Panic when trying to set a nil Var

This wasn't caught, and would cause errors later that weren't easy to trace.

1 files changed, 3 insertions, 0 deletions

diff --git a/tx.go b/tx.go
index 45f8006..d4f343a 100644
--- a/tx.go
+++ b/tx.go
@@ -69,6 +69,9 @@ func (tx *Tx) Get(v *Var) interface{} {
 
 // Set sets the value of a Var for the lifetime of the transaction.
 func (tx *Tx) Set(v *Var, val interface{}) {
+	if v == nil {
+		panic("nil Var")
+	}
 	tx.writes[v] = val
 }