Fix many editor diagnostics (#1707)

This addresses many IDE warnings resulting from the switch to JSpecify.

Also, this changes the behavior of exporting VmObject; there's no place
in our code that does not force a VmObject prior to export, so
the existing logic around handling nullable values has been removed.

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

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -69,11 +69,11 @@ public record ImportGraph(Map<URI, Set<Import>> imports, Map<URI, URI> resolvedI
         var value = entry.getValue();
         var set = new TreeSet<Import>();
         if (!(value instanceof JsArray array)) {
-          throw new FormatException("array", value.getClass());
+          throw new FormatException("array", value == null ? Void.class : value.getClass());
         }
         for (var elem : array) {
           if (!(elem instanceof JsObject importObj)) {
-            throw new FormatException("object", elem.getClass());
+            throw new FormatException("object", elem == null ? Void.class : elem.getClass());
           }
           set.add(parseImport(importObj));
         }
@@ -98,7 +98,7 @@ public record ImportGraph(Map<URI, Set<Import>> imports, Map<URI, URI> resolvedI
         var key = new URI(entry.getKey());
         var value = entry.getValue();
         if (!(value instanceof String str)) {
-          throw new FormatException("string", value.getClass());
+          throw new FormatException("string", value == null ? Void.class : value.getClass());
         }
         var valueUri = new URI(str);
         ret.put(key, valueUri);

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

@@ -109,6 +109,8 @@ final class JsonRenderer implements ValueRenderer {
               "Values of type `Bytes` cannot be rendered as JSON. Value: %s", (Object) value));
     }
 
+    // Pair coming from the runtime can never admit null (in-language null is represented as PNull)
+    @SuppressWarnings("DataFlowIssue")
     @Override
     public void visitPair(Pair<?, ?> value) {
       try {

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

@@ -18,7 +18,6 @@ package org.pkl.core;
 import java.net.URI;
 import java.util.*;
 import org.jspecify.annotations.Nullable;
-import org.pkl.core.util.LateInit;
 
 /** Describes the property, method and class members of a module. */
 public final class ModuleSchema {
@@ -33,8 +32,8 @@ public final class ModuleSchema {
   private final Map<String, TypeAlias> typeAliases;
   private final Map<String, URI> imports;
 
-  @LateInit private Map<String, PClass> __allClasses;
+  private @Nullable Map<String, PClass> __allClasses;
-  @LateInit private Map<String, TypeAlias> __allTypeAliases;
+  private @Nullable Map<String, TypeAlias> __allTypeAliases;
 
   /** Constructs a {@code ModuleSchema} instance. */
   public ModuleSchema(

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

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -227,9 +227,7 @@ final class PcfRenderer implements ValueRenderer {
             write(currIndent);
             writeIdentifier(name);
 
-            if (value == null) { // unevaluated property
+            if (value instanceof Composite) {
-              write(" = ?");
-            } else if (value instanceof Composite) {
               write(' ');
               visit(value);
             } else {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * 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.
@@ -21,7 +21,9 @@ import java.io.UncheckedIOException;
 import java.net.URI;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.regex.Pattern;
+import org.jspecify.annotations.Nullable;
 import org.msgpack.core.MessagePack;
 import org.msgpack.core.MessageUnpacker;
 import org.pkl.core.runtime.BaseModule;
@@ -111,7 +113,7 @@ public class PklBinaryDecoder extends AbstractPklBinaryDecoder {
 
   @Override
   protected Object doDecodeMap(MapDecodeIterator iter) {
-    var map = CollectionUtils.newLinkedHashMap(iter.getSize());
+    Map<@Nullable Object, @Nullable Object> map = CollectionUtils.newLinkedHashMap(iter.getSize());
     while (iter.hasNext()) {
       var entry = iter.next();
       map.put(entry.getFirst(), entry.getSecond());

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

@@ -54,6 +54,9 @@ final class PropertiesRenderer implements ValueRenderer {
       } else if (value instanceof Map<?, ?> map) {
         doVisitMap(null, map);
       } else if (value instanceof Pair<?, ?> pair) {
+        // Pair coming from the runtime can never admit null (in-language null is represented as
+        // PNull)
+        //noinspection DataFlowIssue
         doVisitKeyAndValue(null, pair.getFirst(), pair.getSecond());
       } else {
         throw new RendererException(

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

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -17,7 +17,7 @@ package org.pkl.core;
 
 import java.io.Serial;
 import java.io.Serializable;
-import org.pkl.core.util.LateInit;
+import org.jspecify.annotations.Nullable;
 
 /** A type parameter of a generic class, type alias, or method. */
 public final class TypeParameter implements Serializable {
@@ -27,7 +27,7 @@ public final class TypeParameter implements Serializable {
   private final String name;
   private final int index;
 
-  @LateInit private volatile Member owner;
+  private volatile @Nullable Member owner;
 
   public TypeParameter(Variance variance, String name, int index) {
     this.variance = variance;
@@ -48,6 +48,7 @@ public final class TypeParameter implements Serializable {
   /** Returns the generic class, type alias, or method that this type parameter belongs to. */
   public Member getOwner() {
     assert owner != null;
+    //noinspection DataFlowIssue
     return owner;
   }
 

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

@@ -18,7 +18,6 @@ package org.pkl.core;
 import java.util.*;
 import java.util.regex.*;
 import org.jspecify.annotations.Nullable;
-import org.pkl.core.util.LateInit;
 
 /**
  * A <a href="https://semver.org/spec/v2.0.0.html">semantic version</a>.
@@ -59,7 +58,7 @@ public final class Version implements Comparable<Version> {
   private final @Nullable String preRelease;
   private final @Nullable String build;
 
-  @LateInit private volatile Identifier[] __preReleaseIdentifiers;
+  private volatile Identifier @Nullable [] __preReleaseIdentifiers;
 
   /** Constructs a semantic version. */
   public Version(
@@ -230,6 +229,7 @@ public final class Version implements Comparable<Version> {
                               : new Identifier(-1, str))
                   .toArray(Identifier[]::new);
     }
+    //noinspection DataFlowIssue
     return __preReleaseIdentifiers;
   }
 

pkl-core/src/main/java/org/pkl/core/ast/expression/literal/BytesLiteralNode.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * 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.
@@ -20,19 +20,19 @@ import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
 import com.oracle.truffle.api.nodes.NodeInfo;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.ast.type.TypeNode.UInt8TypeAliasTypeNode;
 import org.pkl.core.ast.type.VmTypeMismatchException;
 import org.pkl.core.runtime.VmBytes;
 import org.pkl.core.runtime.VmUtils;
-import org.pkl.core.util.LateInit;
 
 @NodeInfo(shortName = "Bytes()")
 public final class BytesLiteralNode extends ExpressionNode {
   @Children private final ExpressionNode[] elements;
 
-  @Child @LateInit private TypeNode typeNode;
+  @Child private @Nullable TypeNode typeNode;
 
   public BytesLiteralNode(SourceSection sourceSection, ExpressionNode[] elements) {
     super(sourceSection);

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

@@ -22,6 +22,7 @@ import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.DirectCallNode;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.runtime.Identifier;
 import org.pkl.core.runtime.VmObjectLike;
@@ -34,7 +35,7 @@ public abstract sealed class AbstractInvokeMethodLexicalNode extends ExpressionN
   protected final int levelsUp;
   private final boolean needsConst;
   @Children private ExpressionNode[] argumentNodes;
-  @Child private DirectCallNode callNode;
+  @Child private @Nullable DirectCallNode callNode;
   @CompilationFinal protected boolean isConstChecked;
 
   protected AbstractInvokeMethodLexicalNode(
@@ -90,6 +91,7 @@ public abstract sealed class AbstractInvokeMethodLexicalNode extends ExpressionN
       callNode = DirectCallNode.create(getCallTarget(owner));
       insert(callNode);
     }
+    assert callNode != null;
     return callNode;
   }
 }

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

@@ -19,17 +19,17 @@ import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.type.TypeNode.UnknownTypeNode;
 import org.pkl.core.runtime.*;
-import org.pkl.core.util.LateInit;
 
 /** Infers the parent to amend in `function createPerson(): Person = new { ... }`. */
 public final class InferParentWithinMethodNode extends ExpressionNode {
   private final VmLanguage language;
   private final Identifier methodName;
-  @Child private ExpressionNode ownerNode;
+  @Child private @Nullable ExpressionNode ownerNode;
-  @CompilationFinal @LateInit private Object inferredParent;
+  @CompilationFinal private @Nullable Object inferredParent;
 
   public InferParentWithinMethodNode(
       SourceSection sourceSection,
@@ -52,6 +52,7 @@ public final class InferParentWithinMethodNode extends ExpressionNode {
 
     CompilerDirectives.transferToInterpreter();
 
+    assert ownerNode != null;
     var owner = (VmObjectLike) ownerNode.executeGeneric(frame);
     assert owner.isPrototype();
 

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

@@ -19,6 +19,7 @@ import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.member.ObjectMethodNode;
 import org.pkl.core.ast.type.TypeNode.UnknownTypeNode;
@@ -26,14 +27,13 @@ import org.pkl.core.runtime.Identifier;
 import org.pkl.core.runtime.VmDynamic;
 import org.pkl.core.runtime.VmLanguage;
 import org.pkl.core.runtime.VmObjectLike;
-import org.pkl.core.util.LateInit;
 
 /** Infers the parent to amend in `obj { local function createPerson(): Person = new { ... } }`. */
 public final class InferParentWithinObjectMethodNode extends ExpressionNode {
   private final VmLanguage language;
   private final Identifier localMethodName;
-  @Child private ExpressionNode ownerNode;
+  @Child private @Nullable ExpressionNode ownerNode;
-  @CompilationFinal @LateInit private Object inferredParent;
+  @CompilationFinal private @Nullable Object inferredParent;
 
   public InferParentWithinObjectMethodNode(
       SourceSection sourceSection,
@@ -58,6 +58,7 @@ public final class InferParentWithinObjectMethodNode extends ExpressionNode {
 
     CompilerDirectives.transferToInterpreter();
 
+    assert ownerNode != null;
     var owner = (VmObjectLike) ownerNode.executeGeneric(frame);
 
     var member = owner.getMember(localMethodName);

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

@@ -18,6 +18,7 @@ package org.pkl.core.ast.expression.member;
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.MemberLookupMode;
 import org.pkl.core.ast.expression.primary.GetEnclosingReceiverNode;
@@ -49,8 +50,8 @@ public final class ReadAmbiguousLocalityPropertyNode extends ExpressionNode {
   private final Identifier name;
   private final int levelsUp;
   private final boolean needsConst;
-  private @Child ExpressionNode readLocalPropertyNode;
+  @Child private @Nullable ExpressionNode readLocalPropertyNode;
-  private @Child ExpressionNode readPropertyNode;
+  @Child private @Nullable ExpressionNode readPropertyNode;
 
   public ReadAmbiguousLocalityPropertyNode(
       SourceSection sourceSection, Identifier name, int levelsUp, boolean needsConst) {

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

@@ -22,6 +22,7 @@ import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.DirectCallNode;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PklBugException;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.member.ObjectMember;
@@ -34,8 +35,8 @@ public final class ReadLocalPropertyNode extends ExpressionNode {
   private final Identifier name;
   private final int levelsUp;
   private final boolean needsConst;
-  @Child private DirectCallNode callNode;
+  @Child private @Nullable DirectCallNode callNode;
-  @CompilationFinal private ObjectMember property;
+  @CompilationFinal @Nullable private ObjectMember property;
 
   public ReadLocalPropertyNode(
       SourceSection sourceSection, Identifier name, int levelsUp, boolean needsConst) {
@@ -91,6 +92,7 @@ public final class ReadLocalPropertyNode extends ExpressionNode {
       callNode = DirectCallNode.create(property.getCallTarget());
       insert(callNode);
     }
+    assert callNode != null;
     return callNode;
   }
 }

pkl-core/src/main/java/org/pkl/core/ast/expression/unary/ImportGlobNode.java

@@ -23,6 +23,7 @@ import com.oracle.truffle.api.nodes.NodeInfo;
 import com.oracle.truffle.api.source.SourceSection;
 import java.io.IOException;
 import java.net.URI;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.SecurityManagerException;
 import org.pkl.core.ast.member.SharedMemberNode;
 import org.pkl.core.externalreader.ExternalReaderProcessException;
@@ -35,13 +36,12 @@ import org.pkl.core.runtime.VmMapping;
 import org.pkl.core.runtime.VmObjectBuilder;
 import org.pkl.core.util.GlobResolver;
 import org.pkl.core.util.GlobResolver.InvalidGlobPatternException;
-import org.pkl.core.util.LateInit;
 
 @NodeInfo(shortName = "import*")
 public class ImportGlobNode extends AbstractImportNode {
   private final String globPattern;
-  @Child @LateInit private SharedMemberNode memberNode;
+  @Child private @Nullable SharedMemberNode memberNode;
-  @CompilationFinal @LateInit private VmMapping cachedResult;
+  @CompilationFinal private @Nullable VmMapping cachedResult;
 
   public ImportGlobNode(
       SourceSection sourceSection,

pkl-core/src/main/java/org/pkl/core/ast/expression/unary/ImportNode.java

@@ -21,6 +21,7 @@ import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.NodeInfo;
 import com.oracle.truffle.api.source.SourceSection;
 import java.net.URI;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.SecurityManagerException;
 import org.pkl.core.http.HttpClientException;
 import org.pkl.core.module.ResolvedModuleKey;
@@ -28,13 +29,12 @@ import org.pkl.core.packages.PackageLoadError;
 import org.pkl.core.runtime.VmContext;
 import org.pkl.core.runtime.VmLanguage;
 import org.pkl.core.runtime.VmTyped;
-import org.pkl.core.util.LateInit;
 
 @NodeInfo(shortName = "import")
 public final class ImportNode extends AbstractImportNode {
   private final VmLanguage language;
 
-  @CompilationFinal @LateInit private VmTyped importedModule;
+  @CompilationFinal private @Nullable VmTyped importedModule;
 
   public ImportNode(
       VmLanguage language,

pkl-core/src/main/java/org/pkl/core/ast/expression/unary/ReadGlobNode.java

@@ -24,6 +24,7 @@ import com.oracle.truffle.api.source.SourceSection;
 import java.io.IOException;
 import java.net.URISyntaxException;
 import org.graalvm.collections.EconomicMap;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.SecurityManagerException;
 import org.pkl.core.ast.member.SharedMemberNode;
 import org.pkl.core.externalreader.ExternalReaderProcessException;
@@ -36,12 +37,11 @@ import org.pkl.core.runtime.VmObjectBuilder;
 import org.pkl.core.util.GlobResolver;
 import org.pkl.core.util.GlobResolver.InvalidGlobPatternException;
 import org.pkl.core.util.IoUtils;
-import org.pkl.core.util.LateInit;
 
 @NodeInfo(shortName = "read*")
 public abstract class ReadGlobNode extends AbstractReadNode {
   private final EconomicMap<String, VmMapping> cachedResults = EconomicMap.create();
-  @Child @LateInit private SharedMemberNode memberNode;
+  @Child private @Nullable SharedMemberNode memberNode;
 
   protected ReadGlobNode(SourceSection sourceSection, ModuleKey currentModule) {
     super(sourceSection, currentModule);
@@ -67,6 +67,7 @@ public abstract class ReadGlobNode extends AbstractReadNode {
   @TruffleBoundary
   public Object read(String globPattern) {
     var cachedResult = cachedResults.get(globPattern);
+    //noinspection ConstantValue
     if (cachedResult != null) return cachedResult;
 
     // use same check as for globbed imports (see AstBuilder)

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

@@ -26,6 +26,7 @@ import org.pkl.core.TypeParameter;
 import org.pkl.core.ast.VmModifier;
 import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.runtime.*;
+import org.pkl.core.util.LateInit;
 
 public final class ClassMethod extends ClassMember {
   private final List<TypeParameter> typeParameters;
@@ -33,7 +34,7 @@ public final class ClassMethod extends ClassMember {
   // null = not deprecated, "" = no/empty message in the @Deprecated body
   private final @Nullable String deprecation;
 
-  @CompilationFinal private FunctionNode functionNode;
+  @CompilationFinal @LateInit private FunctionNode functionNode;
 
   public ClassMethod(
       SourceSection sourceSection,
@@ -61,6 +62,7 @@ public final class ClassMethod extends ClassMember {
   }
 
   public void initFunctionNode(FunctionNode functionNode) {
+    //noinspection ConstantValue
     assert this.functionNode == null;
     this.functionNode = functionNode;
   }

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

@@ -84,6 +84,7 @@ public final class ClassNode extends ExpressionNode {
     // Caching of classes also guarantees that classes are singletons and can be compared by
     // identity,
     // which improves efficiency and performance (for example in shape checks).
+    //noinspection ConstantValue
     if (cachedClass != null) return cachedClass;
 
     CompilerDirectives.transferToInterpreter();

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

@@ -18,7 +18,6 @@ package org.pkl.core.ast.member;
 import com.oracle.truffle.api.frame.FrameDescriptor;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
-import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.PklRootNode;
 import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.runtime.VmLanguage;
@@ -46,7 +45,7 @@ public final class ListingOrMappingTypeCastNode extends PklRootNode {
   }
 
   @Override
-  public @Nullable String getName() {
+  public String getName() {
     return qualifiedName;
   }
 

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

@@ -23,12 +23,11 @@ import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.ast.type.UnresolvedTypeNode;
 import org.pkl.core.runtime.VmLanguage;
-import org.pkl.core.util.LateInit;
 
 public final class LocalTypedPropertyNode extends RegularMemberNode {
   private final VmLanguage language;
-  @Child private UnresolvedTypeNode unresolvedTypeNode;
+  @Child private @Nullable UnresolvedTypeNode unresolvedTypeNode;
-  @Child @LateInit private TypeNode typeNode;
+  @Child private @Nullable TypeNode typeNode;
   private @Nullable Object defaultValue;
   private boolean defaultValueInitialized;
 
@@ -47,6 +46,7 @@ public final class LocalTypedPropertyNode extends RegularMemberNode {
 
   public @Nullable Object getDefaultValue(VirtualFrame frame) {
     if (!defaultValueInitialized) {
+      assert typeNode != null;
       defaultValue =
           typeNode.createDefaultValue(
               frame, language, member.getHeaderSection(), member.getQualifiedName());
@@ -59,6 +59,7 @@ public final class LocalTypedPropertyNode extends RegularMemberNode {
   protected Object executeImpl(VirtualFrame frame) {
     if (typeNode == null) {
       CompilerDirectives.transferToInterpreter();
+      assert unresolvedTypeNode != null;
       typeNode = insert(unresolvedTypeNode.execute(frame));
       unresolvedTypeNode = null;
     }

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

@@ -25,7 +25,6 @@ import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.ast.type.UnresolvedTypeNode;
 import org.pkl.core.runtime.*;
-import org.pkl.core.util.LateInit;
 
 public final class ObjectMethodNode extends RegularMemberNode {
   private final VmLanguage language;
@@ -33,7 +32,7 @@ public final class ObjectMethodNode extends RegularMemberNode {
   @Children private final @Nullable UnresolvedTypeNode[] unresolvedParameterTypeNodes;
   @Child private @Nullable UnresolvedTypeNode unresolvedReturnTypeNode;
 
-  @CompilationFinal @LateInit private FunctionNode functionNode;
+  @CompilationFinal private @Nullable FunctionNode functionNode;
 
   public ObjectMethodNode(
       VmLanguage language,

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

@@ -19,6 +19,7 @@ import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.runtime.*;
 import org.pkl.core.util.LateInit;
@@ -26,7 +27,7 @@ import org.pkl.core.util.LateInit;
 /** Resolves `<type>` to the type's default value in `new <type> { ... }`. */
 public final class GetParentForTypeNode extends ExpressionNode {
   @Child private UnresolvedTypeNode unresolvedTypeNode;
-  @Child private TypeNode typeNode;
+  @Child private @Nullable TypeNode typeNode;
   private final String qualifiedName;
 
   @CompilationFinal @LateInit Object defaultValue;
@@ -49,6 +50,7 @@ public final class GetParentForTypeNode extends ExpressionNode {
 
   @Override
   public Object executeGeneric(VirtualFrame frame) {
+    //noinspection ConstantValue
     if (defaultValue != null) return defaultValue;
     CompilerDirectives.transferToInterpreterAndInvalidate();
 

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

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -19,14 +19,14 @@ import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.NodeInfo;
 import com.oracle.truffle.api.source.SourceSection;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.ExpressionNode;
-import org.pkl.core.util.LateInit;
 
 @NodeInfo(shortName = "as")
 public final class TypeCastNode extends ExpressionNode {
   @Child private ExpressionNode valueNode;
-  @Child private UnresolvedTypeNode unresolvedTypeNode;
+  @Child private @Nullable UnresolvedTypeNode unresolvedTypeNode;
-  @Child @LateInit private TypeNode typeNode;
+  @Child private @Nullable TypeNode typeNode;
 
   public TypeCastNode(
       SourceSection sourceSection,
@@ -43,6 +43,7 @@ public final class TypeCastNode extends ExpressionNode {
       // don't compile unresolvedTypeNode.execute()
       // invalidation is done by insert()
       CompilerDirectives.transferToInterpreter();
+      assert unresolvedTypeNode != null;
       typeNode = insert(unresolvedTypeNode.execute(frame));
       unresolvedTypeNode = null;
     }

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

@@ -239,7 +239,7 @@ public abstract class TypeNode extends PklNode {
   public abstract static class FrameSlotTypeNode extends TypeNode {
     @CompilationFinal protected int slot = -1;
 
-    @CompilationFinal @Child protected WriteFrameSlotNode writeFrameSlotNode;
+    @CompilationFinal @Child protected @Nullable WriteFrameSlotNode writeFrameSlotNode;
 
     protected FrameSlotTypeNode(SourceSection sourceSection) {
       super(sourceSection);

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

@@ -26,7 +26,7 @@ import org.pkl.core.runtime.VmLanguage;
 @NodeInfo(shortName = "is")
 public final class TypeTestNode extends ExpressionNode {
   @Child private ExpressionNode valueNode;
-  @Child private UnresolvedTypeNode unresolvedTypeNode;
+  @Child private @Nullable UnresolvedTypeNode unresolvedTypeNode;
   @Child private @Nullable TypeNode typeNode;
 
   public TypeTestNode(
@@ -49,6 +49,7 @@ public final class TypeTestNode extends ExpressionNode {
       // don't compile unresolvedTypeNode.execute()
       // invalidation is done by insert()
       CompilerDirectives.transferToInterpreter();
+      assert unresolvedTypeNode != null;
       typeNode = insert(unresolvedTypeNode.execute(frame));
       unresolvedTypeNode = null;
     }

pkl-core/src/main/java/org/pkl/core/externalreader/ExternalResourceResolverImpl.java

@@ -103,7 +103,7 @@ final class ExternalResourceResolverImpl implements ExternalResourceResolver {
         readResponses.computeIfAbsent(
             baseUri,
             (uri) -> {
-              var future = new CompletableFuture<byte[]>();
+              var future = new CompletableFuture<byte @Nullable []>();
               var request =
                   new ReadResourceRequest(requestIdGenerator.nextLong(), evaluatorId, uri);
               try {

pkl-core/src/main/java/org/pkl/core/http/JdkHttpClient.java

@@ -46,7 +46,6 @@ import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLException;
 import javax.net.ssl.SSLHandshakeException;
 import javax.net.ssl.TrustManagerFactory;
-import org.pkl.core.SecurityManagerException;
 import org.pkl.core.util.ErrorMessages;
 import org.pkl.core.util.Exceptions;
 
@@ -93,7 +92,7 @@ final class JdkHttpClient implements HttpClient {
       HttpRequest request,
       BodyHandler<T> responseBodyHandler,
       HttpRequestChecker httpRequestChecker)
-      throws IOException, SecurityManagerException {
+      throws IOException {
     try {
       return underlying.send(request, responseBodyHandler);
     } catch (ConnectException e) {

pkl-core/src/main/java/org/pkl/core/messaging/Messages.java

@@ -84,7 +84,7 @@ public final class Messages {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
       if (this == o) {
         return true;
       }

pkl-core/src/main/java/org/pkl/core/module/PathElement.java

@@ -93,12 +93,14 @@ public class PathElement {
     }
 
     /** Returns the element at path {@code basePath}, given a {@link Path}. */
+    @SuppressWarnings("DataFlowIssue") // incorrect analysis; this can return null.
     public @Nullable TreePathElement getElement(Path basePath) {
       var path = basePath.normalize();
       var element = this;
       for (var i = 0; i < path.getNameCount(); i++) {
         var part = path.getName(i).toString();
         element = element.getChildren().get(part);
+        //noinspection ConstantValue
         if (element == null) {
           return null;
         }

pkl-core/src/main/java/org/pkl/core/module/ProjectDependenciesManager.java

@@ -183,6 +183,7 @@ public final class ProjectDependenciesManager {
   public Map<String, Dependency> getLocalPackageDependencies(PackageUri packageUri) {
     ensureDependenciesInitialized();
     var dep = localPackageDependencies.get(packageUri);
+    //noinspection ConstantValue
     assert dep != null;
     return dep;
   }

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

@@ -67,7 +67,7 @@ public abstract class Dependency {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
       if (this == o) {
         return true;
       }
@@ -107,7 +107,7 @@ public abstract class Dependency {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
       if (this == o) {
         return true;
       }

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

@@ -217,6 +217,7 @@ public final class DependencyMetadata {
           var map = new HashMap<>();
           for (var kv : value) {
             var kvObj = (JsObject) kv;
+            assert kvObj != null;
             map.put(parsePObject(kvObj.get("key")), parsePObject(kvObj.get("value")));
           }
           return map;
@@ -294,7 +295,7 @@ public final class DependencyMetadata {
     var ret = new ArrayList<String>(arr.size());
     for (var elem : arr) {
       if (!(elem instanceof String string)) {
-        throw new FormatException("string", elem.getClass());
+        throw new FormatException("string", elem != null ? elem.getClass() : Void.class);
       }
       ret.add(string);
     }
@@ -414,7 +415,7 @@ public final class DependencyMetadata {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (this == o) {
       return true;
     }
@@ -624,8 +625,8 @@ public final class DependencyMetadata {
       jsonWriter.endObject();
     }
 
-    private void writeGenericObject(Object value) throws IOException {
+    private void writeGenericObject(@Nullable Object value) throws IOException {
-      if (value instanceof PNull) {
+      if (value == null || value instanceof PNull) {
         jsonWriter.nullValue();
       } else if (value instanceof PObject pObject) {
         writePObject(pObject);

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

@@ -18,6 +18,7 @@ package org.pkl.core.packages;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.nio.file.Path;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PklBugException;
 import org.pkl.core.Version;
 import org.pkl.core.util.ErrorMessages;
@@ -98,7 +99,7 @@ public final class PackageAssetUri {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (this == o) {
       return true;
     }

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

@@ -118,7 +118,7 @@ public final class PackageUri {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (this == o) {
       return true;
     }

pkl-core/src/main/java/org/pkl/core/project/CanonicalPackageUri.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -17,6 +17,7 @@ package org.pkl.core.project;
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PklBugException;
 import org.pkl.core.packages.PackageUri;
 import org.pkl.core.util.ErrorMessages;
@@ -84,7 +85,7 @@ public record CanonicalPackageUri(URI baseUri, int majorVersion) {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (this == o) {
       return true;
     }

pkl-core/src/main/java/org/pkl/core/project/Project.java

@@ -199,7 +199,7 @@ public final class Project {
         sb.append("\n│");
       }
       sb.append("\n│  ");
-      sb.append(uri.toString());
+      sb.append(uri);
     }
     sb.append("\n└─");
   }
@@ -477,7 +477,7 @@ public final class Project {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (this == o) {
       return true;
     }
@@ -611,7 +611,7 @@ public final class Project {
     }
 
     @Override
-    public boolean equals(Object o) {
+    public boolean equals(@Nullable Object o) {
       if (this == o) {
         return true;
       }

pkl-core/src/main/java/org/pkl/core/project/ProjectDependenciesResolver.java

@@ -141,6 +141,7 @@ public final class ProjectDependenciesResolver {
   private void updateDependency(Dependency dependency) {
     var canonicalPackageUri = CanonicalPackageUri.fromPackageUri(dependency.getPackageUri());
     var currentDependency = resolvedDependencies.get(canonicalPackageUri);
+    //noinspection ConstantValue
     if (currentDependency == null
         || currentDependency.getVersion().compareTo(dependency.getVersion()) < 0) {
       EconomicMaps.put(resolvedDependencies, canonicalPackageUri, dependency);

pkl-core/src/main/java/org/pkl/core/project/ProjectDeps.java

@@ -135,6 +135,7 @@ public final class ProjectDeps {
   }
 
   /** Given a declared dependency, return the resolved dependency. */
+  @SuppressWarnings("DataFlowIssue") // incorrect analysis
   public @Nullable Dependency get(CanonicalPackageUri canonicalPackageUri) {
     return resolvedDependencies.get(canonicalPackageUri);
   }
@@ -150,7 +151,7 @@ public final class ProjectDeps {
   }
 
   @Override
-  public boolean equals(Object o) {
+  public boolean equals(@Nullable Object o) {
     if (this == o) {
       return true;
     }

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

@@ -51,6 +51,8 @@ public final class FileSystemManager {
 
   public static synchronized FileSystem getFileSystem(URI uri) throws IOException {
     var fs = fileSystems.get(uri);
+    // incorrect nullability for `org.graalvm.collections.UnmodifiableEconomicMap`
+    //noinspection ConstantValue
     if (fs != null) {
       var count = counts.get(fs);
       assert count != null;

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

@@ -40,10 +40,10 @@ public final class ModuleInfo {
 
   @LateInit private List<VmTyped> annotations;
 
-  @LateInit private VmTyped __mirror;
+  private @Nullable VmTyped __mirror;
   private final Object mirrorLock = new Object();
 
-  @LateInit private ModuleSchema __moduleSchema;
+  private @Nullable ModuleSchema __moduleSchema;
   private final Object moduleSchemaLock = new Object();
 
   public ModuleInfo(
@@ -65,12 +65,12 @@ public final class ModuleInfo {
   }
 
   public void initAnnotations(List<VmTyped> annotations) {
+    //noinspection ConstantValue
     assert this.annotations == null;
     this.annotations = annotations;
   }
 
   public List<VmTyped> getAnnotations() {
-    assert annotations != null;
     return annotations;
   }
 

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

@@ -101,8 +101,14 @@ public final class StackTraceRenderer {
     if (hint != null) {
       out.append(AnsiTheme.ERROR_MESSAGE_HINT, hint);
     } else {
-      assert hintBuilder != null;
+      out.append(
-      out.append(AnsiTheme.ERROR_MESSAGE_HINT, () -> hintBuilder.accept(out, true));
+          AnsiTheme.ERROR_MESSAGE_HINT,
+          () -> {
+            // nullaway needs this assertion
+            //noinspection ConstantValue
+            assert hintBuilder != null;
+            hintBuilder.accept(out, true);
+          });
     }
     out.append('\n');
   }

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

@@ -491,11 +491,11 @@ public final class TestRunner {
           sb.append("\n  Expected: ");
           appendLocation(sb, expectedLocation);
           sb.append("\n  ");
-          sb.append(AnsiTheme.TEST_EXAMPLE_OUTPUT, expectedValue.replaceAll("\n", "\n  "));
+          sb.append(AnsiTheme.TEST_EXAMPLE_OUTPUT, expectedValue.replace("\n", "\n  "));
           sb.append("\n  Actual: ");
           appendLocation(sb, actualLocation);
           sb.append("\n  ");
-          sb.append(AnsiTheme.TEST_EXAMPLE_OUTPUT, actualValue.replaceAll("\n", "\n  "));
+          sb.append(AnsiTheme.TEST_EXAMPLE_OUTPUT, actualValue.replace("\n", "\n  "));
         });
     return new Failure("Example Failure", sb.toString());
   }

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

@@ -107,6 +107,7 @@ public final class VmContext {
   }
 
   public void initialize(Holder holder) {
+    //noinspection ConstantValue
     assert this.holder == null;
     this.holder = holder;
   }

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

@@ -19,6 +19,7 @@ import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.frame.MaterializedFrame;
 import java.util.Objects;
 import org.graalvm.collections.UnmodifiableEconomicMap;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PClassInfo;
 import org.pkl.core.PObject;
 import org.pkl.core.ast.member.ObjectMember;
@@ -75,12 +76,14 @@ public final class VmDynamic extends VmObject {
   @Override
   @TruffleBoundary
   public PObject export() {
+    assert forced : "Value was not forced prior to export";
+
     var properties =
         CollectionUtils.<String, Object>newLinkedHashMap(EconomicMaps.size(cachedValues));
 
-    iterateMemberValues(
+    iterateAlreadyForcedMemberValues(
         (key, member, value) -> {
-          properties.put(key.toString(), VmValue.exportNullable(value));
+          properties.put(key.toString(), VmValue.export(value));
           return true;
         });
 
@@ -99,9 +102,8 @@ public final class VmDynamic extends VmObject {
 
   @Override
   @TruffleBoundary
-  public boolean equals(Object obj) {
+  public boolean equals(@Nullable Object obj) {
-    if (this == obj) // noinspection Contract
+    if (this == obj) return true;
-    return true;
     if (!(obj instanceof VmDynamic other)) return false;
 
     // could use shallow force, but deep force is cached
@@ -115,6 +117,7 @@ public final class VmDynamic extends VmObject {
       if (isHiddenOrLocalProperty(key)) continue;
 
       var value = cursor.getValue();
+      //noinspection ConstantValue
       assert value != null;
       var otherValue = other.getCachedValue(key);
       if (!value.equals(otherValue)) return false;
@@ -137,6 +140,7 @@ public final class VmDynamic extends VmObject {
       if (isHiddenOrLocalProperty(key)) continue;
 
       var value = cursor.getValue();
+      //noinspection ConstantValue
       assert value != null;
       result += key.hashCode() ^ value.hashCode();
     }

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

@@ -87,13 +87,15 @@ public final class VmListing extends VmListingOrMapping {
   @Override
   @TruffleBoundary
   public List<Object> export() {
+    assert forced : "Value was not forced prior to export";
+
     var properties = new ArrayList<>(EconomicMaps.size(cachedValues));
 
-    iterateMemberValues(
+    iterateAlreadyForcedMemberValues(
         (key, prop, value) -> {
           if (isDefaultProperty(key)) return true;
 
-          properties.add(VmValue.exportNullable(value));
+          properties.add(VmValue.export(value));
           return true;
         });
 
@@ -127,6 +129,7 @@ public final class VmListing extends VmListingOrMapping {
       if (key instanceof Identifier) continue;
 
       var value = cursor.getValue();
+      //noinspection ConstantValue
       assert value != null;
       var otherValue = other.getCachedValue(key);
       if (!value.equals(otherValue)) return false;
@@ -149,6 +152,7 @@ public final class VmListing extends VmListingOrMapping {
       if (key instanceof Identifier) continue;
 
       var value = cursor.getValue();
+      //noinspection ConstantValue
       assert value != null;
       result = 31 * result + value.hashCode();
     }

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

@@ -147,6 +147,7 @@ public final class VmMap extends VmValue implements Iterable<Map.Entry<Object, O
 
     for (var key : other.keyOrder) {
       var value = other.map.get(key);
+      assert value != null;
 
       if (!map.containsKey(key)) {
         keyOrderBuilder.append(key);

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

@@ -21,19 +21,18 @@ import com.oracle.truffle.api.frame.MaterializedFrame;
 import java.util.HashSet;
 import java.util.Map;
 import org.graalvm.collections.UnmodifiableEconomicMap;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.member.ListingOrMappingTypeCastNode;
 import org.pkl.core.ast.member.ObjectMember;
 import org.pkl.core.util.CollectionUtils;
 import org.pkl.core.util.EconomicMaps;
-import org.pkl.core.util.LateInit;
 import org.pkl.core.util.MutableLong;
 
 public final class VmMapping extends VmListingOrMapping {
   private long cachedLength = -1;
 
   @GuardedBy("this")
-  @LateInit
+  private @Nullable VmSet __allKeys;
-  private VmSet __allKeys;
 
   private static final class EmptyHolder {
     private static final VmMapping EMPTY =
@@ -94,13 +93,15 @@ public final class VmMapping extends VmListingOrMapping {
   @Override
   @TruffleBoundary
   public Map<Object, Object> export() {
+    assert forced : "Value was not forced prior to export";
+
     var properties = CollectionUtils.newLinkedHashMap(EconomicMaps.size(cachedValues));
 
-    iterateMemberValues(
+    iterateAlreadyForcedMemberValues(
         (key, prop, value) -> {
           if (isDefaultProperty(key)) return true;
 
-          properties.put(VmValue.export(key), VmValue.exportNullable(value));
+          properties.put(VmValue.export(key), VmValue.export(value));
           return true;
         });
 
@@ -119,9 +120,8 @@ public final class VmMapping extends VmListingOrMapping {
 
   @Override
   @TruffleBoundary
-  public boolean equals(Object obj) {
+  public boolean equals(@Nullable Object obj) {
-    if (this == obj) // noinspection Contract
+    if (this == obj) return true;
-    return true;
     if (!(obj instanceof VmMapping other)) return false;
 
     // could use shallow force, but deep force is cached
@@ -135,6 +135,7 @@ public final class VmMapping extends VmListingOrMapping {
       if (key instanceof Identifier) continue;
 
       var value = cursor.getValue();
+      //noinspection ConstantValue
       assert value != null;
       var otherValue = other.getCachedValue(key);
       if (!value.equals(otherValue)) return false;
@@ -157,6 +158,7 @@ public final class VmMapping extends VmListingOrMapping {
       if (key instanceof Identifier) continue;
 
       var value = cursor.getValue();
+      //noinspection ConstantValue
       assert value != null;
       result += key.hashCode() ^ value.hashCode();
     }

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

@@ -34,7 +34,7 @@ public abstract class VmObject extends VmObjectLike {
   protected final EconomicMap<Object, Object> cachedValues;
 
   protected int cachedHash;
-  private boolean forced;
+  protected boolean forced;
 
   public VmObject(
       MaterializedFrame enclosingFrame,
@@ -204,17 +204,20 @@ public abstract class VmObject extends VmObjectLike {
 
   /**
    * Exports this object's members. Skips local members, hidden members, class definitions, and type
-   * aliases. Members that haven't been forced have a `null` value.
+   * aliases.
+   *
+   * <p>Assumes that this object has already been forced.
    */
   @TruffleBoundary
   protected final Map<String, Object> exportMembers() {
-    var result = CollectionUtils.<String, Object>newLinkedHashMap(EconomicMaps.size(cachedValues));
+    Map<String, Object> result = CollectionUtils.newLinkedHashMap(EconomicMaps.size(cachedValues));
+    assert forced : "Value was not forced prior to export";
 
-    iterateMemberValues(
+    iterateAlreadyForcedMemberValues(
         (key, member, value) -> {
           if (member.isClass() || member.isTypeAlias()) return true;
 
-          result.put(key.toString(), VmValue.exportNullable(value));
+          result.put(key.toString(), VmValue.export(value));
           return true;
         });
 

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

@@ -30,6 +30,7 @@ import org.pkl.core.Composite;
 import org.pkl.core.PClass;
 import org.pkl.core.PClassInfo;
 import org.pkl.core.PType;
+import org.pkl.core.PklBugException;
 import org.pkl.core.Reference;
 import org.pkl.core.TypeAlias;
 import org.pkl.core.util.paguro.RrbTree;
@@ -218,6 +219,15 @@ public final class VmReference extends VmValue {
     normalizeTypes(prop.getType(), clazz.getPClass().getModuleClass(), result);
   }
 
+  private static PClassInfo<?> getClassInfo(Object value) {
+    if (value instanceof VmValue vmValue) return vmValue.getVmClass().getPClassInfo();
+    if (value instanceof String) return PClassInfo.String;
+    if (value instanceof Boolean) return PClassInfo.Boolean;
+    if (value instanceof Long) return PClassInfo.Int;
+    if (value instanceof Double) return PClassInfo.Float;
+    throw new PklBugException("Not a Pkl value: " + value.getClass());
+  }
+
   @SuppressWarnings("DuplicatedCode")
   private static void getCandidateSubscriptType(PType type, Object key, Set<PType> result) {
     if (type == PType.UNKNOWN) {
@@ -244,8 +254,7 @@ public final class VmReference extends VmValue {
       var keyTypes = normalizeTypes(typeArgs.get(0), clazz.getPClass().getModuleClass());
       for (var kt : iterateTypes(keyTypes)) {
         if (kt == PType.UNKNOWN
-            || (kt instanceof PType.Class klazz
+            || (kt instanceof PType.Class klazz && klazz.getPClass().getInfo() == getClassInfo(key))
-                && 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);

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

@@ -34,7 +34,6 @@ import org.pkl.core.ast.type.TypeNode;
 import org.pkl.core.ast.type.TypeNode.ConstrainedTypeNode;
 import org.pkl.core.ast.type.TypeNode.TypeVariableNode;
 import org.pkl.core.ast.type.TypeNode.UnknownTypeNode;
-import org.pkl.core.util.LateInit;
 
 public final class VmTypeAlias extends VmValue {
   private final SourceSection sourceSection;
@@ -48,17 +47,15 @@ public final class VmTypeAlias extends VmValue {
   private final List<TypeParameter> typeParameters;
   private final MaterializedFrame enclosingFrame;
 
-  @LateInit private TypeNode typeNode;
+  private @Nullable TypeNode typeNode;
 
-  @LateInit
   @GuardedBy("pTypeAliasLock")
-  private TypeAlias __pTypeAlias;
+  private @Nullable TypeAlias __pTypeAlias;
 
   private final Object pTypeAliasLock = new Object();
 
-  @LateInit
   @GuardedBy("mirrorLock")
-  private VmTyped __mirror;
+  private @Nullable VmTyped __mirror;
 
   private final Object mirrorLock = new Object();
 
@@ -86,7 +83,6 @@ public final class VmTypeAlias extends VmValue {
   }
 
   public void initTypeCheckNode(TypeNode typeNode) {
-    assert this.typeNode == null;
     this.typeNode = typeNode;
   }
 
@@ -100,6 +96,7 @@ public final class VmTypeAlias extends VmValue {
    */
   @TruffleBoundary
   public SourceSection getBaseTypeSection() {
+    assert typeNode != null;
     if (typeNode instanceof ConstrainedTypeNode constrainedTypeNode) {
       return constrainedTypeNode.getBaseTypeSection();
     }
@@ -116,6 +113,7 @@ public final class VmTypeAlias extends VmValue {
    */
   @TruffleBoundary
   public SourceSection getConstraintSection() {
+    assert typeNode != null;
     if (typeNode instanceof ConstrainedTypeNode) {
       return ((ConstrainedTypeNode) typeNode).getFirstConstraintSection();
     }
@@ -169,6 +167,7 @@ public final class VmTypeAlias extends VmValue {
   }
 
   public TypeNode getTypeNode() {
+    assert typeNode != null;
     return typeNode;
   }
 
@@ -178,6 +177,7 @@ public final class VmTypeAlias extends VmValue {
 
   @TruffleBoundary
   public TypeNode instantiate(TypeNode[] typeArgumentNodes) {
+    assert typeNode != null;
     // 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
@@ -265,6 +265,7 @@ public final class VmTypeAlias extends VmValue {
   }
 
   public VmTyped getTypeMirror() {
+    assert typeNode != null;
     return typeNode.getMirror();
   }
 

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

@@ -29,10 +29,9 @@ import org.pkl.core.ast.ExpressionNode;
 import org.pkl.core.ast.expression.unary.ImportNode;
 import org.pkl.core.ast.member.ObjectMember;
 import org.pkl.core.util.EconomicMaps;
-import org.pkl.core.util.LateInit;
 
 public final class VmTyped extends VmObject {
-  @CompilationFinal @LateInit private VmClass clazz;
+  @CompilationFinal private @Nullable VmClass clazz;
 
   public VmTyped(
       MaterializedFrame enclosingFrame,
@@ -162,6 +161,8 @@ public final class VmTyped extends VmObject {
   @Override
   @TruffleBoundary
   public Composite export() {
+    assert forced : "Value was not forced prior to export";
+    assert clazz != null;
     if (!isModuleObject()) {
       return new PObject(clazz.getPClassInfo(), exportMembers());
     }
@@ -190,6 +191,7 @@ public final class VmTyped extends VmObject {
     if (this == obj) return true;
     if (!(obj instanceof VmTyped other)) return false;
 
+    assert clazz != null;
     if (clazz != other.clazz) return false;
     // could use shallow force, but deep force is cached
     force(false);
@@ -210,6 +212,7 @@ public final class VmTyped extends VmObject {
   public int hashCode() {
     if (cachedHash != 0) return cachedHash;
 
+    assert clazz != null;
     force(false);
     var result = 0;
 

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

@@ -94,6 +94,7 @@ public final class VmObjectFactory<E> {
             ? TypeCheckedPropertyNodeGen.create(null, new FrameDescriptor(), member, bodyNode)
             : new UntypedObjectMemberNode(null, new FrameDescriptor(), member, bodyNode);
     member.initMemberNode(node);
+    //noinspection ConstantValue
     if (members.put(identifier, member) != null) {
       throw new VmExceptionBuilder()
           .bug(
@@ -110,7 +111,6 @@ public final class VmObjectFactory<E> {
   @TruffleBoundary
   public VmTyped create(@Nullable E extraStorage) {
     var clazz = classSupplier.get();
-    assert clazz != null;
 
     var result =
         new VmTyped(VmUtils.createEmptyMaterializedFrame(), clazz.getPrototype(), clazz, members);

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

@@ -46,7 +46,7 @@ import org.pkl.core.stdlib.ExternalPropertyNode;
  * CLI args) would lead to incorrect behavior, as a single base module instance is shared across all
  * language contexts, and properties (whether external or not) are evaluated just once.
  */
-@SuppressWarnings("UnusedParameters")
+@SuppressWarnings("unused")
 public final class BaseNodes {
   private BaseNodes() {}
 
@@ -64,6 +64,7 @@ public final class BaseNodes {
     }
   }
 
+  @SuppressWarnings("unused")
   public abstract static class Regex extends ExternalMethod1Node {
     // cache Regex object to avoid repeated java.util.Pattern.compile()
     @Specialization(guards = "pattern.equals(cachedPattern)")

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

@@ -20,6 +20,7 @@ import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.LoopNode;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.ast.expression.binary.*;
 import org.pkl.core.ast.internal.IsInstanceOfNode;
 import org.pkl.core.ast.internal.IsInstanceOfNodeGen;
@@ -33,7 +34,6 @@ import org.pkl.core.stdlib.base.CollectionNodes.CompareByNode;
 import org.pkl.core.stdlib.base.CollectionNodes.CompareNode;
 import org.pkl.core.stdlib.base.CollectionNodes.CompareWithNode;
 import org.pkl.core.util.EconomicSets;
-import org.pkl.core.util.LateInit;
 
 // duplication between ListNodes and SetNodes is "intentional"
 // (sharing nodes between VmCollection subtypes results in
@@ -1336,7 +1336,7 @@ public final class ListNodes {
 
   public abstract static class toBytes extends ExternalMethod0Node {
 
-    @Child @LateInit private TypeNode typeNode;
+    @Child private @Nullable TypeNode typeNode;
 
     private TypeNode getTypeNode() {
       if (typeNode == null) {

pkl-core/src/main/java/org/pkl/core/stdlib/json/ParserNodes.java

@@ -28,6 +28,7 @@ import org.pkl.core.runtime.*;
 import org.pkl.core.stdlib.ExternalMethod1Node;
 import org.pkl.core.stdlib.PklConverter;
 import org.pkl.core.util.EconomicMaps;
+import org.pkl.core.util.LateInit;
 import org.pkl.core.util.json.JsonHandler;
 import org.pkl.core.util.json.JsonParser;
 import org.pkl.core.util.json.ParseException;
@@ -71,6 +72,8 @@ public final class ParserNodes {
 
     private final Deque<Object> currPath = new ArrayDeque<>();
 
+    @LateInit private Object value;
+
     public Handler(PklConverter converter, boolean useMapping) {
       this.converter = converter;
       this.useMapping = useMapping;
@@ -78,8 +81,6 @@ public final class ParserNodes {
       currPath.push(VmValueConverter.TOP_LEVEL_VALUE);
     }
 
-    private Object value;
-
     @Override
     public void endNull() {
       value = VmNull.withoutDefault();

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

@@ -617,7 +617,7 @@ public final class RendererNodes {
         // - All element types are resolved also.
         // - All string literal types are combined into a single String case.
         var hasString = false;
-        var elements = new ArrayList<TypeNode>();
+        var elements = new ArrayList<@Nullable TypeNode>();
         for (var t : ((UnionTypeNode) type).getElementTypeNodes()) {
           var resolved = resolveType(t);
           if (resolved instanceof StringLiteralTypeNode || resolved instanceof StringTypeNode) {

pkl-core/src/main/java/org/pkl/core/stdlib/test/report/JUnitReporter.java

@@ -21,6 +21,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Consumer;
 import org.graalvm.collections.EconomicMap;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.TestResults;
 import org.pkl.core.TestResults.Error;
 import org.pkl.core.TestResults.TestResult;
@@ -59,8 +60,6 @@ public final class JUnitReporter implements TestReporter {
     var totalTests = allTestResults.stream().mapToLong(TestResults::totalTests).sum();
     var totalFailures = allTestResults.stream().mapToLong(TestResults::totalFailures).sum();
 
-    assert aggregateSuiteName != null;
-
     var attrs =
         buildAttributes(
             "name", aggregateSuiteName,
@@ -206,12 +205,15 @@ public final class JUnitReporter implements TestReporter {
         members.size() - 4);
   }
 
-  private VmMapping buildAttributes(Object... attributes) {
+  private VmMapping buildAttributes(@Nullable Object... attributes) {
     EconomicMap<Object, ObjectMember> attrs = EconomicMaps.create(attributes.length);
-    for (int i = 0; i < attributes.length; i += 2) {
+    for (var i = 0; i < attributes.length; i += 2) {
-      attrs.put(
+      var key = attributes[i];
-          attributes[i],
+      var value = attributes[i + 1];
-          VmUtils.createSyntheticObjectEntry(attributes[i].toString(), attributes[i + 1]));
+      if (key == null || value == null) {
+        continue;
+      }
+      attrs.put(key, VmUtils.createSyntheticObjectEntry(key.toString(), value));
     }
     return new VmMapping(
         VmUtils.createEmptyMaterializedFrame(), BaseModule.getMappingClass().getPrototype(), attrs);

pkl-core/src/main/java/org/pkl/core/util/CollectionUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -18,6 +18,7 @@ package org.pkl.core.util;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
+import org.jspecify.annotations.Nullable;
 
 public final class CollectionUtils {
   private static final float LOAD_FACTOR = 0.75f;
@@ -45,7 +46,8 @@ public final class CollectionUtils {
   }
 
   @TruffleBoundary
-  public static <K, V> LinkedHashMap<K, V> newLinkedHashMap(int expectedSize) {
+  public static <K extends @Nullable Object, V extends @Nullable Object>
+      LinkedHashMap<K, V> newLinkedHashMap(int expectedSize) {
     return new LinkedHashMap<>((int) (expectedSize / LOAD_FACTOR) + 1, LOAD_FACTOR);
   }
 

pkl-core/src/main/java/org/pkl/core/util/EconomicMaps.java

@@ -81,11 +81,13 @@ public final class EconomicMaps {
     return result;
   }
 
+  @SuppressWarnings("DataFlowIssue")
   @TruffleBoundary
   public static <K, V> @Nullable V get(UnmodifiableEconomicMap<K, V> self, K key) {
     return self.get(key);
   }
 
+  @SuppressWarnings("DataFlowIssue")
   @TruffleBoundary
   public static <K, V> @Nullable V get(UnmodifiableEconomicMap<K, V> self, K key, V defaultValue) {
     return self.get(key, defaultValue);

pkl-core/src/main/java/org/pkl/core/util/json/JsonParser.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 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.
@@ -381,6 +381,7 @@ public final class JsonParser {
   }
 
   private void startCapture() {
+    //noinspection ConstantValue
     if (captureBuffer == null) {
       captureBuffer = new StringBuilder();
     }

pkl-core/src/main/java/org/pkl/core/util/json/JsonWriter.java

@@ -25,7 +25,7 @@ import org.jspecify.annotations.Nullable;
 /**
  * Writes a JSON (<a href="http://www.ietf.org/rfc/rfc7159.txt">RFC 7159</a>) encoded value to a
  * stream, one token at a time. The stream includes both literal values (strings, numbers, booleans
- * and nulls) as well as the begin and end delimiters of objects and arrays.
+ * and nulls) as well as the beginning and ending delimiters of objects and arrays.
  *
  * <h3>Encoding JSON</h3>
  *
@@ -195,7 +195,7 @@ public final class JsonWriter implements Closeable, Flushable {
 
   /**
    * Sets the indentation string to be repeated for each level of indentation in the encoded
-   * document. If {@code indent.isEmpty()} the encoded document will be compact. Otherwise the
+   * document. If {@code indent.isEmpty()} the encoded document will be compact. Otherwise, the
    * encoded document will be more human-readable.
    *
    * @param indent a string containing only whitespace.
@@ -418,6 +418,8 @@ public final class JsonWriter implements Closeable, Flushable {
   public JsonWriter value(boolean value) throws IOException {
     writeDeferredName();
     beforeValue();
+    // avoid method dispatch
+    //noinspection SimplifiableConditionalExpression
     out.write(value ? "true" : "false");
     return this;
   }
@@ -433,6 +435,8 @@ public final class JsonWriter implements Closeable, Flushable {
     }
     writeDeferredName();
     beforeValue();
+    // avoid method dispatch
+    //noinspection SimplifiableConditionalExpression
     out.write(value ? "true" : "false");
     return this;
   }

pkl-core/src/main/java/org/pkl/core/util/paguro/RrbTree.java

@@ -922,7 +922,10 @@ public abstract class RrbTree<E> implements BaseList<E>, Indented {
   /** {@inheritDoc} */
   @SuppressWarnings("unchecked")
   @Override
-  public boolean equals(Object other) {
+  public boolean equals(@Nullable Object other) {
+    if (other == null) {
+      return false;
+    }
     if (this == other) {
       return true;
     }