Field concatenation or replication?

[trailbound]

The SystemRDL spec appears to support concatenation and replication operators just as Verilog does, but I'm having trouble getting it to work in PeakRDL Regblock. Am I missing some key to making this work? I have a single bit field which I'm trying to use as a mask on a wider bit field.

reg feature_reg {
    field {
        fieldwidth = 1;
    } enable = 1'b1;
};

reg mode_reg {
    field {
        fieldwidth = 3;
    } feature_mode;
};

addrmap csr_hwmask {
    name = "Hardware Mask Test";

    default regwidth = 32;
    default sw = rw;
    default hw = r;

    feature_reg feature;
    mode_reg mode;

    mode.feature_mode->hwmask = {3{feature.enable}};
};

I also tried concatenation...

    mode.feature_mode->hwmask = {feature.enable, feature.enable, feature.enable};

Both lead to the following error.

hwmask.rdl:45:46: fatal: Concatenation operator can only be used for integral or string types
   mode.feature_mode->hwmask = {3{feature.enable}};

I've been trying to determine if there is a way I need to explicitly set the feature.enable field as an integral type, but I thought it would be integral (bit/logic) by default? If anyone has any insight, I'd be grateful!

[amykyta3]

As I understand the SystemRDL spec, using concatenation or replication operators cannot be used for references. This kind of expression is not supported.

Can you explain more what kind of structure you are attempting to infer? It is hard for me to tell from your example.
Would using the we property me more appropriate instead of hwmask? https://peakrdl-regblock.readthedocs.io/en/latest/props/field.html#we-wel