d: Fix crash on literal empty list

[jackhill/mal.git] / d / step5_tco.d

diff --git a/d/step5_tco.d b/d/step5_tco.d
index 8cef6fa..cc39594 100644 (file)
--- a/d/step5_tco.d
+++ b/d/step5_tco.d
@@ -63,6 +63,10 @@ MalType EVAL(MalType ast, Env env)
         }
 
         auto aste = ast_list.elements;
+        if (aste.length == 0)
+        {
+            return ast;
+        }
         auto a0_sym = cast(MalSymbol) aste[0];
         auto sym_name = a0_sym is null ? "" : a0_sym.name;
         switch (sym_name)