diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/generator/GeneratorObjectLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/generator/GeneratorObjectLiteralNode.java
index 03a9b1a5e..18767d30b 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/generator/GeneratorObjectLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/generator/GeneratorObjectLiteralNode.java
@@ -17,6 +17,7 @@ package org.pkl.core.ast.expression.generator;
 
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Bind;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.Idempotent;
@@ -34,7 +35,7 @@ import org.pkl.core.ast.type.UnresolvedTypeNode;
 import org.pkl.core.runtime.*;
 
 /** An object literal node that contains at least one for- or when-expression. */
-@ImportStatic(BaseModule.class)
+@ImportStatic({BaseModule.class, VmUtils.class})
 public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
   @Children private final GeneratorMemberNode[] memberNodes;
 
@@ -80,6 +81,20 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     return data.storeGeneratorFrames(result);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isDynamicClass()", "checkObjectCannotHaveParameters()"})
+  protected Object evalNullWithDynamicDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    var parentDynamic = (VmDynamic) defaultValue;
+    var data = executeChildren(frame, parentDynamic, parentDynamic.getLength());
+    if (data.hasNoMembers()) {
+      return parentDynamic;
+    }
+    var result = new VmDynamic(frame.materialize(), parentDynamic, data.members(), data.length());
+    return data.storeGeneratorFrames(result);
+  }
+
   @Specialization(guards = "checkObjectCannotHaveParameters()")
   protected VmTyped evalTyped(VirtualFrame frame, VmTyped parent) {
     VmUtils.checkIsInstantiable(parent.getVmClass(), getParentNode());
@@ -91,6 +106,14 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     return new VmTyped(frame.materialize(), parent, parent.getVmClass(), data.members());
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isTypedObjectClass(getClass(defaultValue))", "checkObjectCannotHaveParameters()"})
+  protected Object evalNullWithTypedDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalTyped(frame, (VmTyped) defaultValue);
+  }
+
   @Specialization(guards = "checkListingCannotHaveParameters()")
   protected VmListing evalListing(VirtualFrame frame, VmListing parent) {
     var data = executeChildren(frame, parent, parent.getLength());
@@ -101,6 +124,14 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     return data.storeGeneratorFrames(result);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isListingClass()", "checkListingCannotHaveParameters()"})
+  protected Object evalNullWithListingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalListing(frame, (VmListing) defaultValue);
+  }
+
   @Specialization(guards = "checkMappingCannotHaveParameters()")
   protected VmMapping evalMapping(VirtualFrame frame, VmMapping parent) {
     var data = executeChildren(frame, parent, 0);
@@ -111,10 +142,12 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     return data.storeGeneratorFrames(result);
   }
 
-  @Specialization(guards = "checkObjectCannotHaveParameters()")
-  protected Object evalNull(VirtualFrame frame, VmNull parent) {
-    // assumes that Graal PE can handle recursive call to same node
-    return executeWithParent(frame, parent.getDefaultValue());
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isMappingClass()", "checkMappingCannotHaveParameters()"})
+  protected Object evalNullWithMappingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalMapping(frame, (VmMapping) defaultValue);
   }
 
   @Specialization(guards = "checkIsValidFunctionAmendment(parent)")
@@ -127,6 +160,18 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     return amendFunctionNode.execute(frame, parent);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isFunction(defaultValue)", "checkIsValidFunctionAmendment(defaultValue)"})
+  protected Object evalNullWithFunctionDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached(value = "createAmendFunctionNode(frame)", neverDefault = true)
+          AmendFunctionNode amendFunctionNode) {
+    return evalFunction(frame, (VmFunction) defaultValue, amendFunctionNode);
+  }
+
   @Specialization(guards = {"parent == getDynamicClass()", "checkObjectCannotHaveParameters()"})
   protected VmDynamic evalDynamicClass(VirtualFrame frame, VmClass parent) {
     var data = executeChildren(frame, parent, 0);
@@ -173,8 +218,13 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
   @Fallback
   @TruffleBoundary
   protected void fallback(Object parent) {
+    var value = parent;
+    // blame the non-null type (e.g. blame `Duration` instead of `Null` in the case of `Duration?`)
+    if (value instanceof VmNull vmNull) {
+      value = getNullDefaultValue(vmNull);
+    }
     VmUtils.checkIsInstantiable(
-        parent instanceof VmClass vmClass ? vmClass : VmUtils.getClass(parent), getParentNode());
+        value instanceof VmClass vmClass ? vmClass : VmUtils.getClass(value), getParentNode());
 
     throw exceptionBuilder().unreachableCode().build();
   }
@@ -186,7 +236,7 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     CompilerDirectives.transferToInterpreter();
     throw exceptionBuilder()
         .evalError("objectAmendmentCannotHaveParameters")
-        .withLocation(parameterTypes[0])
+        .withLocation(getParentNode())
         .build();
   }
 
@@ -197,7 +247,7 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     CompilerDirectives.transferToInterpreter();
     throw exceptionBuilder()
         .evalError("listingAmendmentCannotHaveParameters")
-        .withLocation(parameterTypes[0])
+        .withLocation(getParentNode())
         .build();
   }
 
@@ -208,7 +258,7 @@ public abstract class GeneratorObjectLiteralNode extends ObjectLiteralNode {
     CompilerDirectives.transferToInterpreter();
     throw exceptionBuilder()
         .evalError("mappingAmendmentCannotHaveParameters")
-        .withLocation(parameterTypes[0])
+        .withLocation(getParentNode())
         .build();
   }
 
diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ConstantEntriesLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ConstantEntriesLiteralNode.java
index ec8c1b159..f6441af73 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ConstantEntriesLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ConstantEntriesLiteralNode.java
@@ -33,7 +33,7 @@ import org.pkl.core.runtime.*;
  * all entry keys are constants. Example: `new foo { ["one"] = 1 }`
  */
 // IDEA: don't materialize frames if all members have constant values
-@ImportStatic(BaseModule.class)
+@ImportStatic({BaseModule.class, VmUtils.class})
 public abstract class ConstantEntriesLiteralNode extends SpecializedObjectLiteralNode {
   public ConstantEntriesLiteralNode(
       SourceSection sourceSection,
@@ -73,21 +73,38 @@ public abstract class ConstantEntriesLiteralNode extends SpecializedObjectLitera
     return new VmMapping(frame.materialize(), parent, members);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isMappingClass()", "checkIsValidMappingAmendment()"})
+  protected Object evalNullWithMappingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalMapping(frame, (VmMapping) defaultValue);
+  }
+
   @Specialization
   protected VmDynamic evalDynamic(VirtualFrame frame, VmDynamic parent) {
     return new VmDynamic(frame.materialize(), parent, members, parent.getLength());
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(guards = "getClass(defaultValue).isDynamicClass()")
+  protected Object evalNullWithDynamicDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalDynamic(frame, (VmDynamic) defaultValue);
+  }
+
   @Specialization(guards = "checkIsValidListingAmendment()")
   protected VmListing evalListing(VirtualFrame frame, VmListing parent) {
     checkMaxListingMemberIndex(parent.getLength());
     return new VmListing(frame.materialize(), parent, members, parent.getLength());
   }
 
-  @Specialization
-  protected Object evalNull(VirtualFrame frame, VmNull parent) {
-    // assumes that Graal PE can handle recursive call to same node
-    return executeWithParent(frame, parent.getDefaultValue());
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isListingClass()", "checkIsValidListingAmendment()"})
+  protected Object evalNullWithListingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalListing(frame, (VmListing) defaultValue);
   }
 
   @Specialization(guards = "checkIsValidFunctionAmendment(parent)")
@@ -100,6 +117,18 @@ public abstract class ConstantEntriesLiteralNode extends SpecializedObjectLitera
     return amendFunctionNode.execute(frame, parent);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isFunction(defaultValue)", "checkIsValidFunctionAmendment(defaultValue)"})
+  protected Object evalNullWithFunctionDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached(value = "createAmendFunctionNode(frame)", neverDefault = true)
+          AmendFunctionNode amendFunctionNode) {
+    return evalFunction(frame, (VmFunction) defaultValue, amendFunctionNode);
+  }
+
   @Specialization(guards = {"parent == getMappingClass()", "checkIsValidMappingAmendment()"})
   protected VmMapping evalMappingClass(
       VirtualFrame frame, @SuppressWarnings("unused") VmClass parent) {
@@ -127,6 +156,11 @@ public abstract class ConstantEntriesLiteralNode extends SpecializedObjectLitera
   @Fallback
   @TruffleBoundary
   protected void fallback(Object parent) {
-    elementsEntriesFallback(parent, findFirstNonProperty(members), false);
+    var value = parent;
+    // blame the non-null type (e.g. blame `Duration` instead of `Null` in the case of `Duration?`)
+    if (value instanceof VmNull vmNull) {
+      value = getNullDefaultValue(vmNull);
+    }
+    elementsEntriesFallback(value, findFirstNonProperty(members), false);
   }
 }
diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsEntriesLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsEntriesLiteralNode.java
index 56886a59f..9e9893429 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsEntriesLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsEntriesLiteralNode.java
@@ -16,6 +16,7 @@
 package org.pkl.core.ast.expression.literal;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Bind;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.ImportStatic;
@@ -36,7 +37,7 @@ import org.pkl.core.util.EconomicMaps;
  * Object literal that contains both elements and entries (and possibly properties). Example: `new
  * foo { "pigeon", [3] = "barn owl" }`
  */
-@ImportStatic(BaseModule.class)
+@ImportStatic({BaseModule.class, VmUtils.class})
 public abstract class ElementsEntriesLiteralNode extends SpecializedObjectLiteralNode {
   private final ObjectMember[] elements;
   @Children private final ExpressionNode[] keyNodes;
@@ -95,6 +96,14 @@ public abstract class ElementsEntriesLiteralNode extends SpecializedObjectLitera
         parent.getLength() + elements.length);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isListingClass()", "checkIsValidListingAmendment()"})
+  protected Object evalNullWithListingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalListing(frame, (VmListing) defaultValue);
+  }
+
   @Specialization
   protected VmDynamic evalDynamic(VirtualFrame frame, VmDynamic parent) {
     return new VmDynamic(
@@ -104,10 +113,11 @@ public abstract class ElementsEntriesLiteralNode extends SpecializedObjectLitera
         parent.getLength() + elements.length);
   }
 
-  @Specialization
-  protected Object evalNull(VirtualFrame frame, VmNull parent) {
-    // assumes that Graal PE can handle recursive call to same node
-    return executeWithParent(frame, parent.getDefaultValue());
+  @SuppressWarnings("unused")
+  @Specialization(guards = "getClass(defaultValue).isDynamicClass()")
+  protected Object evalNullWithDynamicDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalDynamic(frame, (VmDynamic) defaultValue);
   }
 
   @Specialization(guards = "checkIsValidFunctionAmendment(parent)")
@@ -120,6 +130,18 @@ public abstract class ElementsEntriesLiteralNode extends SpecializedObjectLitera
     return amendFunctionNode.execute(frame, parent);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isFunction(defaultValue)", "checkIsValidFunctionAmendment(defaultValue)"})
+  protected Object evalNullWithFunctionDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached(value = "createAmendFunctionNode(frame)", neverDefault = true)
+          AmendFunctionNode amendFunctionNode) {
+    return evalFunction(frame, (VmFunction) defaultValue, amendFunctionNode);
+  }
+
   @Specialization(guards = {"parent == getListingClass()", "checkIsValidListingAmendment()"})
   protected VmListing evalListingClass(
       VirtualFrame frame, @SuppressWarnings("unused") VmClass parent) {
@@ -145,7 +167,12 @@ public abstract class ElementsEntriesLiteralNode extends SpecializedObjectLitera
   @Fallback
   @TruffleBoundary
   protected void fallback(Object parent) {
-    elementsEntriesFallback(parent, elements[0], true);
+    var value = parent;
+    // blame the non-null type (e.g. blame `Duration` instead of `Null` in the case of `Duration?`)
+    if (value instanceof VmNull vmNull) {
+      value = getNullDefaultValue(vmNull);
+    }
+    elementsEntriesFallback(value, elements[0], true);
   }
 
   @ExplodeLoop
diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsLiteralNode.java
index b68f1ade8..ba7a43b41 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ElementsLiteralNode.java
@@ -32,7 +32,7 @@ import org.pkl.core.util.EconomicMaps;
  * Object literal that contains elements (and possibly properties) but not entries. Example: `new
  * foo { "pigeon" }`
  */
-@ImportStatic(BaseModule.class)
+@ImportStatic({BaseModule.class, VmUtils.class})
 public abstract class ElementsLiteralNode extends SpecializedObjectLiteralNode {
   private final ObjectMember[] elements;
 
@@ -94,10 +94,11 @@ public abstract class ElementsLiteralNode extends SpecializedObjectLiteralNode {
         parent.getLength() + elements.length);
   }
 
-  @Specialization
-  protected Object evalNull(VirtualFrame frame, VmNull parent) {
-    // assumes that Graal PE can handle recursive call to same node
-    return executeWithParent(frame, parent.getDefaultValue());
+  @SuppressWarnings("unused")
+  @Specialization(guards = "getClass(defaultValue).isDynamicClass()")
+  protected Object evalNullWithDynamicDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalDynamicUncached(frame, (VmDynamic) defaultValue);
   }
 
   @Specialization(guards = "checkIsValidFunctionAmendment(parent)")
@@ -110,6 +111,18 @@ public abstract class ElementsLiteralNode extends SpecializedObjectLiteralNode {
     return amendFunctionNode.execute(frame, parent);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isFunction(defaultValue)", "checkIsValidFunctionAmendment(defaultValue)"})
+  protected Object evalNullWithFunctionDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached(value = "createAmendFunctionNode(frame)", neverDefault = true)
+          AmendFunctionNode amendFunctionNode) {
+    return evalFunction(frame, (VmFunction) defaultValue, amendFunctionNode);
+  }
+
   @Specialization(
       guards = {
         "parent == getListingClass()",
@@ -162,10 +175,23 @@ public abstract class ElementsLiteralNode extends SpecializedObjectLiteralNode {
         parent.getLength() + elements.length);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isListingClass()", "checkIsValidListingAmendment()"})
+  protected Object evalNullWithListingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalListingUncached(frame, (VmListing) defaultValue);
+  }
+
   @Fallback
   @TruffleBoundary
   protected void fallback(Object parent) {
-    elementsEntriesFallback(parent, elements[0], true);
+    var value = parent;
+    // blame the non-null type (e.g. blame `Duration` instead of `Null` in the case of `Duration?`)
+    if (value instanceof VmNull vmNull) {
+      value = getNullDefaultValue(vmNull);
+    }
+    elementsEntriesFallback(value, elements[0], true);
   }
 
   // offset element keys according to parentLength
diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/EntriesLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/EntriesLiteralNode.java
index fd8a111ad..4ff4fb9bf 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/EntriesLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/EntriesLiteralNode.java
@@ -38,7 +38,7 @@ import org.pkl.core.util.EconomicMaps;
  * used.) Example: `foo { ["on" + "e"] = 1 }`
  */
 // IDEA: don't materialize frames if all members have constant values
-@ImportStatic(BaseModule.class)
+@ImportStatic({BaseModule.class, VmUtils.class})
 public abstract class EntriesLiteralNode extends SpecializedObjectLiteralNode {
   @Children private final ExpressionNode[] keyNodes;
   private final ObjectMember[] values;
@@ -92,11 +92,26 @@ public abstract class EntriesLiteralNode extends SpecializedObjectLiteralNode {
     return new VmMapping(frame.materialize(), parent, createMapMembers(frame));
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isMappingClass()", "checkIsValidMappingAmendment()"})
+  protected Object evalNullWithMappingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalMapping(frame, (VmMapping) defaultValue);
+  }
+
   @Specialization
   protected VmDynamic evalDynamic(VirtualFrame frame, VmDynamic parent) {
     return new VmDynamic(frame.materialize(), parent, createMapMembers(frame), parent.getLength());
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(guards = {"getClass(defaultValue).isDynamicClass()"})
+  protected Object evalNullWithDynamicDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalDynamic(frame, (VmDynamic) defaultValue);
+  }
+
   @Specialization(guards = "checkIsValidListingAmendment()")
   protected VmListing evalListing(VirtualFrame frame, VmListing parent) {
     return new VmListing(
@@ -107,10 +122,12 @@ public abstract class EntriesLiteralNode extends SpecializedObjectLiteralNode {
         parent.getLength());
   }
 
-  @Specialization
-  protected Object evalNull(VirtualFrame frame, VmNull parent) {
-    // assumes that Graal PE can handle recursive call to same node
-    return executeWithParent(frame, parent.getDefaultValue());
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isListingClass()", "checkIsValidListingAmendment()"})
+  protected Object evalNullWithListingDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalListing(frame, (VmListing) defaultValue);
   }
 
   @Specialization(guards = "checkIsValidFunctionAmendment(parent)")
@@ -123,6 +140,18 @@ public abstract class EntriesLiteralNode extends SpecializedObjectLiteralNode {
     return amendFunctionNode.execute(frame, parent);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isFunction(defaultValue)", "checkIsValidFunctionAmendment(defaultValue)"})
+  protected Object evalNullWithFunctionDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached(value = "createAmendFunctionNode(frame)", neverDefault = true)
+          AmendFunctionNode amendFunctionNode) {
+    return evalFunction(frame, (VmFunction) defaultValue, amendFunctionNode);
+  }
+
   @Specialization(guards = {"parent == getMappingClass()", "checkIsValidMappingAmendment()"})
   protected VmMapping evalMappingClass(
       VirtualFrame frame, @SuppressWarnings("unused") VmClass parent) {
@@ -152,7 +181,12 @@ public abstract class EntriesLiteralNode extends SpecializedObjectLiteralNode {
   @Fallback
   @TruffleBoundary
   protected Object fallback(Object parent) {
-    return elementsEntriesFallback(parent, values[0], false);
+    var value = parent;
+    // blame the non-null type (e.g. blame `Duration` instead of `Null` in the case of `Duration?`)
+    if (value instanceof VmNull vmNull) {
+      value = getNullDefaultValue(vmNull);
+    }
+    return elementsEntriesFallback(value, values[0], false);
   }
 
   @ExplodeLoop
diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ObjectLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ObjectLiteralNode.java
index c8a8d8ea8..7e56ff737 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ObjectLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/ObjectLiteralNode.java
@@ -20,14 +20,17 @@ import com.oracle.truffle.api.dsl.Idempotent;
 import com.oracle.truffle.api.dsl.NodeChild;
 import com.oracle.truffle.api.frame.FrameDescriptor;
 import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.nodes.LoopNode;
 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.UnresolvedTypeNode;
+import org.pkl.core.runtime.BaseModule;
 import org.pkl.core.runtime.VmClass;
 import org.pkl.core.runtime.VmFunction;
 import org.pkl.core.runtime.VmLanguage;
+import org.pkl.core.runtime.VmNull;
 import org.pkl.core.runtime.VmUtils;
 
 // IDEA: don't materialize frames when all members are constants
@@ -57,8 +60,6 @@ public abstract class ObjectLiteralNode extends ExpressionNode {
 
   protected abstract ExpressionNode getParentNode();
 
-  protected abstract Object executeWithParent(VirtualFrame frame, Object parent);
-
   protected abstract ObjectLiteralNode copy(ExpressionNode newParentNode);
 
   protected final AmendFunctionNode createAmendFunctionNode(VirtualFrame frame) {
@@ -71,7 +72,14 @@ public abstract class ObjectLiteralNode extends ExpressionNode {
 
   @Idempotent
   protected static boolean isTypedObjectClass(VmClass clazz) {
-    return !(clazz.isListingClass() || clazz.isMappingClass() || clazz.isDynamicClass());
+    if (clazz.isListingClass()
+        || clazz.isMappingClass()
+        || clazz.isDynamicClass()
+        || clazz.isFunctionClass()
+        || clazz.isFunctionNClass()) {
+      return false;
+    }
+    return BaseModule.getTypedClass().isSuperclassOf(clazz);
   }
 
   protected final boolean checkIsValidFunctionAmendment(VmFunction parent) {
@@ -85,4 +93,25 @@ public abstract class ObjectLiteralNode extends ExpressionNode {
     }
     return true;
   }
+
+  @Idempotent
+  protected final boolean checkIsValidFunctionAmendment(Object parent) {
+    return checkIsValidFunctionAmendment((VmFunction) parent);
+  }
+
+  @Idempotent
+  protected final boolean isFunction(Object value) {
+    return value instanceof VmFunction;
+  }
+
+  protected final Object getNullDefaultValue(VmNull parent) {
+    var value = parent.getDefaultValue();
+    var count = 0;
+    while (value instanceof VmNull n) {
+      value = n.getDefaultValue();
+      count++;
+    }
+    LoopNode.reportLoopCount(this, count);
+    return value;
+  }
 }
diff --git a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/PropertiesLiteralNode.java b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/PropertiesLiteralNode.java
index b35db9438..d58bef4f3 100644
--- a/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/PropertiesLiteralNode.java
+++ b/pkl-core/src/main/java/org/pkl/core/ast/expression/literal/PropertiesLiteralNode.java
@@ -16,7 +16,9 @@
 package org.pkl.core.ast.expression.literal;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Bind;
 import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.ImportStatic;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.FrameDescriptor;
 import com.oracle.truffle.api.frame.VirtualFrame;
@@ -31,6 +33,7 @@ import org.pkl.core.runtime.*;
 
 /** Object literal that contains properties but not elements or entries. */
 // IDEA: don't materialize frame when all members are constants
+@ImportStatic({BaseModule.class, VmUtils.class})
 public abstract class PropertiesLiteralNode extends SpecializedObjectLiteralNode {
   public PropertiesLiteralNode(
       SourceSection sourceSection,
@@ -82,26 +85,77 @@ public abstract class PropertiesLiteralNode extends SpecializedObjectLiteralNode
     return new VmTyped(frame.materialize(), parent, parent.getVmClass(), members);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {
+        "parentClass == getClass(defaultValue)",
+        "isTypedObjectClass(parentClass)",
+        "checkIsValidTypedAmendment(parentClass)"
+      })
+  protected Object evalNullWithTypedObjectDefaultCached(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached("getClass(defaultValue)") VmClass parentClass) {
+    var parentTyped = (VmTyped) defaultValue;
+    return new VmTyped(frame.materialize(), parentTyped, parentTyped.getVmClass(), members);
+  }
+
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {
+        "isTypedObjectClass(getClass(defaultValue))",
+        "checkIsValidTypedAmendment(defaultValue)"
+      })
+  protected Object evalNullWithTypedObjectDefaultUncached(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind(value = "getNullDefaultValue(parent)") Object defaultValue) {
+    var parentTyped = (VmTyped) defaultValue;
+    return new VmTyped(frame.materialize(), parentTyped, parentTyped.getVmClass(), members);
+  }
+
   @Specialization
   protected Object evalDynamic(VirtualFrame frame, VmDynamic parent) {
     return new VmDynamic(frame.materialize(), parent, members, parent.getLength());
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(guards = "getClass(defaultValue).isDynamicClass()")
+  protected Object evalNullWithDynamicDefault(
+      VirtualFrame frame, VmNull parent, @Bind("getNullDefaultValue(parent)") Object defaultValue) {
+    return evalDynamic(frame, (VmDynamic) defaultValue);
+  }
+
   @Specialization(guards = "checkIsValidListingAmendment()")
   protected Object evalListing(VirtualFrame frame, VmListing parent) {
     return new VmListing(frame.materialize(), parent, members, parent.getLength());
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isListingClass()", "checkIsValidListingAmendment()"})
+  protected Object evalNullWithListingDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind(value = "getNullDefaultValue(parent)") Object defaultValue) {
+    return evalListing(frame, (VmListing) defaultValue);
+  }
+
   @ExplodeLoop
   @Specialization(guards = "checkIsValidMappingAmendment()")
   protected Object evalMapping(VirtualFrame frame, VmMapping parent) {
     return new VmMapping(frame.materialize(), parent, members);
   }
 
-  @Specialization
-  protected Object evalNull(VirtualFrame frame, VmNull parent) {
-    // assumes that Graal PE can handle recursive call to same node
-    return executeWithParent(frame, parent.getDefaultValue());
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"getClass(defaultValue).isMappingClass()", "checkIsValidMappingAmendment()"})
+  protected Object evalNullWithMappingDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind(value = "getNullDefaultValue(parent)") Object defaultValue) {
+    return evalMapping(frame, (VmMapping) defaultValue);
   }
 
   // Ultimately, this lambda or a lambda returned from it will call one of the other
@@ -121,6 +175,18 @@ public abstract class PropertiesLiteralNode extends SpecializedObjectLiteralNode
     return amendFunctionNode.execute(frame, parent);
   }
 
+  @SuppressWarnings("unused")
+  @Specialization(
+      guards = {"isFunction(defaultValue)", "checkIsValidFunctionAmendment(defaultValue)"})
+  protected Object evalNullWithFunctionDefault(
+      VirtualFrame frame,
+      VmNull parent,
+      @Bind("getNullDefaultValue(parent)") Object defaultValue,
+      @Cached(value = "createAmendFunctionNode(frame)", neverDefault = true)
+          AmendFunctionNode amendFunctionNode) {
+    return evalFunction(frame, (VmFunction) defaultValue, amendFunctionNode);
+  }
+
   @Specialization(
       guards = {
         "parent == cachedParent",
@@ -199,8 +265,13 @@ public abstract class PropertiesLiteralNode extends SpecializedObjectLiteralNode
   @Specialization
   @TruffleBoundary
   protected void fallback(Object parent) {
+    var value = parent;
+    // blame the non-null type (e.g. blame `Duration` instead of `Null` in the case of `Duration?`)
+    if (value instanceof VmNull vmNull) {
+      value = getNullDefaultValue(vmNull);
+    }
     // should always throw
-    checkIsValidTypedAmendment(parent);
+    checkIsValidTypedAmendment(value);
 
     throw exceptionBuilder().unreachableCode().build();
   }
diff --git a/pkl-core/src/main/java/org/pkl/core/runtime/BaseModule.java b/pkl-core/src/main/java/org/pkl/core/runtime/BaseModule.java
index e43586702..3188ee753 100644
--- a/pkl-core/src/main/java/org/pkl/core/runtime/BaseModule.java
+++ b/pkl-core/src/main/java/org/pkl/core/runtime/BaseModule.java
@@ -19,6 +19,7 @@ import static org.pkl.core.PClassInfo.pklBaseUri;
 
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Idempotent;
 
 public final class BaseModule extends StdLibModule {
   static final VmTyped instance = VmUtils.createEmptyModule();
@@ -91,6 +92,7 @@ public final class BaseModule extends StdLibModule {
     return SetClass.instance;
   }
 
+  @Idempotent
   public static VmClass getListingClass() {
     return ListingClass.instance;
   }
@@ -99,10 +101,12 @@ public final class BaseModule extends StdLibModule {
     return MapClass.instance;
   }
 
+  @Idempotent
   public static VmClass getMappingClass() {
     return MappingClass.instance;
   }
 
+  @Idempotent
   public static VmClass getDynamicClass() {
     return DynamicClass.instance;
   }
@@ -135,6 +139,7 @@ public final class BaseModule extends StdLibModule {
     return RegexMatchClass.instance;
   }
 
+  @Idempotent
   public static VmClass getFunctionClass() {
     return FunctionClass.instance;
   }
diff --git a/pkl-core/src/main/java/org/pkl/core/runtime/VmUtils.java b/pkl-core/src/main/java/org/pkl/core/runtime/VmUtils.java
index 17891b1e3..9dcf29610 100644
--- a/pkl-core/src/main/java/org/pkl/core/runtime/VmUtils.java
+++ b/pkl-core/src/main/java/org/pkl/core/runtime/VmUtils.java
@@ -21,6 +21,7 @@ import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.Truffle;
 import com.oracle.truffle.api.TruffleLanguage;
 import com.oracle.truffle.api.TruffleStackTrace;
+import com.oracle.truffle.api.dsl.Idempotent;
 import com.oracle.truffle.api.frame.*;
 import com.oracle.truffle.api.nodes.*;
 import com.oracle.truffle.api.source.Source;
@@ -528,6 +529,7 @@ public final class VmUtils {
   }
 
   // implements same behavior as AnyNodes#getClass
+  @Idempotent
   public static VmClass getClass(Object value) {
     if (value instanceof VmValue vmValue) {
       return vmValue.getVmClass();
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/lambdas/amendLambdaNullable.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/lambdas/amendLambdaNullable.pkl
new file mode 100644
index 000000000..73ad5f9ce
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/lambdas/amendLambdaNullable.pkl
@@ -0,0 +1,9 @@
+class Person { name: String }
+
+hidden x: Mixin<Person>?
+
+local y = (x) {
+  name = "Fred"
+}
+
+res = y.apply(new Person {})
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing1.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing1.pkl
index 0d4d4f1ee..6f322aac4 100644
--- a/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing1.pkl
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing1.pkl
@@ -26,6 +26,25 @@ res2 = new Listing {
   new Mapping { ["one"] = 1; ["two"] = 2 }
 }
 
+res2n = (Null(new Listing {})) {
+  null
+  true
+  42
+  1.23
+  "foo"
+  Regex("bar")
+  5.gb
+  3.min
+  Pair(1, 2)
+  List(1, 2, 3)
+  Set(1, 2, 3)
+  Map("one", 1, "two", 2)
+  new Dynamic { name = "Pigeon"; age = 42 }
+  new Person { name = "Pigeon"; age = 42 }
+  new Listing { 1; 2; 3 }
+  new Mapping { ["one"] = 1; ["two"] = 2 }
+}
+
 res3 = new Listing {
   id(null)
   id(true)
@@ -44,3 +63,22 @@ res3 = new Listing {
   id(new Listing { 1; 2; 3 })
   id(new Mapping { ["one"] = 1; ["two"] = 2 })
 }
+
+res3n = (Null(new Listing {})) {
+  id(null)
+  id(true)
+  id(42)
+  id(1.23)
+  id("foo")
+  id(Regex("bar"))
+  id(5.gb)
+  id(3.min)
+  id(Pair(1, 2))
+  id(List(1, 2, 3))
+  id(Set(1, 2, 3))
+  id(Map("one", 1, "two", 2))
+  id(new Dynamic { name = "Pigeon"; age = 42 })
+  id(new Person { name = "Pigeon"; age = 42 })
+  id(new Listing { 1; 2; 3 })
+  id(new Mapping { ["one"] = 1; ["two"] = 2 })
+}
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing2.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing2.pkl
index afe04222e..058d758de 100644
--- a/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing2.pkl
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/listings/listing2.pkl
@@ -73,11 +73,20 @@ res8 = test.catch(() -> (x) { ["wrong type"] = "value" })
 res8a = test.catch(() -> (x) { [id("wrong type")] = id("value") })
 
 res9 = test.catch(() -> new Listing { foo = "bar" })
+res9n = test.catch(() -> (Null(new Listing {})) { foo = "bar" })
 res10 = test.catch(() -> (x) { foo = "foo" })
+res10n = test.catch(() -> (Null(x)) { foo = "foo" })
 res11 = test.catch(() -> new Listing { "one"; foo = "foo" })
+res11n = test.catch(() -> (Null(new Listing { "one" })) { foo = "foo" })
 res12 = test.catch(() -> (x) { "four"; foo = "foo" })
+res12n = test.catch(() -> (Null(x)) { "four"; foo = "foo" })
 res12a = test.catch(() -> (x) { id("four"); foo = "foo" })
+res12an = test.catch(() -> (Null(x)) { id("four"); foo = "foo" })
 res13 = test.catch(() -> (x) { [1] = "updated two"; foo = "foo" })
+res13n = test.catch(() -> (Null(x)) { [1] = "updated two"; foo = "foo" })
 res13a = test.catch(() -> (x) { [id(1)] = id("updated two"); foo = "foo" })
+res13an = test.catch(() -> (Null(x)) { [id(1)] = id("updated two"); foo = "foo" })
 res14 = test.catch(() -> (x) { "four"; [1] = "updated two"; foo = "foo" })
+res14n = test.catch(() -> (Null(x)) { "four"; [1] = "updated two"; foo = "foo" })
 res14a = test.catch(() -> (x) { id("four"); [id(1)] = id("updated two"); foo = "foo" })
+res14an = test.catch(() -> (Null(x)) { id("four"); [id(1)] = id("updated two"); foo = "foo" })
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/mappings/mapping1.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/mappings/mapping1.pkl
index dbe97271b..e93551162 100644
--- a/pkl-core/src/test/files/LanguageSnippetTests/input/mappings/mapping1.pkl
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/mappings/mapping1.pkl
@@ -26,6 +26,25 @@ res2 = new Mapping {
   [new Mapping { ["one"] = 1; ["two"] = 2 }] = new Mapping { ["one"] = 1; ["two"] = 2 }
 }
 
+res2n = (Null(new Mapping {})) {
+  [null] = null
+  [true] = true
+  [42] = 42
+  [1.23] = 1.23
+  ["foo"] = "foo"
+  [Regex("bar")] = Regex("bar")
+  [5.gb] = 5.gb
+  [3.min] = 3.min
+  [Pair(1, 2)] = Pair(1, 2)
+  [List(1, 2, 3)] = List(1, 2, 3)
+  [Set(1, 2, 3)] = Set(1, 2, 3)
+  [Map("one", 1, "two", 2)] = Map("one", 1, "two", 2)
+  [new Dynamic { name = "Pigeon"; age = 42 }] = new Dynamic { name = "Pigeon"; age = 42 }
+  [new Person { name = "Pigeon"; age = 42 }] = new Person { name = "Pigeon"; age = 42 }
+  [new Listing { 1; 2; 3 }] = new Listing { 1; 2; 3 }
+  [new Mapping { ["one"] = 1; ["two"] = 2 }] = new Mapping { ["one"] = 1; ["two"] = 2 }
+}
+
 res3 = new Mapping {
   [id(null)] = id(null)
   [id(true)] = id(true)
@@ -44,3 +63,34 @@ res3 = new Mapping {
   [id(new Listing { 1; 2; 3 })] = id(new Listing { 1; 2; 3 })
   [id(new Mapping { ["one"] = 1; ["two"] = 2 })] = id(new Mapping { ["one"] = 1; ["two"] = 2 })
 }
+
+res3n = (Null(new Mapping {})) {
+  [id(null)] = id(null)
+  [id(true)] = id(true)
+  [id(42)] = id(42)
+  [id(1.23)] = id(1.23)
+  [id("foo")] = id("foo")
+  [id(Regex("bar"))] = id(Regex("bar"))
+  [id(5.gb)] = id(5.gb)
+  [id(3.min)] = id(3.min)
+  [id(Pair(1, 2))] = id(Pair(1, 2))
+  [id(List(1, 2, 3))] = id(List(1, 2, 3))
+  [id(Set(1, 2, 3))] = id(Set(1, 2, 3))
+  [id(Map("one", 1, "two", 2))] = id(Map("one", 1, "two", 2))
+  [id(new Dynamic { name = "Pigeon"; age = 42 })] = id(new Dynamic { name = "Pigeon"; age = 42 })
+  [id(new Person { name = "Pigeon"; age = 42 })] = id(new Person { name = "Pigeon"; age = 42 })
+  [id(new Listing { 1; 2; 3 })] = id(new Listing { 1; 2; 3 })
+  [id(new Mapping { ["one"] = 1; ["two"] = 2 })] = id(new Mapping { ["one"] = 1; ["two"] = 2 })
+}
+
+// ConstantEntriesLiteralNode
+res4 = new Mapping {
+  ["foo"] = "1"
+  ["bar"] = "2"
+}
+
+// ConstantEntriesLiteralNode
+res4n = (Null(new Mapping {})) {
+  ["foo"] = "1"
+  ["bar"] = "2"
+}
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/constantEntries.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/constantEntries.pkl
new file mode 100644
index 000000000..93f72054b
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/constantEntries.pkl
@@ -0,0 +1,47 @@
+// Covers ConstantEntriesLiteralNode's specializations for amending a `VmNull` whose default value
+// is each of the underlying parent types it supports. All entry keys below are constants, so
+// these bodies compile to ConstantEntriesLiteralNode rather than EntriesLiteralNode.
+import "pkl:test"
+
+// evalNullWithMappingDefault
+local mapping = Null(new Mapping { ["a"] = 1 })
+res1 = (mapping) {
+  ["b"] = 2
+}
+
+// evalNullWithDynamicDefault
+local dynamic = Null(new Dynamic { a = 1 })
+res2 = (dynamic) {
+  ["b"] = 2
+}
+
+// evalNullWithListingDefault
+local listing = Null(new Listing { "a"; "b" })
+res3 = (listing) {
+  [0] = "updated a"
+}
+
+// evalNullWithFunctionDefault
+local fun = Null(() -> new Mapping { ["a"] = 1 })
+local amendedFun = (fun) {
+  ["b"] = 2
+}
+res4 = amendedFun.apply()
+
+// error: listing entry index out of range
+res5 = test.catch(() -> (Null(new Listing { "a" })) { [5] = "value" })
+
+// error: listing cannot have a property (other than `default`)
+res6 = test.catch(() -> (Null(new Listing { "a" })) { [0] = "updated a"; foo = "bar" })
+
+// error: mapping cannot have a property (other than `default`)
+res7 = test.catch(() -> (Null(new Mapping { ["a"] = 1 })) { ["b"] = 2; foo = "bar" })
+
+// error: function amendment with wrong parameter count
+local twoArgFun = (x, y) -> new Mapping {}
+res8 = test.catch(() -> (Null(twoArgFun)) { x -> ["a"] = 1 })
+
+hidden foo: "foo"?
+
+// error: default value's type has no matching specialization; falls back to the generic error
+res9 = test.catch(() -> (foo) { ["a"] = 1 })
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/elements.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/elements.pkl
new file mode 100644
index 000000000..16b89b58a
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/elements.pkl
@@ -0,0 +1,37 @@
+// Covers ElementsLiteralNode's specializations for amending a `VmNull` whose default value is
+// each of the underlying parent types it supports.
+import "pkl:test"
+
+// evalNullWithDynamicDefault
+local dynamic = Null(new Dynamic { a = 1 })
+res1 = (dynamic) {
+  "b"
+  "c"
+}
+
+// evalNullWithListingDefault
+local listing = Null(new Listing { "a" })
+res2 = (listing) {
+  "b"
+  "c"
+}
+
+// evalNullWithFunctionDefault
+local fun = Null(() -> new Listing { "a" })
+local amendedFun = (fun) {
+  "b"
+}
+res3 = amendedFun.apply()
+
+// error: mapping cannot have an element
+res4 = test.catch(() -> (Null(new Mapping { ["a"] = 1 })) { "b" })
+
+// error: listing cannot have a property (other than `default`)
+res5 = test.catch(() -> (Null(new Listing { "a" })) { "b"; foo = "bar" })
+
+// error: function amendment with wrong parameter count
+local twoArgFun = (x, y) -> new Listing {}
+res6 = test.catch(() -> (Null(twoArgFun)) { x -> "b" })
+
+// error: default value's type has no matching specialization; falls back to the generic error
+res7 = test.catch(() -> (Null(42)) { "b" })
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/elementsEntries.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/elementsEntries.pkl
new file mode 100644
index 000000000..dd39eaf47
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/elementsEntries.pkl
@@ -0,0 +1,45 @@
+// Covers ElementsEntriesLiteralNode's specializations for amending a `VmNull` whose default value
+// is each of the underlying parent types it supports. Element and entry keys are mixed, and at
+// least one key is non-constant (via `id()`), matching this node's shape.
+import "pkl:test"
+
+function id(x) = x
+
+// evalNullWithDynamicDefault
+local dynamic = Null(new Dynamic { "a" })
+
+res1 = (dynamic) {
+  [id(0)] = "updated a"
+  "b"
+}
+
+// evalNullWithListingDefault
+local listing = Null(new Listing { "a"; "b" })
+res2 = (listing) {
+  "c"
+  [id(0)] = "updated a"
+}
+
+// evalNullWithFunctionDefault
+local fun = Null(() -> new Listing { "a" })
+local amendedFun = (fun) {
+  "b"
+  [id(0)] = "updated a"
+}
+res3 = amendedFun.apply()
+
+// error: mapping cannot have an element
+res4 = test.catch(() -> (Null(new Mapping { ["a"] = 1 })) { "b"; [id("c")] = 2 })
+
+// error: listing entry index out of range
+res5 = test.catch(() -> (Null(new Listing { "a" })) { "b"; [id(5)] = "value" })
+
+// error: listing cannot have a property (other than `default`)
+res6 = test.catch(() -> (Null(new Listing { "a" })) { "b"; [id(0)] = "updated a"; foo = "bar" })
+
+// error: function amendment with wrong parameter count
+local twoArgFun = (x, y) -> new Listing {}
+res7 = test.catch(() -> (Null(twoArgFun)) { x -> "b"; [id(0)] = "updated a" })
+
+// error: default value's type has no matching specialization; falls back to the generic error
+res8 = test.catch(() -> (Null(42)) { "b"; [id(0)] = "updated a" })
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/entries.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/entries.pkl
new file mode 100644
index 000000000..248e1e3fc
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/entries.pkl
@@ -0,0 +1,53 @@
+// Covers EntriesLiteralNode's specializations for amending a `VmNull` whose default value is
+// each of the underlying parent types it supports. At least one entry key below is non-constant
+// (via `id()`) so that these bodies compile to EntriesLiteralNode rather than
+// ConstantEntriesLiteralNode.
+import "pkl:test"
+
+function id(x) = x
+
+// evalNullableMapping
+local mapping = Null(new Mapping { ["a"] = 1 })
+res1 = (mapping) {
+  [id("b")] = 2
+}
+
+// evalNullWithDynamicDefault
+local dynamic = Null(new Dynamic { a = 1 })
+res2 = (dynamic) {
+  [id("b")] = 2
+}
+
+// evalNullWithListingDefault
+local listing = Null(new Listing { "a"; "b" })
+res3 = (listing) {
+  [id(0)] = "updated a"
+}
+
+// evalNullWithFunctionDefault
+local fun = Null(() -> new Mapping { ["a"] = 1 })
+local amendedFun = (fun) {
+  [id("b")] = 2
+}
+res4 = amendedFun.apply()
+
+// error: listing entry with wrong key type
+res5 = test.catch(() -> (Null(new Listing { "a" })) { [id("wrong type")] = "value" })
+
+// error: listing entry index out of range
+res6 = test.catch(() -> (Null(new Listing { "a" })) { [id(5)] = "value" })
+
+// error: mapping cannot have a property (other than `default`)
+res7 = test.catch(() -> (Null(new Mapping { ["a"] = 1 })) { foo = "bar"; [id("b")] = 2 })
+
+// error: duplicate key
+res8 = test.catch(() -> (Null(new Mapping {})) { [id("a")] = 1; [id("a")] = 2 })
+
+// error: function amendment with wrong parameter count
+local twoArgFun = (x, y) -> new Mapping {}
+res9 = test.catch(() -> (Null(twoArgFun)) { x -> [id("a")] = 1 })
+
+hidden foo: "foo"?
+
+// error: default value's type has no matching specialization; falls back to the generic error
+res10 = test.catch(() -> (foo) { [id("a")] = 1 })
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/generator.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/generator.pkl
new file mode 100644
index 000000000..7074a2cf3
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/generator.pkl
@@ -0,0 +1,68 @@
+// Covers GeneratorObjectLiteralNode's specializations for amending a `VmNull` whose default value
+// is each of the underlying parent types it supports. Each body contains a `for`- or
+// when-generator, which is what forces this node type instead of ElementsLiteralNode/
+// EntriesLiteralNode/PropertiesLiteralNode.
+import "pkl:test"
+
+local class Person {
+  name: String
+  age: Int = 0
+}
+
+// evalNullWithDynamicDefault
+local dynamic = Null(new Dynamic { a = 1 })
+res1 = (dynamic) {
+  for (i in List(2, 3)) {
+    i
+  }
+}
+
+// evalNullWithTypedDefault
+local person = Null(new Person { name = "Pigeon" })
+res2 = (person) {
+  when (true) {
+    age = 10
+  }
+}
+
+// evalNullWithListingDefault
+local listing = Null(new Listing { "a" })
+res3 = (listing) {
+  for (i in List(2, 3)) {
+    i
+  }
+}
+
+// evalNullableMapping
+local mapping = Null(new Mapping { ["a"] = 1 })
+res4 = (mapping) {
+  for (i in List(2, 3)) {
+    [i] = i
+  }
+}
+
+// evalNullWithFunctionDefault
+local fun = Null(() -> new Dynamic { a = 1 })
+local amendedFun = (fun) {
+  for (i in List(2, 3)) {
+    i
+  }
+}
+res5 = amendedFun.apply()
+
+// error: listing amendment cannot have parameters
+res6 = test.catch(() -> (Null(new Listing { "a" })) { x -> for (i in List(2)) { i } })
+
+// error: mapping amendment cannot have parameters
+res7 = test.catch(() -> (Null(new Mapping { ["a"] = 1 })) { x -> for (i in List(2)) { [i] = i } })
+
+// error: object amendment cannot have parameters
+res8 = test.catch(() -> (Null(new Dynamic { a = 1 })) { x -> for (i in List(2)) { i } })
+
+hidden foo: "foo"?
+
+// error: default value's type has no matching specialization; falls back to the generic error
+res9 = test.catch(() -> (foo) { for (i in List(2)) { i } })
+
+hidden x: List<Int>?
+res10 = test.catch(() -> ((x) { when (true) { foo = 1 } }))
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/properties.pkl b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/properties.pkl
new file mode 100644
index 000000000..377d8ecef
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/input/nullParents/properties.pkl
@@ -0,0 +1,63 @@
+// Covers PropertiesLiteralNode's specializations for amending a `VmNull` whose default value is
+// each of the underlying parent types it supports.
+import "pkl:test"
+
+local class Person {
+  name: String
+  age: Int = 0
+}
+
+// evalNullWithTypedDefault
+local person = Null(new Person { name = "Pigeon" })
+res1 = (person) {
+  age = 3
+}
+
+// evalNullWithDynamicDefault
+local dynamic = Null(new Dynamic { name = "Pigeon" })
+res2 = (dynamic) {
+  age = 3
+}
+
+// evalNullWithListingDefault
+local listing = Null(new Listing { "one"; "two" })
+res3 = (listing) {
+  default = (_) -> "three"
+}.getOrDefault(5)
+
+// evalNullableMapping
+local mapping = Null(new Mapping { ["one"] = 1 })
+res4 = (mapping) {
+  default = (_) -> 0
+}.getOrDefault("missing")
+
+// evalNullWithFunctionDefault
+local fun = Null(() -> new Dynamic { zero = 0 })
+local amendedFun = (fun) {
+  amended = "amended"
+}
+res5 = amendedFun.apply()
+
+// error: typed object amendment with an unknown property
+res6 = test.catch(() -> (Null(new Person { name = "Pigeon" })) { nickname = "Pidge" })
+
+// error: listing cannot have a property (other than `default`)
+res7 = test.catch(() -> (Null(new Listing { "one" })) { foo = "bar" })
+
+// error: mapping cannot have a property (other than `default`)
+res8 = test.catch(() -> (Null(new Mapping { ["one"] = 1 })) { foo = "bar" })
+
+// error: function amendment with wrong parameter count
+local twoArgFun = (x, y) -> new Dynamic {}
+res9 = test.catch(() -> (Null(twoArgFun)) { x -> prop = x })
+
+hidden foo: "foo"?
+
+// error: default value's type has no matching specialization; falls back to the generic error
+res10 = test.catch(() -> (foo) { foo = "bar" })
+
+hidden clazz: Class?
+
+res11 = (clazz) {
+  x = 1
+}
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/lambdas/amendLambdaNullable.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/lambdas/amendLambdaNullable.pcf
new file mode 100644
index 000000000..dbb0e933c
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/lambdas/amendLambdaNullable.pcf
@@ -0,0 +1,3 @@
+res {
+  name = "Fred"
+}
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing1.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing1.pcf
index 2161d6d9f..8008f555c 100644
--- a/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing1.pcf
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing1.pcf
@@ -30,6 +30,37 @@ res2 {
     ["two"] = 2
   }
 }
+res2n {
+  null
+  true
+  42
+  1.23
+  "foo"
+  Regex("bar")
+  5.gb
+  3.min
+  Pair(1, 2)
+  List(1, 2, 3)
+  Set(1, 2, 3)
+  Map("one", 1, "two", 2)
+  new {
+    name = "Pigeon"
+    age = 42
+  }
+  new {
+    name = "Pigeon"
+    age = 42
+  }
+  new {
+    1
+    2
+    3
+  }
+  new {
+    ["one"] = 1
+    ["two"] = 2
+  }
+}
 res3 {
   null
   true
@@ -61,3 +92,34 @@ res3 {
     ["two"] = 2
   }
 }
+res3n {
+  null
+  true
+  42
+  1.23
+  "foo"
+  Regex("bar")
+  5.gb
+  3.min
+  Pair(1, 2)
+  List(1, 2, 3)
+  Set(1, 2, 3)
+  Map("one", 1, "two", 2)
+  new {
+    name = "Pigeon"
+    age = 42
+  }
+  new {
+    name = "Pigeon"
+    age = 42
+  }
+  new {
+    1
+    2
+    3
+  }
+  new {
+    ["one"] = 1
+    ["two"] = 2
+  }
+}
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing2.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing2.pcf
index be9103ae4..4b7c1cc85 100644
--- a/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing2.pcf
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/listings/listing2.pcf
@@ -55,11 +55,20 @@ res7a = "Element index `-1` is out of range `0`..`2`."
 res8 = "Expected key of type `Int`, but got type `String`."
 res8a = "Expected key of type `Int`, but got type `String`."
 res9 = "Object of type `Listing` cannot have a property (other than `default`)."
+res9n = "Object of type `Listing` cannot have a property (other than `default`)."
 res10 = "Object of type `Listing` cannot have a property (other than `default`)."
+res10n = "Object of type `Listing` cannot have a property (other than `default`)."
 res11 = "Object of type `Listing` cannot have a property (other than `default`)."
+res11n = "Object of type `Listing` cannot have a property (other than `default`)."
 res12 = "Object of type `Listing` cannot have a property (other than `default`)."
+res12n = "Object of type `Listing` cannot have a property (other than `default`)."
 res12a = "Object of type `Listing` cannot have a property (other than `default`)."
+res12an = "Object of type `Listing` cannot have a property (other than `default`)."
 res13 = "Object of type `Listing` cannot have a property (other than `default`)."
+res13n = "Object of type `Listing` cannot have a property (other than `default`)."
 res13a = "Object of type `Listing` cannot have a property (other than `default`)."
+res13an = "Object of type `Listing` cannot have a property (other than `default`)."
 res14 = "Object of type `Listing` cannot have a property (other than `default`)."
+res14n = "Object of type `Listing` cannot have a property (other than `default`)."
 res14a = "Object of type `Listing` cannot have a property (other than `default`)."
+res14an = "Object of type `Listing` cannot have a property (other than `default`)."
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/mappings/mapping1.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/mappings/mapping1.pcf
index a34aeccef..2ba1a11e8 100644
--- a/pkl-core/src/test/files/LanguageSnippetTests/output/mappings/mapping1.pcf
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/mappings/mapping1.pcf
@@ -43,6 +43,50 @@ res2 {
     ["two"] = 2
   }
 }
+res2n {
+  [null] = null
+  [true] = true
+  [42] = 42
+  [1.23] = 1.23
+  ["foo"] = "foo"
+  [Regex("bar")] = Regex("bar")
+  [5.gb] = 5.gb
+  [3.min] = 3.min
+  [Pair(1, 2)] = Pair(1, 2)
+  [List(1, 2, 3)] = List(1, 2, 3)
+  [Set(1, 2, 3)] = Set(1, 2, 3)
+  [Map("one", 1, "two", 2)] = Map("one", 1, "two", 2)
+  [new {
+    name = "Pigeon"
+    age = 42
+  }] {
+    name = "Pigeon"
+    age = 42
+  }
+  [new {
+    name = "Pigeon"
+    age = 42
+  }] {
+    name = "Pigeon"
+    age = 42
+  }
+  [new {
+    1
+    2
+    3
+  }] {
+    1
+    2
+    3
+  }
+  [new {
+    ["one"] = 1
+    ["two"] = 2
+  }] {
+    ["one"] = 1
+    ["two"] = 2
+  }
+}
 res3 {
   [null] = null
   [true] = true
@@ -87,3 +131,55 @@ res3 {
     ["two"] = 2
   }
 }
+res3n {
+  [null] = null
+  [true] = true
+  [42] = 42
+  [1.23] = 1.23
+  ["foo"] = "foo"
+  [Regex("bar")] = Regex("bar")
+  [5.gb] = 5.gb
+  [3.min] = 3.min
+  [Pair(1, 2)] = Pair(1, 2)
+  [List(1, 2, 3)] = List(1, 2, 3)
+  [Set(1, 2, 3)] = Set(1, 2, 3)
+  [Map("one", 1, "two", 2)] = Map("one", 1, "two", 2)
+  [new {
+    name = "Pigeon"
+    age = 42
+  }] {
+    name = "Pigeon"
+    age = 42
+  }
+  [new {
+    name = "Pigeon"
+    age = 42
+  }] {
+    name = "Pigeon"
+    age = 42
+  }
+  [new {
+    1
+    2
+    3
+  }] {
+    1
+    2
+    3
+  }
+  [new {
+    ["one"] = 1
+    ["two"] = 2
+  }] {
+    ["one"] = 1
+    ["two"] = 2
+  }
+}
+res4 {
+  ["foo"] = "1"
+  ["bar"] = "2"
+}
+res4n {
+  ["foo"] = "1"
+  ["bar"] = "2"
+}
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/constantEntries.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/constantEntries.pcf
new file mode 100644
index 000000000..bc94a80d6
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/constantEntries.pcf
@@ -0,0 +1,21 @@
+res1 {
+  ["a"] = 1
+  ["b"] = 2
+}
+res2 {
+  a = 1
+  ["b"] = 2
+}
+res3 {
+  "updated a"
+  "b"
+}
+res4 {
+  ["a"] = 1
+  ["b"] = 2
+}
+res5 = "Element index `5` is out of range `0`..`0`."
+res6 = "Object of type `Listing` cannot have a property (other than `default`)."
+res7 = "Object of type `Mapping` cannot have a property (other than `default`)."
+res8 = "Expected a function with 1 parameters, but got 2."
+res9 = "Cannot instantiate, or amend an instance of, external class `String`."
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/elements.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/elements.pcf
new file mode 100644
index 000000000..fed5edc03
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/elements.pcf
@@ -0,0 +1,18 @@
+res1 {
+  a = 1
+  "b"
+  "c"
+}
+res2 {
+  "a"
+  "b"
+  "c"
+}
+res3 {
+  "a"
+  "b"
+}
+res4 = "Object of type `Mapping` cannot have an element."
+res5 = "Object of type `Listing` cannot have a property (other than `default`)."
+res6 = "Expected a function with 1 parameters, but got 2."
+res7 = "Expected value of type `Object | Function<Object>`, but got type `Int`. Value: 42"
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/elementsEntries.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/elementsEntries.pcf
new file mode 100644
index 000000000..3c988ce32
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/elementsEntries.pcf
@@ -0,0 +1,18 @@
+res1 {
+  "updated a"
+  "b"
+}
+res2 {
+  "updated a"
+  "b"
+  "c"
+}
+res3 {
+  "updated a"
+  "b"
+}
+res4 = "Object of type `Mapping` cannot have an element."
+res5 = "Element index `5` is out of range `0`..`0`."
+res6 = "Object of type `Listing` cannot have a property (other than `default`)."
+res7 = "Expected a function with 1 parameters, but got 2."
+res8 = "Expected value of type `Object | Function<Object>`, but got type `Int`. Value: 42"
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/entries.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/entries.pcf
new file mode 100644
index 000000000..7d471fd1a
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/entries.pcf
@@ -0,0 +1,22 @@
+res1 {
+  ["a"] = 1
+  ["b"] = 2
+}
+res2 {
+  a = 1
+  ["b"] = 2
+}
+res3 {
+  "updated a"
+  "b"
+}
+res4 {
+  ["a"] = 1
+  ["b"] = 2
+}
+res5 = "Expected key of type `Int`, but got type `String`."
+res6 = "Element index `5` is out of range `0`..`0`."
+res7 = "Object of type `Mapping` cannot have a property (other than `default`)."
+res8 = "Duplicate definition of member `\"a\"`."
+res9 = "Expected a function with 1 parameters, but got 2."
+res10 = "Cannot instantiate, or amend an instance of, external class `String`."
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/generator.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/generator.pcf
new file mode 100644
index 000000000..d6c4908b6
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/generator.pcf
@@ -0,0 +1,29 @@
+res1 {
+  a = 1
+  2
+  3
+}
+res2 {
+  name = "Pigeon"
+  age = 10
+}
+res3 {
+  "a"
+  2
+  3
+}
+res4 {
+  ["a"] = 1
+  [2] = 2
+  [3] = 3
+}
+res5 {
+  a = 1
+  2
+  3
+}
+res6 = "Expected a function that returns a `Listing`, but got a `Listing`."
+res7 = "Expected a function that returns a `Mapping`, but got a `Mapping`."
+res8 = "Expected a function that returns an object, but got an object."
+res9 = "Cannot instantiate, or amend an instance of, external class `String`."
+res10 = "Cannot instantiate, or amend an instance of, external class `List`."
diff --git a/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/properties.pcf b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/properties.pcf
new file mode 100644
index 000000000..a27ab438d
--- /dev/null
+++ b/pkl-core/src/test/files/LanguageSnippetTests/output/nullParents/properties.pcf
@@ -0,0 +1,22 @@
+res1 {
+  name = "Pigeon"
+  age = 3
+}
+res2 {
+  name = "Pigeon"
+  age = 3
+}
+res3 = "three"
+res4 = 0
+res5 {
+  zero = 0
+  amended = "amended"
+}
+res6 = "Cannot find property `nickname` in object of type `properties#Person`."
+res7 = "Object of type `Listing` cannot have a property (other than `default`)."
+res8 = "Object of type `Mapping` cannot have a property (other than `default`)."
+res9 = "Expected a function with 1 parameters, but got 2."
+res10 = "Cannot instantiate, or amend an instance of, external class `String`."
+res11 {
+  x = 1
+}