When working on supporting the MVT JVM verifier, I have come across an issue with I suspect ValueType::mhName(). Dots, '.', within names are not translated to '/' for the JVM.

runner finished test: valhalla/mvt/modules/Driver.java
Failed. Execution failed: `main' threw exception: java.lang.IllegalStateException: java.lang.ClassFormatError: Illegal method name "p.internal.Point_getter$x" in class p/internal/Point_getter$x