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This PR (HEAD: 42a93a2) has been imported to Gerrit for code review.

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Message from Gerrit User 7435:

Patch Set 2:

I don't think this is correct. The language specification only allows comparing functions with nil, so reflect.DeepEqual should not do more than that.

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then we need change the language specification, how it can be logically sound that you can do f1 := func() {}; fn2 := f1 but not f2 == f1

The language spec already covers this:

Slice, map, and function values are not comparable. However, as a special case, a slice, map, or function value may be compared to the predeclared identifier nil.

So this code won't even compile:

var a func()
var b func()
var c = a == b

deepEqual is in kind of a tough spot here, because it's being asked to do something - compare two values of function type - when the language spec declares such comparisons to be illegal. Not just having an undefined result, but it's a question you're not allowed to ask. deepEqual chose false as the answer. Another possible answer is to panic, but that has its own issues.

What would you have deepEqual do instead? Comparing the function address isn't enough - some functions might be closures. And due to the way shared library linking is done, identical references to the same function in different packages might have different function addresses (one would be the address of a trampoline that jumps to the other).

ok, it's way more complicated. close this now.