Segmentation fault on AlwaysFFAssignmentOutsideConditional slang-tidy checker

[rubenbuchatskiy]

Describe the bug
When running slang-tidy on example below, it crashes.

To Reproduce
Consider the following code:

module test(output reg out);
    always_ff @ (*) begin
        convert(out);
    end

    task convert;
        output out1;
    endtask
endmodule

Segmentation fault occurs on AlwaysFFAssignmentOutsideConditional slang-tidy checker, I guess because out expression's syntax is null when trying to get location.