diff --git a/src/reader/expect_expr_xs.cpp b/src/reader/expect_expr_xs.cpp
index b4383f0b..f8a17836 100644
--- a/src/reader/expect_expr_xs.cpp
+++ b/src/reader/expect_expr_xs.cpp
@@ -188,7 +188,7 @@ namespace xo {
             scope log(XO_DEBUG(c_debug_flag));
 
             log && log(xtag("exstype", this->exs_type_),
-                       xtag("expr", expr));
+                       xtag("expr", expr.promote()));
 
             std::unique_ptr<exprstate> self = p_psm->pop_exprstate();
 
diff --git a/utest/reader.test.cpp b/utest/reader.test.cpp
index 2c9a490d..d73fc972 100644
--- a/utest/reader.test.cpp
+++ b/utest/reader.test.cpp
@@ -18,7 +18,8 @@ namespace xo {
                 //{"def foo : f64 = 2.0 * 3.14159265;"},
                 {"def foo = lambda (x : f64) 3.1415965;"},
                 {"def foo = lambda (x : f64, y : f64) 3.1415965;"},
-                {"def foo = lambda (x : f64) x;"}
+                {"def foo = lambda (x : f64) x;"},
+                {"def foo = lambda (x : f64) { def y = x * x; y; }"},
             };
         }