From 1f30c682a8486dde594bef6dc05af9ab97f78fa6 Mon Sep 17 00:00:00 2001
From: "Wenzel P. P. Peppmeyer" <wenzel.peppmeyer@gmx.de>
Date: Thu, 29 Sep 2016 01:26:18 +0200
Subject: [PATCH] clarify what arguments are defined in what where-clause

---
 doc/Type/Signature.pod6 | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/doc/Type/Signature.pod6 b/doc/Type/Signature.pod6
index 7b1ffa0c7..f383f2e19 100644
--- a/doc/Type/Signature.pod6
+++ b/doc/Type/Signature.pod6
@@ -138,6 +138,17 @@ The first of those can be shortened to
 i.e., you can use a literal directly as a type and value constraint
 on an anonymous parameter.
 
+Any argument in a C<Signature> is declared in a C<where>-clause that is
+following that argument. Therefor, the C<where>-clause of the last argument got
+access to all arguments of a signature that are not part of a sub-signature.
+For sub-signature place the C<where>-clause inside the sub-signature.
+
+    sub one-of-them(:$a, :$b, :$c where { $a.defined ^^ $b.defined ^^ $c.defined } ) {
+        $a // $b // $c
+    };
+    say one-of-them(c=>42);
+    # OUTPUT«42␤»
+
 =head3 Constraining Slurpy Arguments
 
 L<Slurpy arguments|Slurpy_(A.K.A._Variadic)_Parameters> can not have type