diff --git a/include/xo/reader/exprstate.hpp b/include/xo/reader/exprstate.hpp
index bf93a3f5..3c5e2e6a 100644
--- a/include/xo/reader/exprstate.hpp
+++ b/include/xo/reader/exprstate.hpp
@@ -97,22 +97,26 @@ namespace xo {
             virtual void on_expr(ref::brw<Expression> expr,
                                  exprstatestack * p_stack,
                                  rp<Expression> * p_emit_expr);
+
             /** update exprstate when expecting a symbol **/
             virtual void on_symbol(const std::string & symbol,
                                    exprstatestack * p_stack,
                                    rp<Expression> * p_emit_expr);
+
             /** update exprstate when expeccting a typedescr **/
             virtual void on_typedescr(TypeDescr td,
                                       exprstatestack * p_stack,
                                       rp<Expression> * p_emit_expr);
+
             /** update exprstate when expecting a formal parameter **/
             virtual void on_formal(const rp<Variable> & formal,
                                    exprstatestack * p_stack,
                                    rp<Expression> * p_emit_expr);
+
             /** update expression when epecting a formal parameter list **/
             virtual void on_formal_arglist(const std::vector<rp<Variable>> & argl,
-                                           exprstatestack * p_stack,
-                                           rp<Expression> * p_emit_expr);
+                                           parserstatemachine * p_psm);
+
             /** print human-readable representation on @p os **/
             virtual void print(std::ostream & os) const;
 
diff --git a/include/xo/reader/lambda_xs.hpp b/include/xo/reader/lambda_xs.hpp
index 59f9f78a..b60f14a6 100644
--- a/include/xo/reader/lambda_xs.hpp
+++ b/include/xo/reader/lambda_xs.hpp
@@ -45,8 +45,7 @@ namespace xo {
             virtual void on_lambda_token(const token_type & tk,
                                          parserstatemachine * p_psm) override;
             virtual void on_formal_arglist(const std::vector<rp<Variable>> & argl,
-                                           exprstatestack * p_stack,
-                                           rp<Expression> * p_emit_expr) override;
+                                           parserstatemachine * p_psm) override;
             virtual void on_expr(ref::brw<Expression> expr,
                                  exprstatestack * p_stack,
                                  rp<Expression> * p_emit_expr) override;
diff --git a/src/reader/expect_formal_arglist_xs.cpp b/src/reader/expect_formal_arglist_xs.cpp
index 6bb9b099..dc400aeb 100644
--- a/src/reader/expect_formal_arglist_xs.cpp
+++ b/src/reader/expect_formal_arglist_xs.cpp
@@ -94,13 +94,11 @@ namespace xo {
                                                       parserstatemachine * p_psm)
         {
             auto p_stack = p_psm->p_stack_;
-            auto p_emit_expr = p_psm->p_emit_expr_;
 
             if (farglxs_type_ == formalarglstatetype::argl_1b) {
                 std::unique_ptr<exprstate> self = p_stack->pop_exprstate();
 
-                p_stack->top_exprstate().on_formal_arglist(this->argl_,
-                                                           p_stack, p_emit_expr);
+                p_stack->top_exprstate().on_formal_arglist(this->argl_, p_psm);
             } else {
                 exprstate::on_rightparen_token(tk, p_psm);
             }
diff --git a/src/reader/exprstate.cpp b/src/reader/exprstate.cpp
index ba58eb79..c9d14c82 100644
--- a/src/reader/exprstate.cpp
+++ b/src/reader/exprstate.cpp
@@ -125,14 +125,15 @@ namespace xo {
 
         void
         exprstate::on_formal_arglist(const std::vector<rp<Variable>> & argl,
-                                     exprstatestack * p_stack,
-                                     rp<Expression> * /*p_emit_expr*/)
+                                     parserstatemachine * p_psm)
         {
             /* returning type description to something that wants it */
 
             constexpr bool c_debug_flag = true;
             scope log(XO_DEBUG(c_debug_flag));
 
+            auto p_stack = p_psm->p_stack_;
+
             log && log(xtag("exstype",
                             p_stack->top_exprstate().exs_type()));
 
diff --git a/src/reader/lambda_xs.cpp b/src/reader/lambda_xs.cpp
index 8824ab26..7aaf657d 100644
--- a/src/reader/lambda_xs.cpp
+++ b/src/reader/lambda_xs.cpp
@@ -44,15 +44,16 @@ namespace xo {
 
         void
         lambda_xs::on_formal_arglist(const std::vector<rp<Variable>> & argl,
-                                     exprstatestack * p_stack,
-                                     rp<Expression> * p_emit_expr)
+                                     parserstatemachine * p_psm)
         {
+            auto p_stack = p_psm->p_stack_;
+
             if (lmxs_type_ == lambdastatetype::lm_1) {
                 this->lmxs_type_ = lambdastatetype::lm_2;
                 this->argl_ = argl;
                 expect_expr_xs::start(p_stack);
             } else {
-                exprstate::on_formal_arglist(argl, p_stack, p_emit_expr);
+                exprstate::on_formal_arglist(argl, p_psm);
             }
         }