Modelsim 10.5b, from Intel (Altera) Quartus 17.1

** Error (suppressible): (vsim-3009) TSCALE - Module 'MAC_tx_addr_add' does not have a timeunit/timeprecision specification in effect, but other modules do.

Time: 0 ps Iteration: 0 Instance: /tb_top/U_MAC_top/U_MAC_tx/U_MAC_tx_addr_add File: ../../../../rtl/verilog/MAC_tx/MAC_tx_addr_add.v

Adding to MAC_tx_addr_add.v the line

`timescale 1 ns / 1 ns

solved this error.