Add missing file

helper_crates/vtable/src/compile_fail_tests.rs

@@ -0,0 +1,89 @@
+mod m1 {
+
+    /**
+    ```
+    use vtable::*;
+    #[vtable]
+    struct MyVTable {
+        foo: fn(VRef<'_, MyVTable>) -> u32,
+        create: fn(&MyVTable)->VBox<MyVTable>,
+        drop: fn(VRefMut<'_, MyVTable>),
+    }
+    struct S(u32);
+    impl My for S {
+        fn foo(&self) -> u32 { self.0 }
+        fn create() -> Self { S(55) }
+    }
+    struct R(u8);
+    impl My for R {
+        fn foo(&self) -> u32 { (self.0 + 3) as _ }
+        fn create() -> Self { R(8) }
+    }
+    MyVTable_static!(S);
+    MyVTable_static!(R);
+    let x = S::VTABLE.create();
+    ```
+    */
+    #[cfg(doctest)]
+    const _: u32 = 0;
+
+    /**
+    Test that one cannot call a function of the vtable with the wrong type
+    ```compile_fail
+    use vtable::*;
+    #[vtable]
+    struct MyVTable {
+        foo: fn(VRef<'_, MyVTable>) -> u32,
+        create: fn(&MyVTable)->VBox<MyVTable>,
+        drop: fn(VRefMut<'_, MyVTable>),
+    }
+    struct S(u32);
+    impl My for S {
+        fn foo(&self) -> u32 { self.0 }
+        fn create() -> Self { S(55) }
+    }
+    struct R(u8);
+    impl My for R {
+        fn foo(&self) -> u32 { (self.0 + 3) as _ }
+        fn create() -> Self { R(8) }
+    }
+    MyVTable_static!(S);
+    MyVTable_static!(R);
+    let x = S::VTABLE.create();
+    //unsafe     // must compile when unsafe
+    { (R_VT.foo)(x.borrow()); }
+    ```
+    */
+    #[cfg(doctest)]
+    const _: u32 = 0;
+}
+
+mod test_vrefmut {
+    /**
+    VRefMut cannot be cloned
+    ```compile_fail
+    use vtable::*;
+    #[vtable]
+    struct MyVTable { }
+    fn xx(x : VRefMut<'a, MyVTable>) {
+        let x2 = x.clone()
+    }
+    ```
+    */
+    #[cfg(doctest)]
+    const _1: u32 = 0;
+
+    /**
+    VRefMut's dereference cannot be copied
+    ```compile_fail
+    use vtable::*;
+    #[vtable]
+    struct MyVTable { }
+    fn xx(x : VRefMut<'a, MyVTable>) {
+        let x2 = *x;
+    }
+    ```
+    */
+    #[cfg(doctest)]
+    const _2: u32 = 0;
+}