Support nested constructed native types in java-transient-0

7 files changed, 203 insertions, 53 deletions

diff --git a/examples/15-transient-0/output/java/src/main/java/org/zwobble/example/types/data/transient0/HobgoblinTransient0Data.java b/examples/15-transient-0/output/java/src/main/java/org/zwobble/example/types/data/transient0/HobgoblinTransient0Data.java
index 0044a4a..1eea54c 100644
--- a/examples/15-transient-0/output/java/src/main/java/org/zwobble/example/types/data/transient0/HobgoblinTransient0Data.java
+++ b/examples/15-transient-0/output/java/src/main/java/org/zwobble/example/types/data/transient0/HobgoblinTransient0Data.java
@@ -276,11 +276,13 @@ public final class HobgoblinTransient0Data {
 
     public static void encodeStructWithGenericNative(org.zwobble.example.types.data.StructWithGenericNative value, java.io.OutputStream outputStream, java.util.Map<org.zwobble.example.types.transient0.HobgoblinTransient0TaggedSharedValue, java.lang.Long> sharedValues) throws java.io.IOException {
         org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.encodeGenericNative(value.a(), outputStream, sharedValues, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::encodeInt32, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::encodeString);
+        org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.encodeGenericNative(value.b(), outputStream, sharedValues, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::encode$constructedType$0, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::encode$constructedType$1);
     }
 
     public static org.zwobble.example.types.data.StructWithGenericNative decodeStructWithGenericNative(java.io.InputStream inputStream, java.util.List<java.lang.Object> sharedValues) throws java.io.IOException {
         var a = org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.decodeGenericNative(inputStream, sharedValues, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::decodeInt32, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::decodeString);
-        return new org.zwobble.example.types.data.StructWithGenericNative(a);
+        var b = org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.decodeGenericNative(inputStream, sharedValues, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::decode$constructedType$0, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::decode$constructedType$1);
+        return new org.zwobble.example.types.data.StructWithGenericNative(a, b);
     }
 
     public static void encodeStructWithBox(org.zwobble.example.types.data.StructWithBox value, java.io.OutputStream outputStream, java.util.Map<org.zwobble.example.types.transient0.HobgoblinTransient0TaggedSharedValue, java.lang.Long> sharedValues) throws java.io.IOException {
@@ -498,6 +500,43 @@ public final class HobgoblinTransient0Data {
         return new org.zwobble.example.types.data.StructWithSharedSumAndVariant(a, b);
     }
 
+    private static void encode$constructedType$0(java.util.Optional<String> value, java.io.OutputStream outputStream, java.util.Map<org.zwobble.example.types.transient0.HobgoblinTransient0TaggedSharedValue, java.lang.Long> sharedValues) throws java.io.IOException {
+        org.zwobble.example.types.transient0.HobgoblinTransient0Builtins.encodeBool(value.isPresent(), outputStream, sharedValues);
+        if (value.isPresent()) {
+            org.zwobble.example.types.transient0.HobgoblinTransient0Builtins.encodeString(value.get(), outputStream, sharedValues);
+        }
+    }
+
+    private static java.util.Optional<String> decode$constructedType$0(java.io.InputStream inputStream, java.util.List<java.lang.Object> sharedValues) throws java.io.IOException {
+        var value$isPresent = org.zwobble.example.types.transient0.HobgoblinTransient0Builtins.decodeBool(inputStream, sharedValues);
+        java.util.Optional<String> value;
+        if (value$isPresent) {
+            var value$element = org.zwobble.example.types.transient0.HobgoblinTransient0Builtins.decodeString(inputStream, sharedValues);
+            value = java.util.Optional.of(value$element);
+        } else {
+            value = java.util.Optional.empty();
+        }
+        return value;
+    }
+
+    private static void encode$constructedType$1(org.zwobble.example.types.data.GenericNative<java.util.Optional<String>, org.zwobble.example.types.data.GenericNative<String, String>> value, java.io.OutputStream outputStream, java.util.Map<org.zwobble.example.types.transient0.HobgoblinTransient0TaggedSharedValue, java.lang.Long> sharedValues) throws java.io.IOException {
+        org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.encodeGenericNative(value, outputStream, sharedValues, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::encode$constructedType$0, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::encode$constructedType$2);
+    }
+
+    private static org.zwobble.example.types.data.GenericNative<java.util.Optional<String>, org.zwobble.example.types.data.GenericNative<String, String>> decode$constructedType$1(java.io.InputStream inputStream, java.util.List<java.lang.Object> sharedValues) throws java.io.IOException {
+        var value = org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.decodeGenericNative(inputStream, sharedValues, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::decode$constructedType$0, org.zwobble.example.types.data.transient0.HobgoblinTransient0Data::decode$constructedType$2);
+        return value;
+    }
+
+    private static void encode$constructedType$2(org.zwobble.example.types.data.GenericNative<String, String> value, java.io.OutputStream outputStream, java.util.Map<org.zwobble.example.types.transient0.HobgoblinTransient0TaggedSharedValue, java.lang.Long> sharedValues) throws java.io.IOException {
+        org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.encodeGenericNative(value, outputStream, sharedValues, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::encodeString, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::encodeString);
+    }
+
+    private static org.zwobble.example.types.data.GenericNative<String, String> decode$constructedType$2(java.io.InputStream inputStream, java.util.List<java.lang.Object> sharedValues) throws java.io.IOException {
+        var value = org.zwobble.example.types.data.transient0.HobgoblinTransient0Data.decodeGenericNative(inputStream, sharedValues, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::decodeString, org.zwobble.example.types.transient0.HobgoblinTransient0Builtins::decodeString);
+        return value;
+    }
+
     // Custom area start: org.zwobble.example.types.data.transient0.HobgoblinTransient0Data body
     public static void encodeNative(
         Native value,
diff --git a/examples/15-transient-0/output/rust/src/gen/data.rs b/examples/15-transient-0/output/rust/src/gen/data.rs
index 856d60f..6f1d5b5 100644
--- a/examples/15-transient-0/output/rust/src/gen/data.rs
+++ b/examples/15-transient-0/output/rust/src/gen/data.rs
@@ -124,6 +124,7 @@ pub struct StructWithNative {
 #[derive(Clone, Debug, Hash, PartialEq)]
 pub struct StructWithGenericNative {
     pub a: crate::data::GenericNative::<::core::primitive::i32, ::std::string::String>,
+    pub b: crate::data::GenericNative::<::std::option::Option::<::std::string::String>, crate::data::GenericNative::<::std::option::Option::<::std::string::String>, crate::data::GenericNative::<::std::string::String, ::std::string::String>>>,
 }
 
 #[derive(Clone, Debug, Hash, PartialEq)]
diff --git a/examples/15-transient-0/output/rust/src/gen/data/transient_0.rs b/examples/15-transient-0/output/rust/src/gen/data/transient_0.rs
index c497b57..383a564 100644
--- a/examples/15-transient-0/output/rust/src/gen/data/transient_0.rs
+++ b/examples/15-transient-0/output/rust/src/gen/data/transient_0.rs
@@ -276,12 +276,14 @@ pub fn decode_struct_with_native(reader: &mut impl std::io::Read, shared_values:
 
 pub fn encode_struct_with_generic_native(value: &crate::data::StructWithGenericNative, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
     todo!();
+    todo!();
     ::std::io::Result::Ok(())
 }
 
 pub fn decode_struct_with_generic_native(reader: &mut impl std::io::Read, shared_values: &mut ::std::vec::Vec::<::std::sync::Arc::<dyn ::std::any::Any + ::std::marker::Sync + ::std::marker::Send>>) -> ::std::io::Result::<crate::data::StructWithGenericNative> {
     let a = todo!();
-    ::std::io::Result::Ok(crate::data::StructWithGenericNative { a: a })
+    let b = todo!();
+    ::std::io::Result::Ok(crate::data::StructWithGenericNative { a: a, b: b })
 }
 
 pub fn encode_struct_with_box(value: &crate::data::StructWithBox, writer: &mut impl std::io::Write, shared_values: &mut ::std::collections::HashMap::<::core::primitive::usize, ::core::primitive::i64>) -> ::std::io::Result::<()> {
diff --git a/examples/15-transient-0/src/data.hob b/examples/15-transient-0/src/data.hob
index 1fb173e..df96916 100644
--- a/examples/15-transient-0/src/data.hob
+++ b/examples/15-transient-0/src/data.hob
@@ -88,6 +88,7 @@ native GenericNative[A, B] {
 
 struct StructWithGenericNative {
     field a: GenericNative[Int32, String];
+    field b: GenericNative[Option[String], GenericNative[Option[String], GenericNative[String, String]]];
 }
 
 struct StructWithBox {
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
index b0f63e7..c9c4ea0 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/javatransient0/JavaTransient0Generator.java
@@ -60,12 +60,11 @@ public class JavaTransient0Generator implements Generator {
         List<TypedNamespaceNode> namespaces,
         TypesInfo typesInfo
     ) throws IOException {
-        var context = new Context(typesInfo);
-
         write(generateSupportTypes());
-        write(generateBuiltins(context));
+        write(generateBuiltins(new Context(NamespaceName.of(), typesInfo)));
 
         for (var namespace : namespaces) {
+            var context = new Context(namespace.namespaceName(), typesInfo);
             var javaCompilationUnits = generateNamespace(namespace, context);
 
             write(javaCompilationUnits);
@@ -268,7 +267,7 @@ public class JavaTransient0Generator implements Generator {
                         generateEncodeInt64Method(),
                         generateDecodeInt64Method(),
                         generateEncodeStringMethod(context),
-                        generateDecodeStringMethod()
+                        generateDecodeStringMethod(context)
                     ),
                     DocComment.EMPTY
                 )
@@ -446,7 +445,7 @@ public class JavaTransient0Generator implements Generator {
         );
     }
 
-    private JavaMethodDeclaration generateDecodeStringMethod() {
+    private JavaMethodDeclaration generateDecodeStringMethod(Context context) {
         var bytesLengthVariableName = JavaIdentifier.of("bytesLength");
         var bytesVariableName = JavaIdentifier.of("bytes");
 
@@ -454,7 +453,8 @@ public class JavaTransient0Generator implements Generator {
 
         statements.addAll(generateDecode(
             bytesLengthVariableName,
-            NativeTypes.INT_64
+            NativeTypes.INT_64,
+            context
         ));
 
         statements.add(generateAssertLessThanIntMax(
@@ -506,14 +506,36 @@ public class JavaTransient0Generator implements Generator {
             transient0JavaName
         );
 
+        var body = new ArrayList<JavaClassBodyDeclaration>();
+
+        for (var statement : namespace.body()) {
+            body.addAll(generateNamespaceStatement(statement, context));
+        }
+
+        for (
+            var constructedTypeIndex = 0;
+            constructedTypeIndex < context.constructedTypes.size();
+            constructedTypeIndex++
+        ) {
+            var constructedType = context.constructedTypes.get(constructedTypeIndex);
+            body.add(generateEncodeConstructedTypeMethod(
+                constructedType,
+                constructedTypeIndex,
+                context
+            ));
+            body.add(generateDecodeConstructedTypeMethod(
+                constructedType,
+                constructedTypeIndex,
+                context
+            ));
+        }
+
         return List.of(
             new JavaCompilationUnit(
                 new JavaClassDeclaration(
                     transient0JavaTypeRef,
                     List.of(),
-                    namespace.body().stream()
-                        .flatMap(statement -> generateNamespaceStatement(statement, context))
-                        .toList(),
+                    body,
                     DocComment.EMPTY
                 )
             )
@@ -537,33 +559,33 @@ public class JavaTransient0Generator implements Generator {
         );
     }
 
-    private Stream<JavaClassBodyDeclaration> generateNamespaceStatement(
+    private List<JavaClassBodyDeclaration> generateNamespaceStatement(
         TypedNamespaceStatementNode statement,
         Context context
     ) {
         return switch (statement) {
             case TypedEnumDefinitionNode enumDefinition -> {
-                yield Stream.concat(
-                    Stream.of(generateEncodeEnumMethod(enumDefinition, context)),
-                    generateDecodeEnumMethod(enumDefinition)
-                );
+                yield Lists.concat(List.of(
+                    List.of(generateEncodeEnumMethod(enumDefinition, context)),
+                    generateDecodeEnumMethod(enumDefinition, context)
+                ));
             }
 
             case TypedNativeTypeDefinitionNode _ -> {
-                yield Stream.of();
+                yield List.of();
             }
 
             case TypedStructDefinitionNode structDefinition -> {
-                yield Stream.of(
+                yield List.of(
                     generateEncodeStructMethod(structDefinition, context),
-                    generateDecodeStructMethod(structDefinition)
+                    generateDecodeStructMethod(structDefinition, context)
                 );
             }
 
             case TypedSumDefinitionNode sumDefinition -> {
-                yield Stream.of(
+                yield List.of(
                     generateEncodeSumMethod(sumDefinition, context),
-                    generateDecodeSumMethod(sumDefinition, context.typesInfo)
+                    generateDecodeSumMethod(sumDefinition, context)
                 );
             }
         };
@@ -587,12 +609,15 @@ public class JavaTransient0Generator implements Generator {
         );
     }
 
-    private Stream<JavaClassBodyDeclaration> generateDecodeEnumMethod(TypedEnumDefinitionNode enumDefinition) {
+    private List<JavaClassBodyDeclaration> generateDecodeEnumMethod(
+        TypedEnumDefinitionNode enumDefinition,
+        Context context
+    ) {
         var enumJavaTypeRef = this.javaGenerator.generateTypeRef(enumDefinition.type());
         var ordinal = JavaIdentifier.of("ordinal");
         var enumValues = JavaIdentifier.of(this.javaGenerator.generateTypeName(enumDefinition.type().name()).value() + "$values");
 
-        return Stream.of(
+        return List.of(
             new JavaFieldDeclaration(
                 JavaVisibility.PRIVATE,
                 JavaMemberKind.STATIC,
@@ -608,7 +633,7 @@ public class JavaTransient0Generator implements Generator {
             generateDecodeMethod(
                 enumDefinition.type(),
                 new JavaBlock(Stream.concat(
-                    generateDecode(ordinal, NativeTypes.INT_32).stream(),
+                    generateDecode(ordinal, NativeTypes.INT_32, context).stream(),
                     Stream.of(new JavaReturn(new JavaArrayAccess(
                         new JavaRef(enumValues),
                         new JavaRef(ordinal)
@@ -640,7 +665,10 @@ public class JavaTransient0Generator implements Generator {
         );
     }
 
-    private JavaMethodDeclaration generateDecodeStructMethod(TypedStructDefinitionNode structDefinition) {
+    private JavaMethodDeclaration generateDecodeStructMethod(
+        TypedStructDefinitionNode structDefinition,
+        Context context
+    ) {
         var structJavaTypeRef = this.javaGenerator.generateTypeRef(structDefinition.type());
 
         return generateDecodeMethod(
@@ -654,7 +682,8 @@ public class JavaTransient0Generator implements Generator {
                         structDefinition.fields().get().stream()
                             .flatMap(field -> generateDecode(
                                 this.javaGenerator.generateFieldName(field.name()),
-                                field.type().value()
+                                field.type().value(),
+                                context
                             ).stream()),
                         Stream.of(new JavaReturn(new JavaNewExpression(
                             structJavaTypeRef,
@@ -710,22 +739,22 @@ public class JavaTransient0Generator implements Generator {
 
     private JavaMethodDeclaration generateDecodeSumMethod(
         TypedSumDefinitionNode sumDefinition,
-        TypesInfo typesInfo
+        Context context
     ) {
         var decodeStatements = new ArrayList<JavaBlockStatement>();
 
         var variantTag = JavaIdentifier.of("variantTag");
 
-        decodeStatements.addAll(generateDecode(variantTag, NativeTypes.INT_32));
+        decodeStatements.addAll(generateDecode(variantTag, NativeTypes.INT_32, context));
 
         var cases = new ArrayList<JavaSwitchRule>();
 
-        for (var variant : typesInfo.sumVariants(sumDefinition.type())) {
+        for (var variant : context.typesInfo.sumVariants(sumDefinition.type())) {
             var variantVariable = JavaIdentifier.of(VALUE_NAME.value() + "$" + variant.tag());
 
             var statements = new ArrayList<JavaBlockStatement>();
 
-            statements.addAll(generateDecode(variantVariable, variant.containerType()));
+            statements.addAll(generateDecode(variantVariable, variant.containerType(), context));
 
             statements.add(new JavaReturn(new JavaRef(variantVariable)));
 
@@ -850,8 +879,13 @@ public class JavaTransient0Generator implements Generator {
 
     private JavaMethodRef generateEncodeMethodRef(Type type, Context context) {
         return switch (type) {
-            case ConstructedNativeType _ -> {
-                throw new UnsupportedOperationException("TODO");
+            case ConstructedType constructedType -> {
+                var constructedTypeIndex = context.constructedTypeIndex(constructedType);
+                var methodName = generateEncodeConstructedTypeMethodName(constructedTypeIndex);
+                yield new JavaMethodRef(
+                    generateTransient0TypeRef(context.namespaceName),
+                    methodName
+                );
             }
 
             case SimpleType simpleType ->  {
@@ -871,6 +905,28 @@ public class JavaTransient0Generator implements Generator {
         };
     }
 
+    private static JavaIdentifier generateEncodeConstructedTypeMethodName(int constructedTypeIndex) {
+        return JavaIdentifier.of("encode$constructedType$" + constructedTypeIndex);
+    }
+
+    private JavaMethodDeclaration generateEncodeConstructedTypeMethod(
+        ConstructedType constructedType,
+        int constructedTypeIndex,
+        Context context
+    ) {
+        return new JavaMethodDeclaration(
+            generateEncodeConstructedTypeMethodName(constructedTypeIndex),
+            JavaVisibility.PRIVATE,
+            JavaMemberKind.STATIC,
+            JavaTypeRef.VOID,
+            generateEncodeParams(this.javaGenerator.generateTypeRef(constructedType)),
+            List.of(JavaTypeRef.IO_EXCEPTION),
+            Optional.of(new JavaBlock(
+                generateEncode(new JavaRef(VALUE_NAME), constructedType, context)
+            ))
+        );
+    }
+
     private JavaBlockStatement generateEncode(
         JavaExpression value,
         NamespaceName typeNamespaceName,
@@ -893,17 +949,21 @@ public class JavaTransient0Generator implements Generator {
         );
     }
 
-    private List<JavaBlockStatement> generateDecode(JavaIdentifier target, Type type) {
+    private List<JavaBlockStatement> generateDecode(
+        JavaIdentifier target,
+        Type type,
+        Context context
+    ) {
         return switch (type) {
             case ConstructedNativeType constructedNativeType -> {
                 if (constructedNativeType.constructor().equals(NativeTypes.BOX)) {
-                    yield generateDecode(target, constructedNativeType.args().getFirst());
+                    yield generateDecode(target, constructedNativeType.args().getFirst(), context);
                 } else if (constructedNativeType.constructor().equals(NativeTypes.LIST)) {
-                    yield generateDecodeList(target, constructedNativeType.args().getFirst());
+                    yield generateDecodeList(target, constructedNativeType.args().getFirst(), context);
                 } else if (constructedNativeType.constructor().equals(NativeTypes.OPTION)) {
-                    yield generateDecodeOption(target, constructedNativeType.args().getFirst());
+                    yield generateDecodeOption(target, constructedNativeType.args().getFirst(), context);
                 } else if (constructedNativeType.constructor().equals(NativeTypes.SHARED)) {
-                    yield generateDecodeShared(target, constructedNativeType.args().getFirst());
+                    yield generateDecodeShared(target, constructedNativeType.args().getFirst(), context);
                 } else {
                     yield List.of(
                         generateDecode(
@@ -911,7 +971,7 @@ public class JavaTransient0Generator implements Generator {
                             constructedNativeType.namespaceName(),
                             constructedNativeType,
                             constructedNativeType.args().stream()
-                                .<JavaExpression>map(typeArg -> generateDecodeMethodRef(typeArg))
+                                .<JavaExpression>map(typeArg -> generateDecodeMethodRef(typeArg, context))
                                 .toList()
                         )
                     );
@@ -938,10 +998,15 @@ public class JavaTransient0Generator implements Generator {
         };
     }
 
-    private JavaMethodRef generateDecodeMethodRef(Type type) {
+    private JavaMethodRef generateDecodeMethodRef(Type type, Context context) {
         return switch (type) {
-            case ConstructedNativeType _ -> {
-                throw new UnsupportedOperationException("TODO");
+            case ConstructedType constructedType -> {
+                var constructedTypeIndex = context.constructedTypeIndex(constructedType);
+                var methodName = generateDecodeConstructedTypeMethodName(constructedTypeIndex);
+                yield new JavaMethodRef(
+                    generateTransient0TypeRef(context.namespaceName),
+                    methodName
+                );
             }
 
             case SimpleType simpleType ->  {
@@ -961,6 +1026,29 @@ public class JavaTransient0Generator implements Generator {
         };
     }
 
+    private static JavaIdentifier generateDecodeConstructedTypeMethodName(int constructedTypeIndex) {
+        return JavaIdentifier.of("decode$constructedType$" + constructedTypeIndex);
+    }
+
+    private JavaMethodDeclaration generateDecodeConstructedTypeMethod(
+        ConstructedType constructedType,
+        int constructedTypeIndex,
+        Context context
+    ) {
+        return new JavaMethodDeclaration(
+            generateDecodeConstructedTypeMethodName(constructedTypeIndex),
+            JavaVisibility.PRIVATE,
+            JavaMemberKind.STATIC,
+            this.javaGenerator.generateTypeRef(constructedType),
+            generateDecodeParams(),
+            List.of(JavaTypeRef.IO_EXCEPTION),
+            Optional.of(new JavaBlock(Lists.concat(List.of(
+                generateDecode(VALUE_NAME, constructedType, context),
+                List.of(new JavaReturn(new JavaRef(VALUE_NAME)))
+            ))))
+        );
+    }
+
     private JavaBlockStatement generateDecode(
         JavaIdentifier target,
         NamespaceName typeNamespaceName,
@@ -1019,7 +1107,8 @@ public class JavaTransient0Generator implements Generator {
 
     private List<JavaBlockStatement> generateDecodeList(
         JavaIdentifier target,
-        Type elementType
+        Type elementType,
+        Context context
     ) {
         var size = JavaIdentifier.of(target.value() + "$size");
         var index = JavaIdentifier.of(target.value() + "$index");
@@ -1027,7 +1116,7 @@ public class JavaTransient0Generator implements Generator {
 
         var statements = new ArrayList<JavaBlockStatement>();
 
-        statements.addAll(generateDecode(size, NativeTypes.INT_64));
+        statements.addAll(generateDecode(size, NativeTypes.INT_64, context));
 
         statements.add(generateAssertLessThanIntMax(
             size,
@@ -1049,7 +1138,7 @@ public class JavaTransient0Generator implements Generator {
 
         var forBodyStatements = new ArrayList<JavaBlockStatement>();
 
-        forBodyStatements.addAll(generateDecode(element, elementType));
+        forBodyStatements.addAll(generateDecode(element, elementType, context));
 
         forBodyStatements.add(new JavaExpressionStatement(new JavaMethodCall(
             new JavaRef(target),
@@ -1115,14 +1204,15 @@ public class JavaTransient0Generator implements Generator {
 
     private List<JavaBlockStatement> generateDecodeOption(
         JavaIdentifier target,
-        Type elementType
+        Type elementType,
+        Context context
     ) {
         var isPresent = JavaIdentifier.of(target.value() + "$isPresent");
         var element = JavaIdentifier.of(target.value() + "$element");
 
         var statements = new ArrayList<JavaBlockStatement>();
 
-        statements.addAll(generateDecode(isPresent, NativeTypes.BOOL));
+        statements.addAll(generateDecode(isPresent, NativeTypes.BOOL, context));
 
         statements.add(new JavaLocalVariableDeclaration(
             Optional.of(JavaTypeRef.optional(this.javaGenerator.generateReferenceTypeRef(elementType))),
@@ -1132,7 +1222,7 @@ public class JavaTransient0Generator implements Generator {
 
         var ifTrue = new ArrayList<JavaBlockStatement>();
 
-        ifTrue.addAll(generateDecode(element, elementType));
+        ifTrue.addAll(generateDecode(element, elementType, context));
 
         ifTrue.add(new JavaExpressionStatement(new JavaBinaryOperation(
             JavaBinaryOperator.ASSIGN,
@@ -1229,13 +1319,14 @@ public class JavaTransient0Generator implements Generator {
 
     private List<JavaBlockStatement> generateDecodeShared(
         JavaIdentifier target,
-        Type type
+        Type type,
+        Context context
     ) {
         var id = JavaIdentifier.of(target.value() + "$id");
         var decodedValue = JavaIdentifier.of(target.value() + "$decodedValue");
 
         return Lists.concat(List.of(
-            generateDecode(id, NativeTypes.INT_64),
+            generateDecode(id, NativeTypes.INT_64, context),
             List.of(
                 generateAssertLessThanIntMax(
                     id,
@@ -1291,7 +1382,7 @@ public class JavaTransient0Generator implements Generator {
                         ))
                     )),
                     new JavaBlock(Lists.concat(List.of(
-                        generateDecode(decodedValue, type),
+                        generateDecode(decodedValue, type, context),
                         List.of(
                             new JavaExpressionStatement(new JavaMethodCall(
                                 new JavaRef(SHARED_VALUES_NAME),
@@ -1398,10 +1489,26 @@ public class JavaTransient0Generator implements Generator {
     }
 
     private static class Context {
+        private final NamespaceName namespaceName;
         private final TypesInfo typesInfo;
+        private final Map<ConstructedType, Integer> constructedTypeIndexes = new HashMap<>();
+        private final List<ConstructedType> constructedTypes = new ArrayList<>();
 
-        public Context(TypesInfo typesInfo) {
+        public Context(NamespaceName namespaceName, TypesInfo typesInfo) {
+            this.namespaceName = namespaceName;
             this.typesInfo = typesInfo;
         }
+
+        public int constructedTypeIndex(ConstructedType type) {
+            var existingIndex = constructedTypeIndexes.get(type);
+            if (existingIndex != null) {
+                return existingIndex;
+            }
+
+            var index = constructedTypes.size();
+            constructedTypeIndexes.put(type, index);
+            constructedTypes.add(type);
+            return index;
+        }
     }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/types/ConstructedType.java b/src/main/java/org/zwobble/hobgoblin/compiler/types/ConstructedType.java
index 03d4718..6224331 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/types/ConstructedType.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/types/ConstructedType.java
@@ -1,4 +1,4 @@
 package org.zwobble.hobgoblin.compiler.types;
 
-public sealed interface ConstructedType permits ConstructedNativeType {
+public sealed interface ConstructedType extends Type permits ConstructedNativeType {
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/types/Type.java b/src/main/java/org/zwobble/hobgoblin/compiler/types/Type.java
index b483209..90dcc9b 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/types/Type.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/types/Type.java
@@ -1,5 +1,5 @@
 package org.zwobble.hobgoblin.compiler.types;
 
-public sealed interface Type extends TypeLevelValue permits ConstructedNativeType, ConstructibleType, EnumType, SimpleNativeType, SimpleType, StructType, SumType, TypeLevelValueType, TypeParam {
+public sealed interface Type extends TypeLevelValue permits ConstructedNativeType, ConstructedType, ConstructibleType, EnumType, SimpleNativeType, SimpleType, StructType, SumType, TypeLevelValueType, TypeParam {
     String name();
 }