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 // Using an environment that is not a debuggee should throw.

 load(libdir + 'asserts.js');

 var g = newGlobal();

 var dbg = new Debugger;

 let gw = dbg.addDebuggee(g);

 var log;

 function check(env) {

   assertEq(env.inspectable, false);

   assertThrowsInstanceOf(() => env.type, Error);

   assertThrowsInstanceOf(() => env.object, Error);

   assertThrowsInstanceOf(() => env.parent, Error);

   assertThrowsInstanceOf(() => env.callee, Error);

   assertThrowsInstanceOf(() => env.names(), Error);

   assertThrowsInstanceOf(() => env.find('x'), Error);

   assertThrowsInstanceOf(() => env.getVariable('x'), Error);

   assertThrowsInstanceOf(() => env.setVariable('x'), Error);

 }

 dbg.onDebuggerStatement = function (frame) {

   log += 'd';

   let env = frame.environment;

   dbg.removeDebuggee(g);

   check(env);

 }

 log = '';

 g.eval('let x = 42; debugger;');

 assertEq(log, 'd');

 dbg.addDebuggee(g);

 g.eval('function f() { }');

 let env = gw.getOwnPropertyDescriptor('f').value.environment;

 assertEq(env.type, 'object');

 dbg.removeDebuggee(g);

 check(env);