Number string concatenation uses arithmetic operations instead of string concatenation

[kosukeymzk]

Hello, thanks for this useful software !

I found an incident that seems to be a problem with string concatenation.

Version: 3.1.1.RELEASE

Environment:
OpenJDK 17.0.2
Spring 5.3.23

Source:

<p th:text="${'1' + '2'}"><p>

my expectations

12

actual output

3

Since we are dealing with numbers as strings, we think that string concatenation will be performed in operations using +.
Please point out if there are any mistakes.