...

example/program.nub

@@ -3,6 +3,6 @@ import c
 global func main(argc: i64, argv: i64) {
     printf("args: %d, starts at %p\n", argc, argv)
 
-    x: i8 = (i8)320000
+
-    printf("%d\n", x)
+    printf("%s\n", list.text)
 }

src/compiler/Nub.Lang/Backend/Generator.cs

@@ -8,11 +8,11 @@ public class Generator
 {
     private readonly List<DefinitionNode> _definitions;
     private readonly StringBuilder _builder = new();
-    private readonly Dictionary<string, int> _prefixIndexes = new();
     private readonly Dictionary<string, Variable> _variables = new();
     private readonly List<string> _strings = [];
     private readonly Stack<string> _breakLabels = new();
     private readonly Stack<string> _continueLabels = new();
+    private int _variableIndex;
     private bool _codeIsReachable = true;
 
     public Generator(List<DefinitionNode> definitions)
@@ -72,7 +72,7 @@ public class Generator
                         throw new ArgumentOutOfRangeException();
                 }
             }
-            case NubCustomType nubCustomType:
+            case NubStructType:
             {
                 return "l";
             }
@@ -114,7 +114,7 @@ public class Generator
                         throw new ArgumentOutOfRangeException();
                 }
             }
-            case NubCustomType nubCustomType:
+            case NubStructType nubCustomType:
             {
                 return ":" + nubCustomType.Name;
             }
@@ -159,7 +159,7 @@ public class Generator
                         throw new ArgumentOutOfRangeException();
                 }
             }
-            case NubCustomType nubCustomType:
+            case NubStructType nubCustomType:
             {
                 return ":" + nubCustomType.Name;
             }
@@ -170,7 +170,7 @@ public class Generator
         }
     }
 
-    private static int QbeTypeSize(NubType type)
+    private int QbeTypeSize(NubType type)
     {
         switch (type)
         {
@@ -201,9 +201,14 @@ public class Generator
                         throw new ArgumentOutOfRangeException();
                 }
             }
-            case NubCustomType nubCustomType:
+            case NubStructType nubCustomType:
             {
-                return 8;
+                var definition = _definitions.OfType<StructDefinitionNode>().FirstOrDefault(s => s.Name == nubCustomType.Name);
+                if (definition == null)
+                {
+                    throw new Exception($"Cannot determine size of non-existent type {nubCustomType}");
+                }
+                return definition.Fields.Sum(f => QbeTypeSize(f.Type));
             }
             default:
             {
@@ -246,19 +251,19 @@ public class Generator
             switch (FQT(parameter.Type))
             {
                 case "sb":
-                    parameterName = GenName("c");
+                    parameterName = GenName();
                     _builder.AppendLine($"    %{parameterName} =w extsb %{parameter.Name}");
                     break;
                 case "ub":
-                    parameterName = GenName("c");
+                    parameterName = GenName();
                     _builder.AppendLine($"    %{parameterName} =w extub %{parameter.Name}");
                     break;
                 case "sh":
-                    parameterName = GenName("c");
+                    parameterName = GenName();
                     _builder.AppendLine($"    %{parameterName} =w extsh %{parameter.Name}");
                     break;
                 case "uh":
-                    parameterName = GenName("c");
+                    parameterName = GenName();
                     _builder.AppendLine($"    %{parameterName} =w extuh %{parameter.Name}");
                     break;
             }
@@ -403,9 +408,9 @@ public class Generator
 
     private void GenerateIf(IfNode ifStatement)
     {
-        var trueLabel = GenName("true");
+        var trueLabel = GenName();
-        var falseLabel = GenName("false");
+        var falseLabel = GenName();
-        var endLabel = GenName("endif");
+        var endLabel = GenName();
 
         var result = GenerateExpression(ifStatement.Condition);
         _builder.AppendLine($"    jnz {result}, @{trueLabel}, @{falseLabel}");
@@ -450,9 +455,9 @@ public class Generator
 
     private void GenerateWhile(WhileNode whileStatement)
     {
-        var conditionLabel = GenName("condition");
+        var conditionLabel = GenName();
-        var iterationLabel = GenName("iteration");
+        var iterationLabel = GenName();
-        var endLabel = GenName("endloop");
+        var endLabel = GenName();
 
         _breakLabels.Push(endLabel);
         _continueLabels.Push(conditionLabel);
@@ -734,7 +739,7 @@ public class Generator
             throw new NotSupportedException("Casting is only supported for primitive types");
         }
 
-        var outputLabel = GenName("c");
+        var outputLabel = GenName();
 
         switch (primitiveInputType.Kind)
         {
@@ -779,7 +784,7 @@ public class Generator
                     case PrimitiveTypeKind.U8:
                         return input;
                     case PrimitiveTypeKind.F64:
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extsw {input}");
                         _builder.AppendLine($"    %{outputLabel} =d sltof %{extLabel}");
                         return $"%{outputLabel}";
@@ -790,7 +795,7 @@ public class Generator
                         _builder.AppendLine($"    %{outputLabel} =l call $nub_i32_to_string(w {input})");
                         return $"%{outputLabel}";
                     case PrimitiveTypeKind.Any:
-                        var extAnyLabel = GenName("ext");
+                        var extAnyLabel = GenName();
                         _builder.AppendLine($"    %{extAnyLabel} =l extsw {input}");
                         return $"%{extAnyLabel}";
                     case PrimitiveTypeKind.Bool:
@@ -815,28 +820,28 @@ public class Generator
                         return input;
                     case PrimitiveTypeKind.F64:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extsh {input}");
                         _builder.AppendLine($"    %{outputLabel} =d sltof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.F32:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extsh {input}");
                         _builder.AppendLine($"    %{outputLabel} =s swtof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.String:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extsh {input}");
                         _builder.AppendLine($"    %{outputLabel} =l call $nub_i32_to_string(w %{extLabel})");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.Any:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extsh {input}");
                         return $"%{extLabel}";
                     }
@@ -862,28 +867,28 @@ public class Generator
                         return input;
                     case PrimitiveTypeKind.F64:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extsb {input}");
                         _builder.AppendLine($"    %{outputLabel} =d sltof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.F32:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extsb {input}");
                         _builder.AppendLine($"    %{outputLabel} =s swtof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.String:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extsb {input}");
                         _builder.AppendLine($"    %{outputLabel} =l call $nub_i32_to_string(w %{extLabel})");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.Any:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extsb {input}");
                         return $"%{extLabel}";
                     }
@@ -933,7 +938,7 @@ public class Generator
                     case PrimitiveTypeKind.U8:
                         return input;
                     case PrimitiveTypeKind.F64:
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extuw {input}");
                         _builder.AppendLine($"    %{outputLabel} =d ultof %{extLabel}");
                         return $"%{outputLabel}";
@@ -944,7 +949,7 @@ public class Generator
                         _builder.AppendLine($"    %{outputLabel} =l call $nub_u32_to_string(w {input})");
                         return $"%{outputLabel}";
                     case PrimitiveTypeKind.Any:
-                        var extAnyLabel = GenName("ext");
+                        var extAnyLabel = GenName();
                         _builder.AppendLine($"    %{extAnyLabel} =l extuw {input}");
                         return $"%{extAnyLabel}";
                     case PrimitiveTypeKind.Bool:
@@ -969,28 +974,28 @@ public class Generator
                         return input;
                     case PrimitiveTypeKind.F64:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extuh {input}");
                         _builder.AppendLine($"    %{outputLabel} =d ultof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.F32:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extuh {input}");
                         _builder.AppendLine($"    %{outputLabel} =s uwtof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.String:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extuh {input}");
                         _builder.AppendLine($"    %{outputLabel} =l call $nub_u32_to_string(w %{extLabel})");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.Any:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extuh {input}");
                         return $"%{extLabel}";
                     }
@@ -1016,28 +1021,28 @@ public class Generator
                         return input;
                     case PrimitiveTypeKind.F64:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extub {input}");
                         _builder.AppendLine($"    %{outputLabel} =d ultof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.F32:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extub {input}");
                         _builder.AppendLine($"    %{outputLabel} =s uwtof %{extLabel}");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.String:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =w extub {input}");
                         _builder.AppendLine($"    %{outputLabel} =l call $nub_u32_to_string(w %{extLabel})");
                         return $"%{outputLabel}";
                     }
                     case PrimitiveTypeKind.Any:
                     {
-                        var extLabel = GenName("ext");
+                        var extLabel = GenName();
                         _builder.AppendLine($"    %{extLabel} =l extub {input}");
                         return $"%{extLabel}";
                     }
@@ -1196,15 +1201,13 @@ public class Generator
 
     private string GenerateStructInitializer(StructInitializerNode structInitializer)
     {
-        var structDefinition = _definitions.OfType<StructDefinitionNode>()
+        var structDefinition = _definitions.OfType<StructDefinitionNode>().FirstOrDefault(s => s.Name == structInitializer.StructType.Name);
-            .FirstOrDefault(s => s.Name == structInitializer.StructType.Name);
-
         if (structDefinition == null)
         {
             throw new Exception($"Struct {structInitializer.StructType.Name} is not defined");
         }
 
-        var structVar = GenName("struct");
+        var structVar = GenName();
 
         var size = structDefinition.Fields.Sum(x => QbeTypeSize(x.Type));
         _builder.AppendLine($"    %{structVar} =l alloc8 {size}");
@@ -1216,14 +1219,14 @@ public class Generator
             if (structInitializer.Initializers.TryGetValue(field.Name, out var fieldValue))
             {
                 var var = GenerateExpression(fieldValue);
-                var offsetLabel = GenName("offset");
+                var offsetLabel = GenName();
                 _builder.AppendLine($"    %{offsetLabel} =l add %{structVar}, {i * QbeTypeSize(field.Type)}");
                 _builder.AppendLine($"    store{SQT(field.Type)} {var}, %{offsetLabel}");
             }
             else if (field.Value.HasValue)
             {
                 var var = GenerateExpression(field.Value.Value);
-                var offsetLabel = GenName("offset");
+                var offsetLabel = GenName();
                 _builder.AppendLine($"    %{offsetLabel} =l add %{structVar}, {i * QbeTypeSize(field.Type)}");
                 _builder.AppendLine($"    store{SQT(field.Type)} {var}, %{offsetLabel}");
             }
@@ -1265,10 +1268,10 @@ public class Generator
             throw new Exception($"Field {structFieldAccessor.Field} is not defined in struct {structType.Name}");
         }
 
-        var offsetLabel = GenName("offset");
+        var offsetLabel = GenName();
         _builder.AppendLine($"    %{offsetLabel} =l add {@struct}, {fieldIndex * QbeTypeSize(structFieldAccessor.Type)}");
 
-        var outputLabel = GenName("field");
+        var outputLabel = GenName();
         _builder.AppendLine($"    %{outputLabel} ={SQT(structFieldAccessor.Type)} load{SQT(structFieldAccessor.Type)} %{offsetLabel}");
 
         return $"%{outputLabel}";
@@ -1282,11 +1285,9 @@ public class Generator
         return $"%{outputLabel}";
     }
 
-    private string GenName(string prefix = "v")
+    private string GenName()
     {
-        var index = _prefixIndexes.GetValueOrDefault(prefix, 0);
+        return $"v{++_variableIndex}";
-        _prefixIndexes[prefix] = index + 1;
-        return $"{prefix}{index}";
     }
 
     private class Variable

src/compiler/Nub.Lang/Frontend/Lexing/Lexer.cs

@@ -50,6 +50,8 @@ public class Lexer
         ['*'] = Symbol.Star,
         ['/'] = Symbol.ForwardSlash,
         ['!'] = Symbol.Bang,
+        ['^'] = Symbol.Caret,
+        ['&'] = Symbol.Ampersand,
     };
     
     private string _src = string.Empty;

src/compiler/Nub.Lang/Frontend/Lexing/SymbolToken.cs

@@ -39,5 +39,7 @@ public enum Symbol
     Star,
     ForwardSlash,
     New,
-    Struct
+    Struct,
+    Caret,
+    Ampersand
 }

src/compiler/Nub.Lang/Frontend/Parsing/Parser.cs

@@ -76,6 +76,7 @@ public class Parser
             {
                 throw new Exception($"Modifiers: {string.Join(", ", modifiers)} is not valid for an extern function");
             }
+
             return new ExternFuncDefinitionNode(name.Value, parameters, returnType);
         }
 
@@ -86,10 +87,11 @@ public class Parser
         {
             throw new Exception($"Modifiers: {string.Join(", ", modifiers)} is not valid for a local function");
         }
+
         return new LocalFuncDefinitionNode(name.Value, parameters, body, returnType, global);
     }
 
-    private StructDefinitionNode ParseStruct(List<Modifier> modifiers)
+    private StructDefinitionNode ParseStruct(List<Modifier> _)
     {
         var name = ExpectIdentifier().Value;
 
@@ -324,11 +326,10 @@ public class Parser
                     {
                         // This is ugly
                         var nextToken = Peek();
-                    if (nextToken is { Value: IdentifierToken })
+                        if (nextToken is { Value: IdentifierToken or SymbolToken { Symbol: Symbol.Caret } })
                         {
                             var startIndex = _index;
-                        var identifierToken = ExpectIdentifier();
+                            var type = ParseType();
-                        var type = NubType.Parse(identifierToken.Value);
 
                             if (TryExpectSymbol(Symbol.CloseParen))
                             {
@@ -498,17 +499,6 @@ public class Parser
         return identifier;
     }
 
-    private LiteralToken ExpectLiteral()
-    {
-        var token = ExpectToken();
-        if (token is not LiteralToken literal)
-        {
-            throw new Exception($"Expected {nameof(LiteralToken)} but got {token.GetType().Name}");
-        }
-
-        return literal;
-    }
-
     private Optional<Token> Peek()
     {
         while (_index < _tokens.Count && _tokens.ElementAt(_index) is SymbolToken { Symbol: Symbol.Whitespace })

src/compiler/Nub.Lang/Frontend/Typing/TypeChecker.cs

@@ -10,44 +10,29 @@ public class TypeCheckingException : Exception
 public class TypeChecker
 {
     private readonly Dictionary<string, NubType> _variables = new();
-    private readonly Dictionary<string, (List<FuncParameter> Parameters, Optional<NubType> ReturnType)> _functions = new();
+    private readonly List<DefinitionNode> _definitions;
-    private readonly Dictionary<string, Dictionary<string, NubType>> _structs = new();
     private NubType? _currentFunctionReturnType;
     private bool _hasReturnStatement;
 
-    public void TypeCheck(List<DefinitionNode> definitions)
+    public TypeChecker(List<DefinitionNode> definitions)
     {
-        CollectDefinitions(definitions);
+        _definitions = definitions;
-
-        foreach (var definition in definitions)
-        {
-            if (definition is LocalFuncDefinitionNode funcDef)
-            {
-                TypeCheckFunction(funcDef);
     }
+
+    public void TypeCheck()
+    {
+        foreach (var structDef in _definitions.OfType<StructDefinitionNode>())
+        {
+            TypeCheckStructDef(structDef);
+        }
+   
+        foreach (var funcDef in _definitions.OfType<LocalFuncDefinitionNode>())
+        {
+            TypeCheckFuncDef(funcDef);
         }
     }
 
-    private void CollectDefinitions(List<DefinitionNode> definitions)
+    private void TypeCheckStructDef(StructDefinitionNode structDef)
-    {
-        foreach (var definition in definitions)
-        {
-            switch (definition)
-            {
-                case StructDefinitionNode structDef:
-                    RegisterStruct(structDef);
-                    break;
-                case LocalFuncDefinitionNode funcDef:
-                    RegisterFunction(funcDef);
-                    break;
-                case ExternFuncDefinitionNode externFuncDef:
-                    RegisterExternFunction(externFuncDef);
-                    break;
-            }
-        }
-    }
-
-    private void RegisterStruct(StructDefinitionNode structDef)
     {
         var fields = new Dictionary<string, NubType>();
         foreach (var field in structDef.Fields)
@@ -56,22 +41,20 @@ public class TypeChecker
             {
                 throw new TypeCheckingException($"Duplicate field '{field.Name}' in struct '{structDef.Name}'");
             }
+
+            if (field.Value.HasValue)
+            {
+                if (!TypeCheckExpression(field.Value.Value).Equals(field.Type))
+                {
+                    throw new TypeCheckingException("Default field initializer does not match the defined type");
+                }
+            }
+            
             fields[field.Name] = field.Type;
         }
-        _structs[structDef.Name] = fields;
     }
 
-    private void RegisterFunction(LocalFuncDefinitionNode funcDef)
+    private void TypeCheckFuncDef(LocalFuncDefinitionNode funcDef)
-    {
-        _functions[funcDef.Name] = (funcDef.Parameters, funcDef.ReturnType);
-    }
-
-    private void RegisterExternFunction(ExternFuncDefinitionNode funcDef)
-    {
-        _functions[funcDef.Name] = (funcDef.Parameters, funcDef.ReturnType);
-    }
-
-    private void TypeCheckFunction(LocalFuncDefinitionNode funcDef)
     {
         _variables.Clear();
         _currentFunctionReturnType = funcDef.ReturnType.HasValue ? funcDef.ReturnType.Value : null;
@@ -146,13 +129,28 @@ public class TypeChecker
 
     private NubType TypeCheckFuncCall(FuncCall funcCall)
     {
-        if (!_functions.TryGetValue(funcCall.Name, out var funcSignature))
+        var localFuncDef = _definitions.OfType<LocalFuncDefinitionNode>().FirstOrDefault(f => f.Name == funcCall.Name);
+        var externFuncDef = _definitions.OfType<ExternFuncDefinitionNode>().FirstOrDefault(f => f.Name == funcCall.Name);
+
+        List<FuncParameter> parameters;
+        Optional<NubType> returnType;
+        if (localFuncDef != null)
+        {
+            parameters = localFuncDef.Parameters;
+            returnType = localFuncDef.ReturnType;
+        }
+        else if (externFuncDef != null)
+        {
+            parameters = externFuncDef.Parameters;
+            returnType = externFuncDef.ReturnType;
+        }
+        
+        else
         {
             throw new TypeCheckingException($"Function '{funcCall.Name}' is not defined");
         }
 
-        var paramTypes = funcSignature.Parameters;
+        if (parameters.Take(parameters.Count - 1).Any(x => x.Variadic))
-        if (paramTypes.Take(paramTypes.Count - 1).Any(x => x.Variadic))
         {
             throw new TypeCheckingException($"Function '{funcCall.Name}' has multiple variadic parameters");
         }
@@ -162,13 +160,13 @@ public class TypeChecker
             var argType = TypeCheckExpression(funcCall.Parameters[i]);
 
             NubType paramType;
-            if (i < paramTypes.Count)
+            if (i < parameters.Count)
             {
-                paramType = paramTypes[i].Type;
+                paramType = parameters[i].Type;
             }
-            else if (paramTypes.LastOrDefault()?.Variadic ?? false)
+            else if (parameters.LastOrDefault()?.Variadic ?? false)
             {
-                return paramTypes[^1].Type;
+                return parameters[^1].Type;
             }
             else
             {
@@ -181,7 +179,7 @@ public class TypeChecker
             }
         }
 
-        return funcSignature.ReturnType.HasValue ? funcSignature.ReturnType.Value : NubPrimitiveType.Any;
+        return returnType.HasValue ? returnType.Value : NubPrimitiveType.Any;
     }
 
     private void TypeCheckIf(IfNode ifNode)
@@ -322,36 +320,47 @@ public class TypeChecker
 
     private NubType TypeCheckStructInitializer(StructInitializerNode structInit)
     {
+        var initialized = new HashSet<string>();
+        
         var structType = structInit.StructType;
-        if (structType is not NubCustomType customType)
+        if (structType is not NubStructType customType)
         {
             throw new TypeCheckingException($"Type '{structType}' is not a struct type");
         }
 
-        if (!_structs.TryGetValue(customType.Name, out var fields))
+        var definition = _definitions.OfType<StructDefinitionNode>().FirstOrDefault(s => s.Name == structInit.StructType.Name);
+        if (definition == null)
         {
             throw new TypeCheckingException($"Struct type '{customType.Name}' is not defined");
         }
 
         foreach (var initializer in structInit.Initializers)
         {
-            if (!fields.TryGetValue(initializer.Key, out var fieldType))
+            var definitionField = definition.Fields.FirstOrDefault(f => f.Name == initializer.Key);
+            if (definitionField == null)
             {
                 throw new TypeCheckingException($"Field '{initializer.Key}' does not exist in struct '{customType.Name}'");
             }
 
             var initializerType = TypeCheckExpression(initializer.Value);
-            if (!AreTypesCompatible(initializerType, fieldType))
+            if (!AreTypesCompatible(initializerType, definitionField.Type))
             {
-                throw new TypeCheckingException($"Cannot initialize field '{initializer.Key}' of type '{fieldType}' with expression of type '{initializerType}'");
+                throw new TypeCheckingException($"Cannot initialize field '{initializer.Key}' of type '{definitionField.Type}' with expression of type '{initializerType}'");
-            }
             }
             
-        foreach (var field in fields)
+            initialized.Add(initializer.Key);
+        }
+        
+        foreach (var field in definition.Fields.Where(f => f.Value.HasValue))
         {
-            if (!structInit.Initializers.ContainsKey(field.Key))
+            initialized.Add(field.Name);
+        }
+
+        foreach (var field in definition.Fields)
         {
-                throw new TypeCheckingException($"Field '{field.Key}' of struct '{customType.Name}' is not initialized");
+            if (!initialized.Contains(field.Name))
+            {
+                throw new TypeCheckingException($"Struct field '{field.Name}' is not initialized on type '{customType.Name}'");
             }
         }
 
@@ -361,23 +370,24 @@ public class TypeChecker
     private NubType TypeCheckStructFieldAccess(StructFieldAccessorNode fieldAccess)
     {
         var structType = TypeCheckExpression(fieldAccess.Struct);
-            
+        if (structType is not NubStructType customType)
-        if (structType is not NubCustomType customType)
         {
             throw new TypeCheckingException($"Cannot access field '{fieldAccess.Field}' on non-struct type '{structType}'");
         }
 
-        if (!_structs.TryGetValue(customType.Name, out var fields))
+        var definition = _definitions.OfType<StructDefinitionNode>().FirstOrDefault(s => s.Name == customType.Name);
+        if (definition == null)
         {
             throw new TypeCheckingException($"Struct type '{customType.Name}' is not defined");
         }
 
-        if (!fields.TryGetValue(fieldAccess.Field, out var fieldType))
+        var field = definition.Fields.FirstOrDefault(f => f.Name == fieldAccess.Field);
+        if (field == null)
         {
             throw new TypeCheckingException($"Field '{fieldAccess.Field}' does not exist in struct '{customType.Name}'");
         }
 
-        return fieldType;
+        return field.Type;
     }
 
     private static bool AreTypesCompatible(NubType sourceType, NubType targetType)

src/compiler/Nub.Lang/NubType.cs

@@ -18,7 +18,7 @@ public abstract class NubType
             return new NubPrimitiveType(kind.Value);
         }
 
-        return new NubCustomType(s);
+        return new NubStructType(s);
     }
 
     public override bool Equals(object? obj) => obj is NubType item && Name.Equals(item.Name);
@@ -26,16 +26,11 @@ public abstract class NubType
     public override string ToString() => Name;
 }
 
-public class NubCustomType(string name) : NubType(name);
+public class NubStructType(string name) : NubType(name);
 
-public class NubPrimitiveType : NubType
+public class NubPrimitiveType(PrimitiveTypeKind kind) : NubType(KindToString(kind))
 {
-    public NubPrimitiveType(PrimitiveTypeKind kind) : base(KindToString(kind))
+    public PrimitiveTypeKind Kind { get; } = kind;
-    {
-        Kind = kind;
-    }
-
-    public PrimitiveTypeKind Kind { get; }
 
     public static NubPrimitiveType I64 => new(PrimitiveTypeKind.I64);
     public static NubPrimitiveType I32 => new(PrimitiveTypeKind.I32);

src/compiler/Nub.Lang/Program.cs

@@ -44,8 +44,8 @@ internal static class Program
         var modules = RunFrontend(input);
         var definitions = modules.SelectMany(f => f.Definitions).ToList();
 
-        var typeChecker = new TypeChecker();
+        var typeChecker = new TypeChecker(definitions);
-        typeChecker.TypeCheck(definitions);
+        typeChecker.TypeCheck();
 
         var generator = new Generator(definitions);
         var result = generator.Generate();