Variable Declaration Inside Eval Inside With

consider the next code:

var obj = {};
with(obj) {
var x = 10;
}
print(x);
print(obj.x);

It prints 10 and undefined. Here, one could expect that obj.x get the
value 10. But it's not the case, because variable declarations are
placed at the start of function code (or global code), so the
previous code is equivalent with:

var obj;
var x;
obj = {};
with(obj) {
x = 10;
}
print(x);
print(obj.x);

You can clearly see now that x is placed in the outer context. But
consider the next:

var obj = {};
with(obj) {
eval("var x = 10;");
}
print(x);
print(obj.x);

I was expecting that obj.x would get the value 10 here. But no, it
gives the same output as the previous code. I tested it with
spidermonkey, kjs and ie jscript. Looking at the ECMA spec, I could
not find anything that describes that behaviour. Code: