While debugging a V8 issue I just realised another incompatibility
with introducing lexical function declarations in sloppy mode that I
think we haven't observed yet. Consider the following code:
function f() {
var x = 0
try {
throw 1
} catch (x) {
eval("function g() { return x }")
}
return g()
}
This function is legal, and supposed to return 1 according to my
reading of the ES5 spec. But lexically scoped function declarations
should make it throw a ReferenceError instead.
Unlike the other legacy issues with sloppy-mode lexical function
scoping that we have discussed before this one is actually covered by
the current spec. Is such a breaking change an issue? V8 currently
crashes on the above code, so this particular example probably is not
a real-world problem. 8) However, there are simpler examples, e.g.:
function f() {
if (true) { eval("function g() { return 1 }") }
return g()
}
Do we know if this is something that occurs in practice?
/Andreas
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