diff --git a/include/xo/parser/parser.hpp b/include/xo/parser/parser.hpp
index ba903311..6b474ff5 100644
--- a/include/xo/parser/parser.hpp
+++ b/include/xo/parser/parser.hpp
@@ -243,7 +243,7 @@ namespace xo {
         private:
             expraction on_def(exprstatestack * p_stack);
             expraction on_symbol(const token_type & tk, exprstatestack * p_stack);
-            expraction on_colon();
+            expraction on_colon(exprstatestack * p_stack);
             expraction on_singleassign();
             expraction on_f64(const token_type & tk);
 
diff --git a/src/parser/parser.cpp b/src/parser/parser.cpp
index 0bf2c8a6..0b1436cd 100644
--- a/src/parser/parser.cpp
+++ b/src/parser/parser.cpp
@@ -387,7 +387,7 @@ namespace xo {
         }
 
         expraction
-        exprstate::on_colon() {
+        exprstate::on_colon(exprstatestack * /*p_stack*/) {
             constexpr bool c_debug_flag = true;
             scope log(XO_DEBUG(c_debug_flag));
 
@@ -508,7 +508,7 @@ namespace xo {
                 return expraction();
 
             case tokentype::tk_colon:
-                return this->on_colon();
+                return this->on_colon(p_stack);
 
             case tokentype::tk_doublecolon:
             case tokentype::tk_semicolon: