i have module A with

class X

in it, and module B which depends on A, and

class Y : X()

in AS, everything looks fine, and i can click through on X in Y’s declaration to open up X. however, when i build (thourgh AS or command line), it says X cannot be found. this only happens with kotlin classes

Have you added the Kotlin plugin to module A? This happened to me and all I had to do was add the kotlin android plugin and all worked out well

Yes. Module A builds successfully on its own.

Probably adding the same plugin to Module B will help. Have you been able to build the project?