'scope' confusion

[Andy]

In the following code, I can pass a non-`scope` argument to a 
function expecting a `scope` parameter, but I can't pass a 
`scope` argument. That seems backwards?

```
@safe @nogc pure nothrow:

void main() {
	string[2] notScope = ["one", "two"];
	f(notScope);

	scope string[2] yesScope = ["one", "two"];
	f(yesScope);
}

void f(scope string[] expectingScope) {}
```

Output (of `dmd a.d -preview=dip1000`):

```
a.d(8): Error: cannot take address of `scope` local `yesScope` in 
`@safe` function `main`
a.d(8): Error: cannot cast expression `yesScope` of type 
`string[2]` to `string[]`
```

The error only happens in dmd 2.099.0 -- it didn't happen in 
2.098.1 .

------

There is another even simpler case that doesn't work in either 
version:

```
@safe @nogc pure nothrow:

void main() {
	scope string[2] xs = ["one", "two"];
	foreach (scope immutable string x; xs) {}
}
```

Output (of `dmd a.d -preview=dip1000`):

```
a.d(5): Error: cannot take address of `scope` local `xs` in 
`@safe` function `main`
```