FULL PRODUCT VERSION :
java version "1.8.0_112"
Java(TM) SE Runtime Environment (build 1.8.0_112-b15)
Java HotSpot(TM) 64-Bit Server VM (build 25.112-b15, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Linux ______ 4.4.0-21-generic #37-Ubuntu SMP Mon Apr 18 18:33:37 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
Nashorn crashes when running valid ES6 JavaScript code. Beyond that, this is a difficult error to describe with words. For a better understanding of the problem, please see the "Steps to Reproduce" and the "Actual Result" below.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
I save the following into a file called 'bug.js':

  try { // Must be within a `try`
    let x = 0; // Must use `let` instead of `var`; our variable must be defined before some possible `throw`, and it must be given some initial value
    if (false || false) { throw {}; } // We need `false || false` so this block doesn't get optimized away, since we need some apparent possibility of a `throw`
    x = 0.0; // It seems necessary that the internal type of `x` changes; if `x` is set to `1`, it will be fine, but setting it to a string or double triggers this error
    x; // `x` must be referenced again after being set
  } catch (e) {}

  print("Everything is okay") // Just kidding; it's not, since we don't get here before the JVM explodes

Then, I run this from my terminal: jjs --language=es6 bug.js

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
That it prints out "Everything is okay"
ACTUAL -
It produces an error, whose output is listed in the section below

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" java.lang.VerifyError: Bad local variable type
Exception Details:
  Location:
    jdk/nashorn/internal/scripts/Script$bug.:program(Ljdk/nashorn/internal/runtime/ScriptFunction;Ljava/lang/Object;)Ljava/lang/Object; @67: iload
  Reason:
    Type top (current frame, locals[7]) is not assignable to integer
  Current Frame:
    bci: @67
    flags: { }
    locals: { 'jdk/nashorn/internal/runtime/ScriptFunction', 'java/lang/Object', 'jdk/nashorn/internal/runtime/ScriptObject', top, top, 'jdk/nashorn/internal/runtime/Undefined', 'jdk/nashorn/internal/scripts/JO0P0', top, top, 'jdk/nashorn/internal/scripts/JO4' }
    stack: { 'jdk/nashorn/internal/runtime/ECMAException' }
  Bytecode:
    0x0000000: 2ab6 0014 4dbb 0016 5903 b800 1a2c b700
    0x0000010: 1e3a 0619 06b8 0024 4db2 0028 3a05 0357
    0x0000020: 039a 0007 0399 0029 bb00 2a59 04b8 001a
    0x0000030: b700 2d3a 0919 0959 b800 3312 3406 1018
    0x0000040: b800 3a15 0787 3907 b200 283a 05bf 0e5c
    0x0000050: 3907 5cb8 0040 3a05 4a18 075c b800 403a
    0x0000060: 054a 29b8 0040 3a05 a700 393a 06bb 0048
    0x0000070: 5905 b800 1a2c b700 493a 0719 074d 2c19
    0x0000080: 0659 c100 3699 0009 c000 36b4 004c ba00
    0x0000090: 5800 002c b600 5b4d a700 092c b600 5b4d
    0x00000a0: bf2c ba00 6100 00b2 0028 1263 ba00 6700
    0x00000b0: 003a 0519 05b0
  Exception Handler Table:
    bci [30, 104] => handler: 107
    bci [126, 147] => handler: 155
  Stackmap Table:
    full_frame(@40,{Object[#16],Object[#110],Object[#47],Top,Top,Object[#112],Object[#22]},{})
    same_frame(@78)
    full_frame(@107,{Object[#16],Object[#110],Object[#47],Top,Top,Object[#110],Object[#22]},{Object[#70]})
    full_frame(@142,{Object[#16],Object[#110],Object[#72],Top,Top,Object[#110],Object[#70],Object[#72]},{Object[#72],Object[#110]})
    same_locals_1_stack_item_frame(@155,Object[#70])
    full_frame(@161,{Object[#16],Object[#110],Object[#47],Top,Top,Object[#110],Object[#110]},{})

at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Class.java:2583)
at java.lang.Class.getDeclaredField(Class.java:2068)
at jdk.nashorn.internal.runtime.Context$ContextCodeInstaller$1.run(Context.java:209)
at jdk.nashorn.internal.runtime.Context$ContextCodeInstaller$1.run(Context.java:204)
at java.security.AccessController.doPrivileged(Native Method)
at jdk.nashorn.internal.runtime.Context$ContextCodeInstaller.initialize(Context.java:204)
at jdk.nashorn.internal.codegen.CompilationPhase$InstallPhase.transform(CompilationPhase.java:508)
at jdk.nashorn.internal.codegen.CompilationPhase.apply(CompilationPhase.java:624)
at jdk.nashorn.internal.codegen.Compiler.compile(Compiler.java:654)
at jdk.nashorn.internal.runtime.Context.compile(Context.java:1319)
at jdk.nashorn.internal.runtime.Context.compileScript(Context.java:1253)
at jdk.nashorn.internal.runtime.Context.compileScript(Context.java:625)
at jdk.nashorn.tools.Shell.runScripts(Shell.java:316)
at jdk.nashorn.tools.Shell.run(Shell.java:171)
at jdk.nashorn.tools.Shell.main(Shell.java:135)
at jdk.nashorn.tools.Shell.main(Shell.java:111)

REPRODUCIBILITY :
This bug can be reproduced always.