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 // The script and environment of a non-debuggee frame are inaccessible.

 load(libdir + 'asserts.js');

 var g = newGlobal();

 var dbg = new Debugger;

 var log;

 dbg.onDebuggerStatement = function (frame) {

   log += frame.type;

   // Initially, 'frame' is a debuggee frame, and we should be able to see its script and environment.

   assertEq(frame.script instanceof Debugger.Script, true);

   assertEq(frame.environment instanceof Debugger.Environment, true);

   // If we make g no longer a debuggee, then trying to touch the frame at

   // all show throw.

   dbg.removeDebuggee(g);

   assertThrowsInstanceOf(() => frame.script, Error);

   assertThrowsInstanceOf(() => frame.environment, Error);

 }

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

 log = '';

 dbg.addDebuggee(g);

 g.f();

 assertEq(log, 'call');

 log = '';

 dbg.addDebuggee(g);

 g.eval('debugger;');

 assertEq(log, 'eval');