add fn type_name_of_val
This function is often useful during testing and mirrors `align_of_val` and `size_of_val`.
# Example
Showing the default type of integers.
```rust
let x = 7;
println!("per default, integers have the type: {}", std::any::type_name_of_val(&x));
```
To my knowledge this can currently not be done without defining a function similar to `type_name_of_val`.
I noticed that in documentation to `Any` trait the old trait object syntax is used, which could be confusing for newcomers, since we generally recommend using `dyn Trait` instead of just `Trait`. This PR changes the documentation comment, so that it uses `&dyn Any`, `&mut dyn Any` and `Box<dyn Any>`, correspondingly.
This changes the docs referring to where a user should be wary of depending on "Any" trait impls from warning about relying on them "outside" of their code to warning about relying on them "inside" of their code.
Add PartialOrd, Ord derivations to TypeId
I want to be able to sort a `Vec` of types which contain `TypeId`s, so an `Ord` derivation would be very useful to me. `Hash` and `PartialEq`/`Eq` already exist, so the missing `PartialOrd` and `Ord` derivations feel like an oversight to me.
I want to be able to sort a `Vec` of types which contain `TypeId`s, so an `Ord` derivation would be very useful to me. `Hash` already exists, so the missing `PartialOrd` and `Ord` derivations feel like an oversight to me.
A few categories:
* Links into compiler docs were just all removed as we're not generating
compiler docs.
* Move up one more level to forcibly go to std docs to fix inlined documentation
across the facade crates.
This is a bit weird since unsized types can't be used in trait objects,
but Any is *also* used as pure marker trait since Reflect isn't stable.
There are many cases (e.g. TypeMap) where all you need is a TypeId.
