stop having identity casts be lexprs
that made no sense (see test), and was incompatible with borrowck.
Fixes#36936.
beta-nominated since (bad) regression.
r? @eddyb
Refactor away RBML from rustc_metadata.
RBML and `ty{en,de}code` have had their long-overdue purge. Summary of changes:
* Metadata is now a tree encoded in post-order and with relative backward references pointing to children nodes. With auto-deriving and type safety, this makes maintenance and adding new information to metadata painless and bug-free by default. It's also more compact and cache-friendly (cache misses should be proportional to the depth of the node being accessed, not the number of siblings as in EBML/RBML).
* Metadata sizes have been reduced, for `libcore` it went down 16% (`8.38MB` -> `7.05MB`) and for `libstd` 14% (`3.53MB` -> `3.03MB`), while encoding more or less the same information
* Specialization is used in the bundled `libserialize` (crates.io `rustc_serialize` remains unaffected) to customize the encoding (and more importantly, decoding) of various types, most notably those interned in the `TyCtxt`. Some of this abuses a soundness hole pending a fix (cc @aturon), but when that fix arrives, we'll move to macros 1.1 `#[derive]` and custom `TyCtxt`-aware serialization traits.
* Enumerating children of modules from other crates is now orthogonal to describing those items via `Def` - this is a step towards bridging crate-local HIR and cross-crate metadata
* `CrateNum` has been moved to `rustc` and both it and `NodeId` are now newtypes instead of `u32` aliases, for specializing their decoding. This is `[syntax-breaking]` (cc @Manishearth ).
cc @rust-lang/compiler
Replace `_, _` with `..` in patterns
This is how https://github.com/rust-lang/rust/issues/33627 looks in action.
Looks especially nice in leftmost/rightmost positions `(first, ..)`/`(.., last)`.
I haven't touched libsyntax intentionally because the feature is still unstable.
Updated e0493 to new format (+ bonus).
Part of #35233.
Fixes#35999.
r? @jonathandturner
I'm not satisfied with the bonus part, there has to be an easier way to reach into the `Drop`'s span implementation. I'm all ears. :)
[MIR] track Location in MirVisitor, combine Location
All the users of MirVisitor::visit_statement implement their own statement index tracking. This PR move the tracking into MirVisitor itself.
Also, there were 2 separate implementations of Location that were identical. This PR eliminates one of them.
