diff --git a/schala-lang/src/lib.rs b/schala-lang/src/lib.rs
index 0c580fb..e0ad609 100644
--- a/schala-lang/src/lib.rs
+++ b/schala-lang/src/lib.rs
@@ -36,7 +36,7 @@ mod eval;
 pub struct Schala {
   state: eval::State<'static>,
   symbol_table: Rc<RefCell<symbol_table::SymbolTable>>,
-  type_context: typechecking::TypeContext,
+  type_context: typechecking::TypeContext<'static>,
 }
 
 impl Schala {
diff --git a/schala-lang/src/typechecking.rs b/schala-lang/src/typechecking.rs
index bdf89b1..d6c175c 100644
--- a/schala-lang/src/typechecking.rs
+++ b/schala-lang/src/typechecking.rs
@@ -9,6 +9,7 @@ use itertools::Itertools;
 */
 
 use parsing;
+use util::StateStack;
 
 pub type TypeName = Rc<String>;
 type TypeResult<T> = Result<T, String>;
@@ -28,11 +29,13 @@ enum TConst {
   Custom(String)
 }
 
-pub struct TypeContext;
+pub struct TypeContext<'a> {
+  values: StateStack<'a, TypeName, Type>
+}
 
-impl TypeContext {
-  pub fn new() -> TypeContext {
-    TypeContext { }
+impl<'a> TypeContext<'a> {
+  pub fn new() -> TypeContext<'static> {
+    TypeContext { values: StateStack::new(None) }
   }
 
   pub fn debug_types(&self) -> String {
@@ -45,7 +48,7 @@ impl TypeContext {
   }
 }
 
-impl TypeContext {
+impl<'a> TypeContext<'a> {
   fn infer_block(&mut self, block: &Vec<parsing::Statement>) -> TypeResult<Type> {
     let mut output = Type::Const(TConst::Unit);
     for statement in block {
@@ -60,6 +63,13 @@ impl TypeContext {
     }
   }
   fn infer_decl(&mut self, decl: &parsing::Declaration) -> TypeResult<Type> {
+    use parsing::Declaration::*;
+    match decl {
+      Binding { name, expr, .. } => {
+
+      },
+      _ => (),
+    }
     Ok(Type::Const(TConst::Unit))
   }
   fn infer_expr(&mut self, expr: &parsing::Expression) -> TypeResult<Type> {
@@ -79,6 +89,10 @@ impl TypeContext {
     Ok(match expr {
       NatLiteral(_) => Type::Const(Nat),
       StringLiteral(_) => Type::Const(StringT),
+      Call { f, arguments } =>  {
+
+        return Err(format!("NOTDONE"))
+      },
       _ => Type::Const(Unit)
     })
   }
diff --git a/schala-lang/src/util.rs b/schala-lang/src/util.rs
index 33217f3..0e8cadf 100644
--- a/schala-lang/src/util.rs
+++ b/schala-lang/src/util.rs
@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use std::hash::Hash;
 use std::cmp::Eq;
 
+//TODO rename this ScopeStack
 #[derive(Default, Debug)]
 pub struct StateStack<'a, T: 'a, V: 'a>  where T: Hash + Eq {
   parent: Option<&'a StateStack<'a, T, V>>,
@@ -27,6 +28,7 @@ impl<'a, T, V> StateStack<'a, T, V> where T: Hash + Eq {
       (Some(value), _) => Some(value),
     }
   }
+  //TODO rename new_scope
   pub fn new_frame(&'a self, name: Option<String>) -> StateStack<'a, T, V> where T: Hash + Eq {
     StateStack {
       parent: Some(self),