feat(any): make `Grouped` trait unsafe and encapsulate `AnyOutput`

fields

Declare `Grouped` as `unsafe trait` to make its soundness invariant
visible.
Make `AnyOutput.type_id` and `member_id` private; add public accessors
and
the `unsafe fn new_bare` constructor.

1 files changed, 5 insertions, 2 deletions

diff --git a/mingling_core/src/program/collection/mock.rs b/mingling_core/src/program/collection/mock.rs
index 5847f10..dbe4789 100644
--- a/mingling_core/src/program/collection/mock.rs
+++ b/mingling_core/src/program/collection/mock.rs
@@ -23,9 +23,12 @@ pub enum MockProgramCollect {
     Bar,
 }
 
-impl Grouped<MockProgramCollect> for MockProgramCollect {
+/// SAFETY: This is a mock type used only for temporary testing.
+/// It will never actually enter the macro system.
+/// The internal `panic!` ensures that `member_id` will never be executed.
+unsafe impl Grouped<MockProgramCollect> for MockProgramCollect {
     fn member_id() -> MockProgramCollect {
-        MockProgramCollect::Foo
+        panic!("Attempting to read an unsafe enum type");
     }
 }