Commit Graph
138 Commits
Author SHA1 Message Date
Dana Jansens ab12da7d03 Rename BoundMethod::function_id to function_decl_id (#4775)
The InstId in this field is to an instruction that declares the
function, rather than the function itself, so that diagnostics can print
where the function is coming from. The type of the function (the
FunctionType instruction) is the type (the type_id) of the
function_decl_id. So we rename the field to help make this distinction
more clear.

Followup to #4739
2025-01-08 19:08:56 +00:00
Boaz Brickner 74395ce693 Change name poisoning implementation to allow better diagnostics (#4764)
Change the implementation to use an explicit `is_poisoned` bit instead
of `InstId::PoisonedName` value.
Zero behavior change.
This would allow to more easily change the API to support accessing the
poisoning declaration so we can have better name poisoning diagnosis.
#4622
2025-01-08 08:36:14 +00:00
725e80f0d3 Fix a bug importing declarations in generics (#4752)
Imported declarations that are contained within a generic, such as an
`impl forall...` would be given an abstract symbolic constant value
instead of a concrete generic value in some cases where the function was
used in an api file and impl file of the same library. This caused #4679
to fail using `ImplicitAs.Convert` transitively imported from the
prelude.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-01-02 23:56:43 +00:00
c5fd8f42b8 ImplWitness (#4679)
* 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>
2025-01-02 23:03:11 +00:00
josh11bandJosh L 5169a1862e Require a definition in the same file as an impl declaration (#4719)
This PR detects the failures that #4709 fixes.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2024-12-20 17:00:53 +00:00
Jon Ross-PerkinsandRichard Smith 3f9a06aee3 Look at flipping clang-tidy's misc-* to enable-by-default (#4699)
I was wondering, instead of treating `misc` differently and enabling
specific checks, maybe we can flip that since we actually seem okay with
most of the checks?

The main check I'm enabling, with significant edits here, is
`misc-no-recursion`. But maybe this is helpful to enable, even with the
necessary NOLINTs, since we want to avoid recursion in the toolchain?
This PR shows some example fixes in subst.cpp (which are more stylistic,
since the code shouldn't actually have recursed due to its structure; I
think we could remove the warning on TryResolveInst the same way). Some
also just don't seem worth fixing, like those in tests files (I didn't
see a way to exclude files in .clang-tidy, so instead I'm using
NOLINTBEGIN). But I think we might actually want to fix inst_namer, and
there's enough in convert that I didn't look closely.

Also, I made some protected -> private style fixes based on
`misc-non-private-member-variables-in-classes` (this is also how I
noticed `class Real` versus `struct Real`). With node_stack, it looks
like the `protected` wasn't even used. [Per
style](https://google.github.io/styleguide/cppguide.html#Access_Control),
data members should be private outside tests. But since we can't
trivially exclude `protected` members in tests, I'm turning it off -- I
don't view it as offering enough benefit on the whole.

migrate_cpp issues are preexisting (I believe we just aren't monitoring
it), but changes there make `bazel build --config=clang-tidy -k //...`
work cleanly.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2024-12-17 21:20:37 +00:00
9c8773da1b Basic name poisoning support (#4654)
https://github.com/carbon-language/carbon-lang/issues/4622
When using an unqualified name, disallow declaring that name in all
scopes that would make it ambiguous in retrospect.
Doesn't include support for poisoning in `impl library` (see new test
for that with TODO).
Implemented by introduce `InstId::PoisonedName` and entries with it to
`NameScope`.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
2024-12-17 21:08:26 +00:00
Richard Smith 62f7345bb7 Import support for Call and BoundMethod. (#4695) 2024-12-17 08:26:18 +00:00
Richard Smith a10c79569e Model Core.Int as a class type (#4644)
Instead of treating `Core.Int` as the toolchain's builtin `IntType`,
model it as a class that adapts the builtin type. This aligns us better
with the intended language model, gives an associated library for
`impl`s involving `Core.Int` to live within, and opens the door adding
member functions to `Core.Int` if we decide that is desirable.
Remarkably it also seems to make the formatted SemIR a little smaller,
because a call to a generic class generates less IR than a call to a
function.
2024-12-16 22:19:23 +00:00
Richard Smith 0d835699e3 Import support for array types. (#4675) 2024-12-12 23:09:28 +00:00
Richard Smith 758b6c42ba Produce a note indicating where the specific was used from if monomorphization fails. (#4662)
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.
2024-12-11 22:34:10 +00:00
Richard Smith 47285b6207 Include a fully-qualified name when stringifying types. (#4657)
For example, format the `ImplicitAs` interface as `Core.ImplicitAs`
rather than simply `ImplicitAs`.

When importing an entity in a namespace, also import a declaration of
the enclosing namespace if necessary so that we can determine its name.
2024-12-11 16:33:53 +00:00
Richard Smith eabe9f117a Track complete types required by a generic. (#4652)
When a generic requires a symbolic type to be complete, add a new
`require_complete_type` instruction to the generic eval block. During
monomorphization of such an instruction, require that type to be
complete.
2024-12-10 03:00:28 +00:00
Boaz Bricknerandjonmeow daba2c72cf [NFC] Convert NameScope from struct to class (#4623)
This is a preparation change for adding name poisoning support
(https://github.com/carbon-language/carbon-lang/issues/4622), which is
expected to require more elaborate logic around NameScope since a name
can be not defined yet, defined, or poisoned.

The API separates looking up a name from getting the full entry since we
have cases where the entries are invalidated between the time we're
looking for the name and when we access (and sometimes modify) the
entry.

This change has the following benefits:
* `names` and `name_map` are internal to `NameScope` and are guaranteed
to match.
* `extended_scopes` and `import_ir_scopes` can not be manipulated (only
new scopes can be added).
* `inst_id`, `name_id` and `parent_scope_id` are constants.
* `has_error` can only be mutated from false to true.

---------

Co-authored-by: jonmeow <jperkins@google.com>
2024-12-06 21:50:50 +00:00
Jon Ross-Perkins 1cba3328f7 Finish removing BuiltinInstKind (#4637) 2024-12-05 22:07:51 +00:00
Jon Ross-Perkins efab39cbd9 Remove InstId::Builtin members (#4632)
- `InstId::Builtin<Inst>` -> `<Inst>::SingletonInstId`
- `InstId::PackageNamespace` -> `Namespace::PackageInstId`
2024-12-05 18:13:46 +00:00
Richard Smith 80a3dc83bc Fix impl lookup to properly look in the IR containing a transitively-imported entity. (#4625) 2024-12-04 21:38:19 +00:00
josh11bandJosh L 6260f0fecf Fix bug introduced in #4613 (#4624)
Issue was not properly handling `ImportRef` instructions in
`AddAssociatedEntities` in `check/import_ref.cpp`. Using `CARBON_CHECK`
instead of `CARBON_FATAL` was hiding the error.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2024-12-04 21:16:54 +00:00
Jon Ross-Perkins 0e92e6cc5a Switch TypeId::TypeType to TypeType::SingletonTypeId, and similar (#4619)
`ids.h` and `ids.cpp` are the manual edits, everything else is
search-and-replace.

The full list of things moved is:

- `TypeId::TypeType`
- `TypeId::AutoType`
- `TypeId::Error`
- `ConstantId::Error`

This is to unblock removing `InstId::Builtin*`.
2024-12-04 18:40:50 +00:00
Geoff RomerandRichard Smith 78d7a7c291 Remove return_slot_id (#4577)
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2024-12-04 00:21:24 +00:00
33110d096c Facet types support rewrite (where .A =...) constraints (#4613)
* Rewrite constraints are stored in a facet type, substituted, imported,
and formatted.
* We now distinguish `.Self` from other symbolic bindings in two ways:
* `.Self` itself now has an invalid compile time binding index (since it
doesn't bind to any of the generic parameters). As a result, we no
longer need to create a generic region in `handle_where.cpp`.
* There is a new phase tracking values that are only symbolic because
they transitively depend on `.Self`. This allows us to give the result
of a `where` expression template phase as long as it doesn't use any
symbolic constants other than `.Self` or other designators.
* `AddConstant` has been removed from `check/context` since it was only
used from `eval`. This meant less plumbing of the phase change.
* Evaluation of `BindSymbolicName` now also performs substitution into
its type.
* Include a bit more information in some diagnostics.
* `StringifyTypeExpr` outputs rewrites, which required adding support
for associated entities as well.
  * Associated entities now have an entity name set when importing.
* Adds tests for some interesting cases with rewrites and uses of
`.Self` mixed with other symbolic constants.

Still to do:
* There is no validation that any particular type satisfies rewrite
constraints.
  * Access to members of a facet type do not see the rewritten values.
* Impls don't recognize whether associated constants have rewrites
setting their values.
  * No support for resolving facet types.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2024-12-03 22:44:39 +00:00
Richard Smith 831dd2c929 Fix importing of the complete_type_witness for a generic class. (#4600)
We need to create an instruction on import to attach the generic
constant value to.
2024-11-28 00:13:21 +00:00
Richard SmithandJon Ross-Perkins d6ec885eb3 Track the type as written in BaseDecl and AdaptDecl. (#4564)
Represent the type as an `InstId` rather than as a `TypeId` to preserve
how it was written and better support tracking its value in a generic.
Add accessors to `Class` to get the base and adapted type to reduce code
duplication, and add `TypeStore::GetObjectRepr` to make it easier to map
from a type to its possibly-adapted object representation type. In
passing, also move `GetIntTypeInfo` and `GetUnqualifiedType` into
`TypeStore`.

This fixes specifics of generic adapters to properly look at the
specific adapted type, and also fixes importing of adapters.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-11-27 22:26:30 +00:00
Richard Smith c0faa81961 Switch most of ImportRefResolver to non-member functions (#4584)
In preparation for further refactoring, switch away from member
functions for most of `ImportRefResolver`.

Split `ImportRefResolver` into a context class that exposes the value
stores for the source and destination files, and a derived class that
maintains a worklist. The idea is to statically enforce that functions
that take `ImportContext` cannot accidentally add new work, because they
don't have access to the work queue.
2024-11-26 01:44:59 +00:00
Geoff RomerandJon Ross-Perkins 4f816dd03f Remove param_refs and implicit_param_refs (#4479)
This introduces `calling_convention_param_ids`, a single block that
consolidates all the information that was being used by consumers of
`param_refs` and `implicit_param_refs`, in a form that's easier to
produce and typically easier to consume.

See also [this Discord
discussion](https://discord.com/channels/655572317891461132/655578254970716160/1300545448909738125)
regarding the decision to keep the return slot last in the SemIR calling
convention, even though it goes first in the LLVM calling convention.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-11-22 18:34:21 +00:00
67f2c9ce26 Add a FacetValue instruction (#4545)
The new `FacetValue` instruction represents `C as I` for some type `C`
and facet type `I`. It is named `FacetValue` instead of just `Facet` to
parallel the `FacetType` instruction.

This PR uses this instruction represent the facet value `Self` in an
`impl` declaration. This instruction will be used in the future to also
support things like:

* `C as I` where `C` is a class; and
* forming a specific for a generic with a `T:! I` parameter where `T` is
being given a concrete value.

(Here `I` is an interface or other non-`type` facet type.)

Also do some renaming and add some comments to make things a bit more
clear.

* `FacetTypeAccess` -> `FacetAccessType` to clarify this is not access
of a facet type, but access of the type of a facet
* `.facet_id` -> `.facet_value_inst_id` to parallel the `FacetValue`
instruction

`FacetAccessWitness` will be in a future PR.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2024-11-21 22:29:53 +00:00
Richard Smith 5e4038048b Import the full list of extended scopes. (#4562)
Replace the special case adding the base class to the list of extended
scopes with a fully general approach. We use an ImportRef to lazily
import the extended scopes on first lookup.
2024-11-21 20:56:39 +00:00
Jon Ross-Perkins 4a80d6758d Rename the builtin FloatType to LegacyFloatType, Error to ErrorInst (#4555)
This is for more clearly distinct names, and to make it a clearer
transition from `BuiltinInst` for name conflicts. `FloatType` is also an
instruction, and we have `Carbon::Error` (common/error.h). This avoids
affecting tests, although the name is embedded in the builtin test.

In `LegacyFloatType`, `Legacy` because I was having trouble coming up
with a more appropriate name. I'm not clear this is a `FloatLiteralType`
at present, it needs some work to mirror `IntLiteralType`.

In `ErrorInst`, the suffix `Inst` was discussed as good and similar to
`BuiltinInst` (although I'm trying to get rid of that).
2024-11-19 20:37:39 +00:00
josh11bandJosh L abd12c18c7 Support extended scopes that are parameterized types (#4524)
* The `extended_scopes` in a `NameScope` were represented by a
`NameScopeId`. Replace that with an `InstId` of an instruction returning
the type that is extending this name scope.
* `Context::LookupQualifiedName` now can take multiple scopes to look
in.
* `GetAsLookupScope` was moved out of `member_access.cpp` and is now
`Context::AppendLookupScopesForConstant`

This PR also fixes some existing issues that were revealed as part of
writing and testing this PR:
* Additional validation and handling of invalid ids.
* `extend impl` in a class is not properly imported yet, but at least
now it doesn't crash.

The change to use an `InstId` also allowed some diagnostics and
formatting to be improved.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2024-11-13 23:48:02 +00:00
3ba4997855 Canonicalize away bit width and embed small integers into IntIds (#4487)
The first change here is to canonicalize away bit width when tracking
integers in our shared value store. This lets us have a more definitive
model of "what is the mathematical value". It also frees us to use more
efficient bit widths when available, such as bits inside the ID itself.

For canonicalizing, we try to minimize the width adjustments and
maximize the use of the SSO in APInt, and so we never shrink belowe
64-bits and grow in multiples of the word bit width in the
implementation. We also canonicalize to the signed 2s compliment
representation so we can represent negative numbers in an intuitive way.

The canonicalizing requires getting the bit width out of the type and
adjusting to it within the toolchain when doing any kind of math, and
this PR updates various places to do that, as well as adding some
convenience APIs to assist.

Then we take advantage of the canonical form and embed small integers
into the ID itself rather than allocating storage for them and
referencing them with an index. This is especially helpful for the
pervasive small integers such as the sizes of types, arrays, etc. Those
no longer require indirection at all. Various short-cut APIs to take
advantage of this have also been added.

This PR improves lexing by about 5% when there are lots of `i32` types.

---------

Co-authored-by: Dana Jansens <danakj@orodu.net>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-11-13 09:36:20 +00:00
josh11bandJosh L 39ed62dad7 Add facet_types() accessor to Check::Context (#4518)
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
2024-11-13 01:20:07 +00:00
David Blaikie 79c5c47911 Preserve the is_dynamic property of classes when importing them (#4501)
The test update shows a class derived from an imported base class with a
vptr, and without this change the derived class got its own vptr, with
this change the derived class can see the base is dynamic, so the
derived doesn't need to add a vptr and can rely on the base class's vptr
instead.
2024-11-12 16:11:19 +00:00
a69c2630f9 Replace InterfaceType with FacetType (#4499)
This does a few things:
* Replaces the single `TypeId` in the `FacetTypeInfo` struct with a
vector of `InterfaceId`, `SpecificId` pairs (sorted in id order)
representing the set of interface requirements of the facet type. This
will later be used to support facet types with multiple interface
requirements (as in `I & J` or `I where .Self impls J`).
* Replace `InterfaceType` instructions (used as the type of an
`InterfaceDecl` instruction) with `FacetType` instructions (introduced
in #4460) with a (newly introduced) `FacetTypeFromInterface()` function.
* Replace code that consumed `InterfaceType` values with code that
consumed `FaceType` values. I've generally left the assumption in the
code that it is dealing with a single interface, using the (newly
introduced) `FacetTypeInfo::TryAsSingleInterface`, and producing an
error otherwise. There isn't yet support for the `&` operator or `where
.Self impls`, so this is generally a good assumption for now, except you
can get a facet type with no associated interfaces from a `type
where`... expression. In some cases, the facet type value is pulled from
the evaluation of an `InterfaceDecl` instruction, where the single
interface assumption will hold permanently.
* Some related cleans up: nicer stringification and formatting of facet
types, suppression of some errors when there already was an error.

There is still a lot left to do, including:
* Type `type` should be a facet type with a reserved id, replacing the
built-in instruction.
* Code using `TryAsSingleInterface` should generally be upgraded to
handle more than (or less than) one interface. Name lookup should be
particularly exciting.
* Operator `&` should be defined on facet types, unioning their
interface and other requirements.
* Requirements from a `where` clause don't do anything yet.
* Impls and impl lookup need to resolve facet types, and do things like
determine if all the associated constants are given values.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
2024-11-11 18:01:50 +00:00
Geoff RomerandRichard Smith 5759ad8b42 Remove forward references from binding patterns (#4494)
This is primarily to free up space in the BindingPattern insts, but as a
side effect it moves the link between BindingPattern and its BindName
out of the SemIR, and into a transient data structure in Context.

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2024-11-08 20:18:22 +00:00
Jon Ross-Perkins be56ff87c6 Convert StructTypeField to a specific type. (#4492)
This converts `StructTypeField` from an instruction to a dedicated type,
with its own store. This had originated from discussing how
`.GetAs<SemIR::StructTypeField>` was more prevalent than for other
instructions, but is probably more interesting for the storage savings
(16 bytes StructTypeField + 4 byte LocId + 4 byte InstId -> 8 byte
StructTypeField).

Due to the different structure, these now have their own stack during
construction, reducing (but not eliminating) `args_type_info_stack_`
use-cases.

The test changes of different InstIds is expected because structs and
classes generate fewer instructions now. Other than that, results should
remain the same.

I'm generally trying to avoid unrelated cleanup here due to the PR size,
though I did scrutinize the `VerifyOnFinish` calls, adding one and
commenting others (putting them in member order because that's how I was
checking what was verified and what wasn't).
2024-11-06 21:38:27 +00:00
Richard Smith a68acb1975 Fix crash lowering an imported impl method. (#4489)
While we don't need a lookup table for an imported impl from a different
library, we do still need to import the name scope so we can compute the
parent scope for mangling purposes.
2024-11-05 20:38:26 +00:00
Richard Smith 9c8ca2f6e9 Don't track generic insts created while importing an impl. (#4485)
Fixes a crash when we unexpectedly find a symbolic binding is created in
a non-generic entity.
2024-11-05 02:55:17 +00:00
Richard Smith db76e81630 Rename IntLiteral to IntValue. (#4475)
This instruction represents integer values, whether they come from
literals or calculations, so it the old name is inaccurate. I also plan
to rename `BigInt` to `IntLiteral` based on recent discussion and this
change aims to avoid confusion stemming from the same name being used
for two different things.

I'm not renaming `FloatLiteral` because recent discussion suggests we
may want distinct `FloatLiteral` versus `FloatValue` representations in
SemIR.
2024-11-02 01:19:39 +00:00
Richard Smith fab07726c9 Add import support for int_type. (#4466) 2024-10-31 23:05:25 +00:00
Richard Smith 3192cfc776 Add import support for specific_function constants. (#4465)
These can currently only be imported as part of the eval block for a
generic, because they only show up as the callee of a call instruction.
2024-10-31 20:13:05 +00:00
Geoff RomerandJon Ross-Perkins e20e8bfbea Consolidate caller match in one function call (#4446)
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-10-29 23:31:50 +00:00
Richard Smith a0609b9155 Don't eagerly import all impls. (#4447)
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.
2024-10-26 00:38:24 +00:00
Geoff Romer b67d03126e Separate inst kind for out params (#4442) 2024-10-24 15:22:32 +00:00
Geoff Romer 9266f867f9 Model the return slot as an output parameter (#4432)
Also fix `Param` insts to have meaningful names in pretty-printing, to
help clarify relationship with return slot.
2024-10-23 16:53:34 +00:00
Geoff RomerandJon Ross-Perkins 9d942f4633 Generate parameter pattern-match IR from pattern IR (#4388)
Also propagate the pattern IR along with the pattern-match IR, and use
it where appropriate.

Strictly speaking, some parts of the pattern-match IR are allocated
eagerly, while traversing the pattern's parse tree, but they still
aren't actually emitted until we traverse the associated pattern insts.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-10-16 19:15:29 +00:00
82937e1a3c Change how to get info for a parameter (#4366)
Updates `SemIR::Function::GetParamFromParamRefId` to return more
information in the form of a new `ParamInfo` struct. This struct has a
method for getting the `NameId` from the name binding instruction. The
callers previously got it from the `Param` instruction, but the plan is
for that instruction to no longer be associated with a name.

---------

Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
2024-10-04 16:30:00 +00:00
Richard Smith 568ad197d1 Track the instruction used to name the type and constraint in an impl. (#4368)
This is necessary in order to have access to the specific versions of
their constant values in a generic impl.

Stub out impl deduction.
2024-10-04 00:06:55 +00:00
Geoff Romer e617d64939 Remove parameter-constant arrays from import_ref (#4360)
This makes the code more resilient to changes in the structure of
parameter insts, and could help avoid bugs by making the
ImportRefResolver's data structures the single source of truth.
2024-10-03 19:39:12 +00:00
Richard Smith 5ab957d012 Make ImplDecls evaluate to themselves. (#4352)
Change ImplDecls so they evaluate to themselves in general, rather than
having a special case in import handling that pretends that they do.
2024-09-27 22:39:56 +00:00
Richard SmithandJon Ross-Perkins 2f3ad26f0e Basic support for declaring generic impls. (#4336)
Update impl handling to more closely match other kinds of declaration,
including support for declaring and defining gneeric `impl`s.

When of performing redeclaration lookup for impls by looking for the
self and constraint type, produce a list of impls rather than a single
impl because it's possible for there to be multiple impls with different
deduced parameters but the same self type and constraint. Following
#3763, only consider impls to be redeclarations if they're spelled the
same, not just if they have the same self and constraint types.

No support yet for impl selection to deduce the arguments of a generic
impl.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
2024-09-27 21:18:24 +00:00