Could not compile plugin for Linux

If Linux not in my Blacklist platform, I have many errors like this:

non-constant-expression cannot be
narrowed from type ‘unsigned long’ to
‘int32’ (aka ‘int’) in initializer
list [-Wc++11-narrowing]

inside Unreal gen files.
The generated code relative to my int32 variable, initialized like this.

int32 var = 1;

Clang version is 10.0.1
How to fix this?