From a3349f25369ff64bc256fbd5a3a896a5c7afc3ea Mon Sep 17 00:00:00 2001
From: Nicolas Boulenguez <nicolas.boulenguez@free.fr>
Date: Wed, 9 Oct 2024 19:41:32 +0200
Subject: [PATCH] crystal: prevent defmacro! from mutating its argument

---
 impls/crystal/step8_macros.cr | 4 +++-
 impls/crystal/step9_try.cr    | 4 +++-
 impls/crystal/stepA_mal.cr    | 4 +++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/impls/crystal/step8_macros.cr b/impls/crystal/step8_macros.cr
index 464b952867..2c7ac4e755 100755
--- a/impls/crystal/step8_macros.cr
+++ b/impls/crystal/step8_macros.cr
@@ -154,7 +154,9 @@ module Mal
         eval_error "wrong number of argument for 'defmacro!'" unless list.size == 3
         a1 = list[1].unwrap
         eval_error "1st argument of 'defmacro!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
-        return Mal::Type.new env.set(a1.str, eval(list[2], env).tap { |n| n.is_macro = true })
+        mac = eval(list[2], env).dup
+        mac.is_macro = true
+        return Mal::Type.new env.set(a1.str, mac)
       else
         evaluated_first = eval(list.first, env)
         f = evaluated_first.unwrap
diff --git a/impls/crystal/step9_try.cr b/impls/crystal/step9_try.cr
index 180073a95a..984158b28f 100755
--- a/impls/crystal/step9_try.cr
+++ b/impls/crystal/step9_try.cr
@@ -154,7 +154,9 @@ module Mal
         eval_error "wrong number of argument for 'defmacro!'" unless list.size == 3
         a1 = list[1].unwrap
         eval_error "1st argument of 'defmacro!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
-        return Mal::Type.new env.set(a1.str, eval(list[2], env).tap { |n| n.is_macro = true })
+        mac = eval(list[2], env).dup
+        mac.is_macro = true
+        return Mal::Type.new env.set(a1.str, mac)
       when "try*"
         catch_list = list.size >= 3 ? list[2].unwrap : Mal::Type.new(nil)
         return eval(list[1], env) unless catch_list.is_a? Mal::List
diff --git a/impls/crystal/stepA_mal.cr b/impls/crystal/stepA_mal.cr
index dba243a052..2857c89d13 100755
--- a/impls/crystal/stepA_mal.cr
+++ b/impls/crystal/stepA_mal.cr
@@ -160,7 +160,9 @@ module Mal
         eval_error "wrong number of argument for 'defmacro!'" unless list.size == 3
         a1 = list[1].unwrap
         eval_error "1st argument of 'defmacro!' must be symbol: #{a1}" unless a1.is_a? Mal::Symbol
-        return Mal::Type.new env.set(a1.str, eval(list[2], env).tap { |n| n.is_macro = true })
+        mac = eval(list[2], env).dup
+        mac.is_macro = true
+        return Mal::Type.new env.set(a1.str, mac)
       when "try*"
         catch_list = list.size >= 3 ? list[2].unwrap : Mal::Type.new(nil)
         return eval(list[1], env) unless catch_list.is_a? Mal::List