Separate compilation with modular JARs?

[Jesse Glick]

Unless I am missing something, I am finding it impossible to make Jigsaw's javac run sanely with modular JARs or unpacked class trees, i.e. without having to use jmod or 
multi-module layout. Basically I just want to run javac exactly like you would with JDK 7 for a project with multiple physically separated components and acyclic 
dependencies: with an explicit classpath for each component, and with module-info.java compiled to module-info.class with error checking, while enforcing module-based 
accessibility (i.e. honoring 'exports' and similar). But it does not work:

mkdir -p modone/src/pkgone modone/bin modtwo/src/pkgtwo modtwo/bin
echo 'module modone at 1 {exports pkgone;}' > modone/src/module-info.java
echo 'package pkgone; public class C1 {}' > modone/src/pkgone/C1.java
echo 'module modtwo at 1 {requires modone at 1; class pkgtwo.C2;}' > modtwo/src/module-info.java
echo 'package pkgtwo; public class C2 extends pkgone.C1 {public static void main(String... args) {System.out.println(new C2());}}' > modtwo/src/pkgtwo/C2.java
javac -d modone/bin modone/src/module-info.java modone/src/pkgone/C1.java
javac -classpath modone/bin -d modtwo/bin modtwo/src/module-info.java modtwo/src/pkgtwo/C2.java

fails with:

error: Cannot resolve module dependencies using Jigsaw module resolver
   modtwo@=1: Cannot resolve
1 error

with no further explanation. Same if I use -modulepath instead of -classpath. Even more worrisome, if I remove the 'requires' clause then compilation succeeds, whereas I 
would expect classes from modone to be considered inaccessible in this case.

Also if I try to run the result:

java -modulepath modone/bin:modtwo/bin -m two

I get another error:

Error: -classpath and -cp cannot be used with -m

and -modulepath is not recognized by this command at all.

Is it planned for javac and java to work nicely with unpacked modules but just not yet implemented?