Compiling code with Enums in without doing a clean compile causes runtime VerifyError

[j-mie6]

When compiling code with Enums, unless a clean compile is done, then at runtime when an Enum is encountered (for example, here I have an enum Operator ...) an error like the following is triggered:

[error] (run-main-b) java.lang.VerifyError: Bad type on operand stack
[error] Exception Details:
[error]   Location:
[error]     compiler/Parser.createTable()Lscala/collection/immutable/List; @10: invokevirtual
[error]   Reason:
[error]     Type 'compiler/expr/Operator$' (current frame, stack[3]) is not assignable to 'compiler/expr/Operator'
[error]   Current Frame:
[error]     bci: @10
[error]     flags: { }
[error]     locals: { 'compiler/ChimeraParser' }
[error]     stack: { uninitialized 0, uninitialized 0, 'scala/Predef$', 'compiler/expr/Operator$' }
[error]   Bytecode:
[error]     0000000: bb00 4a59 b200 b3b2 02bf b602 c3b6 02c7
[error]     0000010: b702 cab9 02cf 0100 b202 d2b9 02d8 0200
[error]     0000020: c002 da2a ba02 e300 00b2 02e8 b602 ecb6
[error]     0000030: 02ef c002 dab0

This is running 0.16.0-RC3 cross compiling with a 2.12.8 library.

[smarter]

Can you provide a minimal project that reproduces the problem ?

[j-mie6]

Here you go!

minimal-bug2.zip

This is a fun one! Two files are necessary, no cross-compilation necessary. valueOf is at fault! Run the following commands:

bash> sbt
sbt> ;clean;compile
sbt> runMain foo.Detonator

This should run fine and produce "ok!". Now edit Detonator.scala by adding whitespace or something. Run the following:

sbt> compile
sbt> runMain foo.Detonator

And boom!

info] Running foo.Detonator 
[error] (run-main-1) java.lang.VerifyError: Bad type on operand stack
[error] Exception Details:
[error]   Location:
[error]     foo/Detonator$.boom()V @5: invokevirtual
[error]   Reason:
[error]     Type 'foo/Bomb$' (current frame, stack[0]) is not assignable to 'foo/Bomb'
[error]   Current Frame:
[error]     bci: @5
[error]     flags: { }
[error]     locals: { 'foo/Detonator$' }
[error]     stack: { 'foo/Bomb$', 'java/lang/String' }
[error]   Bytecode:
[error]     0000000: b200 1f12 21b6 0027 57b1               
[error] java.lang.VerifyError: Bad type on operand stack
[error] Exception Details:
[error]   Location:
[error]     foo/Detonator$.boom()V @5: invokevirtual
[error]   Reason:
[error]     Type 'foo/Bomb$' (current frame, stack[0]) is not assignable to 'foo/Bomb'
[error]   Current Frame:
[error]     bci: @5
[error]     flags: { }
[error]     locals: { 'foo/Detonator$' }
[error]     stack: { 'foo/Bomb$', 'java/lang/String' }
[error]   Bytecode:
[error]     0000000: b200 1f12 21b6 0027 57b1               
[error] 
[error]         at foo.Detonator.main(Detonator.scala)
[error]         at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[error]         at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[error]         at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[error]         at java.base/java.lang.reflect.Method.invoke(Method.java:566)

[bishabosha]

Ok so I found that under incremental compilation, Detonator.boom is rewritten as shown by this diff:

@@ -114,10 +114,10 @@ public final class foo.Detonator$ implements scala.Serializable
  public void boom();
      descriptor: ()V
      flags: ACC_PUBLIC
      Code:
        stack=2, locals=1, args_size=1
           0: getstatic     #31                 // Field foo/Bomb$.MODULE$:Lfoo/Bomb$;
           3: ldc           #33                 // String Kaboom
-          5: invokevirtual #39                 // Method foo/Bomb$.valueOf:(Ljava/lang/String;)Lfoo/Bomb;
+          5: invokevirtual #39                 // Method foo/Bomb.valueOf:(Ljava/lang/String;)Lfoo/Bomb;
           8: pop
           9: return

The rewritten code tries to invokevirtual the static method foo/Bomb.valueOf, instead of the virtual method foo/Bomb$.valueOf, and the types of the arguments no longer match

[ekrich]

Any progress on this issue? This should fix my issue with serialization and allow all my tests to pass.
Reference as above: ekrich/sconfig#55