A liner of a combustor wall assembly generally defines a combustion chamber and includes a film cooling circuit having a channel communicating through a hot face of a substrate of the liner. An aperture of the circuit is defined by the substrate, extends through the cold face and is in fluid communication with the channel. The hot face of the substrate is covered with a coating that extends over and thus defines in-part the channel. A film cooling hole extends through the coating and is in fluid communication with the channel. A method of manufacturing the circuit includes casting the substrate with the aperture and hole; then placing an insert into the channel prior to application of the coating over the substrate and insert. The insert is then removed and the film cooling hole is formed through the coating.