I'd like to make it easier to initialize function local immutable/const data. Here's the type of problem I'd like to alleviate:

const string[100] int__str;
const int[string] str__int;

for (int i = 0; i < 100; ++i)
{
    auto str = to!string(i);
    int__str[i] = str; // ERROR: Can't modify const
    str__int[str] = i; // ERROR: Can't modify const
}

In short, I want to initialize two different const variables at once (in the same loop or other block). If I needed to initialize only one const variable, I could use a lambda:

const string[100] int__str = {
    string[100] tmp;
    // ... init tmp ...
    return tmp;
}();

...But I can't see any easy solution for initializing two or more const variables at the same time.

Here's my proposal: "initialization scope". You'd use it like this:

initialization {
    const string[100] int__str;
    const int[string] str__int;

    for (int i = 0; i < 100; ++i)
    {
        auto str = to!string(i);
        int__str[i] = str; // OK
        str__int[str] = i; // OK
    }
}

string s = int__str[42]; // OK
int__str[42] = "43" // ERROR: Can't modify const

As you can see, 'initialization scope' would be a scope that is not a lexical scope (like static if), it merely makes all const and immutable variables created in that scope modifiable inside that scope but not after it.