did define equality on function and map values.
Function equality was problematic in the presence of closures
(when are two closures equal?)
while map equality compared pointers, not the maps' content, which was usually
not what the user would want.
</p>

<p>
Go 1 addressed these issues.
First, structs and arrays can be compared for equality and inequality
(<code>==</code> and <code>!=</code>),
and therefore be used as map keys,
provided they are composed from elements for which equality is also defined,
us