Fixes link failures when referencing a symbol involving a fingerprint
from a different package.
Previously we included the `Namespace`'s `import_id` as part of its
fingerprint, which caused local and imported namespaces to get different
fingerprints. We now store the `import_id` on the `NameScope` instead of
on the `Namespace` inst to avoid this problem.
Also, when we reach a package-level `NameScopeId`, consistently
fingerprint it as a (package name, library name) pair. Previously the
fingerprinting depended on whether it was imported or not, as an
imported `NameScopeId` had a parent scope (the current package). We need
to include the library name here so that private entities with the same
name in different libraries have different fingerprints.
When a class extends an interface, referring to a member name of the
interface as an unqualified name should refer to the class's
corresponding associated entity value, not to the associated entity
itself. Similarly, in an `impl`, unqualified names of associated
entities should refer to the `impl`'s corresponding value for that
entity.
To support this, we treat `impl`s as `extend`ing their implemented facet
type, and we make lookups into an extended facet type use the `Self`
type of the extending `impl` or `class` if lookup finds an associated
entity. We already did the latter if the extending entity was an
interface; this extends the existing support for these other cases.
A nested designator like `.(X.X1).(Y.Y1)` results in nested
ImplWitnessAccess instructions, which can produce cycles in the
toolchain easily when replacing `.Self`.
First, when constructing a facet type like `V:! Z where .Z1 impls (Y
where .Y1 = U)` we substitute replace `.Self` in the nested facet type,
and in this case we replace `.Self` with `.Z1` which contains a `.Self`
of its own. This was coming from us being lazy about replacing `.Self`
in an `impl as` declaration, such as `impl C as Z where .Z1 = .Self`.
The self type is known there, so we can more eagerly replace `.Self` as
we do in a `require impls` declaration. Then the replacement for `.Self`
never comes with a `.Self` that needs to also be replaced. Any resulting
`.Self` would always be the top-level one.
Second, when evaluating ImplWitnessAccess, we were replacing .Self in
the LHS of rewrite constraints, but the `.Self` may itself have a type
that contains rewrite constraints. If one of those rewrite constraints
has nested ImplWitnessAccess instructions, we evaluate the new
ImplWitnessAccess, which again finds rewrite constraints to replace
`.Self` in, and we repeat forever. For this one we just stop replacing
.Self in the LHS of rewrite constraints. Since they are always against
.Self, we can always look in the access facet's type for a value.
While fixing ImplWitness access, also correct the lookup to search
through the types of nested ImplWitnessAccess instructions to find a
rewrite value, since it may find it at any level up to the eventual
`.Self`.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
A `where` expression nested inside a `T impls X` constraint makes
`.Self` ambiguous on the right-hand side of the `where` if `T` is
anything other than `.Self`. After the `where`, the value of a `.Self`
could be `T` or could be the value of `.Self` before the `impls`
constraint: the so-called top-level value of `.Self`.
Implicit use of `.Self` in designators is always allowed, and they are
bound (and replaced by a reference) to the inner-most possible value of
`.Self`. On the right-hand side of the nested `where` above, they have
the value `T as X`.
`.Self impls ...` is also always allowed, since it acts more as a
keyword here, and it always refers to the inner-most possible value of
`.Self`.
Any other explicit use of `.Self` is diagnosed when ambiguous, in any
kind of constraint. This is done in the handling of `WhereExpr` since it
has enough context to allow `.Self impls` (which is an explicit use)
while disallowing other explicit uses. And because it has non-canonical
instructions to work with, so it is able to diagnose errors with precise
locations.
Since `.Self` is no longer going to be marked with depth modifiers, the
eval of `WhereExpr` does not need an input facet value instruction
representing `.Self` to compare with, as they are now going to all be
equivalent. So revert it back to just looking for the `PeriodSelf` name
id, through a shared helper being introduced as `IsPeriodSelf`. And drop
the period self InstId from the `WhereExpr` instruction. This causes
most of the formatted SemIR changes.
Move helpers for working with and replacing `.Self` to their own file,
out of the `facet_type.h` header/cpp files. These are working with
`.Self` facet values more than facet types, though `.Self` is a name
that only exists inside the scope of a facet type.
This resolves some todos, and makes `Convert` safer to call, which
unblocks some changes in pattern matching that I'm working on.
Assisted-by: Gemini 3.1 Pro via Antigravity
This is a step toward removing the index from `InitForm`, so that equal
form values always have equal representations.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This allows us to capture the location at which a type literal was used,
even in the cases where we don't otherwise need to create a new
instruction to represent the type such as for `char` or `str`.
The logic used to build the underlying type is now marked as desugaring.
For cases such as `iN`, this causes the call to `Core.Int` to no longer
be added as a dedicated IR instruction, and instead its constant value
is used directly as the value of the `type_literal`. This results in
this being on balance a reduction in the size of the IR.
This also fixes a crash in C++ interop when using a `char` literal as a
template argument. The crash was caused by the template argument not
having an associated location when mapping to a C++ location. See
changes to check/testdata/interop/cpp/template/type_param.carbon for an
example that used to crash before this change.
Update alias handling to allow an alias to point at any type literal,
reinstating support for aliases for type literals such as `bool` and
`i32` that had previously worked but stopped working when we
transitioned those types to being defined in the prelude. See changes to
toolchain/check/testdata/alias/builtins.carbon.
All the test changes other than the two mentioned above are mechanical
autoupdate changes switching to the new instruction.
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.
Pursuant to recent decisions on #6124, switch `Destroy` to use a
`CustomWitness` for its implementation. Right now this is manufacturing
no-op implementation functions on each lookup, which obviously isn't
ideal but is intended as a first pass. I'm mostly trying to find the
right balance between updating the approach to reflect new decisions,
while still breaking apart work in a way.
The `CoreInterface` logic is intended to build on `CoreIdentifier`
support. We have a number of additional interfaces that require
specialized logic, and that'll extend pretty far with C++ interop, so it
seemed easiest to have a generic function for it. That's what's
replacing the logic inside C++ interop that was doing string comparisons
(which could have already been moved to `CoreIdentifier`, I just missed
it in my first pass).
This adds `CustomWitness` support because the `Destroy` witnesses can be
imported cross-file. `CustomWitness` was previously only used for C++
types, which don't yet support import, which is why that wasn't
previously an issue. The addition of `query_specific_interface_id` is
similarly needed in order to get correct sorting of witness blocks when
imported.
This PR also removes builtin constraint logic (note this is in a
separate commit to help review; it's not a separate PR because it's
difficult to split apart without tests breaking). This had been made
generic with the expectation that destroy, copy, move, and conversions
would all need related support. Under the new decision, we are not going
to do blanket impls and will instead just manufacture a `CustomWitness`
for everything.
A lot of SemIR fingerprints change, but that's probably because the
addition of `Destroy` on core classes is yielding structural changes.
Instead of naming the root namespace `package` (because it's accessed by
the `package` keyword), change it to use the current package name. Note,
buried in the checksum changes,
`toolchain/check/testdata/package_expr/fail_not_found.carbon`:
```
- // CHECK:STDERR: fail_not_found.carbon:[[@LINE+4]]:16: error: member name `x` not found in `package` [MemberNameNotFoundInInstScope]
+ // CHECK:STDERR: fail_not_found.carbon:[[@LINE+4]]:16: error: member name `x` not found in `Main` [MemberNameNotFoundInInstScope]
```
for:
```
// CHECK:STDERR: var y: i32 = package.x;
// CHECK:STDERR: ^~~~~~~~~
```
I'll leave it to you if you prefer this; the alternative I see is to
just rename `IsCorePackage` to `IsImportedCorePackage`, and/or change it
to a helper that takes a `Context` and does the right thing with
`parse_tree` (which, I need for `Destroy`-related reasons and was my
default approach).
Just as names from an `extend` scope get included in the containing
scope, so do errors. Apply this logic to `extend require impls`,
propagating any errors up.
This is based on #6465.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
This is a prerequisite for support for interop with C++ template names.
No behavior change here, except that it sadly changes the fingerprinting
for a lot of tests.
The FacetTypeId should never be used directly, since the RequireImpls is
a generic and the facet type may be parameterized by generic bindings.
So instead, it should be accessed through GetConstantValueInSpecific,
which works with the facet type InstId that is also already present on
RequireImpls. This change to use GetConstantValueInSpecific was done in
#6435, so the FacetTypeId is now unused except in formatting. So we can
remove it.
This depends on #6435.
Identifying a facet type is an operation on a pair of (self type, facet
type). It substitutes that self in as the `Self` of any require
declarations in order to form the set of (self type, SpecificInterface)
pairs that constitute the requirements of the IdentifiedFacetType.
Currently we don't pass around any self type, and assume all require
declarations are written against `Self` but this will change in the
future.
By contrast, type completion is done in the abstract and does not form
specifics for the require declarations. The purpose of type completion
is to enumerate the scopes where name lookup can occur and ensure they
are completed.
With this change, type completion is:
- No longer built on top of identification for facet types.
- Recursively ensures all `extend` scopes are complete since name lookup
can find symbols in them.
We add some test cases that demonstrate consistency between a resolving
the specific of a generic class, and a generic interface/constraint,
both used in a type position. In all cases, an invalid specific is not
materialized for the type completion when the specific's arguments are
used in a non-extend context. But they specific is materialized and
checked for type completion when in an extend context (extend impl or
extend require).
Type completion itself does not need to recurse into named constraints
or interfaces as the `extend require` declarations require the type to
be complete immediately, just as for `extend impl` in a class.
We had a test (`fail_incomplete_where.carbon`) with `impl as J where
.Self impls K` and `J` is incomplete, which used to be diagnosed but no
longer is, because we don't require non-extend interfaces to be complete
in type completion, nor in identification. The test was trying to test
the presence of rewrite constraints though, which it didn't even use. So
we remove the diagnostic that we can't hit anymore and replaced it with
a TODO, and add a test that should reach that TODO once qualified
rewrite constraints work.
When importing an Interface or NamedConstraint, walk the block of
`RequireImplsId`s, and for each one:
- Import the RequireImplsDecl from it, which also imports the
`RequireImpls` structure and its id.
- Collect those decls and build a block of `RequireImplsId`s for the
local SemIR to reference from the Interface or NamedConstraint.
The import of RequireImplsDecl is done in a single phase instead of
three, unlike other decls. This is possible since require declarations
have no name, so they can't be referenced by instructions inside them,
thus there's no cycles to concern ourselves with.
They are not used for impl lookup or verifying anything yet, but now
they appear in the textual semir.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
The `RequireDecl` instruction points, via a `RequireImplsId` to a
`RequireImpls` structure in a `ValueStore`. That structure holds the
self-type and facet type, as well as the generic id and parent scope.
`RequireImpls` is always a generic since it only appears in an
`interface` or `constraint`, which both have a generic parameter `Self`
applied to all their members.
The `RequireDecl` instruction evaluates to itself, but drops the
decl_block_id since the instructions within the `require` declaration
are not required in the canonical value which is only used for import.
And import will want to import the `RequireImpls` structure along with
the `Interface` or `NamedConstraint` structure it is in, rather than
recreate it from the decl's instructions. This also avoids repeating all
the instructions within the `require` decl in the textual semir's
constants block.
Adding the `RequireImpls` to the `Interface` or `NamedConstraint`
structure is not yet done, so they are not available for impl lookup or
import yet.
This requires declared FacetTypes to hold NamedConstraintIds (along with
a specific) that are named in an extend or impls requirement. We add
support to stringify and formatter to display the named constraints in
the facet type, and special case when a facet type contains a single
extend named constraint, like we did for a single extend interface.
This means that `RequireIndentifiedFacetType` can now fail, if the facet
type contains a forward-declared named constraint. Add the appropriate
diagnostics for each call to this function, and note the ones that
should change to `RequireCompleteFacetType` in the future with TODOs.
We also add tests for using facet types that can or can't be identified,
or completed, with named constraints in them.
Richard Smith
Dana JansensandRichard Smith
Geoff Romer
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