When a member access names an interface member, perform impl lookup to
find the impl and its corresponding member.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This was previously discussed at
https://discord.com/channels/655572317891461132/655578254970716160/1209975051588210729.
I'm initiating this mainly because we typically use "id" suffixes to
indicate an `IdBase` being passed around and the non-id suffix of
`parse_node` suggests at it carrying more data than it actually does.
There used to be more reason for avoiding `node_id` because
`SemIR::InstId` used to be named `NodeId`, but that's no longer
necessary. As a consequence, I'd like to rename `parse_node` to more
precisely reflect its type.
In full, this is doing:
```
parse_node_kind -> node_kind
parse_node -> node_id
ParseNodeCategory -> NodeCategory
ParseNodeKind -> NodeKind
ParseNode -> NodeId
```
This is primarily in check and sem_ir, but with some `parse_node_kind`
references in parse too.
Pluralization is consistent with name forms on both sides, so that
wasn't part of my replacements.
Check that functions in an `impl` are declared properly. For now, simply
reuse the redeclaration checking logic. Longer-term, we need to check
that the signatures match in a more approximate way, after substituting
the `Self` type into the signature in the `interface`.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Add an instruction to hold the witness table, along with a corresponding
type to keep things simpler. Add `check/impl.{h,cpp}` to house the new
logic. No checking of impls against interfaces is performed yet.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Richard SmithandJon Ross-Perkins