From 0a5a0867e43d1790ac9a7f1d8668f35e07f5e224 Mon Sep 17 00:00:00 2001
From: JimMoen <LnJimMoen@outlook.com>
Date: Thu, 29 Sep 2022 14:05:40 +0800
Subject: [PATCH] fix(rule_func): refine `+` error info when type implicit
 conversion

---
 apps/emqx_rule_engine/src/emqx_rule_funcs.erl | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/apps/emqx_rule_engine/src/emqx_rule_funcs.erl b/apps/emqx_rule_engine/src/emqx_rule_funcs.erl
index 18e61967e..a4791a94d 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_funcs.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_funcs.erl
@@ -338,7 +338,13 @@ null() ->
 
 %% concat 2 strings
 '+'(X, Y) when is_binary(X), is_binary(Y) ->
-    concat(X, Y).
+    concat(X, Y);
+
+%% unsupported type implicit conversion
+'+'(X, Y)
+  when (is_number(X) andalso is_binary(Y)) orelse
+       (is_binary(X) andalso is_number(Y)) ->
+    error(unsupported_type_implicit_conversion).
 
 '-'(X, Y) when is_number(X), is_number(Y) ->
     X - Y.