compiler/Parser.cs

@@ -193,10 +193,14 @@ public class Parser
         if (TryExpectKeyword(Keyword.Let))
         {
             var name = ExpectIdent();
-            ExpectSymbol(Symbol.Colon);
+
-            var type = ParseType();
+            NodeType? type = null;
+            if (TryExpectSymbol(Symbol.Colon))
+                type = ParseType();
+
             ExpectSymbol(Symbol.Equal);
             var value = ParseExpression();
+
             return new NodeStatementVariableDeclaration(TokensFrom(startIndex), name, type, value);
         }
 
@@ -315,6 +319,20 @@ public class Parser
             var target = ParseExpression();
             expr = new NodeExpressionUnary(TokensFrom(startIndex), target, NodeExpressionUnary.Op.Negate);
         }
+        else if (TryExpectSymbol(Symbol.OpenCurly))
+        {
+            var initializers = new List<NodeExpressionStructLiteral.Initializer>();
+            while (!TryExpectSymbol(Symbol.CloseCurly))
+            {
+                var initializerStartIndex = startIndex;
+                var fieldName = ExpectIdent();
+                ExpectSymbol(Symbol.Equal);
+                var fieldValue = ParseExpression();
+                initializers.Add(new NodeExpressionStructLiteral.Initializer(TokensFrom(initializerStartIndex), fieldName, fieldValue));
+            }
+
+            expr = new NodeExpressionStructLiteral(TokensFrom(startIndex), null, initializers);
+        }
         else if (TryExpectSymbol(Symbol.Bang))
         {
             var target = ParseExpression();
@@ -760,10 +778,10 @@ public class NodeStatementReturn(List<Token> tokens, NodeExpression value) : Nod
     public NodeExpression Value { get; } = value;
 }
 
-public class NodeStatementVariableDeclaration(List<Token> tokens, TokenIdent name, NodeType type, NodeExpression value) : NodeStatement(tokens)
+public class NodeStatementVariableDeclaration(List<Token> tokens, TokenIdent name, NodeType? type, NodeExpression value) : NodeStatement(tokens)
 {
     public TokenIdent Name { get; } = name;
-    public NodeType Type { get; } = type;
+    public NodeType? Type { get; } = type;
     public NodeExpression Value { get; } = value;
 }
 
@@ -816,9 +834,9 @@ public class NodeExpressionBoolLiteral(List<Token> tokens, TokenBoolLiteral valu
     public TokenBoolLiteral Value { get; } = value;
 }
 
-public class NodeExpressionStructLiteral(List<Token> tokens, NodeType type, List<NodeExpressionStructLiteral.Initializer> initializers) : NodeExpression(tokens)
+public class NodeExpressionStructLiteral(List<Token> tokens, NodeType? type, List<NodeExpressionStructLiteral.Initializer> initializers) : NodeExpression(tokens)
 {
-    public NodeType Type { get; } = type;
+    public NodeType? Type { get; } = type;
     public List<Initializer> Initializers { get; } = initializers;
 
     public class Initializer(List<Token> tokens, TokenIdent name, NodeExpression value) : Node(tokens)

compiler/TypeChecker.cs

@@ -1,5 +1,6 @@
 using System.Data.Common;
 using System.Diagnostics.CodeAnalysis;
+using System.Formats.Tar;
 
 namespace Compiler;
 
@@ -21,6 +22,7 @@ public class TypeChecker
     private readonly string fileName;
     private readonly string currentModule;
     private readonly NodeDefinitionFunc function;
+    private NubType functionReturnType = null!;
     private readonly ModuleGraph moduleGraph;
     private readonly Scope scope = new();
 
@@ -31,7 +33,16 @@ public class TypeChecker
         var parameters = new List<TypedNodeDefinitionFunc.Param>();
         var invalidParameter = false;
         TypedNodeStatement? body = null;
-        NubType? returnType = null;
+
+        try
+        {
+            functionReturnType = ResolveType(function.ReturnType);
+        }
+        catch (CompileException e)
+        {
+            diagnostics.Add(e.Diagnostic);
+            return null;
+        }
 
         using (scope.EnterScope())
         {
@@ -63,19 +74,10 @@ public class TypeChecker
                 diagnostics.Add(e.Diagnostic);
             }
 
-            try
+            if (body == null || invalidParameter)
-            {
-                returnType = ResolveType(function.ReturnType);
-            }
-            catch (CompileException e)
-            {
-                diagnostics.Add(e.Diagnostic);
-            }
-
-            if (body == null || returnType is null || invalidParameter)
                 return null;
 
-            return new TypedNodeDefinitionFunc(function.Tokens, currentModule, function.Name, parameters, body, returnType);
+            return new TypedNodeDefinitionFunc(function.Tokens, currentModule, function.Name, parameters, body, functionReturnType);
         }
     }
 
@@ -97,7 +99,10 @@ public class TypeChecker
 
     private TypedNodeStatementAssignment CheckStatementAssignment(NodeStatementAssignment statement)
     {
-        return new TypedNodeStatementAssignment(statement.Tokens, CheckExpression(statement.Target), CheckExpression(statement.Value));
+        var target = CheckExpression(statement.Target, null);
+        var value = CheckExpression(statement.Value, target.Type);
+
+        return new TypedNodeStatementAssignment(statement.Tokens, target, value);
     }
 
     private TypedNodeStatementBlock CheckStatementBlock(NodeStatementBlock statement)
@@ -114,27 +119,56 @@ public class TypeChecker
         if (statement.Expression is not NodeExpressionFuncCall funcCall)
             throw BasicError("Expected statement or function call", statement);
 
-        return new TypedNodeStatementFuncCall(statement.Tokens, CheckExpression(funcCall.Target), funcCall.Parameters.Select(CheckExpression).ToList());
+        var target = CheckExpression(funcCall.Target, null);
+        if (target.Type is not NubTypeFunc funcType)
+            throw BasicError("Expected a function type", target);
+
+        if (funcType.Parameters.Count != funcCall.Parameters.Count)
+            throw BasicError($"Expected {funcType.Parameters.Count} parameters but got {funcCall.Parameters.Count}", funcCall);
+
+        var parameters = new List<TypedNodeExpression>();
+        for (int i = 0; i < funcCall.Parameters.Count; i++)
+        {
+            parameters.Add(CheckExpression(funcCall.Parameters[i], funcType.Parameters[i]));
+        }
+
+        return new TypedNodeStatementFuncCall(statement.Tokens, target, parameters);
     }
 
     private TypedNodeStatementIf CheckStatementIf(NodeStatementIf statement)
     {
-        return new TypedNodeStatementIf(statement.Tokens, CheckExpression(statement.Condition), CheckStatement(statement.ThenBlock), statement.ElseBlock == null ? null : CheckStatement(statement.ElseBlock));
+        var condition = CheckExpression(statement.Condition, NubTypeBool.Instance);
+        if (!condition.Type.IsAssignableTo(NubTypeBool.Instance))
+            throw BasicError("Condition part of if statement must be a boolean", condition);
+
+        var thenBlock = CheckStatement(statement.ThenBlock);
+        var elseBlock = statement.ElseBlock == null ? null : CheckStatement(statement.ElseBlock);
+
+        return new TypedNodeStatementIf(statement.Tokens, condition, thenBlock, elseBlock);
     }
 
     private TypedNodeStatementReturn CheckStatementReturn(NodeStatementReturn statement)
     {
-        return new TypedNodeStatementReturn(statement.Tokens, CheckExpression(statement.Value));
+        var value = CheckExpression(statement.Value, functionReturnType);
+        if (!value.Type.IsAssignableTo(functionReturnType))
+            throw BasicError($"Type of returned value ({value.Type}) is not assignable to the return type of the function ({functionReturnType})", value);
+
+        return new TypedNodeStatementReturn(statement.Tokens, value);
     }
 
     private TypedNodeStatementVariableDeclaration CheckStatementVariableDeclaration(NodeStatementVariableDeclaration statement)
     {
-        var type = ResolveType(statement.Type);
+        NubType? type = null;
-        var value = CheckExpression(statement.Value);
+        if (statement.Type != null)
+            type = ResolveType(statement.Type);
 
-        if (!value.Type.IsAssignableTo(type))
+        var value = CheckExpression(statement.Value, type);
+
+        if (type is not null && !value.Type.IsAssignableTo(type))
             throw BasicError("Type of variable does match type of assigned value", value);
 
+        type ??= value.Type;
+
         scope.DeclareIdentifier(statement.Name.Ident, type);
 
         return new TypedNodeStatementVariableDeclaration(statement.Tokens, statement.Name, type, value);
@@ -142,15 +176,22 @@ public class TypeChecker
 
     private TypedNodeStatementWhile CheckStatementWhile(NodeStatementWhile statement)
     {
-        return new TypedNodeStatementWhile(statement.Tokens, CheckExpression(statement.Condition), CheckStatement(statement.Body));
+        var condition = CheckExpression(statement.Condition, NubTypeBool.Instance);
+        if (!condition.Type.IsAssignableTo(NubTypeBool.Instance))
+            throw BasicError("Condition part of if statement must be a boolean", condition);
+
+        var body = CheckStatement(statement.Body);
+
+        return new TypedNodeStatementWhile(statement.Tokens, condition, body);
     }
 
     private TypedNodeStatementMatch CheckStatementMatch(NodeStatementMatch statement)
     {
-        var cases = new List<TypedNodeStatementMatch.Case>();
+        var target = CheckExpression(statement.Target, null);
-        var target = CheckExpression(statement.Target);
+        if (target.Type is not NubTypeEnum enumType)
-        var enumType = (NubTypeEnum)target.Type;
+            throw BasicError("A match statement can only be used on enum types", target);
 
+        var cases = new List<TypedNodeStatementMatch.Case>();
         foreach (var @case in statement.Cases)
         {
             using (scope.EnterScope())
@@ -164,28 +205,29 @@ public class TypeChecker
         return new TypedNodeStatementMatch(statement.Tokens, target, cases);
     }
 
-    private TypedNodeExpression CheckExpression(NodeExpression node)
+    private TypedNodeExpression CheckExpression(NodeExpression node, NubType? expectedType)
     {
         return node switch
         {
-            NodeExpressionBinary expression => CheckExpressionBinary(expression),
+            NodeExpressionBinary expression => CheckExpressionBinary(expression, expectedType),
-            NodeExpressionUnary expression => CheckExpressionUnary(expression),
+            NodeExpressionUnary expression => CheckExpressionUnary(expression, expectedType),
-            NodeExpressionBoolLiteral expression => CheckExpressionBoolLiteral(expression),
+            NodeExpressionBoolLiteral expression => CheckExpressionBoolLiteral(expression, expectedType),
-            NodeExpressionIdent expression => CheckExpressionIdent(expression),
+            NodeExpressionIdent expression => CheckExpressionIdent(expression, expectedType),
-            NodeExpressionIntLiteral expression => CheckExpressionIntLiteral(expression),
+            NodeExpressionIntLiteral expression => CheckExpressionIntLiteral(expression, expectedType),
-            NodeExpressionMemberAccess expression => CheckExpressionMemberAccess(expression),
+            NodeExpressionMemberAccess expression => CheckExpressionMemberAccess(expression, expectedType),
-            NodeExpressionFuncCall expression => CheckExpressionFuncCall(expression),
+            NodeExpressionFuncCall expression => CheckExpressionFuncCall(expression, expectedType),
-            NodeExpressionStringLiteral expression => CheckExpressionStringLiteral(expression),
+            NodeExpressionStringLiteral expression => CheckExpressionStringLiteral(expression, expectedType),
-            NodeExpressionStructLiteral expression => CheckExpressionStructLiteral(expression),
+            NodeExpressionStructLiteral expression => CheckExpressionStructLiteral(expression, expectedType),
-            NodeExpressionEnumLiteral expression => CheckExpressionEnumLiteral(expression),
+            NodeExpressionEnumLiteral expression => CheckExpressionEnumLiteral(expression, expectedType),
             _ => throw new ArgumentOutOfRangeException(nameof(node))
         };
     }
 
-    private TypedNodeExpressionBinary CheckExpressionBinary(NodeExpressionBinary expression)
+    private TypedNodeExpressionBinary CheckExpressionBinary(NodeExpressionBinary expression, NubType? expectedType)
     {
-        var left = CheckExpression(expression.Left);
+        // todo(nub31): Add proper inference here
-        var right = CheckExpression(expression.Right);
+        var left = CheckExpression(expression.Left, null);
+        var right = CheckExpression(expression.Right, null);
         NubType type;
 
         switch (expression.Operation)
@@ -275,9 +317,10 @@ public class TypeChecker
         };
     }
 
-    private TypedNodeExpressionUnary CheckExpressionUnary(NodeExpressionUnary expression)
+    private TypedNodeExpressionUnary CheckExpressionUnary(NodeExpressionUnary expression, NubType? expectedType)
     {
-        var target = CheckExpression(expression.Target);
+        // todo(nub31): Add proper inference here
+        var target = CheckExpression(expression.Target, null);
         NubType type;
 
         switch (expression.Operation)
@@ -315,12 +358,12 @@ public class TypeChecker
         };
     }
 
-    private TypedNodeExpressionBoolLiteral CheckExpressionBoolLiteral(NodeExpressionBoolLiteral expression)
+    private TypedNodeExpressionBoolLiteral CheckExpressionBoolLiteral(NodeExpressionBoolLiteral expression, NubType? expectedType)
     {
         return new TypedNodeExpressionBoolLiteral(expression.Tokens, NubTypeBool.Instance, expression.Value);
     }
 
-    private TypedNodeExpression CheckExpressionIdent(NodeExpressionIdent expression)
+    private TypedNodeExpression CheckExpressionIdent(NodeExpressionIdent expression, NubType? expectedType)
     {
         if (expression.Sections.Count == 1)
         {
@@ -345,14 +388,14 @@ public class TypeChecker
         throw BasicError($"Unknown identifier '{string.Join("::", expression.Sections.Select(x => x.Ident))}'", expression);
     }
 
-    private TypedNodeExpressionIntLiteral CheckExpressionIntLiteral(NodeExpressionIntLiteral expression)
+    private TypedNodeExpressionIntLiteral CheckExpressionIntLiteral(NodeExpressionIntLiteral expression, NubType? expectedType)
     {
         return new TypedNodeExpressionIntLiteral(expression.Tokens, NubTypeSInt.Get(32), expression.Value);
     }
 
-    private TypedNodeExpressionMemberAccess CheckExpressionMemberAccess(NodeExpressionMemberAccess expression)
+    private TypedNodeExpressionMemberAccess CheckExpressionMemberAccess(NodeExpressionMemberAccess expression, NubType? expectedType)
     {
-        var target = CheckExpression(expression.Target);
+        var target = CheckExpression(expression.Target, null);
 
         switch (target.Type)
         {
@@ -395,55 +438,105 @@ public class TypeChecker
         }
     }
 
-    private TypedNodeExpressionFuncCall CheckExpressionFuncCall(NodeExpressionFuncCall expression)
+    private TypedNodeExpressionFuncCall CheckExpressionFuncCall(NodeExpressionFuncCall expression, NubType? expectedType)
     {
-        var target = CheckExpression(expression.Target);
+        var target = CheckExpression(expression.Target, null);
         if (target.Type is not NubTypeFunc funcType)
-            throw BasicError($"Cannot invoke function call on type '{target.Type}'", target);
+            throw BasicError("Expected a function type", target);
 
-        var parameters = expression.Parameters.Select(CheckExpression).ToList();
+        if (funcType.Parameters.Count != expression.Parameters.Count)
+            throw BasicError($"Expected {funcType.Parameters.Count} parameters but got {expression.Parameters.Count}", expression);
+
+        var parameters = new List<TypedNodeExpression>();
+        for (int i = 0; i < expression.Parameters.Count; i++)
+        {
+            parameters.Add(CheckExpression(expression.Parameters[i], funcType.Parameters[i]));
+        }
 
         return new TypedNodeExpressionFuncCall(expression.Tokens, funcType.ReturnType, target, parameters);
     }
 
-    private TypedNodeExpressionStringLiteral CheckExpressionStringLiteral(NodeExpressionStringLiteral expression)
+    private TypedNodeExpressionStringLiteral CheckExpressionStringLiteral(NodeExpressionStringLiteral expression, NubType? expectedType)
     {
         return new TypedNodeExpressionStringLiteral(expression.Tokens, NubTypeString.Instance, expression.Value);
     }
 
-    private TypedNodeExpressionStructLiteral CheckExpressionStructLiteral(NodeExpressionStructLiteral expression)
+    private TypedNodeExpressionStructLiteral CheckExpressionStructLiteral(NodeExpressionStructLiteral expression, NubType? expectedType)
     {
-        var type = ResolveType(expression.Type);
+        if (expression.Type != null)
-        if (type is not NubTypeStruct structType)
-            throw BasicError("Type of struct literal is not a struct", expression.Type); 
-
-        if (!moduleGraph.TryResolveType(structType.Module, structType.Name, structType.Module == currentModule, out var info))
-            throw BasicError($"Type '{structType}' struct literal not found", expression.Type);
-
-        if (info is not Module.TypeInfoStruct structInfo)
-            throw BasicError($"Type '{structType}' is not a struct", expression.Type);
-
-        var initializers = new List<TypedNodeExpressionStructLiteral.Initializer>();
-        foreach (var initializer in expression.Initializers)
         {
-            var field = structInfo.Fields.FirstOrDefault(x => x.Name == initializer.Name.Ident);
+            var type = ResolveType(expression.Type);
-            if (field == null)
+            if (type is not NubTypeStruct structType)
-                throw BasicError($"Field '{initializer.Name.Ident}' does not exist on struct '{structType.Module}::{structType.Name}'", initializer.Name);
+                throw BasicError("Type of struct literal is not a struct", expression);
             
-            var value = CheckExpression(initializer.Value);
+            if (!moduleGraph.TryResolveType(structType.Module, structType.Name, structType.Module == currentModule, out var info))
-            if (!value.Type.IsAssignableTo(field.Type))
+                throw BasicError($"Type '{structType}' struct literal not found", expression);
-                throw BasicError($"Type of assignment ({value.Type}) does not match expected type of field '{field.Name}' ({field.Type})", initializer.Name);
 
-            initializers.Add(new TypedNodeExpressionStructLiteral.Initializer(initializer.Tokens, initializer.Name, value));
+            if (info is not Module.TypeInfoStruct structInfo)
+                throw BasicError($"Type '{structType}' is not a struct", expression.Type);
+
+            var initializers = new List<TypedNodeExpressionStructLiteral.Initializer>();
+            foreach (var initializer in expression.Initializers)
+            {
+                var field = structInfo.Fields.FirstOrDefault(x => x.Name == initializer.Name.Ident);
+                if (field == null)
+                    throw BasicError($"Field '{initializer.Name.Ident}' does not exist on struct '{structType.Module}::{structType.Name}'", initializer.Name);
+
+                var value = CheckExpression(initializer.Value, field.Type);
+                if (!value.Type.IsAssignableTo(field.Type))
+                    throw BasicError($"Type of assignment ({value.Type}) does not match expected type of field '{field.Name}' ({field.Type})", initializer.Name);
+
+                initializers.Add(new TypedNodeExpressionStructLiteral.Initializer(initializer.Tokens, initializer.Name, value));
+            }
+
+            return new TypedNodeExpressionStructLiteral(expression.Tokens, structType, initializers);
         }
+        else if (expectedType is NubTypeStruct structType)
+        {
+            if (!moduleGraph.TryResolveType(structType.Module, structType.Name, structType.Module == currentModule, out var info))
+                throw BasicError($"Type '{structType}' struct literal not found", expression);
 
-        return new TypedNodeExpressionStructLiteral(expression.Tokens, NubTypeStruct.Get(structType.Module, structType.Name), initializers);
+            if (info is not Module.TypeInfoStruct structInfo)
+                throw BasicError($"Type '{structType}' is not a struct", expression);
+
+            var initializers = new List<TypedNodeExpressionStructLiteral.Initializer>();
+            foreach (var initializer in expression.Initializers)
+            {
+                var field = structInfo.Fields.FirstOrDefault(x => x.Name == initializer.Name.Ident);
+                if (field == null)
+                    throw BasicError($"Field '{initializer.Name.Ident}' does not exist on struct '{structType.Module}::{structType.Name}'", initializer.Name);
+
+                var value = CheckExpression(initializer.Value, field.Type);
+                if (!value.Type.IsAssignableTo(field.Type))
+                    throw BasicError($"Type of assignment ({value.Type}) does not match expected type of field '{field.Name}' ({field.Type})", initializer.Name);
+
+                initializers.Add(new TypedNodeExpressionStructLiteral.Initializer(initializer.Tokens, initializer.Name, value));
+            }
+
+            return new TypedNodeExpressionStructLiteral(expression.Tokens, structType, initializers);
+        }
+        // todo(nub31): Infer anonymous struct types if expectedType is anonymous struct
+        else
+        {
+            var initializers = new List<TypedNodeExpressionStructLiteral.Initializer>();
+            foreach (var initializer in expression.Initializers)
+            {
+                var value = CheckExpression(initializer.Value, null);
+                initializers.Add(new TypedNodeExpressionStructLiteral.Initializer(initializer.Tokens, initializer.Name, value));
+            }
+
+            var type = NubTypeAnonymousStruct.Get(initializers.Select(x => new NubTypeAnonymousStruct.Field(x.Name.Ident, x.Value.Type)).ToList());
+
+            return new TypedNodeExpressionStructLiteral(expression.Tokens, type, initializers);
+        }
     }
 
-    private TypedNodeExpressionEnumLiteral CheckExpressionEnumLiteral(NodeExpressionEnumLiteral expression)
+    private TypedNodeExpressionEnumLiteral CheckExpressionEnumLiteral(NodeExpressionEnumLiteral expression, NubType? expectedType)
     {
-        var value = CheckExpression(expression.Value);
+        // todo(nub31): Infer type of enum variant
-        return new TypedNodeExpressionEnumLiteral(expression.Tokens, NubTypeEnumVariant.Get(NubTypeEnum.Get(expression.Module.Ident, expression.EnumName.Ident), expression.VariantName.Ident), value);
+        var type = NubTypeEnumVariant.Get(NubTypeEnum.Get(expression.Module.Ident, expression.EnumName.Ident), expression.VariantName.Ident);
+        var value = CheckExpression(expression.Value, null);
+        return new TypedNodeExpressionEnumLiteral(expression.Tokens, type, value);
     }
 
     private NubType ResolveType(NodeType node)

examples/math/math.nub

@@ -40,6 +40,12 @@ export func add(a: i32 b: i32): i32
         }
     }
 
+    let color: color = {
+        r = 23
+        g = 23
+        b = 23
+    }
+
     return add_internal(a b)
 }