),
-                  ((VmReference) actualValue).exportType()))
-          .append("\n")
-          .append(indent)
-          .append("Value: ")
-          .append(VmValueRenderer.singleLine(80 - indent.length()).render(actualValue));
-    }
-
-    @Override
-    protected Boolean hasHint() {
-      return false;
-    }
-  }
 }

pkl-core/src/main/java/org/pkl/core/packages/PackageResolvers.java

@@ -45,7 +45,6 @@ import java.util.stream.StreamSupport;
 import java.util.zip.ZipInputStream;
 import org.graalvm.collections.EconomicMap;
 import org.jspecify.annotations.Nullable;
-import org.pkl.core.PklBugException;
 import org.pkl.core.SecurityManager;
 import org.pkl.core.SecurityManagerException;
 import org.pkl.core.http.HttpClient;
@@ -457,17 +456,10 @@ final class PackageResolvers {
     }
 
     private Path getRelativePath(PackageUri uri) {
-      var relativePath =
-          Path.of(
-              CACHE_DIR_PREFIX,
-              IoUtils.encodePath(uri.getUri().getAuthority()),
-              getEffectivePackageUriPath(uri));
-      // ensure the derived path cannot escape the cache directory
-      var resolved = cacheDir.resolve(relativePath).normalize();
-      if (!resolved.startsWith(cacheDir.normalize())) {
-        throw new PklBugException("Package URI escapes the cache directory");
-      }
-      return relativePath;
+      return Path.of(
+          CACHE_DIR_PREFIX,
+          IoUtils.encodePath(uri.getUri().getAuthority()),
+          getEffectivePackageUriPath(uri));
     }
 
     private String getLastSegmentName(PackageUri packageUri) {

pkl-core/src/main/java/org/pkl/core/packages/PackageUri.java

@@ -61,13 +61,6 @@ public final class PackageUri {
       throw new URISyntaxException(
           uri.toString(), ErrorMessages.create("missingPathInPackageUri", uri));
     }
-    // reject `..` segments, percent-encoded or not
-    for (var segment : path.split("/", -1)) {
-      if (segment.equals("..")) {
-        throw new URISyntaxException(
-            uri.toString(), ErrorMessages.create("invalidRelativePathInPackageUri"));
-      }
-    }
     var versionIdx = path.lastIndexOf('@');
     if (versionIdx == -1) {
       throw new URISyntaxException(

pkl-core/src/main/java/org/pkl/core/runtime/Identifier.java

@@ -165,10 +165,6 @@ public final class Identifier implements Comparable<Identifier> {
 
   public static final Identifier ILLEGAL = get("`");
 
-  // members of pkl.ref
-  public static final Identifier PROPERTY = get("property");
-  public static final Identifier KEY = get("key");
-
   // common in lambdas etc
   public static final Identifier IT = get("it");
 

pkl-core/src/main/java/org/pkl/core/runtime/ModuleCache.java

@@ -104,8 +104,6 @@ public final class ModuleCache {
           return PlatformModule.getModule();
         case "project":
           return ProjectModule.getModule();
-        case "ref":
-          return RefModule.getModule();
         case "reflect":
           return ReflectModule.getModule();
         case "release":

pkl-core/src/main/java/org/pkl/core/runtime/RefModule.java

@@ -1,53 +0,0 @@
-/*
- * Copyright © 2026 Apple Inc. and the Pkl project authors. All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.pkl.core.runtime;
-
-import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
-import java.net.URI;
-
-public class RefModule extends StdLibModule {
-  private static final VmTyped instance = VmUtils.createEmptyModule();
-
-  static {
-    loadModule(URI.create("pkl:ref"), instance);
-  }
-
-  public static VmClass getReferenceClass() {
-    return ReferenceClass.instance;
-  }
-
-  public static VmClass getAccessClass() {
-    return AccessClass.instance;
-  }
-
-  private static final class ReferenceClass {
-    static final VmClass instance = loadClass("Reference");
-  }
-
-  private static final class AccessClass {
-    static final VmClass instance = loadClass("Access");
-  }
-
-  @TruffleBoundary
-  private static VmClass loadClass(String className) {
-    var theModule = getModule();
-    return (VmClass) VmUtils.readMember(theModule, Identifier.get(className));
-  }
-
-  public static VmTyped getModule() {
-    return instance;
-  }
-}

pkl-core/src/main/java/org/pkl/core/runtime/VmClass.java

@@ -22,6 +22,7 @@ import com.oracle.truffle.api.dsl.Idempotent;
 import com.oracle.truffle.api.frame.FrameDescriptor;
 import com.oracle.truffle.api.source.SourceSection;
 import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.*;
 import org.graalvm.collections.*;
 import org.jspecify.annotations.Nullable;
@@ -84,6 +85,13 @@ public final class VmClass extends VmValue {
 
   private final Object allHiddenPropertyNamesLock = new Object();
 
+  @GuardedBy("finalizersLock")
+  private @Nullable List<Runnable> __finalizers = null;
+
+  private final Object finalizersLock = new Object();
+
+  private final AtomicInteger uninitializedSuperclassCount = new AtomicInteger(0);
+
   // Helps to overcome recursive initialization issues
   // between classes and annotations in pkl.base.
   @CompilationFinal private volatile boolean isInitialized;
@@ -150,6 +158,83 @@ public final class VmClass extends VmValue {
     prototype.lateInitParent(superclass.getPrototype());
   }
 
+  @TruffleBoundary
+  private void checkAbstractMembers() {
+    if (this.isAbstract()) return;
+    // minimize allocations in the non-error case
+    if (!hasAbstractMember()) return;
+    var abstractMembers = getAbstractMembers();
+    if (abstractMembers.size() == 1) {
+      var member = abstractMembers.get(0);
+      var message =
+          member instanceof ClassProperty
+              ? "noImplementationForAbstractProperty"
+              : "noImplementationForAbstractMethod";
+      throw new VmExceptionBuilder()
+          .evalError(message, getDisplayName(), member.getName().toString())
+          .withSourceSection(getHeaderSection())
+          .build();
+    }
+    var memberList = new StringBuilder();
+    var isFirst = true;
+    for (var member : abstractMembers) {
+      if (isFirst) {
+        isFirst = false;
+      } else {
+        memberList.append('\n');
+      }
+      memberList.append("* ");
+      if (member instanceof ClassProperty) {
+        memberList.append("property ");
+      } else {
+        memberList.append("method ");
+      }
+      memberList.append('`').append(member.getName()).append('`');
+    }
+    throw new VmExceptionBuilder()
+        .evalError("noImplementationForAbstractMembers", getDisplayName(), memberList.toString())
+        .withSourceSection(getHeaderSection())
+        .build();
+  }
+
+  private boolean hasAbstractMember() {
+    var propertyCursor = getAllProperties().getEntries();
+    while (propertyCursor.advance()) {
+      var property = propertyCursor.getValue();
+      if (property.isAbstract()) {
+        return true;
+      }
+    }
+    var methodCursor = getAllMethods().getEntries();
+    while (methodCursor.advance()) {
+      var method = methodCursor.getValue();
+      if (method.isAbstract()) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  private List<ClassMember> getAbstractMembers() {
+    assert this.superclass != null;
+    var result = new ArrayList<ClassMember>();
+    var propertyCursor = getAllProperties().getEntries();
+    while (propertyCursor.advance()) {
+      var property = propertyCursor.getValue();
+      if (property.isAbstract()) {
+        result.add(property);
+      }
+    }
+    var methodCursor = getAllMethods().getEntries();
+    while (methodCursor.advance()) {
+      var method = methodCursor.getValue();
+      if (method.isAbstract()) {
+        result.add(method);
+      }
+    }
+    return result;
+  }
+
   @TruffleBoundary
   public void addProperty(ClassProperty property) {
     prototype.addProperty(property.getInitializer());
@@ -190,8 +275,46 @@ public final class VmClass extends VmValue {
     }
   }
 
+  private void onInitialized(Runnable runnable) {
+    synchronized (finalizersLock) {
+      if (this.__finalizers == null) {
+        this.__finalizers = new ArrayList<>();
+      }
+      this.__finalizers.add(runnable);
+    }
+  }
+
   // Note: Superclasses may not have finished their initialization when this method is called.
   public void notifyInitialized() {
+    var sc = superclass;
+    var isAllInitialized = true;
+    var uninitializedCount = 0;
+    while (sc != null) {
+      if (!sc.isInitialized) {
+        sc.onInitialized(
+            () -> {
+              var count = uninitializedSuperclassCount.decrementAndGet();
+              if (count == 0) {
+                checkAbstractMembers();
+              }
+            });
+        uninitializedCount++;
+        isAllInitialized = false;
+      }
+      sc = sc.superclass;
+    }
+    uninitializedSuperclassCount.set(uninitializedCount);
+    if (isAllInitialized) {
+      checkAbstractMembers();
+    }
+    lock:
+    synchronized (finalizersLock) {
+      if (__finalizers == null) break lock;
+      for (var finalizer : __finalizers) {
+        finalizer.run();
+      }
+      this.__finalizers = null;
+    }
     isInitialized = true;
   }
 
@@ -445,11 +568,6 @@ public final class VmClass extends VmValue {
     return isClass(BaseModule.getVarArgsClass(), "pkl.base#VarArgs");
   }
 
-  @Idempotent
-  public boolean isReferenceClass() {
-    return isClass(RefModule.getReferenceClass(), "pkl.ref#Reference");
-  }
-
   private boolean isClass(@Nullable VmClass clazz, String qualifiedClassName) {
     // may be null during evaluation of base module
     return clazz != null ? this == clazz : getQualifiedName().equals(qualifiedClassName);
@@ -626,62 +744,49 @@ public final class VmClass extends VmValue {
   public PClass export() {
     synchronized (pClassLock) {
       //noinspection ConstantValue
-      if (__pClass != null) {
-        return __pClass;
-      }
+      if (__pClass == null) {
+        var exportedAnnotations = new ArrayList<PObject>();
+        var properties =
+            CollectionUtils.<String, PClass.Property>newLinkedHashMap(
+                EconomicMaps.size(declaredProperties));
+        var methods =
+            CollectionUtils.<String, PClass.Method>newLinkedHashMap(
+                EconomicMaps.size(declaredMethods));
 
-      // if this is not a module class, export this class's module's class first to break the cycle
-      PClass moduleClass = null;
-      if (!classInfo.isModuleClass()) {
-        moduleClass = getModule().getVmClass().export();
-      }
-      // then if the cached value is still null, initialize it
-      if (__pClass != null) {
-        return __pClass;
-      }
+        // set pClass before exporting class members to prevent
+        // infinite recursion in case of cyclic references
+        __pClass =
+            new PClass(
+                VmUtils.exportDocComment(docComment),
+                new SourceLocation(headerSection.getStartLine(), sourceSection.getEndLine()),
+                VmModifier.export(modifiers, true),
+                exportedAnnotations,
+                classInfo,
+                typeParameters,
+                properties,
+                methods);
 
-      var exportedAnnotations = new ArrayList<PObject>();
-      var properties =
-          CollectionUtils.<String, PClass.Property>newLinkedHashMap(
-              EconomicMaps.size(declaredProperties));
-      var methods =
-          CollectionUtils.<String, PClass.Method>newLinkedHashMap(
-              EconomicMaps.size(declaredMethods));
-
-      // set pClass before exporting class members to prevent
-      // infinite recursion in case of cyclic references
-      __pClass =
-          new PClass(
-              VmUtils.exportDocComment(docComment),
-              new SourceLocation(headerSection.getStartLine(), sourceSection.getEndLine()),
-              VmModifier.export(modifiers, true),
-              exportedAnnotations,
-              classInfo,
-              typeParameters,
-              properties,
-              methods,
-              moduleClass);
-
-      for (var parameter : typeParameters) {
-        parameter.initOwner(__pClass);
-      }
-
-      if (supertypeNode != null) {
-        assert superclass != null;
-        __pClass.initSupertype(TypeNode.export(supertypeNode), superclass.export());
-      }
-
-      VmUtils.exportAnnotations(annotations, exportedAnnotations);
-
-      for (var property : EconomicMaps.getValues(declaredProperties)) {
-        if (isClassPropertyDefinition(property)) {
-          properties.put(property.getName().toString(), property.export(__pClass));
+        for (var parameter : typeParameters) {
+          parameter.initOwner(__pClass);
         }
-      }
 
-      for (var method : EconomicMaps.getValues(declaredMethods)) {
-        if (method.isLocal()) continue;
-        methods.put(method.getName().toString(), method.export(__pClass));
+        if (supertypeNode != null) {
+          assert superclass != null;
+          __pClass.initSupertype(TypeNode.export(supertypeNode), superclass.export());
+        }
+
+        VmUtils.exportAnnotations(annotations, exportedAnnotations);
+
+        for (var property : EconomicMaps.getValues(declaredProperties)) {
+          if (isClassPropertyDefinition(property)) {
+            properties.put(property.getName().toString(), property.export(__pClass));
+          }
+        }
+
+        for (var method : EconomicMaps.getValues(declaredMethods)) {
+          if (method.isLocal()) continue;
+          methods.put(method.getName().toString(), method.export(__pClass));
+        }
       }
 
       return __pClass;
@@ -753,13 +858,27 @@ public final class VmClass extends VmValue {
     for (var property : EconomicMaps.getValues(declaredProperties)) {
       if (property.isLocal()) continue;
 
-      // A property is considered a class property definition
-      // if it has a type annotation or has no superdefinition (ad-hoc case).
+      // A property is considered a class property definition if any of the following are true:
+      //
+      // 1. It has a type annotation.
+      // 2. It has no superdefinition.
+      // 3. It is not abstract but its superclass is.
+      //
       // Otherwise, it is considered an object property definition,
       // which means it affects the class prototype but not the class itself.
       // An example for the latter is when `Module.output` is overridden with `output { ... }`.
-      if (property.getTypeNode() != null || !EconomicMaps.containsKey(result, property.getName())) {
+      if (property.getTypeNode() != null) {
         EconomicMaps.put(result, property.getName(), property);
+      } else {
+        var existingProperty = EconomicMaps.get(result, property.getName());
+        if (existingProperty != null && existingProperty.isAbstract() && !this.isAbstract()) {
+          property.lateInitTypeNodeAndModifiers(
+              existingProperty.getTypeNode(),
+              existingProperty.getModifiers() & ~VmModifier.ABSTRACT);
+          EconomicMaps.put(result, property.getName(), property);
+        } else if (existingProperty == null) {
+          EconomicMaps.put(result, property.getName(), property);
+        }
       }
     }
 

pkl-core/src/main/java/org/pkl/core/runtime/VmObjectBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -87,9 +87,4 @@ public final class VmObjectBuilder {
         members,
         elementCount);
   }
-
-  public VmTyped toTyped(VmClass clazz) {
-    return new VmTyped(
-        VmUtils.createEmptyMaterializedFrame(), clazz.getPrototype(), clazz, members);
-  }
 }

pkl-core/src/main/java/org/pkl/core/runtime/VmPklBinaryEncoder.java

@@ -324,22 +324,6 @@ public class VmPklBinaryEncoder extends AbstractRenderer {
     }
   }
 
-  @Override
-  public void visitReference(VmReference value) {
-    try {
-      packer.packArrayHeader(4);
-      packCode(PklBinaryCode.REFERENCE);
-      visit(value.getDomain());
-      visit(value.getData());
-      packer.packArrayHeader(value.getPath().size());
-      for (var access : value.getPath()) {
-        visit(access);
-      }
-    } catch (IOException e) {
-      throw PklBugException.unreachableCode();
-    }
-  }
-
   @Override
   protected void visitEntryKey(Object key, boolean isFirst) {
     visit(key);

pkl-core/src/main/java/org/pkl/core/runtime/VmReference.java

@@ -1,484 +0,0 @@
-/*
- * Copyright © 2025-2026 Apple Inc. and the Pkl project authors. All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.pkl.core.runtime;
-
-import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
-import com.oracle.truffle.api.nodes.DirectCallNode;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-import java.util.function.BiConsumer;
-import java.util.function.Supplier;
-import org.jspecify.annotations.Nullable;
-import org.pkl.core.Composite;
-import org.pkl.core.PClass;
-import org.pkl.core.PClassInfo;
-import org.pkl.core.PType;
-import org.pkl.core.Reference;
-import org.pkl.core.TypeAlias;
-import org.pkl.core.util.paguro.RrbTree;
-import org.pkl.core.util.paguro.RrbTree.ImRrbt;
-
-public final class VmReference extends VmValue {
-
-  private final VmTyped domain;
-  private final Object data;
-  private final ImRrbt<VmTyped> path;
-  // candidate types can only be: PType.Class, PType.Alias (only preservedAliasTypes),
-  // PType.StringLiteral, PType.UNKNOWN, or PType.Union (containing only the previous; flattened)
-  private final PType referentType;
-
-  private boolean forced = false;
-
-  private static VmTyped newAccess(@Nullable String property, @Nullable Object key) {
-    return new VmObjectBuilder()
-        .addProperty(Identifier.PROPERTY, property == null ? VmNull.withoutDefault() : property)
-        .addProperty(Identifier.KEY, key == null ? VmNull.withoutDefault() : key)
-        .toTyped(RefModule.getAccessClass());
-  }
-
-  @TruffleBoundary
-  public VmReference(VmTyped domain, VmClass clazz, Object data) {
-    this(
-        domain,
-        data,
-        RrbTree.empty(),
-        normalizeTypes(new PType.Class(clazz.export()), clazz.getModule().getVmClass().export()));
-  }
-
-  public VmReference(VmTyped domain, Object data, ImRrbt<VmTyped> path, PType referentType) {
-    this.domain = domain;
-    this.data = data;
-    this.referentType = referentType;
-    this.path = path;
-  }
-
-  public VmTyped getDomain() {
-    return domain;
-  }
-
-  public Object getData() {
-    return data;
-  }
-
-  public List<VmTyped> getPath() {
-    return path;
-  }
-
-  public PType getReferentType() {
-    return referentType;
-  }
-
-  // simplifies a type by:
-  // * erasing constraints
-  // * transforming T? into T|Null
-  // * dereferencing aliases (except for well-known stdlib alias types)
-  // * flattening unions
-  // * when moduleClass is supplied, replace PType.MODULE with appropriate PType.Class
-  // * drop PType.Function and PType.TypeVariable
-  private static PType normalizeTypes(PType type, PClass moduleClass) {
-    var types = new HashSet<PType>();
-    normalizeTypes(type, moduleClass, types);
-    return minimizeTypes(types);
-  }
-
-  private static PType minimizeTypes(Set<PType> types) {
-    if (types.size() == 1) return types.iterator().next();
-    // optimization: unknown allows all references, erase all candidates to only unknown
-    if (types.contains(PType.UNKNOWN)) return PType.UNKNOWN;
-    // optimization: All allows all references, erase all candidates to only All
-    if (containsClass(types, BaseModule.getAnyClass().export()))
-      return new PType.Class(BaseModule.getAnyClass().export());
-    var typesList = new ArrayList<>(types);
-    typesList.sort(Comparator.comparing(Object::toString));
-    return new PType.Union(typesList);
-  }
-
-  private static void normalizeTypes(PType type, PClass moduleClass, Set<PType> result) {
-    if (type == PType.UNKNOWN || type == PType.NOTHING || type instanceof PType.StringLiteral) {
-      result.add(type);
-    } else if (type instanceof PType.Class clazz) {
-      if (clazz.getTypeArguments().isEmpty()) {
-        // if a generic type is used without type arguments, it needs to be normalized so all args
-        // are unknown; i.e. with bare List/Map/etc. type annotations (via FinalClassTypeNode).
-        var typeParameterCount = clazz.getPClass().getTypeParameters().size();
-        result.add(
-            typeParameterCount == 0
-                ? clazz
-                : new PType.Class(
-                    clazz.getPClass(), Collections.nCopies(typeParameterCount, PType.UNKNOWN)));
-      } else {
-        var typeArgs = new ArrayList<PType>(clazz.getTypeArguments().size());
-        for (var arg : clazz.getTypeArguments()) {
-          typeArgs.add(normalizeTypes(arg, moduleClass));
-        }
-        result.add(new PType.Class(clazz.getPClass(), typeArgs));
-      }
-    } else if (type instanceof PType.Nullable nullable) {
-      normalizeTypes(nullable.getBaseType(), moduleClass, result);
-      result.add(new PType.Class(BaseModule.getNullClass().export()));
-    } else if (type instanceof PType.Constrained constrained) {
-      normalizeTypes(constrained.getBaseType(), moduleClass, result);
-    } else if (type instanceof PType.Alias alias) {
-      if (isPreservedTypeAlias(alias.getTypeAlias())) {
-        result.add(alias);
-      } else {
-        normalizeTypes(alias.getAliasedType(), alias.getTypeAlias().getModuleClass(), result);
-      }
-    } else if (type instanceof PType.Union union) {
-      for (var t : union.getElementTypes()) {
-        normalizeTypes(t, moduleClass, result);
-      }
-    } else if (type == PType.MODULE) {
-      result.add(new PType.Class(moduleClass));
-    }
-  }
-
-  private static Iterable<PType> iterateTypes(PType t) {
-    if (t instanceof PType.Union union) return union.getElementTypes();
-    return Collections.singleton(t);
-  }
-
-  public @Nullable VmReference withPropertyAccess(Identifier property) {
-    var propString = property.toString();
-    return withAccess(
-        (t, candidates) -> getCandidatePropertyType(t, propString, candidates),
-        () -> newAccess(property.toString(), null));
-  }
-
-  public @Nullable VmReference withSubscriptAccess(Object key) {
-    return withAccess(
-        (t, candidates) -> getCandidateSubscriptType(t, key, candidates),
-        () -> newAccess(null, key));
-  }
-
-  @TruffleBoundary
-  private @Nullable VmReference withAccess(
-      BiConsumer<PType, Set<PType>> checkCandidate, Supplier<VmTyped> makeAccess) {
-    Set<PType> candidates = new HashSet<>();
-    for (var t : iterateTypes(referentType)) {
-      checkCandidate.accept(t, candidates);
-    }
-    if (candidates.isEmpty()) {
-      return null; // no valid access found
-    }
-    return new VmReference(domain, data, path.append(makeAccess.get()), minimizeTypes(candidates));
-  }
-
-  @SuppressWarnings("DuplicatedCode")
-  private static void getCandidatePropertyType(PType type, String property, Set<PType> result) {
-    if (type == PType.UNKNOWN) {
-      result.add(type);
-      return;
-    }
-    // restriction: only class types can have their properties referenced
-    if (!(type instanceof PType.Class clazz)) return;
-    // restriction: cannot reference properties of external classes
-    if (clazz.getPClass().isExternal()) return;
-    if (clazz.getPClass().getInfo() == PClassInfo.Dynamic) {
-      // restriction: cannot reference Dynamic.default
-      if (!property.equals("default")) result.add(PType.UNKNOWN);
-      return;
-    }
-    // restriction: cannot reference Listing/Mapping.default
-    if (clazz.getPClass().getInfo() == PClassInfo.Listing
-        || clazz.getPClass().getInfo() == PClassInfo.Mapping) {
-      return;
-    }
-    // restriction: cannot reference Module.output.
-    //   generalized: properties originally defined in external classes; the only extant example.
-    // This is implemented specifically because this is the only case where an external class
-    //   containing a property can be subclassed.
-    // And this can't check prop.getOwner().isExternal() because fully overriding the property with
-    //   a new type annotation means the owner isn't Module.
-    if (clazz.getPClass().isSubclassOf(BaseModule.getModuleClass().export())
-        && property.equals("output")) return;
-
-    var prop = clazz.getPClass().getAllProperties().get(property);
-    // restriction: cannot reference external properties
-    if (prop == null || prop.isExternal()) {
-      return;
-    }
-    normalizeTypes(prop.getType(), clazz.getPClass().getModuleClass(), result);
-  }
-
-  @SuppressWarnings("DuplicatedCode")
-  private static void getCandidateSubscriptType(PType type, Object key, Set<PType> result) {
-    if (type == PType.UNKNOWN) {
-      result.add(type);
-      return;
-    }
-    if (!(type instanceof PType.Class clazz)) {
-      return;
-    }
-    if (clazz.getPClass().getInfo() == PClassInfo.Dynamic) {
-      result.add(PType.UNKNOWN);
-      return;
-    }
-    if (clazz.getPClass().getInfo() == PClassInfo.Listing
-        || clazz.getPClass().getInfo() == PClassInfo.List) {
-      if (key instanceof Long) {
-        normalizeTypes(clazz.getTypeArguments().get(0), clazz.getPClass().getModuleClass(), result);
-      }
-      return;
-    }
-    if (clazz.getPClass().getInfo() == PClassInfo.Mapping
-        || clazz.getPClass().getInfo() == PClassInfo.Map) {
-      var typeArgs = clazz.getTypeArguments();
-      var keyTypes = normalizeTypes(typeArgs.get(0), clazz.getPClass().getModuleClass());
-      for (var kt : iterateTypes(keyTypes)) {
-        if (kt == PType.UNKNOWN
-            || (kt instanceof PType.Class klazz
-                && klazz.getPClass().getInfo() == PClassInfo.forValue(VmValue.export(key)))
-            || (kt instanceof PType.StringLiteral stringLiteral
-                && stringLiteral.getLiteral().equals(key))) {
-          normalizeTypes(typeArgs.get(1), clazz.getPClass().getModuleClass(), result);
-          return;
-        }
-      }
-    }
-  }
-
-  /**
-   * Tells if this reference's referent type is a subtype of {@code type}. Does not check domain.
-   */
-  public boolean referentTypeIsSubtypeOf(PType type, PClass moduleClass) {
-    // fast path: if referent is unknown it can match any type check
-    if (referentType == PType.UNKNOWN) {
-      return true;
-    }
-
-    var checkType = normalizeTypes(type, moduleClass);
-    // fast path: short circuit if any referent is accepted
-    if (checkType == PType.UNKNOWN || isClass(checkType, BaseModule.getAnyClass().export())) {
-      return true;
-    }
-    // fast path: short circuit if nothing is accepted
-    if (checkType == PType.NOTHING) {
-      return false;
-    }
-
-    return isSubtype(referentType, checkType);
-  }
-
-  private static boolean containsClass(Set<PType> types, PClass pClass) {
-    for (var t : types) {
-      if (isClass(t, pClass)) return true;
-    }
-    return false;
-  }
-
-  private static boolean isClass(PType t, PClass pClass) {
-    return t instanceof PType.Class clazz && clazz.getPClass() == pClass;
-  }
-
-  private static boolean isSubtype(PType a, PType b) {
-    // checks if A is a subtype of B
-    // cases (A -> B)
-    // * A == B
-    // * StringLiteral -> StringLiteral: if literals are the same
-    // * StringLiteral -> Class: B is String
-    // * Char Alias -> Char Alias, StringLiteral (known single character)
-    // * Int Alias -> Class: B is a subtype of Number (Int|Float|Number)
-    // * Int Alias -> Alias
-    //   * same alias
-    //   * Int8 is Int16|Int32
-    //   * Int16 is Int32
-    //   * UInt8 is Int16|Int32|Uint16|UInt32|UInt
-    //   * UInt16 is Int32|UInt32|UInt
-    //   * UInt32 is UInt
-    // * Class -> Class: if same class or A is a subclass of B
-    //   * if type args are present, must have equal number of them
-    //   * for each pair of type args, check variance
-    //     * invariant: A_i must be identical to B_i
-    //     * covariant: A_i must be a subtype of B_i
-    //     * contravariant: B_i must be a subtype of A_i
-    // * Union -> Union: Each elem of A must be a subtype of at least one elem of B
-    // * Non-union -> Union: A must be a subtype of at least one elem of B
-    if (a == b) return true;
-
-    if (a instanceof PType.StringLiteral aStr) {
-      if (b instanceof PType.StringLiteral bStr) {
-        return aStr.getLiteral().equals(bStr.getLiteral());
-      } else if (b instanceof PType.Class bClass) {
-        return bClass.getPClass() == BaseModule.getStringClass().export();
-      }
-    } else if (a instanceof PType.Alias aAlias) {
-      var aa = aAlias.getTypeAlias();
-      if (isIntTypeAlias(aa)) {
-        // special casing for stdlib Int typealiases
-        if (b instanceof PType.Class bClass) {
-          // A is an int alias, B is a Number (sub)class
-          return bClass.getPClass().isSubclassOf(BaseModule.getNumberClass().export());
-        } else if (b instanceof PType.Alias bAlias) {
-          var bb = bAlias.getTypeAlias();
-          if (aa == bb) {
-            return true;
-          }
-          if (aa == BaseModule.getInt8TypeAlias().export()) {
-            return bb == BaseModule.getInt16TypeAlias().export()
-                || bb == BaseModule.getInt32TypeAlias().export();
-          } else if (aa == BaseModule.getInt16TypeAlias().export()) {
-            return bb == BaseModule.getInt32TypeAlias().export();
-          } else if (aa == BaseModule.getUInt8TypeAlias().export()) {
-            return bb == BaseModule.getInt16TypeAlias().export()
-                || bb == BaseModule.getInt32TypeAlias().export()
-                || bb == BaseModule.getUInt16TypeAlias().export()
-                || bb == BaseModule.getUInt32TypeAlias().export()
-                || bb == BaseModule.getUIntTypeAlias().export();
-          } else if (aa == BaseModule.getUInt16TypeAlias().export()) {
-            return bb == BaseModule.getInt32TypeAlias().export()
-                || bb == BaseModule.getUInt32TypeAlias().export()
-                || bb == BaseModule.getUIntTypeAlias().export();
-          } else if (aa == BaseModule.getUInt32TypeAlias().export()) {
-            return bb == BaseModule.getUIntTypeAlias().export();
-          }
-        }
-      }
-    } else if (a instanceof PType.Class aClass && b instanceof PType.Class bClass) {
-      if (!aClass.getPClass().isSubclassOf(bClass.getPClass())) {
-        return false;
-      }
-      var aArgs = aClass.getTypeArguments();
-      var bArgs = bClass.getTypeArguments();
-      var bParams = bClass.getPClass().getTypeParameters();
-      if (aArgs.size() != bArgs.size()) {
-        return false;
-      }
-      // check variance of type args pairwise
-      for (var i = 0; i < aArgs.size(); i++) {
-        if (!switch (bParams.get(i).getVariance()) {
-          case INVARIANT -> aArgs.get(i) == bArgs.get(i);
-          case COVARIANT -> isSubtype(aArgs.get(i), bArgs.get(i));
-          case CONTRAVARIANT -> isSubtype(bArgs.get(i), aArgs.get(i));
-        }) {
-          return false;
-        }
-      }
-      return true;
-    } else if (b instanceof PType.Union bUnion) {
-      if (a instanceof PType.Union aUnion) {
-        a:
-        for (var aElem : aUnion.getElementTypes()) {
-          for (var bElem : bUnion.getElementTypes()) {
-            if (isSubtype(aElem, bElem)) continue a;
-          }
-          return false;
-        }
-        return true;
-      } else {
-        for (var bElem : bUnion.getElementTypes()) {
-          if (isSubtype(a, bElem)) return true;
-        }
-      }
-    }
-    return false;
-  }
-
-  private static boolean isIntTypeAlias(TypeAlias t) {
-    return t == BaseModule.getInt8TypeAlias().export()
-        || t == BaseModule.getInt16TypeAlias().export()
-        || t == BaseModule.getInt32TypeAlias().export()
-        || t == BaseModule.getUInt8TypeAlias().export()
-        || t == BaseModule.getUInt16TypeAlias().export()
-        || t == BaseModule.getUInt32TypeAlias().export()
-        || t == BaseModule.getUIntTypeAlias().export();
-  }
-
-  private static boolean isPreservedTypeAlias(TypeAlias t) {
-    return isIntTypeAlias(t);
-  }
-
-  @Override
-  public VmClass getVmClass() {
-    return RefModule.getReferenceClass();
-  }
-
-  @Override
-  public void force(boolean allowUndefinedValues) {
-    if (forced) return;
-
-    forced = true;
-
-    domain.force(allowUndefinedValues);
-    VmValue.force(data, allowUndefinedValues);
-    for (var elem : path) {
-      elem.force(allowUndefinedValues);
-    }
-  }
-
-  @Override
-  public Reference export() {
-    var pathList = new ArrayList<Composite>(path.size());
-    for (var elem : path) {
-      pathList.add(elem.export());
-    }
-
-    return new Reference(domain.export(), VmValue.export(data), pathList, getReferentType());
-  }
-
-  public PType exportType() {
-    return new PType.Class(
-        RefModule.getReferenceClass().export(),
-        new PType.Class(domain.getVmClass().export()),
-        getReferentType());
-  }
-
-  @Override
-  public void accept(VmValueVisitor visitor) {
-    visitor.visitReference(this);
-  }
-
-  @Override
-  public <T> T accept(VmValueConverter<T> converter, Iterable<Object> path) {
-    return converter.convertReference(this, path);
-  }
-
-  @Override
-  public boolean equals(@Nullable Object o) {
-    if (o == this) return true;
-    if (!(o instanceof VmReference that)) {
-      return false;
-    }
-
-    return domain.equals(that.domain)
-        && data.equals(that.data)
-        && path.equals(that.path)
-        && referentType.equals(that.referentType);
-  }
-
-  @Override
-  public int hashCode() {
-    int result = domain.hashCode();
-    result = 31 * result + data.hashCode();
-    result = 31 * result + path.hashCode();
-    result = 31 * result + referentType.hashCode();
-    return result;
-  }
-
-  // in-language calls _should_ all go through `ToStringNode`.
-  // however, some calls escape through to here currently (e.g. `Listing.join`).
-  @Override
-  public String toString() {
-    var toStringMethod = getVmClass().getDeclaredMethod(Identifier.TO_STRING);
-    assert toStringMethod != null;
-    var callNode = DirectCallNode.create(toStringMethod.getCallTarget());
-    return (String) callNode.call(this, getVmClass().getPrototype());
-  }
-}

pkl-core/src/main/java/org/pkl/core/runtime/VmTypeAlias.java

@@ -32,7 +32,6 @@ import org.pkl.core.TypeParameter;
 import org.pkl.core.ast.VmModifier;
 import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.ast.type.TypeNode.ConstrainedTypeNode;
-import org.pkl.core.ast.type.TypeNode.ReferenceTypeNode;
 import org.pkl.core.ast.type.TypeNode.TypeVariableNode;
 import org.pkl.core.ast.type.TypeNode.UnknownTypeNode;
 import org.pkl.core.util.LateInit;
@@ -178,8 +177,7 @@ public final class VmTypeAlias extends VmValue {
   }
 
   @TruffleBoundary
-  public TypeNode instantiate(
-      TypeNode[] typeArgumentNodes, SourceSection typeAliasTypeNodeSourceSection) {
+  public TypeNode instantiate(TypeNode[] typeArgumentNodes) {
     // Cloning the type node means that the entire type check remains within a single root node,
     // which should be good for interpreted and compiled performance alike:
     // * Fewer root nodes to call
@@ -201,13 +199,6 @@ public final class VmTypeAlias extends VmValue {
           }
           return true;
         });
-    clone.accept(
-        node -> {
-          if (node instanceof ReferenceTypeNode referenceTypeNode) {
-            referenceTypeNode.validateTypeArguments(typeAliasTypeNodeSourceSection);
-          }
-          return true;
-        });
 
     return clone;
   }
@@ -237,8 +228,7 @@ public final class VmTypeAlias extends VmValue {
                 simpleName,
                 getModuleName(),
                 qualifiedName,
-                typeParameters,
-                module.getVmClass().export());
+                typeParameters);
 
         for (var parameter : typeParameters) {
           parameter.initOwner(__pTypeAlias);

pkl-core/src/main/java/org/pkl/core/runtime/VmTypes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,7 +40,6 @@ import com.oracle.truffle.api.dsl.TypeSystem;
   VmRegex.class,
   VmTypeAlias.class,
   VmObjectLike.class,
-  VmReference.class,
-  VmValue.class,
+  VmValue.class
 })
 public class VmTypes {}

pkl-core/src/main/java/org/pkl/core/runtime/VmValueConverter.java

@@ -85,8 +85,6 @@ public interface VmValueConverter<T> {
 
   T convertFunction(VmFunction value, Iterable<Object> path);
 
-  T convertReference(VmReference value, Iterable<Object> path);
-
   /** Returns with an empty identifier if the second value is a RenderDirective */
   Pair<Identifier, T> convertProperty(ClassProperty property, Object value, Iterable<Object> path);
 

pkl-core/src/main/java/org/pkl/core/runtime/VmValueRenderer.java

@@ -271,30 +271,6 @@ public final class VmValueRenderer {
       append("null");
     }
 
-    @Override
-    public void visitReference(VmReference value) {
-      contexts.push(Context.EXPLICIT);
-      append("Reference(");
-      visit(value.getDomain());
-      append(", ");
-      append(value.getReferentType());
-      append(", ");
-      visit(value.getData());
-      append(")");
-      for (var elem : value.getPath()) {
-        var property = VmUtils.readMember(elem, Identifier.PROPERTY);
-        if (property instanceof String propName) {
-          append(".");
-          writeIdentifier(propName);
-        } else {
-          append("[");
-          visit(VmUtils.readMember(elem, Identifier.KEY));
-          append("]");
-        }
-      }
-      contexts.pop();
-    }
-
     private void append(Object value) {
       builder.append(value);
       checkLengthLimit();

pkl-core/src/main/java/org/pkl/core/runtime/VmValueVisitor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -60,8 +60,6 @@ public interface VmValueVisitor {
 
   void visitFunction(VmFunction value);
 
-  void visitReference(VmReference value);
-
   default void visit(Object value) {
     Objects.requireNonNull(value, "Value to be visited must be non-null.");
 

pkl-core/src/main/java/org/pkl/core/stdlib/AbstractRenderer.java

@@ -34,7 +34,6 @@ import org.pkl.core.runtime.VmListing;
 import org.pkl.core.runtime.VmMap;
 import org.pkl.core.runtime.VmMapping;
 import org.pkl.core.runtime.VmNull;
-import org.pkl.core.runtime.VmReference;
 import org.pkl.core.runtime.VmSet;
 import org.pkl.core.runtime.VmTypeAlias;
 import org.pkl.core.runtime.VmTyped;
@@ -398,11 +397,6 @@ public abstract class AbstractRenderer implements VmValueVisitor {
     currSourceSection = prevSourceSection;
   }
 
-  @Override
-  public void visitReference(VmReference value) {
-    cannotRenderTypeAddConverter(value);
-  }
-
   protected void cannotRenderTypeAddConverter(VmValue value) {
     var builder =
         new VmExceptionBuilder()

pkl-core/src/main/java/org/pkl/core/stdlib/PklConverter.java

@@ -46,7 +46,6 @@ public final class PklConverter implements VmValueConverter<Object> {
   private final @Nullable VmFunction nullConverter;
   private final @Nullable VmFunction classConverter;
   private final @Nullable VmFunction typeAliasConverter;
-  private final @Nullable VmFunction referenceConverter;
 
   private PklConverter(
       VmMapping converters, VmMapping convertPropertyTransformers, Object rendererOrParser) {
@@ -77,7 +76,6 @@ public final class PklConverter implements VmValueConverter<Object> {
     nullConverter = typeConverters.get(BaseModule.getNullClass());
     classConverter = typeConverters.get(BaseModule.getClassClass());
     typeAliasConverter = typeConverters.get(BaseModule.getTypeAliasClass());
-    referenceConverter = typeConverters.get(RefModule.getReferenceClass());
   }
 
   public static final PklConverter NOOP =
@@ -201,11 +199,6 @@ public final class PklConverter implements VmValueConverter<Object> {
     return doConvert(value, path, nullConverter);
   }
 
-  @Override
-  public Object convertReference(VmReference value, Iterable<Object> path) {
-    return doConvert(value, path, referenceConverter);
-  }
-
   @Override
   public Pair<Identifier, Object> convertProperty(
       ClassProperty property, Object value, Iterable<Object> path) {

pkl-core/src/main/java/org/pkl/core/stdlib/base/ModuleClassNodes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,6 @@
  */
 package org.pkl.core.stdlib.base;
 
-import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Specialization;
 import java.net.URI;
@@ -31,16 +30,15 @@ public final class ModuleClassNodes {
     @Specialization
     @TruffleBoundary
     protected VmList eval(VmObjectLike self, VmObjectLike other) {
-      if (!self.isModuleObject()) {
-        CompilerDirectives.transferToInterpreter();
-        throw exceptionBuilder().evalError("expectedModuleAsReceiver").build();
-      }
-      if (!other.isModuleObject()) {
-        CompilerDirectives.transferToInterpreter();
-        throw exceptionBuilder().evalError("expectedModuleAsArgument").build();
-      }
       var selfKey = VmUtils.getModuleInfo(self).getModuleKey();
       var selfUri = selfKey.getUri();
+
+      if (!other.isModuleObject()) {
+        throw exceptionBuilder()
+            .evalError("expectedModule")
+            // No meaningful SourceSection available, in this case.
+            .build();
+      }
       var otherKey = VmUtils.getModuleInfo(other).getModuleKey();
       var otherUri = otherKey.getUri();
 

pkl-core/src/main/java/org/pkl/core/stdlib/protobuf/RendererNodes.java

@@ -59,7 +59,6 @@ import org.pkl.core.runtime.VmMap;
 import org.pkl.core.runtime.VmMapping;
 import org.pkl.core.runtime.VmNull;
 import org.pkl.core.runtime.VmPair;
-import org.pkl.core.runtime.VmReference;
 import org.pkl.core.runtime.VmRegex;
 import org.pkl.core.runtime.VmSet;
 import org.pkl.core.runtime.VmTyped;
@@ -555,12 +554,6 @@ public final class RendererNodes {
       builder.append(value);
     }
 
-    @Override
-    public void visitReference(VmReference value) {
-      writePropertyName();
-      builder.append(value);
-    }
-
     /**
      * Resolves types for the purpose of protobuf rendering. "Sees through" nullable types and type
      * aliases, simplifies variations of {@code Int} and {@code String} types (literate string

pkl-core/src/main/java/org/pkl/core/stdlib/ref/RefNodes.java

@@ -1,33 +0,0 @@
-/*
- * Copyright © 2026 Apple Inc. and the Pkl project authors. All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.pkl.core.stdlib.ref;
-
-import com.oracle.truffle.api.dsl.Specialization;
-import com.oracle.truffle.api.frame.VirtualFrame;
-import org.pkl.core.runtime.VmClass;
-import org.pkl.core.runtime.VmReference;
-import org.pkl.core.runtime.VmTyped;
-import org.pkl.core.stdlib.ExternalMethod3Node;
-
-public class RefNodes {
-  public abstract static class Reference extends ExternalMethod3Node {
-    @Specialization
-    protected VmReference eval(
-        VirtualFrame frame, VmTyped self, VmTyped domain, VmClass clazz, Object data) {
-      return new VmReference(domain, clazz, data);
-    }
-  }
-}

pkl-core/src/main/java/org/pkl/core/stdlib/ref/ReferenceNodes.java

@@ -1,46 +0,0 @@
-/*
- * Copyright © 2026 Apple Inc. and the Pkl project authors. All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.pkl.core.stdlib.ref;
-
-import com.oracle.truffle.api.dsl.Specialization;
-import org.pkl.core.runtime.VmList;
-import org.pkl.core.runtime.VmReference;
-import org.pkl.core.stdlib.ExternalMethod0Node;
-
-public class ReferenceNodes {
-  private ReferenceNodes() {}
-
-  public abstract static class getDomain extends ExternalMethod0Node {
-    @Specialization
-    protected Object eval(VmReference self) {
-      return self.getDomain();
-    }
-  }
-
-  public abstract static class getData extends ExternalMethod0Node {
-    @Specialization
-    protected Object eval(VmReference self) {
-      return self.getData();
-    }
-  }
-
-  public abstract static class getPath extends ExternalMethod0Node {
-    @Specialization
-    protected VmList eval(VmReference self) {
-      return VmList.create(self.getPath());
-    }
-  }
-}

pkl-core/src/main/java/org/pkl/core/stdlib/ref/package-info.java

@@ -1,4 +0,0 @@
-@NullMarked
-package org.pkl.core.stdlib.ref;
-
-import org.jspecify.annotations.NullMarked;

pkl-core/src/main/java/org/pkl/core/stdlib/reflect/ReflectNodes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,10 +32,7 @@ public final class ReflectNodes {
     @TruffleBoundary
     protected VmTyped eval(VmTyped self, VmTyped module) {
       if (!module.isModuleObject()) {
-        throw exceptionBuilder()
-            .evalError("expectedModuleAsArgument")
-            .withLocation(getArg1Node())
-            .build();
+        throw exceptionBuilder().evalError("expectedModule").withLocation(getArg1Node()).build();
       }
       return module.getModuleMirror();
     }

pkl-core/src/main/java/org/pkl/core/util/pklbinary/PklBinaryCode.java

@@ -33,7 +33,6 @@ public enum PklBinaryCode {
   TYPEALIAS((byte) 0x0D),
   FUNCTION((byte) 0x0E),
   BYTES((byte) 0x0F),
-  REFERENCE((byte) 0x20),
 
   PROPERTY((byte) 0x10),
   ENTRY((byte) 0x11),
@@ -66,7 +65,6 @@ public enum PklBinaryCode {
       case 0x0D -> PklBinaryCode.TYPEALIAS;
       case 0x0E -> PklBinaryCode.FUNCTION;
       case 0x0F -> PklBinaryCode.BYTES;
-      case 0x20 -> PklBinaryCode.REFERENCE;
 
       case 0x10 -> PklBinaryCode.PROPERTY;
       case 0x11 -> PklBinaryCode.ENTRY;

pkl-core/src/main/resources/org/pkl/core/errorMessages.properties

@@ -203,10 +203,7 @@ Class `{0}` does not have type parameters.
 notASubclassOfTyped=\
 Class `{0}` is not a subtype of `Typed`.
 
-expectedModuleAsReceiver=\
-Expected a module as the receiver, but got an object that amends a module.
-
-expectedModuleAsArgument=\
+expectedModule=\
 Expected a module as argument, but got an object that amends a module.
 
 wrongTypeArgumentCount=\
@@ -289,6 +286,11 @@ External members cannot have a body.
 abstractMemberCannotHaveBody=\
 Abstract members cannot have a body.
 
+abstractMemberInNonAbstractClass=\
+Cannot define an abstract member in a non-abstract class.\n\
+\n\
+A member can only be `abstract` if its enclosing class is also `abstract`.
+
 methodNotDefined1=\
 Method `{0}` is not defined for argument type `{1}`.
 
@@ -388,9 +390,6 @@ Cannot find property `{0}` in object of type `{1}`.\n\
 Did you mean any of the following?\n\
 {2}
 
-cannotFindPropertyInReference=\
-Cannot find property `{0}` in object of type `{1}`.
-
 cannotFindMethodInScope=\
 Cannot find method `{0}`.
 
@@ -862,9 +861,6 @@ Package URIs must have an authority component.\n\
 \n\
 For example, `example.com` in URI `project://example.com/my/package@1.0.0`.
 
-invalidRelativePathInPackageUri=\
-Package URIs cannot contain `..` segments in the URI's "path" component.
-
 unexpectedChecksumInPackageUri=\
 Did not expect to find a checksum component in this package URI.
 
@@ -1181,5 +1177,12 @@ Cannot follow redirect from ''https:'' URL to ''http:'' URL.\
 HTTP Request: `GET {0}`\n\
 Redirected to: `{1}`
 
-invalidReferenceTypeAnnotationWithConstraint=\
-`Reference` referent type argument may not include type constraints.
+noImplementationForAbstractProperty=\
+Class `{0}` should either be declared `abstract`, or should implement property `{1}`.
+
+noImplementationForAbstractMethod=\
+Class `{0}` should either be declared `abstract`, or should implement method `{1}`.
+
+noImplementationForAbstractMembers=\
+Class `{0}` should either be declared `abstract`, or implement the following members:\n\
+{1}

pkl-core/src/test/files/LanguageSnippetTests/input-helper/classes/AbstractModule.pkl

@@ -0,0 +1,3 @@
+abstract module Foo
+
+abstract bar: Int

pkl-core/src/test/files/LanguageSnippetTests/input-helper/errors/ReferencedModule.pkl

@@ -1 +0,0 @@
-foo: String

pkl-core/src/test/files/LanguageSnippetTests/input-helper/errors/ReferencedModuleWithOutputOverride.pkl

@@ -1,7 +0,0 @@
-open module ReferencedModuleWithOutputOverride
-
-foo: String
-
-hidden output: ModuleOutput = new {
-  text = foo
-}

pkl-core/src/test/files/LanguageSnippetTests/input/api/reference.pkl

@@ -1,134 +0,0 @@
-import "pkl:math"
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String =
-    let (data = reference.getData())
-    let (root = if (data is Resource) data.name else data.toString())
-    let (
-      path =
-        reference
-          .getPath()
-          .map((elem) -> if (elem.isProperty) ".\(elem.property)" else "[\(elem.key)]")
-    )
-      "${\(root)\(path.join(""))}"
-}
-
-local const d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-abstract class Resource {
-  name: String
-  hidden fixed $: Ref<Resource>
-}
-
-class A extends Resource {
-  id: String
-  hidden outputs: AProperties
-  hidden fixed $: Ref<A> = ref.Reference(d, A, this)
-}
-
-/// Test doc comment
-class AProperties {
-  foo: Int
-  someMapping: Mapping<String, Int?>
-  someMap: Map<MapKey, Int>
-  someListing: Listing<Int>
-  someList: List<Int>
-  nonInt: String
-}
-
-class B extends Resource {
-  id: String
-  hidden outputs: BProperties
-  hidden fixed $: Ref<B> = ref.Reference(d, B, this)
-}
-
-class BProperties {
-  foo: String
-  someMapping: Mapping<String, String?>
-  someMap: Map<MapKey, String>
-  someListing: Listing<String>
-  someList: List<String>
-  nonString: Int
-}
-
-class MapKey {
-  k: Int
-
-  function toString(): String = "key:\(k)"
-}
-
-class K {
-  aId: String | *Ref<String>?
-  bId: String | *Ref<String>?
-  aProperties: AProperties | *Ref<AProperties>?
-  bProperties: BProperties | *Ref<BProperties>?
-  aValues: Listing<Int | Ref<Int?>>?
-  bValues: Listing<String | Ref<String?>>?
-  splitUnion: Ref<Listing<String> | Listing<Int>>?
-}
-
-a: A = new {
-  name = "a"
-  id = "some-a-value"
-}
-
-b: B = new {
-  name = "b"
-  id = "some-b-value"
-}
-
-aOrB: A | B = a
-aRef: Ref<A> = a.$
-bRef: Ref<B> = b.$
-unknownRef: Ref<A | B> = aRef
-unknownRef2: Ref<A> | Ref<B> = aRef
-unknownRef3: Ref<B | A> = aOrB.$
-
-k: K = new {
-  aId = aRef.id
-  bId = bRef.id
-  aProperties = aRef.outputs
-  bProperties = bRef.outputs
-  aValues {
-    aRef.outputs.foo
-    aRef.outputs.someMapping["key"]
-    aRef.outputs.someMap[new MapKey { k = 123 }]
-    aRef.outputs.someListing[0]
-    aRef.outputs.someList[math.maxInt]
-    bRef.outputs.nonString
-  }
-  bValues {
-    bRef.outputs.foo
-    bRef.outputs.someMapping["key"]
-    bRef.outputs.someMap[new MapKey { k = 123 }]
-    bRef.outputs.someListing[0]
-    bRef.outputs.someList[math.maxInt]
-    aRef.outputs.nonInt
-  }
-}
-
-j: K = new {
-  local aRef2 = unknownRef as Ref<A>
-  aProperties = aRef2.outputs
-  splitUnion = unknownRef.outputs.someListing
-}
-
-refInterpolation = "\(aRef.outputs.someListing[1])"
-kInterpolation = "\(k)"
-aValuesJoined = k.aValues.join("\n")
-
-// ensure that type arguments that are unions are handled correctly
-typeArgs = ref.Reference(d, TypeHolder, null).prop as Ref<Listing<Number | Boolean | String>>
-class TypeHolder {
-  prop: Listing<String | Boolean | Number>
-}
-
-output {
-  renderer {
-    converters {
-      [ref.Reference] = (it) -> it.toString()
-    }
-  }
-}

pkl-core/src/test/files/LanguageSnippetTests/input/basic/reference.pkl

@@ -1,55 +0,0 @@
-amends "../snippetTest.pkl"
-
-import "pkl:ref"
-
-local class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = reference.getData().toString()
-}
-
-local const d: D = new {}
-local typealias Ref<T> = ref.Reference<D, T>
-
-local class Holder {
-  num: Int
-  text: String
-  lit: "literal"
-  small: Int8
-  optional: Mapping<String, Int?>
-  listing: Listing<Int>
-  union: Listing<String> | Listing<Int>
-}
-
-local const h: Holder = new {
-  num = 1
-  text = "t"
-  lit = "literal"
-  small = 8
-  optional { ["k"] = 5 }
-  listing { 1; 2 }
-  union = new Listing<Int> { 1 }
-}
-
-local hRef1: Ref<Holder> = ref.Reference(d, Holder, h)
-local hRef2: Ref<Holder> = ref.Reference(d, Holder, h)
-
-facts {
-  ["equality"] {
-    hRef1 == hRef2
-    hRef1.num == hRef2.num
-    hRef1.lit == hRef2.lit
-    hRef1.small == hRef2.small
-    hRef1.optional["k"] == hRef2.optional["k"]
-    hRef1.listing[0] == hRef2.listing[0]
-    hRef1.union == hRef2.union
-  }
-
-  ["inequality"] {
-    hRef1.num != hRef2.text
-  }
-
-  ["set deduplication"] {
-    Set(hRef1.num, hRef2.num).length == 1
-    Set(hRef1.union, hRef2.union).length == 1
-    Set(hRef1.num, hRef2.text).length == 2
-  }
-}

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberInNonAbstractClass.pkl

@@ -0,0 +1,5 @@
+class Foo {
+  abstract bar: Int
+}
+
+res = new Foo { bar = 5 }

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberInNonAbstractModule.pkl

@@ -0,0 +1 @@
+abstract foo: Int

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented1.pkl

@@ -0,0 +1,19 @@
+abstract class AbstractProperty {
+  abstract foo: Int
+}
+
+abstract class AbstractMethod {
+  abstract function foo(): Int
+}
+
+abstract class AbstractPropertiesAndMethods {
+  abstract foo: Int
+  abstract bar: Int
+  abstract function foo(): Int
+  abstract function bar(): Int
+}
+
+class MyClass extends AbstractProperty {
+}
+
+foo: MyClass

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented2.pkl

@@ -0,0 +1,9 @@
+abstract class AbstractMethod {
+  abstract function foo(): Int
+}
+
+class MyClass extends AbstractMethod {
+}
+
+foo: MyClass
+

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented3.pkl

@@ -0,0 +1,10 @@
+abstract class AbstractPropertiesAndMethods {
+  abstract foo: Int
+  abstract bar: Int
+  abstract function foo(): Int
+  abstract function bar(): Int
+}
+
+class MyClass extends AbstractPropertiesAndMethods {}
+
+foo: MyClass

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMemberNotImplemented4.pkl

@@ -0,0 +1 @@
+extends "../../input-helper/classes/AbstractModule.pkl"

pkl-core/src/test/files/LanguageSnippetTests/input/errors/abstractMethodInNonAbstractClass.pkl

@@ -0,0 +1,5 @@
+class Foo {
+  abstract function bar(): Int
+}
+
+res = new Foo {}

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference1.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-test = ref.Reference(d, String, "") as Ref<Int>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference10.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-typealias Ref<T> = ref.Reference<D, T>
-local d: D = new {}
-
-test = ref.Reference(d, String, "") as Ref<Listing<String(true)>>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference11.pkl

@@ -1,12 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-typealias Ref<T> = ref.Reference<D, T>
-local d: D = new {}
-
-test = ref.Reference(d, String, "") as Ref<Alias1?>
-
-typealias Alias1 = Int | Alias2?
-typealias Alias2 = String(length < 5)

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference12.pkl

@@ -1,12 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-typealias RefAlias1 = ref.Reference<D, Alias1?>
-local d: D = new {}
-
-test = ref.Reference(d, String, "") as RefAlias1
-
-typealias Alias1 = Int | Alias2?
-typealias Alias2 = String(length < 5)

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference13.pkl

@@ -1,8 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, Mapping, "").default

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference14.pkl

@@ -1,8 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, Listing, "").default

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference15.pkl

@@ -1,8 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, Dynamic, "").default

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference16.pkl

@@ -1,10 +0,0 @@
-import "pkl:ref"
-
-import ".../input-helper/errors/ReferencedModule.pkl"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, ReferencedModule.getClass(), "").output

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference17.pkl

@@ -1,10 +0,0 @@
-import "pkl:ref"
-
-import ".../input-helper/errors/ReferencedModuleWithOutputOverride.pkl"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, ReferencedModuleWithOutputOverride.getClass(), "").output

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference18.pkl

@@ -1,12 +0,0 @@
-import "pkl:ref"
-
-import ".../input-helper/errors/ReferencedModuleWithOutputOverride.pkl"
-
-class ModuleSubclass extends ReferencedModuleWithOutputOverride
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, ModuleSubclass, "").output

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference19.pkl

@@ -1,12 +0,0 @@
-import "pkl:ref"
-
-class A {
-  foo: String | Int | Boolean
-}
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-test = ref.Reference(d, A, "").foo as ref.Reference<D, Int | Boolean>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference2.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-test = ref.Reference(d, String, "") as Ref<Boolean | Int>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference20.pkl

@@ -1,15 +0,0 @@
-import "pkl:ref"
-
-class A {
-  foo: String | Int | Boolean
-}
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-
-local test = ref.Reference(d, A, "").foo
-testInterpolation = "test:\(test)"
-
-// this tests that the interpolation appears in the output when referenceToString throws

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference3.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-test = ref.Reference(d, String, "") as Ref<Listing<String>>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference4.pkl

@@ -1,12 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-test = ref.Reference(d, String, "") as Ref<Alias1?>
-
-typealias Alias1 = Int | Alias2?
-typealias Alias2 = Boolean

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference5.pkl

@@ -1,14 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-class D2 extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d2: D2 = new {}
-
-test = ref.Reference(d2, String, "") as Ref<String>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference6.pkl

@@ -1,13 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-class A {
-  b: String
-}
-
-test = ref.Reference(d, String, new A {}).c

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference7.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-local d: D = new {}
-typealias Ref<T> = ref.Reference<D, T>
-
-test = ref.Reference(d, List, List())["hi"]

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference8.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-typealias Ref<T> = ref.Reference<D, T>
-local d: D = new {}
-
-test = ref.Reference(d, String, "") as Ref<String(true)>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/reference9.pkl

@@ -1,9 +0,0 @@
-import "pkl:ref"
-
-class D extends ref.Domain {
-  function renderReference(reference: ref.Reference<D, Any>): String = throw("not supported")
-}
-typealias Ref<T> = ref.Reference<D, T>
-local d: D = new {}
-
-test = ref.Reference(d, String, "") as Ref<String(true) | Int>

pkl-core/src/test/files/LanguageSnippetTests/input/errors/relativePathToNotAModule1.pkl

@@ -1,7 +0,0 @@
-local objectThatAmendsModule = (module) {
-  // add a local property to force this into a new object amends;
-  // empty object amends are optimized away.
-  local qux = 1
-}
-
-res = objectThatAmendsModule.relativePathTo(module)

pkl-core/src/test/files/LanguageSnippetTests/input/errors/relativePathToNotAModule2.pkl

@@ -1,8 +0,0 @@
-local objectThatAmendsModule = (module) {
-  // add a local property to force this into a new object amends;
-  // empty object amends are optimized away.
-  local qux = 1
-}
-
-res = module.relativePathTo(objectThatAmendsModule)
-

pkl-core/src/test/files/LanguageSnippetTests/input/packages/badImport12.error.pkl

@@ -1,2 +0,0 @@
-// relative path in package URI
-res = import("package://localhost:0/%2e%2e/birds@0.5.0#/catalog/Bird.pkl")

pkl-core/src/test/files/LanguageSnippetTests/output/api/reference.pcf

@@ -1,60 +0,0 @@
-a {
-  name = "a"
-  id = "some-a-value"
-}
-b {
-  name = "b"
-  id = "some-b-value"
-}
-aOrB {
-  name = "a"
-  id = "some-a-value"
-}
-aRef = "${a}"
-bRef = "${b}"
-unknownRef = "${a}"
-unknownRef2 = "${a}"
-unknownRef3 = "${a}"
-k {
-  aId = "${a.id}"
-  bId = "${b.id}"
-  aProperties = "${a.outputs}"
-  bProperties = "${b.outputs}"
-  aValues {
-    "${a.outputs.foo}"
-    "${a.outputs.someMapping[key]}"
-    "${a.outputs.someMap[key:123]}"
-    "${a.outputs.someListing[0]}"
-    "${a.outputs.someList[9223372036854775807]}"
-    "${b.outputs.nonString}"
-  }
-  bValues {
-    "${b.outputs.foo}"
-    "${b.outputs.someMapping[key]}"
-    "${b.outputs.someMap[key:123]}"
-    "${b.outputs.someListing[0]}"
-    "${b.outputs.someList[9223372036854775807]}"
-    "${a.outputs.nonInt}"
-  }
-  splitUnion = null
-}
-j {
-  aId = null
-  bId = null
-  aProperties = "${a.outputs}"
-  bProperties = null
-  aValues = null
-  bValues = null
-  splitUnion = "${a.outputs.someListing}"
-}
-refInterpolation = "${a.outputs.someListing[1]}"
-kInterpolation = "new K { aId = Reference(new D {}, String, new A { name = \"a\"; id = \"some-a-value\" }).id; bId = Reference(new D {}, String, new B { name = \"b\"; id = \"some-b-value\" }).id; aProperties = Reference(new D {}, reference#AProperties, new A { name = \"a\"; id = \"some-a-value\" }).outputs; bProperties = Reference(new D {}, reference#BProperties, new B { name = \"b\"; id = \"some-b-value\" }).outputs; aValues { Reference(new D {}, Int, new A { name = \"a\"; id = \"some-a-value\" }).outputs.foo; Reference(new D {}, Int | Null, new A { name = \"a\"; id = \"some-a-value\" }).outputs.someMapping[\"key\"]; Reference(new D {}, Int, new A { name = \"a\"; id = \"some-a-value\" }).outputs.someMap[new MapKey { k = 123 }]; Reference(new D {}, Int, new A { name = \"a\"; id = \"some-a-value\" }).outputs.someListing[0]; Reference(new D {}, Int, new A { name = \"a\"; id = \"some-a-value\" }).outputs.someList[9223372036854775807]; Reference(new D {}, Int, new B { name = \"b\"; id = \"some-b-value\" }).outputs.nonString }; bValues { Reference(new D {}, String, new B { name = \"b\"; id = \"some-b-value\" }).outputs.foo; Reference(new D {}, Null | String, new B { name = \"b\"; id = \"some-b-value\" }).outputs.someMapping[\"key\"]; Reference(new D {}, String, new B { name = \"b\"; id = \"some-b-value\" }).outputs.someMap[new MapKey { k = 123 }]; Reference(new D {}, String, new B { name = \"b\"; id = \"some-b-value\" }).outputs.someListing[0]; Reference(new D {}, String, new B { name = \"b\"; id = \"some-b-value\" }).outputs.someList[9223372036854775807]; Reference(new D {}, String, new A { name = \"a\"; id = \"some-a-value\" }).outputs.nonInt }; splitUnion = null }"
-aValuesJoined = """
-  ${a.outputs.foo}
-  ${a.outputs.someMapping[key]}
-  ${a.outputs.someMap[key:123]}
-  ${a.outputs.someListing[0]}
-  ${a.outputs.someList[9223372036854775807]}
-  ${b.outputs.nonString}
-  """
-typeArgs = "${null.prop}"

pkl-core/src/test/files/LanguageSnippetTests/output/basic/reference.pcf

@@ -1,19 +0,0 @@
-facts {
-  ["equality"] {
-    true
-    true
-    true
-    true
-    true
-    true
-    true
-  }
-  ["inequality"] {
-    true
-  }
-  ["set deduplication"] {
-    true
-    true
-    true
-  }
-}

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberInNonAbstractClass.err

@@ -0,0 +1,8 @@
+–– Pkl Error ––
+Cannot define an abstract member in a non-abstract class.
+
+x | abstract bar: Int
+    ^^^^^^^^
+at abstractMemberInNonAbstractClass#Foo (file:///$snippetsDir/input/errors/abstractMemberInNonAbstractClass.pkl)
+
+A member can only be `abstract` if its enclosing class is also `abstract`.

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberInNonAbstractModule.err

@@ -0,0 +1,8 @@
+–– Pkl Error ––
+Cannot define an abstract member in a non-abstract class.
+
+x | abstract foo: Int
+    ^^^^^^^^
+at abstractMemberInNonAbstractModule (file:///$snippetsDir/input/errors/abstractMemberInNonAbstractModule.pkl)
+
+A member can only be `abstract` if its enclosing class is also `abstract`.

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented1.err

@@ -0,0 +1,10 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented1#MyClass` should either be declared `abstract`, or should implement property `foo`.
+
+xx | class MyClass extends AbstractProperty {
+     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented1#MyClass (file:///$snippetsDir/input/errors/abstractMemberNotImplemented1.pkl)
+
+xx | foo: MyClass
+          ^^^^^^^
+at abstractMemberNotImplemented1 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented1.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented2.err

@@ -0,0 +1,10 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented2#MyClass` should either be declared `abstract`, or should implement method `foo`.
+
+x | class MyClass extends AbstractMethod {
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented2#MyClass (file:///$snippetsDir/input/errors/abstractMemberNotImplemented2.pkl)
+
+x | foo: MyClass
+         ^^^^^^^
+at abstractMemberNotImplemented2 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented2.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented3.err

@@ -0,0 +1,14 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented3#MyClass` should either be declared `abstract`, or implement the following members:
+* property `foo`
+* property `bar`
+* method `foo`
+* method `bar`
+
+x | class MyClass extends AbstractPropertiesAndMethods {}
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented3#MyClass (file:///$snippetsDir/input/errors/abstractMemberNotImplemented3.pkl)
+
+xx | foo: MyClass
+          ^^^^^^^
+at abstractMemberNotImplemented3 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented3.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMemberNotImplemented4.err

@@ -0,0 +1,6 @@
+–– Pkl Error ––
+Class `abstractMemberNotImplemented4` should either be declared `abstract`, or should implement property `bar`.
+
+x | extends "../../input-helper/classes/AbstractModule.pkl"
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMemberNotImplemented4 (file:///$snippetsDir/input/errors/abstractMemberNotImplemented4.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMethodInNonAbstractClass.err

@@ -0,0 +1,8 @@
+–– Pkl Error ––
+Cannot define an abstract member in a non-abstract class.
+
+x | abstract function bar(): Int
+    ^^^^^^^^
+at abstractMethodInNonAbstractClass#Foo (file:///$snippetsDir/input/errors/abstractMethodInNonAbstractClass.pkl)
+
+A member can only be `abstract` if its enclosing class is also `abstract`.

pkl-core/src/test/files/LanguageSnippetTests/output/errors/abstractMethodsNotImplemented.err

@@ -0,0 +1,10 @@
+–– Pkl Error ––
+Class `abstractMethodsNotImplemented#MyClass` either needs to be abstract, or should implement property `foo`.
+
+x | class MyClass extends MyAbstractClass {
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+at abstractMethodsNotImplemented#MyClass (file:///$snippetsDir/input/errors/abstractMethodsNotImplemented.pkl)
+
+x | foo: MyClass
+         ^^^^^^^
+at abstractMethodsNotImplemented (file:///$snippetsDir/input/errors/abstractMethodsNotImplemented.pkl)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/cannotFindStdLibModule.err

@@ -20,7 +20,6 @@ pkl:pklbinary
 pkl:platform
 pkl:Project
 pkl:protobuf
-pkl:ref
 pkl:reflect
 pkl:release
 pkl:semver

pkl-core/src/test/files/LanguageSnippetTests/output/errors/reference1.err

@@ -1,15 +0,0 @@
-–– Pkl Error ––
-Expected value of type `pkl.ref#Reference<reference1#D, Int>`, but got type `pkl.ref#Reference<reference1#D, String>`.
-Value: Reference(new D {}, String, "")
-
-x | typealias Ref<T> = ref.Reference<D, T>
-                       ^^^^^^^^^^^^^^^^^^^
-at reference1#test (file:///$snippetsDir/input/errors/reference1.pkl)
-
-xxx | renderer.renderDocument(value)
-      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-at pkl.base#Module.output.text (pkl:base)
-
-xxx | if (renderer is BytesRenderer) renderer.renderDocument(value) else text.encodeToBytes("UTF-8")
-                                                                         ^^^^
-at pkl.base#Module.output.bytes (pkl:base)

pkl-core/src/test/files/LanguageSnippetTests/output/errors/reference10.err

@@ -1,14 +0,0 @@
-–– Pkl Error ––
-`Reference` referent type argument may not include type constraints.
-
-x | test = ref.Reference(d, String, "") as Ref<Listing<String(true)>>
-                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^
-at reference10#test (file:///$snippetsDir/input/errors/reference10.pkl)
-
-xxx | renderer.renderDocument(value)
-      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-at pkl.base#Module.output.text (pkl:base)
-
-xxx | if (renderer is BytesRenderer) renderer.renderDocument(value) else text.encodeToBytes("UTF-8")
-                                                                         ^^^^
-at pkl.base#Module.output.bytes (pkl:base)