A name followed by the same name with an trailing underscore results in java.lang.NumberFormatException

[sterin]

Type of issue: Bug Report

Please provide the steps to reproduce the problem:

Construct hardware with some name, then construct additional hardware with the same name followed by an underscore. For example:

package foobar

import chisel3._

class Foo extends Module {
  val bar = RegInit(false.B)
  val bar_ = RegInit(false.B)
}

object EmitFoo {
  def main(args: Array[String]): Unit = {
    (new chisel3.stage.ChiselStage).emitVerilog(new Foo)
  }
}

What is the current behavior?

Fails, throws java.lang.NumberFormatException.

[info] running foobar.EmitFoo 
[error] (run-main-0) java.lang.NumberFormatException: For input string: ""
[error] java.lang.NumberFormatException: For input string: ""
[error]         at ... ()
[error]         at ... ()
[error]         at ... (Stack trace trimmed to user code only. Rerun with --full-stacktrace to see the full stack trace)
[error] stack trace is suppressed; run last Compile / bgRunMain for the full output
[error] Nonzero exit code: 1
[error] (Compile / runMain) Nonzero exit code: 1

What is the expected behavior?

Construct the appropriate hardware.

Please tell us about your environment:

Chisel version 3.5.6 and 3.6.0-RC2. Reproducible in the official Scastie environment of 3.6.0-RC2.

Does not reproduce in Chisel 3.5.5 and 3.5.4.

Official 3.6.0-RC2 Scastie:
https://scastie.scala-lang.org/jWaVv1vsSyGSG5I7Rvw9dw

3.5.6 Scastie:
https://scastie.scala-lang.org/fuqkiNCBTkCtnRWgJlLI2Q

Other Information

What is the use case for changing the behavior?

Chisel fails with a completely opaque error message.

[azidar]

@seldridge I believe this is an MFC issue?

[sterin]

@azidar It happens with Chisel 3.5.6 as well. I've added a 3.5.6 Scastie link to the issue. It is not clear from the stack trace, but it occurs inside the compiler plugin.

[azidar]

Ah yeah, sorry totally off base. Looks like a bug from #2856