Convert range primitives to CNF like a boss

[wilzbach]

#5461, but this time hopefully without CI weirdness

[dlang-bot]

Thanks for your pull request, @wilzbach!

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

[andralex]

Love this, I need to approve my own PR :)

[quickfur]

This PR caused a regression:

// Compile with -dip25 and -dip1000
import std.range.primitives;
struct C {
    private S* impl;
}
struct S {
    bool empty;
    @property C front() return { return C(&this); }
    void popFront() { }

    static assert(isInputRange!S); // FAILS
}

The reason this fails is because the new isInputRange condition contains the lambda typeof((R r) => r.front), which is not annotated with return and therefore fails the escaping reference check in the compiler. The old check passes because it assigns the value of front to a local variable.

One might argue that the above code is bad because .front should not escape this like that, but the problem is that S is a private struct returned by a helper function that always allocates it on the heap, so the escaping reference is actually valid. Besides, since front is annotated with return, this usage ought to be allowed; it is incorrect for isInputRange to reject S just because of this.

[quickfur]

This line fails if the range being tested has a front method annotated with return.

[quickfur]

Filed an issue for this regression: https://issues.dlang.org/show_bug.cgi?id=17661