From 7ba59d6508123af9002a6e6b004bbe90e321f970 Mon Sep 17 00:00:00 2001
From: kalmar <kalmar@amu.edu.pl>
Date: Mon, 5 Jun 2017 21:36:31 +0200
Subject: [PATCH] safer coercion of GroupRingElem to GroupRing

---
 src/GroupRings.jl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/GroupRings.jl b/src/GroupRings.jl
index cc2faab..31bbff1 100644
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@@ -131,7 +131,10 @@ function (RG::GroupRing)(x::AbstractVector)
    return result
 end
 
-(RG::GroupRing)(X::GroupRingElem) = RG(X.coeffs)
+function (RG::GroupRing)(X::GroupRingElem)
+   RG == parent(X) || throw("Can not coerce!")
+   return RG(X.coeffs)
+end
 
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