Use it in the instruction namer to make instruction names more stable
across unrelated changes to the toolchain or the prelude.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
* Change `InterfaceWitness` -> `ImplWitness`
* Include a `SpecificId` in the `ImplWitness`. This allows the
`InstBlock` it contains to have its own identity, allowing it to be
changed as the impl is processed. Evaluation only updates the specific.
* Create the `ImplWitness` at the start of the impl definition. In the
future, this will be populated with the values of non-function
associated constants. For now, it starts full of invalid instruction
ids.
* Implements the model suggested in #4672 .
Note that the non-SemIR testdata changes are to these file:
* `toolchain/check/testdata/impl/lookup/fail_todo_undefined_impl.carbon`
* `toolchain/check/testdata/struct/import.carbon`
* `toolchain/check/testdata/tuple/import.carbon`
The last two are due to an import of generics bug exposed by this PR,
which will be fixed in a follow-on.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Instead of providing operations only for `i32`, provide them for all
`iN` and `uN` types.
For now, this excludes the `*Assign`, `Inc` and `Dec` interfaces,
because the implementations for those are defined as Carbon functions
rather than builtins, and we can't yet lower definitions for specific
functions, so converting those to be generic breaks the build for our
examples.
This is a precondition for enabling the new pattern-matching subsystem
to support binding patterns that have `if` expressions in the type
position.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
We defer lowering initialization with constant values, because the use
of the constant can itself be part of a larger constant that we don't
want to emit. However, when the initialization is for an element of a
non-constant aggregate, we do need to initialize the constant portion.
Richard SmithandDana Jansens
Geoff RomerandRichard Smith