Restrict types that can be constructed

6 files changed, 14 insertions, 11 deletions

diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index 964a0000..668a005c 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -1419,7 +1419,6 @@ public class TypeChecker {
 
                 var typeOrConstructor = untyped.typeLevelParams()
                     .map(typeLevelParamNodes -> TypeOrConstructor.constructor(new TypeConstructor<>(
-                        type.name(),
                         typeLevelParamNodes.stream()
                             .map(typeLevelParamNode -> new TypeParam(
                                 new Scope.Struct(type),
diff --git a/src/main/java/org/shedlang/compiler/types/StructType.java b/src/main/java/org/shedlang/compiler/types/StructType.java
index ab9b18a6..04e42057 100644
--- a/src/main/java/org/shedlang/compiler/types/StructType.java
+++ b/src/main/java/org/shedlang/compiler/types/StructType.java
@@ -3,7 +3,7 @@ package org.shedlang.compiler.types;
 /**
  * A set of named fields.
  */
-public record StructType(NamespaceName namespaceName, String name) implements Type {
+public record StructType(NamespaceName namespaceName, String name) implements StructuredType {
     @Override
     public String describe() {
         return namespaceName.toString() + "." + name;
diff --git a/src/main/java/org/shedlang/compiler/types/StructuredType.java b/src/main/java/org/shedlang/compiler/types/StructuredType.java
new file mode 100644
index 00000000..114da180
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/types/StructuredType.java
@@ -0,0 +1,5 @@
+package org.shedlang.compiler.types;
+
+public sealed interface StructuredType extends Type permits StructType {
+    String name();
+}
diff --git a/src/main/java/org/shedlang/compiler/types/Type.java b/src/main/java/org/shedlang/compiler/types/Type.java
index 27d133ee..8ec577bf 100644
--- a/src/main/java/org/shedlang/compiler/types/Type.java
+++ b/src/main/java/org/shedlang/compiler/types/Type.java
@@ -6,5 +6,5 @@ package org.shedlang.compiler.types;
  * found through auxiliary data.
  */
 public sealed interface Type extends TypeLevelValue
-    permits BoolType, BottomType, FunctionType, IntType, NamespaceType, StringType, StructType, SumType, TopType, TupleType, TypeLevelValueType, TypeParam, UnitType {
+    permits BoolType, BottomType, FunctionType, IntType, NamespaceType, StringType, StructuredType, SumType, TopType, TupleType, TypeLevelValueType, TypeParam, UnitType {
 }
diff --git a/src/main/java/org/shedlang/compiler/types/TypeConstructor.java b/src/main/java/org/shedlang/compiler/types/TypeConstructor.java
index 78aa0b61..a43001bc 100644
--- a/src/main/java/org/shedlang/compiler/types/TypeConstructor.java
+++ b/src/main/java/org/shedlang/compiler/types/TypeConstructor.java
@@ -2,13 +2,12 @@ package org.shedlang.compiler.types;
 
 import java.util.List;
 
-public record TypeConstructor<T extends Type>(
-    String name,
+public record TypeConstructor<T extends StructuredType>(
     List<TypeParam> params,
     T genericType
 ) implements TypeLevelValue {
     @Override
     public String describe() {
-        return name;
+        return genericType.name();
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/types/TypeOrConstructor.java b/src/main/java/org/shedlang/compiler/types/TypeOrConstructor.java
index 6c512117..8c040c2d 100644
--- a/src/main/java/org/shedlang/compiler/types/TypeOrConstructor.java
+++ b/src/main/java/org/shedlang/compiler/types/TypeOrConstructor.java
@@ -1,18 +1,18 @@
 package org.shedlang.compiler.types;
 
-public sealed interface TypeOrConstructor<T extends Type> {
-    static <T extends org.shedlang.compiler.types.Type> TypeOrConstructor<T> type(T value) {
+public sealed interface TypeOrConstructor<T extends StructuredType> {
+    static <T extends StructuredType> TypeOrConstructor<T> type(T value) {
         return new Type<>(value);
     }
 
-    static <T extends org.shedlang.compiler.types.Type> TypeOrConstructor<T> constructor(TypeConstructor<T> value) {
+    static <T extends StructuredType> TypeOrConstructor<T> constructor(TypeConstructor<T> value) {
         return new Constructor<>(value);
     }
 
     T toType();
     org.shedlang.compiler.types.Type toMetaType();
 
-    record Type<T extends org.shedlang.compiler.types.Type>(T value) implements TypeOrConstructor<T> {
+    record Type<T extends StructuredType>(T value) implements TypeOrConstructor<T> {
         @Override
         public T toType() {
             return value;
@@ -24,7 +24,7 @@ public sealed interface TypeOrConstructor<T extends Type> {
         }
     }
 
-    record Constructor<T extends org.shedlang.compiler.types.Type>(TypeConstructor<T> value) implements TypeOrConstructor<T> {
+    record Constructor<T extends StructuredType>(TypeConstructor<T> value) implements TypeOrConstructor<T> {
         @Override
         public T toType() {
             return value.genericType();