From 3be404af0488805493a46329d35ad276d739151d Mon Sep 17 00:00:00 2001
From: n5m <72841454+n5m@users.noreply.github.com>
Date: Mon, 9 Nov 2020 10:45:43 +0000
Subject: [PATCH] include example of error-marked copy proc (#15886)

* include example of error-marked copy proc

* Update destructors.rst
---
 doc/destructors.rst | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/doc/destructors.rst b/doc/destructors.rst
index 66f1043b36..e48e360dd5 100644
--- a/doc/destructors.rst
+++ b/doc/destructors.rst
@@ -184,8 +184,14 @@ The general pattern in ``=copy`` looks like:
 
 
 The ``=copy`` proc can be marked with the ``{.error.}`` pragma. Then any assignment
-that otherwise would lead to a copy is prevented at compile-time.
+that otherwise would lead to a copy is prevented at compile-time. This looks like:
 
+.. code-block:: nim
+
+  proc `=copy`(dest: var T; source: T) {.error.}
+
+but a custom error message (e.g., ``{.error: "custom error".}``) will not be emitted
+by the compiler. Notice that there is no ``=`` before the ``{.error.}`` pragma.
 
 Move semantics
 ==============