If a facet type contains `.X impls Y` then later references to `.X`
should know that it impls `Y`. This is done through a stack on the
context like for rewrites, where impl lookup can find constraints from
the current `where` expression being checked.
Similarly, if a facet type contains `.X impls (Y where .Z = T)`, then
`.X.(Y.Z) = T` should be available to later constraints in the facet
type for early application of rewrite rules. We add these rewrites to
the rewrite stack when handling the `impls` constraint
We replace the non-canonical ImplWitnessAccess instruction with an
ImplWitnessAccessSubstituted instruction containing the RHS of a prior
rewrite constraint in the same facet type when possible, in order to
access the value of the prior constraint. We were doing this only in the
designator access path though, not in the compound member access. Join
these two code paths when they construct the ImplWitnessAccess, and
perform the early access there for both.
When an outer type defines an `extend` relationship to an inner type, we
require that inner type to be complete so that we can know that name
lookup can search both scopes as soon as the outer type is complete.
When doing name lookup, we require the type in which we are looking to
be complete. Then, we recursively add extended scopes, but then also
require each of them to be complete again, which inserts
RequireCompleteType instructions into the block doing lookup.
While these new instructions may differ in terms of their specifics,
they are redundant since we already required the type to be complete,
and specifics can not change the completeness of a type. They are also
problematic because a named constraint or interface can extend a scope
with a symbolic specific, by using `Self` as an argument. This inserts a
symbolic instruction into the block doing name lookup, even though that
block may not be generic.
See
[here](https://docs.google.com/document/d/1rWcueFwIfZox6GKVGxiUG4cBzjrZ6djXiIDGyJDtrE4/edit?tab=t.0)
for the design doc.
This also removes the default value of the `result_type_inst_id`
parameter of `HandleAction`, moves it before the action in the parameter
list, and documents it. This solves two problems:
- The default made it easy to forget, leading to unnecessary
`TypeOfInst` instructions.
- When it was present, putting it after the fairly "bulky" action
argument tended to make the callsite harder to read.
Add `InstIs`, `GetInstAs`, and `TryGetInstAs` which act on the
underlying constant instruction in a constant value, to save an explicit
call to `GetInstId`.
```carbon
context.insts().GetAs<InstT>(context.constant_values().GetInstId(const_id))
```
can now be written as simply
```carbon
context.constant_values().GetInstAs<InstT>(const_id)
```
For future work, we might provide `GetInst()` so that
`context.insts().Get(context.constant_values().GetInstId(const_id)` can
be shortened also.
Introduces `Context` and `SoftContext` messages, which can be introduced
through a `ContextBuilder`:
- The `Context` messages come before the diagnostic in the output.
- The first `Context` message steals the diagnostic level from the main
diagnostic, and turns the main diagnostic into a Note attached to the
context.
- A `SoftContext` message works similarly, but if it's preceeded by a
`Context` or `SoftContext` message, then it is dropped. This can be used
as a default/backup scope when nothing more interesting is provided up
the stack, such as in `TryEvalBlockForSpecific`.
The `ContextBuilder` is provided to a callback through
`Diagnostics::ContextScope`, an RAII type `AnnotationScope` but for
context messages.
This allows a high level operation to provide a context message like
"failed to identify facet type {0}" which will then be used as the error
if a diagnostic is produced during identification, with the latter
diagnostic attached as a note to explain why the contextual operation
failed.
In particular, this allows monomorphization errors (such as an array
bound being negative) to be attached to a higher lever operation instead
of being top-level diagnostics themselves, with the monomorphization
site being a note. This inverts the source code locations that appear in
the diagnostic, so that the top-level diagnostic points to the "user
code" which causes the monomorphization.
This is presented as an alternative strategy to #6753, which plumbed
diagnoser callbacks around to achieve the same goals.
We replace the diagnoser callbacks in type completion and operators with
ContextScope callbacks instead, which now provide better diagnostics for
monomorphization errors. Other callers to MakeSpecific do not yet have
ContextScopes introduced in order to turn monomorphization errors into
more interesting diagnostics.
Currently each interface has a `Self` facet internally that becomes a
binding to every entity inside the interface: associated constants,
functions, and require decls. Each of these has to be independently
generic as a result. This makes is challenging in extended name lookup
to move into an extended scope of an interface, as we have a specific
for the interface, but the names within require a different specific
that includes a `Self` facet value.
We generalize this relationship by adding a second generic to Interface,
called `generic_with_self`. When we want to work with entities inside
the interface, we move from the interface-without-specific to the
interface-with-self specific by adding a Self to the specific. This is
done independently of any particular entity inside the Interface, as
those entities are now all members of the interface-with-self generic.
Associated constants no longer need a generic of their own, as they do
not have separate generic bindings. Functions retain a generic, but if
the function has no generic arguments, it will have no bindings of its
own now.
Require decls retain a generic so that their specific can be
instantiated separately from the interface. Requiring the interface to
be complete does not require the types in a require decl to be complete
unless it is modified by `extend`. So we allow them to be completed
later by keeping them in a separate generic.
Named constraints look like interfaces and gain the additional inner
generic-with-self, with the same relationship to require decls.
This removes the need for name lookup to perform Substitution of a Self
facet into the extended scope instruction. Instead, the
`SpecificConstant` instruction inserted by a `require` decl is part of
the interface-with-self generic. When looking through a FacetType for
extended scopes, for each interface, we push the scope with the specific
for the interface-with-self. Then the constant value of the
`SpecificConstant` is correctly modified by the provided self
automatically through applying that specific.
Mainly because "sorting_diagnostic_consumer" is legacy, since
`SortingDiagnosticConsumer` became `SortingConsumer`. Also better
reflecting contents of these files.
Where I'm not renaming, I'm less positive about dropping "diagnostics"
from "file_diagnostics" and "null_diagnostics" (which contain both a
consumer and emitter, and "null.h" seems like poor naming), so not doing
that here. Also "diagnostic.h" contains `struct Diagnostic`, so is a
decent fit.
Assisted-by: Google Antigravity with Gemini 3 Flash
When doing name lookup into an extended scope of an interface or named
constraint, the containing scope has an inner `Self` facet which can
appear in the specific of the extended scope. For instance a constraint
`N` which requires an interface `Z(Self)`:
```js
constraint N {
extend require impls Z(Self);
}
```
When doing member lookup into a facet constrained by `N`, we need to
find the specific interface `Z(...)` where the `Self` is replaced by the
self-type the member lookup is happening on in order for impl lookup to
find a witness later.
Inside that specific interface we repeat the name lookup to find an
associated entity. Then to produce a witness we perform impl lookup
against the specific interface that name lookup returned with the
self-type of the member access. So if we do member access into `A:! N`
for a member `F`, like `A.F`, we would be doing impl lookup with a query
self of `A` and looking for the interface `Z(...)` returned from name
lookup.
When impl lookup has a facet as the query self, which we do here as `A`,
it takes its type (a facet type) and identifies it to find all the
required interfaces, and it substitutes the query self into those
specific interfaces for `Self`. If the `Z(...)` we acquired from name
lookup is `Z(Self)` it will fail the lookup for `A as Z(Self)`, since in
the facet type of `A` it finds a witness for `Z(A)` instead.
Thus, we replace the inner `Self` in extended scopes, such as `N`, with
the self-type of the member access, which produces the extended scope
`Z(A)` for this example. This allows the impl lookup for `A as Z(A)` to
find a witness from the facet type of `A`.
In order to do this, we include an instruction for the inner self when
registering the extended scope. Then, when we find the extended scope in
name lookup, we can use its CompileTimeBindIndex to replace any instance
of that `Self` facet with a new facet. If the self-type of member access
is a type, we construct a FacetValue with an empty facet type that
refers to the type.
This gets us a step closer toward resolving TODOs in member access
around facets, by making the lookup into a facet value a "lookup in
base" operation instead of a "lookup in type of base". However the base
given to find scopes in still remains the facet type of the facet, which
is still a TODO.
Then we can simplify the "lookup in type of base" case a bit, with a
single code path doing the name lookup step. But we keep a TODO where if
the type of base is a facet, we change the lookup target to be the facet
type of the facet instead.
This is toward having name lookup into an interface that is extending a
named constraint work correctly with a `Self` in its specific. To
perform that name lookup, we will need to tell name lookup what is the
base, so that it can replace `Self` with the base. This change gets us
in a position where we can correctly provide the base in the `T.F()`
(lookup in facet) and `t.F()` (lookup in type of facet) correctly and
straightforwardly.
We provide a marginally improved diagnostic when looking into a facet
with an incomplete facet type, which will move into
AppendLookupScopesForConstant once we are looking into the facet
directly instead of its type.
#6289 absentmindedly added fields in more places, and this is undoing
that plus further fixes.
This does some cleanup of types with relation to singletons. For
`TypeType` and `ErrorInst`, they're always complete due to a
`SetComplete` call in `file.cpp`. For `CppVoidType`, it's intended to be
incomplete by construction, and so a `TypeId` should be okay. The intent
though on not generally providing these had been that `GetSingletonType`
needs to be called to get a type to be marked as complete.
In the case of `AutoType`, removing `TypeId`does change a small printing
detail. I think that's old legacy that's just been carried forward.
Otherwise, for both `InstType` and `AutoType`, I've added
`GetSingletonType` calls where they were used in order to ensure
completeness is applied correctly. These calls cause small SemIR
permutations.
This causes `AutoType` to be seen by lowering, so I'm adding a
placeholder for it. Also merging two functions that look like they're
identical in intent -- not sure why they're separate.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
This proposal removes the definition of the term "value binding" as a
primitive
category conversion from reference to value, replacing it with the term
"value
acquisition". The other meaning of "value binding", a binding declared
by a
value binding pattern, is unchanged.
When we do member access `x.F` we attempt to look into the type of `x`
for `F`. If `x` is a facet, we look at its FacetType to find `F`. We
want `facet` and `facet as type` expressions to be generally treated as
equivalent, so we need to get at the "canonical facet value" of `x` in
order to look into its type. Add a new operation that allows us to
preserve the non-canonical `base_id` in the member access for
diagnostics if no conversion to a canonical facet value was needed.
The SymbolicBindingType refers to the type value that will be
substituted in for the BindSymbolicName, but holds onto the EntityNameId
from the BindSymbolicName instead of (or in addition to, for now) the
instruction.
The EntityNameId will be used to look in the ScopeStack to find the
witnesses either from the BindSymbolicName instruction, or other
instructions that specify `impls` constraints against the EntityName.
This will allow us to have the `T` in `I(T)` resolve to a `.Self`
reference in the type so that we get type equality with the binding's
type: `T:! I(.Self)`.
Given `fn f(T:! I, x: T)`, we have a facet type `I`, a facet value `T`
and a value `x` of type `FacetAccessType(T)`.
Previously we explicitly handled the case of member access on `x.F`
where the type is a `FacetAccessType` by looking through it at the facet
value, and then at its facet type. This is already something that impl
lookup does for us, so we can remove this special case.
We also previously had a complex branch handling the case `T.F` on a
facet value, because `PerformImplLookup()` in member access is expecting
a `TypeId`, not a facet value. However, the first thing that branch does
is convert the facet value to a type expression, forming a
`FacetAccessType`.
Unfortuntely, when combined, if we had `x.F` we would convert it from a
value of type `FacetAccessType` to a facet value, and then convert that
to a type as a `FacetAccessType` again. We see this extra
`FacetAccessType` disappear from the SemIR after this change.
In this change, we remove both the inlined replacement of
`PerformImplLookup()` and the explicit handling of `FacetAccessType`. We
drive all member access lookups on the `base_id`'s type through a single
`PerformImplLookup()` call. If the `base_id` is a facet value, to get
the TypeId to look into, we convert the facet value to a
`FacetAccessType`, reducing the complex special cases down to a single
line.
This turns out to be quite important, as several important standard
library types (such as `std::string`) have mixed-access overload sets
for their constructors as an implementation detail. The overall approach
here is:
- Use the most permissive access to determine the access of the overload
set itself. This affects whether name lookup finds the member name at
all.
- After overload resolution, re-check the access of the selected member,
if it's protected or private.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
This makes all `.Self` references in a facet type canonically the same
(which will remain true iff they refer to the same `Self` type in the
future), removing the need to do more complex comparisons between them
using the EntityName, interface, and index. This allows the comparison
of types containing `.Self` references to be done correctly regardless
of where the `.Self` appears, as such type expressions will all be
canonically equal if they otherwise equal now, regardless of whether
they are written in the context where `.Self` could have seen different
`Self` facet types.
In order to retain access to constraints on a base `.Self` facet type,
in the case of applying `where` to an existing facet type, we:
- Give the base facet type as a `RequirementBaseFacetType` constraint so
that eval of `WhereExpr` can find and copy all the constraints off of
it.
- Introduce eager/early rewrite constraint resolution, which allows a
constraint to eagerly resolve access to earlier rewrite constraints
(`where .A = () and .B = .A` is eagerly transformed into `where .A = ()
and .B = ()`) before the full constraint resolution step. This allows
use of rewrite constraints in larger type expressions, such as `where .A
= () and .B = C(.A)` and `C` will know that the argument is `()`.
And update tests to clarify that we should be able to do lookup into a
runtime facet value for an associated constant if the FacetType itself
provides that constant (with a `where` clause), but should not be able
to if it does not.
This fixes a fuzzer-found crash.
Instead of building an eval block as a separate pass at the end of a
generic, build the eval block incrementally.
The larger change here is that asking for the type or constant value of
an instruction now always returns an unattached type or constant value,
in order to preserve the behavior that we previously achieved by doing
the rewrite to attached types and constant values at the end of handling
the generic.
This also incidentally fixes some subtle issues where attached types and
constant values would leak out into check and cause it to get confused
about differences between attached and unattached values. Check should
no longer see attached values except where it explicitly asks for them.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
Remove calls to `InstStore::GetLocId()` to build a LocId from an InstId
now that they can be constructed directly from the InstId. Most uses of
LocId are just plumbing, so this does not affect them. However places
that want to look inside the LocId do not want to work with the InstId
form. In these places, introduce `InstStore::GetResolvedLocId()` which
converts a LocId (or an InstId as an optimization) into a LocId which is
not backed by an InstId. These locations can be printed (they have a
line and column when they are a NodeId), they can have flags added to
them (`ToImplicit`, `ToTokenOnly`), they can be converted to an
underlying ImportIRInstId, or they may be `None`.
`Dump()` is made to print a resolved location instead of printing the
InstId in the location, since (at least in my experience) the resolved
location is what is interesting in debugging, and this saves manual
`MakeInstId` steps in the debugger every time a location is of interest.
The LocId constructor from InstId is made `explicit` to add clarity to
function calls passing an `inst_id` now directly instead of calling
`context.insts().GetLocId(inst_id)`. To avoid needing to construct
`SemIR::LocId(...)` explicitly in all cases though, the diagnostics code
in Check uses `DiagnosticLocId` as its template parameter which accepts
InstId as well and does the construction of LocId from it.
Because LocId now requires an explicit construction from InstId, any
callers to `AddInst()` functions will have to explicitly convert to
LocId if they had an InstId, but not if they pass a NodeId. To make this
difference clear to callers, we `requires` that the input type can be
converted to LocId. This ensures that passing an InstId results in an
error at the callsite where the InstId is passed, instead of generating
a compiler error when trying to construct `LocIdAndInst` inside
`AddInst()`, which is less clear about what went wrong and doesn't seem
entirely intentional.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
We eliminate the `FacetAccessWitness` instruction, which would sometimes
immediately evaluate to a concrete `ImplWitness`, and sometimes remain
symbolic. This instruction is now replaced by `LookupImplWitness` in all
cases. To support the same use cases, when it is evaluated,
`LookupImplWitness` will look in the self value if it's a facet value,
and attempt to return a concrete `ImplWitness` from it before looking
for an `impl` statement.
The `LookupImplWitness` instruction's value is now canonical, even when
it evaluates to a symbolic `LookupImplWitness` instruction, by
canonicalizing the self value of the lookup query. This canonicalization
unwraps `FacetAccessType` and `FacetValue` instructions to get to an
underlying canonical facet value. However we must preserve and use the
non-canonical query while evaluating the instruction in order to look
for a concrete `ImplWitness` if the query self value was a concrete
`FacetValue`. The canonicalization ensures that symbolic witnesses
obtained from a facet value are compatible with those obtained from an
impl statement, as long as the self types originate from the same
canonical facet value though they may have been narrowed.
Member access now unconditionally does a `LookupImplWitness()`
operation, instead of only sometimes doing the lookup for a final impl
declaration.
`EvalImplLookupResult` is marked `[[nodiscard]]` so that we don't
construct it and forget to return it. This was a mistake made at one
point during the creation of this PR. And the `has_concrete_value()`
method no longer has a precondition that `has_value()` is true, since we
want to look for a concrete result only in the new use of
`EvalImplLookupResult` returned from lookup into the query self facet
value.
The TODO from `FacetAccessWitness` evaluation is addressed by ensuring
the index of the witness in the `FacetValue` comes from the required
interfaces of the `FacetValue`'s type, and that the type (a `FacetType`)
is the same facet type used in the query to construct the `FacetValue`'s
witness block. This is made possible by eliminating the
`FacetAccessWitness` indirection. The lookup into a `FacetValue` happens
while evaluating `LookupImplWitness` and it does so directly on the self
value. This gives a consistent view of the witness set and the facet
type, as they both come from the same instruction.
All of this with 400 less lines of code. :)
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
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`.
After #5280 there are a few more typed instructions that have an `InstId
type_inst_id` that always holds a type value. These are converted to
`TypeInstId` to encode this fact in the type system. The
`ConvertAggregateElement()` function in convert.cpp is now able to
receive `TypeInstId` for a couple arguments as well.
Additionally, the `type_inst_id` field of `StructTypeField` is made into
a `TypeInstId`.
The `TupleType::elements_id` is renamed to `TupleType::type_elements_id`
to try record the fact that it's an InstBlock of type value
instructions. We don't introduce a TypeInstBlockId at this time, but it
might be nice to make blocks of TypeInstIds in the future.
To assist in working with a block of InstId that are type values, two
additional helpers are added to the TypeStore:
- GetBlockAsTypeInstIds which turns an `ArrayRef<InstId>` into a range
of `TypeInstId`
- GetBlockAsTypeIds which turns an `ArrayRef<InstId>` into a range of
`TypeId`
We use these helpers in places that iterate over the
`TupleType::type_elements_id`.
In preparation for shifting from `TypeId`s potentially representing
attached types to always representing unattached types, using
[terminology suggested on
Discord](https://discord.com/channels/655572317891461132/963846118964350976/1359286326779973712).
This change causes us to track slightly more type spelling information
through SemIR.
One change that has significant impact on the SemIR output is that we
now build a `struct_type` instruction in each class representing the
types of the fields, including the spelling used for those types. This
is now no longer always identical to the corresponding canonical
`struct_type` for the object representation, so it's built separately
and owned by the class.
Also remove `TypeBlock` support entirely, as its only use was
representing `TupleType`s, which now use an `InstBlock`.
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>
This gives a slightly simpler representation for `UnboundElementType`s
in eval blocks, and in principle allows us to preserve the spelling of a
field's type into the `UnboundElementType` and thereby into a field
reference, although as of right now this doesn't affect our diagnostic
output in any way.
During error recovery for a field with a non-concrete type, preserve the
type in the `UnboundElementType` regardless. It's not really problematic
to have a non-concrete type there, and this makes it easier to track the
instruction used to specify the type.
This is a step towards switching symbolic types to always be abstract
during type checking.
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`.
Instead of storing a `TypeId` that always refer to a facet type that
always contains exactly a single interface, store the interface
directly.
Also improve stringification of `LookupImplWitness` and witness access
into it, switching to using newly-added functionality for stringifying
specific interfaces.
Perhaps we will disallow member lookup on and conversion of runtime
facet values. For now, leave a TODO and produce a TODO diagnostic
instead of crashing.
Related to #5241.
Reduce usage of `GetConstantInSpecific` to a single caller in constant
evaluation, with a TODO to remove that.
This gets us closer to being able to fully perform type-checking against
abstract types instead of types anchored within a particular generic.
Fixes#5186
With @zygoloid's kind assistance, this generalizes the existing
non-const lowering of ClassInit, that had previously only handled
InitializeFrom, to find other cases - such as a nested ClassInit used to
initialize a class member.
This refactors the `FindReturnSlotArgForInitializer` from
`check/convert.cpp` into `sem_ir/file.{h,cpp}` for use from lowering
(since lower doesn't depend on check, which I assume is an intentional
layering constraint - so figured it made sense to move it to sem_ir, and
found one or two similar-ish utility functions in `sem_ir/file.{h,cpp}`,
so figured that was a good spot)
What this does:
- Adds tracking where storage is allocated.
- Determines if that storage supports destruction and, if so, records
the `destroy` function for it.
- Calls any found `destroy` functions when going out-of-scope.
What this does not do:
- Precise scope tracking of temporaries. We currently don't define
temporary scopes, which would probably be the solution.
- Destruction for anything but a `class` with `fn destroy`, in an
implicit return. That excludes:
- Classes with members that need destruction, particularly in the
absence of `fn destroy`.
- Structs, tuples, and arrays.
- Explicit returns, break, continue, nested scopes.
Noting the exclusions in particular, I think those will need work to
support, but this should set the right framework.
The cleanup block concept stems from clang and trying to share code
across cleanups, from discussion with chandlerc. Note in this
implementation I try to find `destroy` functions early on: that's so
that, when destruction is present on multiple paths, particularly
non-shared paths, we only bind the `destroy` method once.
Implementation-wise, I'll note this adds a `has_cleanup` flag to
`TemporaryStorage` and `VarStorage`. There are several related options,
but this felt similar to other information we're trying to track on
instructions. My goal with this is to mitigate the chance of accidental
calls where the storage may not be tracked for destruction. Alternatives
I considered were to not add the flag (I was worried about heightened
risk of errors), or to just add a concept for the relevant `requires`
(which just felt inconsistent).
Cleanup logic ends up in control_flow in this change because I thought
it was a reasonably consistent place for the cleanup block concept and
its pretty direct control flow interactions.
Resolves TODO by creating new function `GetAssociatedValue` with the
logic from `PerformCompoundMemberAccess` restricted to the
non-instance-binding case.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
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>
Implements the rule:
> For compound member access `a.(b)` where `b` names a _non-instance_
member of an interface `I`:
> * `a` is implicitly converted to `I`
> * let `T` be the result of symbolically evaluating the converted
expression
> * `impl` lookup is performed for `T as I`.
>
> Instance binding is never performed.
See
https://docs.carbon-lang.dev/docs/design/expressions/member_access.html#impl-lookup-for-compound-member-access.
Before this PR, non-instance members were treated as instance members.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
* `IsInstanceMethod` can look in the function's `self_param_id` instead
of iterating through all of the implicit parameter patterns.
* An associated entity is always associated with a single interface, so
we don't need to handle the case when it isn't.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
The name scope lookup and member name lookup both need to handle the
case where the base inst is a FacetAccessType. Then we move from the
FacetAccessType to the FacetType which is the type of the instruction
inside the FacetAccessType.
We do name lookup on FacetType already, so "unwrapping" the
FacetAccessType to the FacetType just makes use of that path. Similarly
we do member access on FacetType already, so we can reuse that codepath
with the FacetType found in the FacetAccessType.
There aren't remaining uses on `Context` other than `DiagnosticEmitter`
itself. I'm adding `SemIRLoc` because I feel odd about having both
`Carbon::Check::DiagnosticBuilder` and
`Carbon::DiagnosticEmitter<T>::DiagnosticBuilder`, but it seems
relatively little additional typing outside the handful of
`DiagnosticEmitter` uses on `Context` itself:
```
Context::DiagnosticEmitter
DiagnosticEmitter<SemIRLoc>
Context::DiagnosticBuilder
SemIRLocDiagnosticBuilder
Context::BuildDiagnosticFn
BuildSemIRLocDiagnosticFn
```
Also clean up #include's while I'm finishing here.
This in particular uses free functions because it's likely to end up
more consistent with types (versus a wrapper object for InstStore).
Note, this is unlikely to have a performance impact, but if it does, we
can look into related approaches (and we've already discussed using
LTO).
Renames `PendingBlock::AddInst` to `PendingBlock::Add` because
`MakeElementAccessInst` expects the matching name to exist.
This creates a new check/type.h for most logic, and also moves some
functions to TypeStore in sem_ir/type.h. My approach for TypeStore is to
focus on moving the read-only functions there.
Dana Jansens
Geoff Romer
Jon Ross-Perkins
Richard Smith
David Blaikie