diff --git a/new_ast.cpp b/new_ast.cpp
index 34314eb..5ba7281 100644
--- a/new_ast.cpp
+++ b/new_ast.cpp
@@ -325,7 +325,8 @@ ast_float(Token *pos, F64 value){
 }
 
 function Ast_Atom *
-ast_int(Token *pos, S64 integer){
+ast_int(Token *pos, U64 integer){
+  assert(integer <= S64MAX);
   AST_NEW(Atom, VALUE, pos, AST_EXPR | AST_ATOM);
   result->type = untyped_int;
   result->int_val = integer;
diff --git a/new_types.kl b/new_types.kl
index 7cde920..08dda11 100644
--- a/new_types.kl
+++ b/new_types.kl
@@ -1,13 +1,13 @@
 
 unary_test :: ()
-  int_val :: 1251525
-  uns: U64 = -int_val
+  int_val :: 125152553512512512512 // @todo
   float_val :: 124.42
   conversion: F64 = -+int_val
   float2 := -float_val
   unsigned: Int = -+-+-int_val
 
 
+  // uns: U64 = -int_val
   // int_float: S64 = float_val
   // string :: -"Thing"
   // boolean :: -true
diff --git a/typecheck.cpp b/typecheck.cpp
index 6f17265..6fd70d7 100644
--- a/typecheck.cpp
+++ b/typecheck.cpp
@@ -15,6 +15,7 @@ convert_untyped(Token *pos, Value a, Ast_Resolved_Type *new_type){
   assert(is_untyped(a.type));
   assert(new_type);
 
+  assert(a.int_val <= S64MAX);
   if(is_int(a.type) && is_int(new_type)){
     assert(a.type == untyped_int);
     switch(new_type->kind){
@@ -57,6 +58,7 @@ convert_untyped(Token *pos, Value a, Ast_Resolved_Type *new_type){
 
 function S64
 value_get_int(Value value){
+  assert(value.int_val <= S64MAX);
   assert(is_float(value.type) || is_int(value.type));
   S64 result = 0;
   switch(value.type->kind){
@@ -579,7 +581,6 @@ resolve_expr(Ast_Expr *ast, Ast_Resolved_Type *expected_type, Sym *lambda_to_res
             Value value = eval_unary(node->pos, node->op, op.value);
             rewrite_into_const(node, Ast_Unary, value);
             return operand_const_rvalue(value);
-
           }
           return operand_rvalue(op.type);
         }break;