rename mir::Constant -> mir::ConstOperand, mir::ConstKind -> mir::Const
Also, be more consistent with the `to/eval_bits` methods... we had some that take a type and some that take a size, and then sometimes the one that takes a type is called `bits_for_ty`.
Turns out that `ty::Const`/`mir::ConstKind` carry their type with them, so we don't need to even pass the type to those `eval_bits` functions at all.
However this is not properly consistent yet: in `ty` we have most of the methods on `ty::Const`, but in `mir` we have them on `mir::ConstKind`. And indeed those two types are the ones that correspond to each other. So `mir::ConstantKind` should actually be renamed to `mir::Const`. But what to do with `mir::Constant`? It carries around a span, that's really more like a constant operand that appears as a MIR operand... it's more suited for `syntax.rs` than `consts.rs`, but the bigger question is, which name should it get if we want to align the `mir` and `ty` types? `ConstOperand`? `ConstOp`? `Literal`? It's not a literal but it has a field called `literal` so it would at least be consistently wrong-ish...
``@oli-obk`` any ideas?
Currently we stop compilation, but some users might want to keep going.
This is needed for us to test against rustc tests. Other tools, such as
Kani, also implements parts of their logic as a backend so it is
important for compilation to continue.
Invoking StableMir::run() on a crate that has any compilation error was
crashing the entire process. Instead, return a `CompilerError` so the
user knows compilation did not succeed.
I believe ICE will also be converted to `CompilerError`.
I'm also adding a return value to the callback, because I think it will
be handy for users (at least it was for my current task of implementing
a tool to validate stable-mir). However, if people disagree,
I can remove that.
Tweaks and improvements on SMIR around generics_of and predicates_of
r? `@oli-obk`
This allows an API like the following ...
```rust
let trait_decls = stable_mir::all_trait_decls().iter().map(|trait_def| {
let trait_decl = stable_mir::trait_decl(trait_def);
let generics = trait_decl.generics_of();
let predicates = trait_decl.predicates_of().predicates;
```
I didn't like that much `trait_def.trait_decl()` which is it possible but adding a method to a def_id that loads up a whole trait definition looks backwards to me.
Add missing high-level stable_mir::generics_of fn
We forgot to add this function in https://github.com/rust-lang/rust/pull/115092, as we have done on https://github.com/rust-lang/rust/pull/115084 and other high level APIs.
At some point I think we should re-organize the structure of the code but this is what we have for now.
r? `@compiler-errors`
Would have assigned `@oli-obk` but he is still on vacations
Add stable for Constant in smir
Previously https://github.com/rust-lang/rust/pull/114587 we covered much of the groundwork needed to cover Const in smir, so there is no reason keep `Constant` as String.
r? `@spastorino`
