From df914fb9c7eeee62b050164d95f99bb81b395bc9 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 2 Aug 2026 12:39:49 +0100
Subject: Handle Box and Shared when determining constructibility

---
 .../compiler/analysis/ArbitraryValueAnalysis.java  | 23 +++++++++++++++++++---
 .../hobgoblin/compiler/builtins/NativeTypes.java   | 12 +++++++++++
 2 files changed, 32 insertions(+), 3 deletions(-)

(limited to 'src/main/java/org/zwobble')

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/analysis/ArbitraryValueAnalysis.java b/src/main/java/org/zwobble/hobgoblin/compiler/analysis/ArbitraryValueAnalysis.java
index d7b3c60..6bc4852 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/analysis/ArbitraryValueAnalysis.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/analysis/ArbitraryValueAnalysis.java
@@ -2,6 +2,7 @@ package org.zwobble.hobgoblin.compiler.analysis;
 
 import org.zwobble.hobgoblin.compiler.analysis.errors.SumTypeHasNoVariantsError;
 import org.zwobble.hobgoblin.compiler.analysis.errors.TypeIsInfiniteError;
+import org.zwobble.hobgoblin.compiler.builtins.NativeTypes;
 import org.zwobble.hobgoblin.compiler.typechecker.TypesInfo;
 import org.zwobble.hobgoblin.compiler.types.*;
 
@@ -31,9 +32,25 @@ public class ArbitraryValueAnalysis {
         }
 
         return switch (type) {
-            case ConstructedNativeType _ ->
-                // TODO: Handle Box and Shared
-                true;
+            case ConstructedNativeType constructedNativeType -> {
+                if (
+                    constructedNativeType.constructor().equals(NativeTypes.BOX) ||
+                    constructedNativeType.constructor().equals(NativeTypes.SHARED)
+                ) {
+                    yield isNonRecursivelyConstructable(
+                        constructedNativeType.args().getFirst(),
+                        seenTypes,
+                        typesInfo
+                    );
+                } else if (
+                    constructedNativeType.constructor().equals(NativeTypes.LIST) ||
+                    constructedNativeType.constructor().equals(NativeTypes.OPTION)
+                ) {
+                    yield true;
+                } else {
+                    throw new UnsupportedOperationException("TODO");
+                }
+            }
 
             case EnumType _ ->
                 true;
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/builtins/NativeTypes.java b/src/main/java/org/zwobble/hobgoblin/compiler/builtins/NativeTypes.java
index 9d81063..485df8c 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/builtins/NativeTypes.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/builtins/NativeTypes.java
@@ -29,6 +29,10 @@ public class NativeTypes {
         LIST_INNER
     );
 
+    public static Type list(Type elementType) {
+        return new ConstructedNativeType(LIST, List.of(elementType));
+    }
+
     public static final SimpleNativeType OPTION_INNER = SimpleNativeType.builtin("Option");
 
     public static TypeConstructor<SimpleNativeType> OPTION = new TypeConstructor<>(
@@ -36,10 +40,18 @@ public class NativeTypes {
         OPTION_INNER
     );
 
+    public static Type option(Type elementType) {
+        return new ConstructedNativeType(OPTION, List.of(elementType));
+    }
+
     public static final SimpleNativeType SHARED_INNER = SimpleNativeType.builtin("Shared");
 
     public static TypeConstructor<SimpleNativeType> SHARED = new TypeConstructor<>(
         List.of(new TypeParam("T")),
         SHARED_INNER
     );
+
+    public static Type shared(Type elementType) {
+        return new ConstructedNativeType(SHARED, List.of(elementType));
+    }
 }
-- 
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