These constant instructions are all TypeInstId already in their type,
and this makes their names match.
Change the name of MakeSingletonInstId as well and update its comment.
We frequently want to operate on singletons. Per discussion, drop
`Singleton` to make the code shorter.
This started off as wanting to write `inst_id.is_error()`, but the
dependency relationship between ids.h and singleton_insts.h would
require some kind of delayed evaluation to allow the implementation to
remain in headers (which I suspect is helpful to have for inlining). I
could have added something like `IsErrorInst`, forward declared in ids.h
and defined in singleton_insts.h (which would always be included by
typed_insts.h), but the template approach felt like a decent balance
between (a) removing the boilerplate `::SingletonInstId`, (b)
understandability, (c) still visually mirroring if we immediately return
a singleton, and (d) flexibility for more than just `ErrorInst`. But TBH
I'd probably still have written `is_error()` if it didn't require
addressing the cross-header cycle.
Then I tried `SemIR::InstId::Is<SemIR::ErrorInst>`, which generally
worked with types but generated the complaint that it didn't shorten
*all* singleton uses. So pulling back on `::Is`, and instead just
dropping `Singleton`.
TypeInstId is an InstId whose constant value has a type of TypeType.
This includes:
- Type value instructions, the `ClassType` or `IntLiteralType`
instructions.
- Constraint value instructions, which are the `FacetType` and
`TypeType` instructions, each of which also have type TypeType.
TypeInstId encodes in the type system that it is safe to convert the
instruction's value to a TypeId, and CHECKs at construction that this
invariant is maintained.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
While facets may come with a rewrite for an associated constant, they
are symbolic. A final impl has the ability to provide a concrete value
instead, which allows generic code to use the concrete value in place of
the associated constant's (fully qualified) name.
For instance, instead of `I.Type`, the concrete type `()` can be used if
there is an `impl final [T:! type] T as I where .Type = ()` impl.
This does not yet cache the result of the lookups.
Depends on https://github.com/carbon-language/carbon-lang/pull/5255
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Use that instead of `AddInstInNoBlock` to get the value of an
instruction when evaluation might depend on the `InstId` but only the
`ConstantId` of the instruction is desired by the consumer.
For each kind of instruction, specify whether its constant evaluation
needs an `InstId` or not. If it does, ensure that all constant
evaluation of that instruction provides one. Otherwise, allow calling
into the evaluator without providing an `InstId`.
This allows us to reliably use the `InstId` in evaluation steps that
either need a location or need to look at the original operands of the
instruction prior to evaluation, and also to support `TryEvalInst` calls
safely for instructions whose evaluation does not need an `InstId`.
This builds on #5212 which is adding ArgAndKind. This further modifies
CARBON_KIND_SWITCH support so that we can use it with ArgAndKind in
addition to Inst. That creates a quirk where it's easier if ArgAndKind
provides `kind` as an accessor instead of a data member, so I'm just
switching it to a class.
#5171 ran into an issue where the wrong kind was associated with an arg
(`auto arg1 = RefineOperand(context, loc_id, arg0_kind,
action.arg1());`). This PR is trying to reduce risk of similar errors by
replaced `ArgKinds()` with instead an `ArgAndKind` structure and
corresponding accessors.
A couple things I considered and discarded were:
- Adding `CARBON_KIND_SWITCH` support (in this PR -- see #5216).
- The particular way that `ForCase` works would need to change, and I
was hesitant to do that here.
- But this is why I did add `As` to `ArgAndKind`, because it had me
thinking in that direction.
- Trying to make wrapper functions like `MutateArgs(callback_fn);`. This
kind of approach gets a little messy due to some of the conditional
passes, and in particular the reverse-iteration done for `PopOperand` in
subst.cpp
- Making something like `args_and_kinds() -> std::array<ArgAndKind, 2>`.
There's one spot where iteration is already set up as a loop, but for
others it felt a little convoluted with less gain than
`MutateArgs`-style things.
I'm not sure if there's a better way to set up the table generators, I
might keep tinkering with those for ideas.
It is possible to construct a symbolic impl lookup query that, when
evaluated against a specific, will have a self type that is:
- A facet value instruction with a symbolic constant value
- That constant value is rewritten to a FacetValue pointing through a
FacetAccessType to a symbolic facet value.
Impl lookup looks through the FacetValue to the type inside since
FacetValue will reduce the number of interfaces available to match the
minimum deduced requirements.
Impl lookup also unwraps FacetAccessType in the self type of the query
and the impl, so that queries on FacetAccessType and on facet values can
both compare against the impl's self type with a simple constant value
equality check.
We were unwrapping FacetAccessType on the way into impl lookup, and then
assumed that meant it would never be a FacetAccessType in the symbolic
impl lookup instruction. However, as we can see, the query self
instruction can be symbolic and its value can be rewritten. And in that
case it can contain or become a FacetAccessType.
So we need to also unwrap the FacetAccessType when doing a symbolic impl
lookup.
Closes#5187
The instruction does act somewhat like a witness, saying that an impl
does exist for a lookup, but the instruction more concretely represents
an impl lookup - since that is done when it is evaluated.
Add a new instruction called ImplSymbolicWitness which represents a
search for an impl declaration given a self type and an interface to
find implemented for the self type. The self type is stored as a
constant instruction id, rather than as a ConstantId, as instructions
don't currently support holding ConstantId. The interface is stored as a
SpecificInterface but we can't fit all of it directly into the
instruction. So we add a new id to refer to the SpecificInterface as
follows.
Add a new SpecificInterfaceId which indexes into a canonical value store
on SemIR::File. This tracks all `SpecificInterface`s stored in an
instruction - specifically the ImplSymbolicWitness instruction.
The SpecificInterface on Impl is still stored there as a value, not as
an id, and no id is eagerly constructed for it. We wait until an id is
needed to make one. Since they are canonical, a new id is only create
when a new SpecificInterface value is seen.
When doing impl lookup, and the query is not concrete, and the impl is
not effectively final, the query needs to consider future impls that may
specialize either the self type or the constaint to make a more precise
match and replace the found impl declaration. Instead of returning the
ImplWitness instruction from the found impl, we generate a
ImplSymbolicWitness instruction, storing the query so that it can be
replayed later. This instruction is added to the generic eval block and
thus will be re-evaluated later with a SpecificId that may make the
query more concrete. When evaluating the instruction and replaying the
query, the lookup has the same conditions and if it does not decide to
use the found impl concretely, then the same instruction is returned
from eval, leaving it as symbolic.
--- Impl lookup changes ---
Impl lookup gets a little more interesting now. It continues to look in
the facet value for a witness if the self type is a facet value. Then
falls back to looking for an impl declaration. This step is no longer
done directly. Instead, we construct a ImplSymbolicWitness instruction
and evaluate it immediately for each interface that are in the query
facet type.
The ImplSymbolicWitness instruction, when evaluated, calls back to the
impl lookup code, with a query specific interface. There we resume back
into the same code path as from before, finding a witness in an impl
declaration. But we may return "found a non-final impl" instead of a
concrete witness. If eval receives this back, it evaluates to the
current ImplSymbolicWitness instruction as the resulting constant value.
To pass lookup failures back through eval, a result of InstId::None from
the second step of impl lookup will result in a non-constant value,
which is used as a signal back up the stack to the original impl lookup
function that the lookup failed. Using a non-constant value here would
break evaluation of the generic eval block if impl lookup could fail
there, however we know it will not since we only leave behind an
ImplSymbolicWitness instruction in the eval block if we found at least
one matching impl already, and we just want to look for a better match
with a more specific query.
We must take care to not store a reference into any value store across
computation in impl lookup, since impl lookup can recurse into itself
invalidate those stores. That includes the SpecificInterface obtained
from a SpecificInterfaceId, which impl lookup also inserts into the
store.
--- The long tail ---
Adding a new instruction and a new id type requires a myriad of changes
to support them:
We add Dump() support for SpecificInterfaceId. And fix a crash in Dump
for SpecificId::None. We also add MakeSpecificInterfaceId() for dumping
arbitrary ids.
The type of ImplSymbolicWitness is a new singleton builtin type
instruction called WitnessSymbolicType (like WitnessType is the type for
an ImplWitness).
Both ImplSymbolicWitness and WitnessSymbolicType are given `Value` as
their expression category as they are builtin constant values. And
BuildInfo() in TypeCompleter is taught about them both, returning a
`ValueRepr::Copy`.
WitnessSymbolicType is added to the set of SingletonInstKinds, so that
it can have a singleton instrution id as a static member.
Lower's BuildTypeForInst() is taught to make an empty struct for
WitnessSymbolicType, similar to WitnessType.
Instruction formatter (FormatterImpl) grows support for printing a
SpecificInterfaceId so that it can print both arguments of
ImplSymbolicWitness on the RHS when printing the SemIR instruction. To
print a SpecificInterfaceId, it prints both the interface id and the
specific id (if there is one). For example, for a query on a generic
interface `Z` with one parameter, the RHS includes the query, interface,
and specific:
```
%Z.impl_symbolic_witness: <symbolic witness> = impl_symbolic_witness %U, @Z, @Z(%U.as_type) [symbolic]
```
IdKind is extended to include SpecificInterfaceId.
InstFingerprinter is taught to look through SpecificInterfaceId and use
the interface and specific ids in the fingerprint.
InstNamer is taught about SpecificInterfaceId, counting the interfaces
when building an index. It is also tought about ImplSymbolicWitness,
using the name of the interface within and the `.impl_symbolic_witness`
suffix. For example, here the LHS is named after the interface in the
query:
```
%Z.impl_symbolic_witness: <symbolic witness> = impl_symbolic_witness %U, @Z, @Z(%U.as_type) [symbolic]
```
StringifyTypeExpr is taught about WitnessSymbolicType, which uses its IR
name since it's a singleton. And about ImplSymbolicWitness which uses
its constant value. The handling of ImplWitnessAccess also needed to be
adjusted, since it assumed that ImplWitnessAccess::witness_id would
always be a FacetAccessWitness, but it can now also be an
ImplSymbolicWitness. (It seems that the witness_id is also assigned
ImplWitness instructions, but those ImplWitnessAccess instructions don't
ever seem to get stringified in a diagnostic at this time.) At the
moment the ImplWitnessAccess with a symbolic witness is just stringified
as "<symbolic>", such as in:
```
x.carbon:1:2: error: cannot implicitly convert value of type `()` to `<symbolic>` [ConversionFailure]
let a: C(D).(Z.X) = ();
^~
```
There is a TODO left behind to include more information there.
The TypeStructure builder is made to handle WitnessSymbolicType and
WitnessType. These come up now in deduce where a generic impl will have
a ImplSymbolicWitness in a FacetValue for a generic self type. The query
may have a concrete ImplWitness in the same position. Since deduce tries
to deduce through the FacetValue, it tries to convert ImplWitness to
ImplSymbolicWitness, tries to do an impl lookup for `impl ImplWitness as
ImplicitAs(ImplSymbolicWitness)` and causes us to build type structures
with each of these.
Subst is updated to handle pushing and popping SpecificInterfaceId.
Without this, when finishing a generic's eval block, we would walk into
the ImplSymbolicWitness instruction, and its arguments, and fail to
recurse down into the SpecificInterfaceId. Then any specifics inside
would be left as "orphaned" without any generic id attached to them, and
we would never update the instructions in the SpecificInterface's
instructions (inside its own SpecificId) with new constant values when
evaluating the generic eval block against a specific. To do this we push
the specific_id inside the SpecificInterface, and when popping we pop
the specific_id then construct a new canonical SpecificInterface with it
and return that id.
We add support for importing ImplSymbolicWitness by importing its self
constant instruction and specific interface id. However we also had to
add import support for SpecificImplFunction, which can now appear in the
generic eval block for a generic impl declaration, and thus must be
imported with the declaration. This is done very similarly to
SpecificFunction, except the `type_id` is a singleton value.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
When the parameter is a deduced symbolic FacetValue, refering to a
BindSymbolicName, and the argument is a concrete FacetValue that would
match the FacetType requirements on the BindSymbolicName's type, we
currently do not deduce that the argument matches the parameter.
The argument is not _converted_ to the parameter type because they are
both FacetValues of the same FacetType type. However they are also not
equal constant values so the argument is not saved as a deduced match
for the parameter.
In order to accept the FacetValue, we need to consider them as
`deduce_through`, which attempts to deduce each of the fields in the
argument FacetValue against the fields in the parameter FacetValue.
This deduces that the argument's concrete type matches the symbolic
BindSymbolicName and its witnesses are the same.
Since the parameter is a FacetValue, its argument is not the type that
needs to be recorded as the deduced type for the binding. The
BindSymbolicName inside the parameter is the place that we need to find
the deduced type for the binding. So simply walking into the FacetValue
gets us to that position, where we eventually record the deduced
argument type as being the concrete type from the original argument
FacetValue.
Similarly, when determining what interfaces are satisfied by a
FacetValue for deduce, we want to use the full type available in the
FacetValue rather than just those from its FacetType. Determining
availability of interfaces here is equivalent to converting, and we want
converting a FacetValue to always work on the full available type info.
Only API access (member lookup) is restricted by a FacetValue to the
interfaces provided by its FacetType type.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
If a self type is FacetAccessType, we look through it at the facet
value, both for the query and the impl declaration. This ensures that
while FacetAccessTypes match each other for constant value equality
still, they an also match with facet value queries, such as:
```
impl forall [T:! Y] T as Z {}
^ FacetAccessType for BindSymbolicName of type FacetType(provides Y).
fn F(y:! Y) {
y as Z;
^ Facet value
}
```
Here the facet value and FacetAccessType don't have the same constant
value. Deduction will give the `T!: y` binding the facet value of `y`,
but the `T` in `T as Z` is a FacetAccessType to that binding, which is a
different constant value. Looking through the FacetAccessType gives us
the desired constant value for comparison with the query.
Additionally if the query self value is a FacetValue instruction, look
through that at the underlying type value. Impl lookup is used to
convert from one type or facet value to a new facet value of the desired
facet type. We want facet values to always be able to convert to
everything possible, rather than to have that restricted to just their
current FacetType:
https://github.com/carbon-language/carbon-lang/issues/5137. So this
allows queries such as `(C as Y) as Z` for a class `C` and interfaces
`Y` and `Z`.
New planned direction is to not require completeness. Updated comments
to reflect that some care will be needed once named constraints are
supported. Long term plan is [discussed in
#5089](https://github.com/carbon-language/carbon-lang/pull/5089#discussion_r1985908453):
> We have some options. In our last conversation, it sounded like it
would be beneficial for named constraints to have their own witnesses,
with entries in declaration order. This would allow accesses to the
named constraint while it was being defined. So there would be something
of a hierarchy in a facet type witness, with a named constraint taking a
single slot in a facet type witness, independent of its definition.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
When converting from a facet value (an instruction whose type is
FacetType), we require making a FacetAccessType
to have a type instruction when building the resulting FacetValue.
Otherwise, the conversion is the same for values of type TypeType, and
we relax the convert function to support either.
Corrects the test expectations for converting `Goat as Animal`, a facet
value of type FacetType, into `Eats`, a facet type of type TypeType.
This would be a promotion in the typish hierarchy which is incorrect. We
had an extra case in Convert that was handling this, and it's now
removed. `Animal`, a facet type, does still correctly convert into
`Eats`, a facet type, if `impl Animal as Eats` exists.
Deduction can do conversion, and conversion can import impls from the
Core package. If you have the right number of impls in your ImplStore at
that moment, it will reallocate and any pointer into context.impls()
will be invalidated.
In particular, in impl lookup, we currentl loop over context.impls() and
do deduction on each impl. So this can break the for loop. Additionally,
we pass around a reference to the currently-being-looked-at Impl, which
becomes invalidated.
This is very challenging to test in any reliable way as you need a
specific number of impls in your ImplStore. I hit it when making changes
to a test in the middle of a bunch of file splits. Putting the same test
in its own file did not trigger the issue. It was caught by ASAN, which
showed:
- The memory was allocated by SmallVector in handle_impl when making the
Impl.
- The memory was freed by SmallVector reallocating in import_ref.cpp
- The memory was accessed when reading through the `impl` reference in
FindWitnessInImpls(). I was able to reproduce by printing the
`impl.interface.interface_id` after the call to GetWitnessIdForImpl()
which does the deduction.
I didn't save the ASAN stack and now I can't find the exact permutation
of the test file that caused it to occur in order to reproduce. :(
To avoid the UAF we stop passing around the Impl reference, and pass
around either the ImplId, or values from the Impl. To avoid copying the
entirety of the impl ids in context.impls() into a separate container in
order to iterate safely, we move the early outs from
GetWitnessIdForImpl() up to the caller where it can use them to reduce
the number impl ids that we iterate over. Type structures will be able
to further reduce the size of this set.
This required allowing incomplete facet types where previously
completeness was required. Once we support named constraints, we will
need a way to consistently go from an interface to a facet type witness
index without requiring the interface to be complete in these cases.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
A query facet type may contain multiple required interfaces, in which
case impl lookup should return an ImplWitness for an impl that is used
for each interface in the query. We bundle these together into an
instruction block and return that from impl lookup. The witnesses are in
the same order as the interfaces in the
`CompleteFacetType::required_interfaces`. This allows walking the
`required_interfaces` to find an interface to give an index that can
also be used to grab a witness from this set, or from FacetValue.
FacetValue now has an InstBlockId for the set of witnesses of the
FacetType, instead of a single ImplWitness instruction id.
FacetAccessWitness includes the index of the witness (determined from
the position in `required_interfaces`) of the witness it's accessing
from the FacetType.
The
toolchain/check/testdata/facet/no_prelude/fail_todo_call_combined_impl_witness.carbon
test demonstrates the fix in the resulting SemIR. We can see the calls
to methods on a multi-interface FacetType result in a FacetAccessWitness
with an index of the correct interface, and this results in a witness
that leads to the correct impl's function.
There is a TODO in member access, where it does not have a
`CompleteFacetType` yet, so it uses the index in
`FacetTypeInfo::impls_constraints` instead, but this can be incorrect in
the presence of named constraints, which when completed can add more
interfaces to the `CompleteFacetType` and which are sorted into an
arbitrary order with the rest there.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Impl lookup for an interface `I` for a facet with facet type requiring
an interface `I` will now succeed, getting the witness from the facet.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Dana Jansens <danakj@orodu.net>
If the query facet type has more than one interface, we must find an
impl that provides that interface for the query type for each interface.
This just looks like a for loop over the interfaces and ensuring we
found one impl witness for every one.
However the impl matching must change since it can't look at the
constant value of the entire query facet type for comparison with the
impl, as that query facet type may be for multiple interfaces and we are
looking to match an impl of a single interface.
To do this we break the query facet type up into each interface and make
sure the interface ids match. Then ensure that the impl was able to
deduce any generic parameters using the specific of the single query
interface.
There are some TODOs left here:
1. If the facet type for the query or the impl constraint has
"other_requirements" then we can't verify that they match since they are
lost. We fall back to comparing the constant id of the query to the
impl's constraint (after deducing generics in the impl). This correctly
eliminates mismatches but eagerly eliminates impls that could match the
query interface as well when there's more than one interface in the
query.
2. We don't return a witness for every interface in the query facet
type. Since we can't demonstrate any use of the witness there yet, for
cases that can have more than one interface in the query facet type,
this doesn't break anything that was previously working. The return
value is currently treated as a bool for cases with multiple interfaces
in the facet type (as a test for "can this be converted") but the
converted-to facet value's witnesses are unused.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
The resulting facet type has its complete facet type canonicalized by
sorting and deduplicating the `required_interfaces`.
Impl lookup now uses the complete facet type. It continues to diagnose
with a TODO if it sees a complete facet type with 0 or more than 1
interface in it. Impl lookup to convert from a type to a facet value
hits this diagnosis.
Member lookup by name works on a facet type with more than one interface
because the name knows which interface to look for from the name, and
AppendLookupScopesForConstant() looks through all interfaces on the
complete facet type already to get the correct scope for the name.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
If the `impl as` clause is on a generic interface, the parameters to the
generic may be constrained by _other_ interfaces. This then requires
another impl lookup, but it should be looking for a different impl since
it's for a different interface.
To avoid considering the same impl again, we discard it from
consideration if the interface itself does not match the interface being
queried.
Note that the query FacetType can have more than one interface in it
eventually, and a `context.TODO()` call is left to notify when we run
into this.
Cycles are defined as reaching two independent lookups in a chain that
have all the same types involved. The acyclic rule states that this is
not possible and results in an error:
https://docs.carbon-lang.dev/docs/design/generics/details.html#acyclic-rule
To do this we need to track the types involved in impl lookup. The
interface constant includes the whole facet type being looked up, which
includes any specific types for generics or where constraints. Thus we
just need to compare the constant ids to look for this condition.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Currently it returns false which just ends typechecking. Instead handle
the error state later and avoid firing overlapping diagnostics in
'extend impl as'.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
If 'extend impl' is invalid, mark the impl as invalid by putting an
ErrorInst in the witness_id field.
The construction of the witness_id can otherwise return an ErrorInst but
impl lookup was not checking for that. Now have impl lookup check for an
error there before attempting to deduce generic parameters, which avoids
infinite recursion through deduction in cases like a cyclical impl of
itself.
Adds a testcase for infinite impl-of-itself lookup found by fuzzer.
The fn receiving a facet type needs to deduce a type from a
FacetAccessType, which is the SemIR type representing the parameter type
that is a generic parameter. For example:
```
fn F[T: Interface](val: T);
```
Here T is a generic parameter that is a facet value, but the `val`
parameter's type is the facet value converted from a FacetType to a
TypeType, with `as type`. The result of that conversion is a
FacetAccessType. So the deduction code sees a FacetAccessType for the
type of `val`.
We make deduction undo the `as type` conversion to move back to the `T`
parameter declaration, which has type FacetType in order to deduce the
required facet value (which is itself a type constrained by the
FacetType). And when we have a facet value (of type FacetType) to be
deduced, we will also convert the argument if it is of an appropriate
type to a FacetValue that matches the FacetType using the changes from
PR #4863.
Tests with `impl forall` can cause impl deduction to recurse forever and
crash, so those tests are omitted in this PR and they will come in
follow-up work that address the infinite recursion.
Rebased on top of PR #4885
High level, replacing `Id::Invalid` with `Id::None` and `Id::is_valid`
with `Id::has_value` for clarity, as discussed
[here](https://discord.com/channels/655572317891461132/655578254970716160/1331664574545395794).
The `IntId` refactoring is needed together with `AnyIdBase` because it's
also used with `ValueStore`.
Note, trying to be careful not to rewrite `EnumBase::InvalidIndex`, or
`is_valid` in general (e.g., `IdKind::is_valid`).
I've tried to sequence commits here:
1. Automatic replacements:
- `((?:Id|Index)(?: |::|\(|Base(?:\(|::)))Invalid((?:Index)?\W)` ->
`$1None$2`
- `<invalid>` -> `<none>`
- `InvalidNodeId` -> `NoneNodeId`
- `/\*invalid\*/` -> `/*none*/`
- `id((?:_|\(\))(?:\.|->))is_valid` -> `id$1has_value`
2. Manual edits:
- In `int.h` and `int_test.cpp`
- `IntT` has `is_value`, which I'm renaming to `is_embedded_value`.
- Manual edits to comments in this file.
- `AnyIdBase` and `IdBase`
- Declaration of `is_valid` -> `has_value`, `InvalidIndex` ->
`NoneIndex`.
- In `ids.h` and `ids.cpp`
- `is_valid` -> `has_value`
- `// An explicitly invalid ID.` -> `// An ID with no value.`; similar
for index
- Various math on `InvalidIndex` -> `NoneIndex`
- Various mentions of "valid" in comments
- In `value_store.h`, for `IdT::Invalid`, plus one comment
- In `impl.h` and `tokenized_buffer.h`, we had different initialization
of `::None` values (versus `ids.h` syntax) that I fixed manually.
- Spot checks to compile
- Particularly where `is_valid` replacements didn't catch spots due to
different naming.
3. Autoupdate tests
4. verbose.carbon (NOAUTOUPDATE)
5. Comment spot checks
Note there are probably other mentions of "Invalid" that should be swept
up, but I'd like to argue for merging and separating out remaining
cleanup since this is so sweeping (and likely to hit merge conflicts
from churn). We'll probably have lingering mentions of "invalid" for a
bit regardless, just because there are uses of "invalid" in non-Id APIs.
* 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>
Also fix a bug in `Context::GetClassType` that previously tried to
complete the class type before returning it. That's not correct --
`GetCompleteTypeImpl` is only appropriate for cases where the type can
trivially be completed and completing it can't fail -- and led to
infinite recursion with this change because we would call `GetClassType`
when producing a diagnostic if completing that class type failed.
This is essentially the result of looking at `.begin()` uses. We also
frequently do `std::shuffle`, but unfortunately STLExtras doesn't
provide a wrapper for that.
Instead, eagerly import only the impls from the api file corresponding
to the current file, if any, because we need those for impl
redeclaration lookup. For all other cases, load only the impls in
libraries that are referenced as part of an impl lookup query.
Dana Jansens
Thomas Köppe
Jon Ross-Perkins
Geoff RomerandDana Jansens
