diff --git a/13/ast.hpp b/13/ast.hpp
index 1e2f8b5..162f1e0 100644
--- a/13/ast.hpp
+++ b/13/ast.hpp
@@ -8,11 +8,14 @@
 #include "instruction.hpp"
 #include "env.hpp"
 #include "definition.hpp"
+#include "location.hh"
 #include "global_scope.hpp"
 
 struct ast {
     type_env_ptr env;
+    yy::location loc;
 
+    ast(yy::location l) : env(nullptr), loc(std::move(l)) {}
     virtual ~ast() = default;
 
     virtual void print(int indent, std::ostream& to) const = 0;
@@ -48,8 +51,8 @@ using branch_ptr = std::unique_ptr<branch>;
 struct ast_int : public ast {
     int value;
 
-    explicit ast_int(int v)
-        : value(v) {}
+    explicit ast_int(int v, yy::location l = yy::location())
+        : ast(std::move(l)), value(v) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -61,8 +64,8 @@ struct ast_int : public ast {
 struct ast_lid : public ast {
     std::string id;
 
-    explicit ast_lid(std::string i)
-        : id(std::move(i)) {}
+    explicit ast_lid(std::string i, yy::location l = yy::location())
+        : ast(std::move(l)), id(std::move(i)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -74,8 +77,8 @@ struct ast_lid : public ast {
 struct ast_uid : public ast {
     std::string id;
 
-    explicit ast_uid(std::string i)
-        : id(std::move(i)) {}
+    explicit ast_uid(std::string i, yy::location l = yy::location())
+        : ast(std::move(l)), id(std::move(i)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -89,8 +92,8 @@ struct ast_binop : public ast {
     ast_ptr left;
     ast_ptr right;
 
-    ast_binop(binop o, ast_ptr l, ast_ptr r)
-        : op(o), left(std::move(l)), right(std::move(r)) {}
+    ast_binop(binop o, ast_ptr l, ast_ptr r, yy::location lc = yy::location())
+        : ast(std::move(lc)), op(o), left(std::move(l)), right(std::move(r)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -103,8 +106,8 @@ struct ast_app : public ast {
     ast_ptr left;
     ast_ptr right;
 
-    ast_app(ast_ptr l, ast_ptr r)
-        : left(std::move(l)), right(std::move(r)) {}
+    ast_app(ast_ptr l, ast_ptr r, yy::location lc = yy::location())
+        : ast(std::move(lc)), left(std::move(l)), right(std::move(r)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -118,8 +121,8 @@ struct ast_case : public ast {
     type_ptr input_type;
     std::vector<branch_ptr> branches;
 
-    ast_case(ast_ptr o, std::vector<branch_ptr> b)
-        : of(std::move(o)), branches(std::move(b)) {}
+    ast_case(ast_ptr o, std::vector<branch_ptr> b, yy::location l = yy::location())
+        : ast(std::move(l)), of(std::move(o)), branches(std::move(b)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -136,8 +139,8 @@ struct ast_let : public ast {
 
     std::vector<basic_definition> translated_definitions;
 
-    ast_let(definition_group g, ast_ptr i)
-        : definitions(std::move(g)), in(std::move(i)) {}
+    ast_let(definition_group g, ast_ptr i, yy::location l = yy::location())
+        : ast(std::move(l)), definitions(std::move(g)), in(std::move(i)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);
@@ -155,8 +158,8 @@ struct ast_lambda : public ast {
     std::set<std::string> free_variables;
     ast_ptr translated;
 
-    ast_lambda(std::vector<std::string> ps, ast_ptr b)
-        : params(std::move(ps)), body(std::move(b)) {}
+    ast_lambda(std::vector<std::string> ps, ast_ptr b, yy::location l = yy::location())
+        : ast(std::move(l)), params(std::move(ps)), body(std::move(b)) {}
 
     void print(int indent, std::ostream& to) const;
     void find_free(std::set<std::string>& into);