1 files changed, 2 insertions, 1 deletions
diff --git a/src/c.bqn b/src/c.bqn
index 6cb1260b..72232152 100644
--- a/src/c.bqn
+++ b/src/c.bqn
@@ -175,7 +175,8 @@ Parse ← {r‿vn‿ind←𝕨⋄nv←≠vn
   idbc←¯1⌽⟨⥊⍉>ib,3¨ed,ex≠⊸(«-⊢)ed,14¨ed⟩
 
   ta←tr∧2(>∨|)ps(⊢-T)+`¬ro
-  fa←/(ta∨ro∨«⊸∨ps<aa)<(r=1)∨»op
+  fa←/(fe←ta∨ro∨«⊸∨ps<aa)<ff←(r=1)∨»op
+  "Second-level parts of a train must be functions"_err_(g⊸⊏) tr>fe∨ff
   dy←fa⊏«(𝕩=⊑bO)<(tr∧r≥0)∨ro<r=0
   ob←pr⊏/¯1(⊢-»)u←⍷∧pr←𝕩⊏˜pi←/𝕩<sep
   cn←pi∾lt←/𝕩≥ci←vi+nv⋄ob∾↩(ci-˜≠u)+lt⊏𝕩