var foo = {name: "foo"};
foo.name;
var foo;
foo.name;
eval("var foo;");
foo.name;

When you run the forementioned code, the first two foo.name statements execute fine just as expected; even after foo has been initialized in the first line, the second "var foo" statement doesn't unset the variable.

However, the third foo.name statement causes an exception:
Uncaught exception - TypeError: cannot convert undefined to object

When you inspect the variable foo after the eval() statement, you find out that it has been unset (set to undefined), which in my view is incorrect behaviour. All variable declarations and assignments inside eval() should behave as if they were executed in the outside of eval(). Or does ECMA-262 specify otherwise? Seems unlikely.

This bug is present in 1.6.0 and master branch, and thus likely in all versions.