[macro] Cannot access static field "" from a class instance

Create two files:

Test.hx
```haxe
class Test {
public static macro function test() { // if you remove "macro" from the function. All works fine.
return macro null;
}
public static function main() {
var e = new Example();
e.macroFn(); // here is the compile error
}
}
```
Example.hx
```haxe
import haxe.macro.Expr;

class Example {
public function new() {}
public macro function macroFn(tthis:Expr) {
return macro {};
}
}
```

You get the error:
```
src/Test.hx:9: characters 7-14 : Cannot access static field macroFn from a class instance
```

tested with haxe 4.0.5 and latest nightly build 4.1.0-rc.1+adc9ed1b2

Edit (just for info):

The same issue also applies if you try it with @:using

Example.hx
```haxe
@:using(ExampleUsing)
class Example {
public function new() {}
}
```

ExampleUsing.hx
```haxe
import haxe.macro.Expr;

class ExampleUsing {
public static macro function macroFn(tthis:ExprOf) {
return macro {};
}
}
```