Undriven struct members do not trigger -Wunassigned-variable

[jrudess]

Unsure if this is a bug report or a feature request. The warnings that check for reading unassigned variables has a small gap if that variable is a member of a struct, but this might be intentional.

In the following example, only member 's.a' is driven and 's.b' is undriven.

Top level design units:
    top

Build succeeded: 0 errors, 0 warnings

typedef struct {
    logic a;
    logic b;
} s_t;

module top(
    output logic x, y, z
);
    s_t s;
    always_comb s.a = 1'b1;

    always_comb begin
        if (s.b) begin
            x = 1'b1;
        end else begin
            x = 1'b0;
        end
    end

    always_comb y = s.b;

    always_comb begin
        z = s.b ? 1'b1 : 1'b0;
    end

endmodule

[MikePopoloski]

Yes, it's intentional. I can add a new warning set for struct members though.

[jrudess]

I'm assuming that a full struct initialization would count as all members having a driver (s = '0). Most code is written this way, it's just the occasional one-off module where the designer uses individual assign statements for each struct member that I've hit a few cases of missed drivers. A new warning here would be great to help push finding the issue to earlier in the process.