The current system with AstIds has two primaraly drawbacks:
* It is possible to manufacture IDs out of thin air.
For example, it's possible to create IDs for items which are not
considered in CrateDefMap due to cfg. Or it is possible to mixup
structs and unions, because they share ID space.
* Getting the ID of a parent requires a secondary index.
Instead, the plan is to pursue the more traditional approach, where
each items stores the id of the parent declaration. This makes
`FromSource` more awkward, but also more correct: now, to get from an
AST to HIR, we first do this recursively for the parent item, and the
just search the children of the parent for the matching def
2205: Implement bulitin line! macro r=matklad a=edwin0cheng
This PR implements bulitin macro `line!` and add basic infra-structure for other bulitin macros:
1. Extend `MacroDefId` to support builtin macros
2. Add a `quote!` macro for simple quasi quoting.
Note that for support others builtin macros, eager macro expansion have to be supported first, this PR not try to handle it. :)
Co-authored-by: Edwin Cheng <edwin0cheng@gmail.com>
This removes the special casing for the "core" prelude.
Whenever a later dependency also exports a prelude, it will replace
the formerly imported prelude. The utilized prelude then depends
purely on import order.
This adds support for completion and goto definition of
types defined within the "core" crate. The core crate is
added as a dependency to each crate in the project.
The core crate exported it's own prelude. This caused
now all crates to inherit the core crates prelude instead
of the std crates. In order to avoid the problem the
prelude resolution has been changed to overwrite
an already resolved prelude if this was set to a crate
named core - in order to pick a better prelude like std.
Fixes#2199
