diff --git a/schala-lang/language/src/lib.rs b/schala-lang/language/src/lib.rs
index 1c36b66..e5cdafc 100644
--- a/schala-lang/language/src/lib.rs
+++ b/schala-lang/language/src/lib.rs
@@ -128,9 +128,16 @@ fn symbol_table(handle: &mut Schala, input: ast::AST, comp: Option<&mut Unfinish
   }
 }
 
-fn typechecking(handle: &mut Schala, input: ast::AST, _comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
+fn typechecking(handle: &mut Schala, input: ast::AST, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
 
-  handle.type_context.typecheck(&input).map(|_| input)
+  handle.type_context.typecheck(&input).map(|ty| {
+    comp.map(|comp| {
+      let artifact = TraceArtifact::new("type", ty);
+      comp.add_artifact(artifact);
+    });
+
+    input
+  })
 }
 
 fn ast_reducing(handle: &mut Schala, input: ast::AST, comp: Option<&mut UnfinishedComputation>) -> Result<reduced_ast::ReducedAST, String> {
diff --git a/schala-lang/language/src/typechecking.rs b/schala-lang/language/src/typechecking.rs
index 68c610d..e900ea7 100644
--- a/schala-lang/language/src/typechecking.rs
+++ b/schala-lang/language/src/typechecking.rs
@@ -13,12 +13,14 @@ type TypeResult<T> = Result<T, TypeError>;
 #[derive(Debug, Clone)]
 struct TypeError { }
 
+#[derive(Debug, Clone)]
 enum MonoType {
   Var(Rc<String>),
   Const(Rc<String>),
   Arrow(Rc<String>)
 }
 
+#[derive(Debug, Clone)]
 struct PolyType {
   vars: Vec<Rc<String>>,
   ty: MonoType
@@ -29,9 +31,9 @@ impl TypeContext {
     TypeContext { }
   }
 
-  pub fn typecheck(&mut self, ast: &AST) -> Result<(), String> {
+  pub fn typecheck(&mut self, ast: &AST) -> Result<String, String> {
     match self.infer_ast(ast) {
-      Ok(_) => Ok(()),
+      Ok(t) => Ok(format!("{:?}", t)),
       Err(err) => Err(format!("Type error: {:?}", err))
     }
   }
@@ -41,7 +43,7 @@ impl TypeContext {
   fn infer_ast(&mut self, ast: &AST) -> TypeResult<MonoType> {
     let mut output = MonoType::Const(Rc::new("Unit".to_string()));
     for statement in ast.0.iter() {
-      match statement {
+      output = match statement {
         Statement::ExpressionStatement(ref expr) => self.infer_expr(expr)?,
         Statement::Declaration(ref decl) => self.infer_decl(decl)?,
       };
@@ -57,14 +59,14 @@ impl TypeContext {
   }
 
   fn infer_decl(&mut self, expr: &Declaration) -> TypeResult<MonoType> {
-    unimplemented!()
+    Ok(MonoType::Const(Rc::new("Unimplemented".to_string())))
   }
 
   fn infer_expr_type(&mut self, expr_type: &ExpressionType) -> TypeResult<MonoType> {
     use self::ExpressionType::*;
     match expr_type {
       NatLiteral(_) => Ok(MonoType::Const(Rc::new("Nat".to_string()))),
-      _ => unimplemented!()
+      _ => Ok(MonoType::Const(Rc::new("Unimplemented".to_string())))
     }
   }
 }