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 // frame.eval throws if frame is a generator frame that isn't currently on the stack

 load(libdir + "asserts.js");

 var g = newGlobal();

 g.eval("function gen(a) { debugger; yield a; }");

 g.eval("function test() { debugger; }");

 var dbg = new Debugger(g);

 var genframe;

 var hits = 0;

 dbg.onDebuggerStatement = function (frame) {

     if (frame.callee.name == 'gen')

         genframe = frame;

     else

         assertThrowsInstanceOf(function () { genframe.eval("a"); }, Error);

     hits++;

 };

 g.eval("var it = gen(42); assertEq(it.next(), 42); test();");

 assertEq(hits, 2);