Bad lint raised "Use 'const' with the constructor to improve performance"

[sbatezat]

I'v just upgraded flutter to 3.10.6 & flutter_lints to 3.0.1
I've got a lint issue on my Widget "Use 'const' with the constructor to improve performance".
But it's not a const! If I accept to change it to a const, lint issue disappear but I'm unable to build the application :

Error: Not a constant expression.
my_file.dart:154
borderRadius: BorderRadius.all(_cardBorderRadius),

The code where there is an issue :

class MyWidget extends StatelessWidget {
  // A final global variable... yes, it's not a const it's final...
  final _cardBorderRadius = const Radius.circular(12);
  
  BorderRadius _buildBorderRadius() {
    // Here is the lint issue: lint should not ask for a const keyword before the border radius declaration
    return BorderRadius.all(_cardBorderRadius);
  }
}