%Warning-NEWERSTD: t/t_param_default_bad.v:7:26: Parameter requires default value, or use IEEE 1800-2009 or later. 7 | module m #(parameter int Foo); | ^~~ ... For warning description see https://verilator.org/warn/NEWERSTD?v=latest ... Use "/* verilator lint_off NEWERSTD */" and lint_on around source to disable this message. %Error: t/t_param_default_bad.v:7:26: Parameter without default value is never given value (IEEE 1800-2023 6.20.1): 'Foo' : ... note: In instance 't.foo' 7 | module m #(parameter int Foo); | ^~~ %Error: Exiting due to