From 0ff4365945540b6654901f9e727918531b184340 Mon Sep 17 00:00:00 2001
From: Markus Hauru <markus@mhauru.org>
Date: Wed, 22 Jan 2020 14:22:03 +0100
Subject: [PATCH] A more helpful error message when splatting into @ncon.

---
 src/indexnotation/tensormacros.jl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/indexnotation/tensormacros.jl b/src/indexnotation/tensormacros.jl
index fc3602aa..4595eeb0 100644
--- a/src/indexnotation/tensormacros.jl
+++ b/src/indexnotation/tensormacros.jl
@@ -184,6 +184,9 @@ function _nconmacro(tensors, indices, kwargs = nothing)
     else
         throw(ArgumentError("invalid @ncon syntax"))
     end
+    if any(isa(ta, Expr) && ta.head === :... for ta in tensorargs)
+        throw(ArgumentError("@ncon does not support splats (...) in tensor lists."))
+    end
     conjlist = fill(false, length(tensorargs))
     for i = 1:length(tensorargs)
         if tensorargs[i] isa Expr