Update the rules for member access:
- Simple member access `a.b`
- If `a` names a scope, performs name lookup and optionally `impl`
lookup.
- Otherwise, `a.b` is shorthand for `a.(typeof(a).b)` and always
performs instance binding.
- Compound member access `a.(m)` does optional `impl` lookup and always
performs instance binding.
- This is a change from only performing instance binding if `m` is an
instance member.
- New operation `a.impl(m)` is introduced. It always performs `impl`
lookup, and nothing else.
- The `BindToType` interface is removed. Only instance binding may be
customized (using the `BindToValue` and `BindToRef` interfaces).
As a result, member access doesn't use whether the right operand is an
instance member anymore. Instead, instance binding is performed whenever
it would be plausible, and a new syntax is used to opt out.
Assisted-by: Gemini via Antigravity
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Recently noticed this issue when creating a proposal using
`new_proposal.py` in a `jj` workspace.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Incorporates changes from these proposals:
- #2022
- #2875
- #3262
- #3763
- #3848
- #5434
A small amount of updating was done to lambdas.md and variadics.md to
harmonize with these changes.
Assisted-by: Gemini via Antigravity
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
Also:
- Introduce `buf` so that existing examples using arrays can be updated
to use it.
- Update the examples linked to on the Carbon front page to something
closer to what we expect, moving away from old array syntax. Uses
`slice` though that name hasn't been settled. Updating the SVGs actually
referenced will need to be done as a separate step.
- Update links to the expression operators while I'm touching that
section.
Assisted-by: Gemini via Antigravity
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Nicholas Bishop <nbishop@nbishop.net>
Note that #7266 has already updated the toolchain for `char`, but not
`Core.CharLiteral`.
Assisted-by: Gemini via Antigravity
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
`@` refers to the current workspace's working copy, but if we want the
command to respect the working copies of other workspaces, we should use
`working_copies()` instead; see
https://docs.jj-vcs.dev/latest/revsets/#functions .
Also remove `all() &` while here, since it is always redundant.
Assisted-by: Google Antigravity
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
In particular, bazel builds would previously fail in
`workspace_status.py` if you didn't have a `.git` with this error:
> ```
> ERROR: <builtin>: BazelWorkspaceStatusAction stable-status.txt failed:
Failed to determine workspace status: Process exited with status 1
> fatal: not a git repository (or any of the parent directories): .git
> ```
Assisted-by: Google Antigravity
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
- A parameter binding can be marked `ref` instead of `var` or the
default. It will bind to reference argument expressions in the caller
and produces a reference expression in the callee.
- Unlike pointers, a `ref` binding can't be rebound to a different
object.
- This replaces `addr`, and is not restricted to the `self` parameter.
- A `ref` binding, like a value binding, can't be used in fields of
classes or structs.
- When calling functions, arguments to non-`self` `ref` parameters are
also marked with `ref`.
- The return of a function can optionally be marked `ref`, `val`, or
`var`. These control the category of the call expression invoking the
function, and how the return expression is returned.
- These may be mixed for functions returning tuple or struct forms.
- The address of a `ref` binding is `nocapture` and `noalias`.
- We mark parameters of a function that may be referenced by the return
value with `bound`.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Geoff Romer <gromer@google.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
We make 5 changes:
- Allow `require Self impls I` in an `interface` or `constraint` scope
to omit the `Self`, so it can be written `require impls I`.
- Rename `extend I` to `extend require impls I` in an `interface` or
`constraint` scope.
- Define `extend impl as I` and `extend final impl as I` in an
`interface` scope to copy the members of `I` and define an `impl` of `I`
in terms of the extending interface.
- Allow a non-final `impl` to overlap a final `impl` as long as it isn't
subsumed by the final `impl`. The final `impl` will be given priority on
the overlap.
- Allow `final` on a `match_first` block, used to declare overlapping
final impls.
These features work together to allow a form of interface extension
where:
- Types only need to `impl` the extending interface to also get an
`impl` of the extended interface.
- Multiple interfaces can extend the same interface.
- An interface can extend multiple interfaces.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Dana Jansens <danakj@orodu.net>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
```
class C {
impl as I;
}
```
is redeclared
```
impl C.(as I)
```
for purposes of `match_first`/`impl_priority` blocks and definitions.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
* "extending non-facet-type constraint" is already diagnosed by
`ImplAsNonFacetType`
* `impl` declarations with errors in the facet type no longer require
definitions
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Dana Jansens <danakj@orodu.net>
Implements some of the changes from proposal #5168.
* The data structure for complete facet types has been repurposed for
identified facet types. Identified facet types are now a concept in the
toolchain, but without named constraint support they are not
substantially different from incomplete facet types.
* Identified facet types keep the list of required specific interfaces
in sorted order, for efficiency improvements in impl lookup. Found
another way to identify the interface to impl (or number of impls if not
1).
* Forward `impl` declarations of identified but incomplete facet types
are allowed unless the facet type has rewrites. An incomplete facet type
with rewrites is already either an error or has more than one interface
and so can't be implemented, so this case can't be exercised very well
yet.
* Forward `impl` declarations of interface without rewrites use a
placeholder inst block for the witness.
* Changed some machinery to use RequireIdentifiedFacetType to access the
interfaces of the facet type so we only need to add support for
expanding named constraints into interfaces in one place.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Dana Jansens <danakj@orodu.net>
Don't look for a user-defined conversion (implementation of `As` or
`ImplicitAs`) if the builtin conversion to a facet type fails impl
lookup. This is the behavior we want, and reduces noise in diagnostics.
Partial implementation of #5122. Still to do:
* Give an error if the users tries to implement such a conversion, since
it is now unreachable.
* Add notes to the diagnostic explaining why impl lookup failed.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
As of #5087, these terms are no longer synonyms. This change preserves
the original meaning.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Merges in the "subtyping" tests from the `impl/lookup` directory along
with some new tests into
`convert_facet_value_to_narrowed_facet_type.carbon` in the `facet`
directory.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
This example motivated a decision to add a feature where we do impl
lookup to see if there is a matching `final` impl even in some cases
where it is already established that the type implements the interface.
I don't know when we plan on implementing this, but I wanted to capture
the example as test so we would have a TODO to address it.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
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>
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>
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>
Exclude SemIR since the point of the test is that it diagnoses something
invalid, not that any particular SemIR is produced.
Co-authored-by: Josh L <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>
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>
Here are some test changes so the diffs that come from my upcoming
functionality changes are easier to see. Upcoming functionality
includes:
* Compound member access with non-instance associated constants will
change to comply with the design
https://docs.carbon-lang.dev/docs/design/expressions/member_access.html#impl-lookup-for-compound-member-access
in #5059 .
* Impl lookup will add support for finding impl witnesses in facets
#5060
I'm also making the toolchain/check/testdata/impl/compound.carbon test
into a no_prelude version, and adding a version that tests with
importing.
---------
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>
TODO to resolve whether it should conditionally say "object of"
depending on the category
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Make facet types complete like other types. This means that in the body
of an interface, the type of `Self` is incomplete. This involved fixing
an issue where eval of a specific_id that was already canonical was not
resolving the specific declaration, which could occur as part of
substituting into a facet type.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Dana Jansens <danakj@orodu.net>
Expands the CompleteTypeInfo to include information about abstract
classes and computes that information as part of completing the type.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Dana Jansens <danakj@orodu.net>
Currently the toolchain does not recognize that tuples and structs with
abstract elements should be considered abstract.
Also make the existing `fail_abstract` test into a `no_prelude` test.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
* Add `RequireCompleteFacetType` and `ResolveFacetTypeImplWitness` to
`check::Context`. Goal was to move code from `impl.cpp` (mostly) without
functional changes.
* Complete type information is cached with the facet type, and is stored
in a `complete_facet_types()` table.
* Main functional change is to diagnose attempts to use a rewrite
constraint on an associated function. Some existing diagnostics have
been updated.
* Remove `check::Context::RequireDefinedType`:
* For class types, use `RequireCompleteType`
* For facet types, use `RequireCompleteFacetType`
* Introduce a `SemIR::SpecificInterface` to hold an interface and
specific id pair.
* Keep the specific interface ids in the impl object.
* Avoid some extra copies in `Dump` functions.
* Future work missing from this PR:
* Resolving for member access or actions that require impl lookup.
* Resolving rewrites constraints that refer to non-concrete values.
* Any support for adding implied constraints that result from a `where`
clause (though TODOs have been added).
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: Dana Jansens <danakj@orodu.net>
Based on [the lastest thinking on
#4672](https://github.com/carbon-language/carbon-lang/issues/4672#issuecomment-2606209281)
, require a full syntactic match for impl redeclaration, instead of
excluding the `where` restriction. This means no updates to the impl
witness on redeclaration, and no diagnostics that those updates are
consistent.
Not included in this PR, but will need to be done in the future:
* Support for assigning values to associated constants in the body of
the impl definition. This will require moving the checking that
non-function associated constants are set from the definition start to
definition end.
* Identify semantic redeclarations that are not syntactic matches to
give a failed redeclaration diagnostic. This should be done once we are
already identifying impl declarations with the same type structure in
order to require they be identified in an impl_priority/match_first
block.
* Merging of the functions in `check/impl.cpp` that are now always
called together.
Also add some test coverage of `where` parsing I developed in PR I've
now abandoned because of this new simplification of the impl
redeclaration semantics.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
With this change, we now support impl of interfaces with non-function
associated constants.
Also:
* Make impl diagnostics use more consistent names
* Make some impl tests "no_prelude"
Still to do:
* Facet type resolution as a separate, reusable step
* Using the assigned values of associated constants (see
`fail_todo_use_assoc_const.carbon`)
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
* Implement ignoring the difference between `Self as` and `as`, as well
as `where` clauses at the end of an `impl` declaration when checking
whether `impl` declarations match, from #3763.
* Allow impl declarations with different constraint ids to match, as
long as the facet type of the constraint has the same interface_id and
specific_id.
* Add some TODOs reflecting future facet type resolution.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
In practice, I am unable to call constructors like `SemIR::InstId` from
a debugger. I first tried to use
https://clang.llvm.org/docs/AttributeReference.html#noinline to make
some non-inline calls to the constructor, but that didn't work:
```
toolchain/sem_ir/dump.cpp:245:23: error: 'noinline' attribute is ignored because there exists no call expression inside the statement [-Werror,-Wignored-attributes]
245 | [[clang::noinline]] return InstId(inst);
|
```
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Follow-on to #4669 . Did some manual testing, but may have not exercised
all code paths.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
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>
* 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>
Note that I left some calls to `is_defined()` where I thought they were
interchangeable.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Comment became out of date with #4698 . Seems better to delete instead
of update this comment.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
The instructions did not match the example. The VSCode settings suggests
the example is the correct one.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
When substituting into a generic in order to form a generic eval block,
we form `SpecificId`s to track the list of arguments that should
eventually be used to form a specific referenced by the eval block.
Values within that specific are not needed and won't ever be used, so
it's safe to skip forming them in the first place.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
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>
* 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>
Goal is to reduce churn in names in test updates (by churning a lot of
them in this PR).
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
* Make the step stack into a class
* Make the operations on the stack (pushing, popping, test for done)
into methods on the stack class.
* Add more kinds of steps (array bound and name).
* Rewrite cases to use the new kinds of steps. Afterward, none use
`Step::Next()` or the step index, so those get removed.
* Add another convenience method `PushTypeId`.
* Remove the `SemIR::File&` member from the steps, since it doesn't
change.
Hopefully using `step_stack.Push`... calls makes it clear that they are
resolved in the reverse order they are executed.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
* Change format:
* previously there was a single link per talk, the video if available
* now there are separate "video" and "slide" links
* Adds link to video for 2024 CppNorth talk
* Adds link to slides for 2024 LLVM Developers' Meeting
* Restores links to slides from past years
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Adds `FacetAccessWitness` instruction and uses it in `member_access.cpp`
to support accessing members of facets. Still to do: interface witness
access is producing runtime values when it should produce symbolic
values.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Previously it would allow interface mismatches. We only need to support
the case where there is a single interface, though, which makes checking
much more straightforward.
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
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>
As discussed in #4530 . This required switching to using
`llvm::IntrusiveRefCntPtr` in a number of places.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
* 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>
