Canon is happy when Tamron and SIGMA are allowed to make Canon RF mount lenses.

It is another news that will make Canon camera users happy because recently it has been opened for famous independent lens manufacturers, both Tamron and SIGMA, to have the opportunity to produce lenses with Canon RF mount. In the beginning, Tamron launched a lens with an RF mount, the Tamron 1-20mm F/2.8 Di III-A RXD (Model B060), for cameras using APS-C sensors, while SIGMA opened a lens production line. There are 6 models released with RF mount: SIGMA 18-50mm f/2.8 DC DN, SIGMA 10-18mm f/2.8 DC DN, SIGMA 16mm f/1.4 DC DN, SIGMA 23mm f/1.4 DC DN, SIGMA 30mm f. /1.4 DC DN and SIGMA 56mm f/1.4 DC DN, which are also used with APS-C sensor cameras. Of course, all lenses released will be fully compatible with Canon cameras that have RF mounts.

Source:

photorumors