...

compiler/Generator.cs

@@ -399,13 +399,13 @@ public class Generator
 
     private string EmitExpressionEnumLiteral(TypedNodeExpressionEnumLiteral expression)
     {
-        var enumType = (NubTypeEnum)expression.Type;
+        var enumVariantType = (NubTypeEnumVariant)expression.Type;
 
-        if (!moduleGraph.TryResolveType(enumType.Module, enumType.Name, true, out var info))
+        if (!moduleGraph.TryResolveType(enumVariantType.EnumType.Module, enumVariantType.EnumType.Name, true, out var info))
             throw new UnreachableException();
 
         var enumInfo = (Module.TypeInfoEnum)info;
-        var tag = enumInfo.Variants.ToList().FindIndex(x => x.Name == expression.EnumVariant);
+        var tag = enumInfo.Variants.ToList().FindIndex(x => x.Name == enumVariantType.Variant);
 
         var initializerValues = new Dictionary<string, string>();
 
@@ -417,7 +417,7 @@ public class Generator
 
         var initializerStrings = initializerValues.Select(x => $".{x.Key} = {x.Value}");
 
-        return $"({CType(expression.Type)}){{ .tag = {tag}, .{expression.EnumVariant} = {{ {string.Join(", ", initializerStrings)} }} }}";
+        return $"({CType(expression.Type)}){{ .tag = {tag}, .{enumVariantType.Variant} = {{ {string.Join(", ", initializerStrings)} }} }}";
     }
 
     private string EmitExpressionMemberAccess(TypedNodeExpressionMemberAccess expression)
@@ -449,6 +449,7 @@ public class Generator
             NubTypeBool => "bool" + (varName != null ? $" {varName}" : ""),
             NubTypeStruct type => $"struct {NameMangler.Mangle(type.Module, type.Name, type)}" + (varName != null ? $" {varName}" : ""),
             NubTypeEnum type => $"struct {NameMangler.Mangle(type.Module, type.Name, type)}" + (varName != null ? $" {varName}" : ""),
+            NubTypeEnumVariant type => CType(type.EnumType, varName),
             NubTypeSInt type => $"int{type.Width}_t" + (varName != null ? $" {varName}" : ""),
             NubTypeUInt type => $"uint{type.Width}_t" + (varName != null ? $" {varName}" : ""),
             NubTypePointer type => CType(type.To) + (varName != null ? $" *{varName}" : "*"),

compiler/NubType.cs

@@ -8,6 +8,21 @@ namespace Compiler;
 public abstract class NubType
 {
     public abstract override string ToString();
+
+    [Obsolete("Use IsAssignableTo instead of ==", error: true)]
+    public static bool operator ==(NubType? a, NubType? b) => throw new InvalidOperationException("Use IsAssignableTo");
+
+    [Obsolete("Use IsAssignableTo instead of ==", error: true)]
+    public static bool operator !=(NubType? a, NubType? b) => throw new InvalidOperationException("Use IsAssignableTo");
+
+    public bool IsAssignableTo(NubType target)
+    {
+        return (this, target) switch
+        {
+            (NubTypeEnumVariant variant, NubTypeEnum targetEnum) => ReferenceEquals(variant.EnumType, targetEnum),
+            _ => ReferenceEquals(this, target),
+        };
+    }
 }
 
 public class NubTypeVoid : NubType
@@ -135,6 +150,30 @@ public class NubTypeEnum : NubType
     public override string ToString() => $"enum {Module}::{Name}";
 }
 
+public class NubTypeEnumVariant : NubType
+{
+    private static readonly Dictionary<(NubTypeEnum EnumType, string Variant), NubTypeEnumVariant> Cache = new();
+
+    public static NubTypeEnumVariant Get(NubTypeEnum enumType, string variant)
+    {
+        if (!Cache.TryGetValue((enumType, variant), out var variantType))
+            Cache[(enumType, variant)] = variantType = new NubTypeEnumVariant(enumType, variant);
+
+        return variantType;
+    }
+
+    private NubTypeEnumVariant(NubTypeEnum enumType, string variant)
+    {
+        EnumType = enumType;
+        Variant = variant;
+    }
+
+    public NubTypeEnum EnumType { get; }
+    public string Variant { get; }
+
+    public override string ToString() => $"{EnumType}.{Variant}";
+}
+
 public class NubTypePointer : NubType
 {
     private static readonly Dictionary<NubType, NubTypePointer> Cache = new();
@@ -245,11 +284,21 @@ public class TypeEncoder
                 sb.Append(')');
                 break;
 
-            case NubTypeEnum st:
+            case NubTypeEnum e:
-                sb.Append("E(");
+                sb.Append("EN(");
-                sb.Append(st.Module);
+                sb.Append(e.Module);
                 sb.Append(':');
-                sb.Append(st.Name);
+                sb.Append(e.Name);
+                sb.Append(')');
+                break;
+
+            case NubTypeEnumVariant ev:
+                sb.Append("EV(");
+                sb.Append(ev.EnumType.Module);
+                sb.Append(':');
+                sb.Append(ev.EnumType.Name);
+                sb.Append(':');
+                sb.Append(ev.Variant);
                 sb.Append(')');
                 break;
 
@@ -364,10 +413,33 @@ public class TypeDecoder
         return NubTypeStruct.Get(module, name);
     }
 
-    private NubTypeEnum DecodeEnum()
+    private NubType DecodeEnum()
     {
         var sb = new StringBuilder();
 
+        if (TryExpect('V'))
+        {
+            Expect('(');
+            while (!TryExpect(':'))
+                sb.Append(Consume());
+
+            var module = sb.ToString();
+            sb.Clear();
+
+            while (!TryExpect(':'))
+                sb.Append(Consume());
+
+            var name = sb.ToString();
+
+            while (!TryExpect(')'))
+                sb.Append(Consume());
+
+            var variant = sb.ToString();
+
+            return NubTypeEnumVariant.Get(NubTypeEnum.Get(module, name), variant);
+        }
+        else if (TryExpect('N'))
+        {
             Expect('(');
             while (!TryExpect(':'))
                 sb.Append(Consume());
@@ -383,6 +455,9 @@ public class TypeDecoder
             return NubTypeEnum.Get(module, name);
         }
 
+        throw new Exception($"Expected 'V' or 'N'");
+    }
+
     private bool TryPeek(out char c)
     {
         if (index >= encoded.Length)

compiler/Parser.cs

@@ -802,7 +802,7 @@ public class NodeStatementMatch(List<Token> tokens, NodeExpression target, List<
 
     public class Case(List<Token> tokens, TokenIdent type, TokenIdent variableName, NodeStatement body) : Node(tokens)
     {
-        public TokenIdent Type { get; } = type;
+        public TokenIdent Variant { get; } = type;
         public TokenIdent VariableName { get; } = variableName;
         public NodeStatement Body { get; } = body;
     }

compiler/TypeChecker.cs

@@ -47,7 +47,7 @@ public class TypeChecker
                     continue;
                 }
 
-                scope.DeclareIdentifier(parameter.Name.Ident, parameterType, null);
+                scope.DeclareIdentifier(parameter.Name.Ident, parameterType);
                 parameters.Add(new TypedNodeDefinitionFunc.Param(parameter.Tokens, parameter.Name, parameterType));
             }
 
@@ -69,7 +69,7 @@ public class TypeChecker
                 diagnostics.Add(e.Diagnostic);
             }
 
-            if (body == null || returnType == null || invalidParameter)
+            if (body == null || returnType is null || invalidParameter)
                 return null;
 
             return new TypedNodeDefinitionFunc(function.Tokens, moduleName, function.Name, parameters, body, returnType);
@@ -129,10 +129,10 @@ public class TypeChecker
         var type = ResolveType(statement.Type);
         var value = CheckExpression(statement.Value);
 
-        if (type != value.Type)
+        if (!value.Type.IsAssignableTo(type))
             throw new CompileException(Diagnostic.Error("Type of variable does match type of assigned value").At(fileName, value).Build());
 
-        scope.DeclareIdentifier(statement.Name.Ident, type, value.EnumVariant);
+        scope.DeclareIdentifier(statement.Name.Ident, type);
 
         return new TypedNodeStatementVariableDeclaration(statement.Tokens, statement.Name, type, value);
     }
@@ -152,9 +152,9 @@ public class TypeChecker
         {
             using (scope.EnterScope())
             {
-                scope.DeclareIdentifier(@case.VariableName.Ident, NubTypeEnum.Get(enumType.Module, enumType.Name), @case.Type.Ident);
+                scope.DeclareIdentifier(@case.VariableName.Ident, NubTypeEnumVariant.Get(NubTypeEnum.Get(enumType.Module, enumType.Name), @case.Variant.Ident));
                 var body = CheckStatement(@case.Body);
-                cases.Add(new TypedNodeStatementMatch.Case(@case.Tokens, @case.Type, @case.VariableName, body));
+                cases.Add(new TypedNodeStatementMatch.Case(@case.Tokens, @case.Variant, @case.VariableName, body));
             }
         }
 
@@ -321,13 +321,10 @@ public class TypeChecker
     private TypedNodeExpressionLocalIdent CheckExpressionIdent(NodeExpressionLocalIdent expression)
     {
         var type = scope.GetIdentifierType(expression.Value.Ident);
-        if (!type.HasValue)
+        if (type is null)
             throw new CompileException(Diagnostic.Error($"Identifier '{expression.Value.Ident}' is not declared").At(fileName, expression.Value).Build());
 
-        return new TypedNodeExpressionLocalIdent(expression.Tokens, type.Value.Type, expression.Value)
+        return new TypedNodeExpressionLocalIdent(expression.Tokens, type, expression.Value);
-        {
-            EnumVariant = type.Value.EnumVariant
-        };
     }
 
     private TypedNodeExpressionModuleIdent CheckExpressionModuleIdent(NodeExpressionModuleIdent expression)
@@ -371,23 +368,20 @@ public class TypeChecker
 
                 return new TypedNodeExpressionMemberAccess(expression.Tokens, field.Type, target, expression.Name);
             }
-            case NubTypeEnum enumType:
+            case NubTypeEnumVariant enumVariantType:
             {
-                if (target.EnumVariant == null)
+                if (!moduleGraph.TryResolveModule(enumVariantType.EnumType.Module, out var module))
-                    throw new CompileException(Diagnostic.Error($"Cannot access member '{expression.Name.Ident}' on enum '{enumType}' without knowing the variant").At(fileName, target).Build());
+                    throw new CompileException(Diagnostic.Error($"Module '{enumVariantType.EnumType.Module}' not found").At(fileName, expression.Target).Build());
 
-                if (!moduleGraph.TryResolveModule(enumType.Module, out var module))
+                if (!module.TryResolveType(enumVariantType.EnumType.Name, moduleName == enumVariantType.EnumType.Module, out var typeDef))
-                    throw new CompileException(Diagnostic.Error($"Module '{enumType.Module}' not found").At(fileName, expression.Target).Build());
+                    throw new CompileException(Diagnostic.Error($"Type '{enumVariantType.EnumType.Name}' not found in module '{enumVariantType.EnumType.Module}'").At(fileName, expression.Target).Build());
-
-                if (!module.TryResolveType(enumType.Name, moduleName == enumType.Module, out var typeDef))
-                    throw new CompileException(Diagnostic.Error($"Type '{enumType.Name}' not found in module '{enumType.Module}'").At(fileName, expression.Target).Build());
 
                 if (typeDef is not Module.TypeInfoEnum enumDef)
-                    throw new CompileException(Diagnostic.Error($"Type '{enumType.Module}::{enumType.Name}' is not an enum").At(fileName, expression.Target).Build());
+                    throw new CompileException(Diagnostic.Error($"Type '{enumVariantType.EnumType.Module}::{enumVariantType.EnumType.Name}' is not an enum").At(fileName, expression.Target).Build());
 
-                var variant = enumDef.Variants.FirstOrDefault(x => x.Name == target.EnumVariant);
+                var variant = enumDef.Variants.FirstOrDefault(x => x.Name == enumVariantType.Variant);
                 if (variant == null)
-                    throw new CompileException(Diagnostic.Error($"Type '{target.Type}' does not have a variant '{target.EnumVariant}'").At(fileName, expression.Target).Build());
+                    throw new CompileException(Diagnostic.Error($"Type '{target.Type}' does not have a variant named '{enumVariantType.Variant}'").At(fileName, expression.Target).Build());
 
                 var field = variant.Fields.FirstOrDefault(x => x.Name == expression.Name.Ident);
                 if (field == null)
@@ -437,7 +431,7 @@ public class TypeChecker
                 throw new CompileException(Diagnostic.Error($"Field '{initializer.Name.Ident}' does not exist on struct '{expression.Module.Ident}::{expression.Name.Ident}'").At(fileName, initializer.Name).Build());
 
             var value = CheckExpression(initializer.Value);
-            if (value.Type != field.Type)
+            if (!value.Type.IsAssignableTo(field.Type))
                 throw new CompileException(Diagnostic.Error($"Type of assignment ({value.Type}) does not match expected type of field '{field.Name}' ({field.Type})").At(fileName, initializer.Name).Build());
 
             initializers.Add(new TypedNodeExpressionStructLiteral.Initializer(initializer.Tokens, initializer.Name, value));
@@ -471,16 +465,13 @@ public class TypeChecker
                 throw new CompileException(Diagnostic.Error($"Field '{initializer.Name.Ident}' does not exist on enum variant '{expression.Module.Ident}::{expression.EnumName.Ident}.{expression.VariantName.Ident}'").At(fileName, initializer.Name).Build());
 
             var value = CheckExpression(initializer.Value);
-            if (value.Type != field.Type)
+            if (!value.Type.IsAssignableTo(field.Type))
                 throw new CompileException(Diagnostic.Error($"Type of assignment ({value.Type}) does not match expected type of field '{field.Name}' ({field.Type})").At(fileName, initializer.Name).Build());
 
             initializers.Add(new TypedNodeExpressionEnumLiteral.Initializer(initializer.Tokens, initializer.Name, value));
         }
 
-        return new TypedNodeExpressionEnumLiteral(expression.Tokens, NubTypeEnum.Get(expression.Module.Ident, expression.EnumName.Ident), initializers)
+        return new TypedNodeExpressionEnumLiteral(expression.Tokens, NubTypeEnumVariant.Get(NubTypeEnum.Get(expression.Module.Ident, expression.EnumName.Ident), expression.VariantName.Ident), initializers);
-        {
-            EnumVariant = expression.VariantName.Ident
-        };
     }
 
     private NubType ResolveType(NodeType node)
@@ -519,7 +510,7 @@ public class TypeChecker
 
     private sealed class Scope
     {
-        private readonly Stack<Dictionary<string, (NubType Type, string? EnumVariant)>> scopes = new();
+        private readonly Stack<Dictionary<string, NubType>> scopes = new();
 
         public IDisposable EnterScope()
         {
@@ -527,12 +518,12 @@ public class TypeChecker
             return new ScopeGuard(this);
         }
 
-        public void DeclareIdentifier(string name, NubType type, string? enumVariant)
+        public void DeclareIdentifier(string name, NubType type)
         {
-            scopes.Peek().Add(name, (type, enumVariant));
+            scopes.Peek().Add(name, type);
         }
 
-        public (NubType Type, string? EnumVariant)? GetIdentifierType(string name)
+        public NubType? GetIdentifierType(string name)
         {
             foreach (var scope in scopes)
             {
@@ -649,7 +640,6 @@ public class TypedNodeStatementMatch(List<Token> tokens, TypedNodeExpression tar
 public abstract class TypedNodeExpression(List<Token> tokens, NubType type) : TypedNode(tokens)
 {
     public NubType Type { get; } = type;
-    public string? EnumVariant { get; init; }
 }
 
 public class TypedNodeExpressionIntLiteral(List<Token> tokens, NubType type, TokenIntLiteral value) : TypedNodeExpression(tokens, type)