Implement the toolchain side of proposal #7254, removing the `:!`
binding
syntax for generic and template parameters in favor of the keywords
`generic`,
`template`, and `runtime` plus contextual defaults for phase.
For valid programs this is semantics-preserving: each binding resolves
to the
same phase, and produces the same SemIR, as it did under `:!`/`:`. The
parser
derives a binding's phase from its syntactic context plus any explicit
phase
keyword; new diagnostics and error recovery for misused keywords are
described
below.
Implementation details for each component:
- Lexer: remove the `:!` (`ColonExclaim`) token, move its virtual
parse-node
budget onto `:`, and add the `generic` and `runtime` keywords.
- Parser: thread a `BindingContext` (`ExplicitParam`, `DeducedParam`, or
`CompileTimeEntityParam`) from declaration introducers down through
parameter
lists to each binding pattern, using a one-token lookahead to
distinguish a
name-qualifier parameter list from a declaration's own final list.
Parameters
of a compile-time entity (`class`, `interface`, `constraint`, `choice`,
`alias`, `export`, `namespace`) and deduced `[]` parameters default to
checked
generic; explicit function parameters and local bindings default to
runtime.
`HandleBindingPattern` resolves the phase from that context plus the
keyword: a
`generic` keyword needs no node of its own (the phase is carried by the
binding's node kind), while a `runtime` keyword is preserved as a
`RuntimeBindingName` node so `check` can name it in a diagnostic. A
phase
keyword that is merely redundant with the contextual default is
diagnosed
here, without invalidating the parse tree.
- Check: a phase keyword that is invalid for its context (for example
`runtime`
on a checked-generic parameter) is diagnosed here, and recovers by
building an
error binding that still introduces the name so that later uses of it do
not
produce cascading errors.
The removed `:!` syntax is now rejected as an ordinary parse error.
The `form`/`:?`/`->?` ("extended types") portion of proposal #7254 is
left for a
separate change.
Assisted-by: Claude Code
In #7436 we stopped substituting `.Self` when collecting witnesses out
of a facet type. While this was correct, it did not capture all the
cases that need to avoid substituting `.Self`. And it poisoned the
`IdentifiedFacetType` cache by not replacing `.Self` but storing the
result in the cache. This led to incoherent behaviour, where the result
of an impl lookup would change depending on which ones had been done
previously.
Now we use a flag to track for each `.Self` if we're currently
type-checking inside the scope where it was introduced in a facet type.
While inside that scope, identify should not replace the `.Self`. Any
use of it should remain as-is since we don't yet know what value will
replace it. We call this state "frozen" since it should not be modified
by identify. This requires a substitution step when we leave the scope
that introduced the `.Self`, to remove the flag. The flag is set in the
`EntityName` of the `SymbolicBinding`, and is part of the canonical
value, since `.Self` can become part of types, which are constants, and
the flag needs to follow it for correct behaviour.
We also have to ensure the flag is the same when doing comparison with
constants from inside a facet type and constants from outside. For
instance in `(Z where .Z1 = ()) where .Z2 = .Z1`, when we arrive at the
second `.Z1` its `.Self` will be frozen, while the `.Z1 = ()` contains a
non-frozen `.Self`. So we add the frozen flag to the first when storing
it in `where_stack` in order to compare the constant values of the two
`.Z1`.
The `WhereExpr` requirement inst kinds now have an `InstConstantKind` of
`AlwaysUnique` instead of `Never`. This allows us to add them to the
usual InstBlocks, and in an `eval fn` body they have a constant value,
so eval does not fail when trying to call that function. We have to be
careful to not consider `AlwaysUnique` as being actually concrete
though, since their constant value erases `.Self`-dependence. This
allows us to stop special casing them when thawing the requirements
block in a `WhereExpr`, and we can just thaw each `InstId` in the block
in a straightforward manner.
We add the new flag to the instruction's fingerprint and name in
formatted semir.
This adds SemIR structs and implements building `observe` lists, as well
as naming, formatting, and importing `observe` declarations.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
The bulk of this change is changing most pattern insts to be `Always`
rather than `AlwaysUnique` constants, so that they can be wrapped in
`SpecificConstant`s to perform substitution. That then lets thunking
rely much more on `SpecificConstant` wrappers instead of deep-copying
the inst tree with modified types.
This approach to thunking should scale better, particularly as things
like form generics make function signatures more complex, because we can
leverage the existing support for constant evaluation and substitution.
Unfortunately, applying this approach to binding patterns will require
more work; see the TODO near the top of `thunk.cpp` for details.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Fix import logic to make all imported packages be children of the
`NameScopeId::Package` scope. Previously, indirectly-imported packages
would end up as children of their importing package's scope, which
resulted in them not being treated as packages at all, and in particular
not being fingerprinted as packages.
Fixing that caused a failure in the fingerprinting logic as we started
to encounter packages with no correspoding import scopes. Instead of
looking for import scopes, use a simpler mechanism to map packages to
their package names, and clean up.
Unfortunately the latter change churns all the fingerprints again :(
Hopefully this is the last time for a while.
When we import from another library in the same package, its entities
end up with our library as their parent scope, resulting in cross-file
fingerprint mismatches. Instead, only include the library ID when
fingerprinting either a package-private entity or an `ImportIRId` that
refers to a particular `SemIR::File`.
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.
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.
The impl's body block has to end before we make its ImplDecl
instruction, and the witness instructions come later, so they don't end
up in the body block. Currently they just end up in the enclosing (file,
typically, or class) scope block.
Add a new InstBlockId to Impl for holding witness instructions, and
explicitly insert them into that block. Then include those instructions
into the scope of the Impl for naming, and format them into the Impl
right after the body block.
This is based on #6484
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>
If it's just `TypeType` then the `BindSymbolicName` appears directly in
type positions, but if it is replaced with another facet value, then we
would need to insert a `FacetAccessType` around it. By giving it a
`FacetType` type, like other `BindSymbolicName`s we make it consistent
and avoid having to introduce extra instructions.
We add a virtual node (`CompileTimeBindingPatternStart`) as the first
child of `CompileTimeBindingPattern` which holds the identifier
underneath it, so that it is checked just before the type expression of
the `CompileTimeBindingPattern`. When we reach this virtual node during
check, we add `.Self` as a name in the current scope, and when we reach
`CompileTimeBindingPattern` we remove it from scope, which ensures it's
present during only the checking of the type expression for the compile
time pattern.
At the moment the `.Self` has a different type (it's a `TypeType`) than
other `.Self` in the facet type (which are a single `FacetType`), but
the intention is to immediately substitute it out of the facet type
entirely, replacing it with a reference to the compile time binding (a
`BindSymbolicName`) itself. A TODO has been added for this.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Change impls from `<interface>.impl` to `<self>.as.<interface>.impl`,
and *member* functions to `<parent scope>.<fn>` (non-member functions
exclude their parent scope). Stop special-casing builtin functions,
given the new naming scheme.
The purpose of this is to make it clearer when a member function is
being accessed and, if so, which member function. In particular, we
often access interface `Op` functions. The builtin function
special-casing was intended to help with that, but we still have lots of
`Op` functions. This particular approach should make the interactions
clearer.
This changes up queueing of block IDs a little because, in particular,
we need to process bodies of entities only after constants finish
processing. But, it should also result in less memory usage during
processing because it means we have less on the insts stack at any given
time, since we track a block rather than all instructions contained by
the block.
This drops file_test runtime from about 3s to 2.5s on my machine, which
is now ~30% faster than before #5653 slowed things down by adding a lot
of stuff to the production prelude.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Where `--no-dump-sem-ir` is used, change to `--dump-sem-ir-ranges=only`.
Otherwise, add `--dump-sem-ir-ranges=if-present` with a TODO to change
to `only`.
Note, SemIR is affected just because the extra comments change line
numbers in files where splits aren't in use.
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>
This was originally needed to support constant evaluation of name
expressions, but that's now done in a different way.
This is actually a step toward treating all patterns as constants. The
upcoming change will do so in a slightly different way, and so it will
simplify the review to start from a baseline where patterns are never
constant.
This allows us to import the table for a given impl only once, while we
can import many ImplWitness instructions with different specifics for a
generic impl.
For example in convert_facet_value_to_narrowed_facet_type.carbon we see
that a single witness table is imported for the BitAnd interface, with
multiple witnesses (for different specifics) imported and sharing the
same table.
The ImplWitnessTable now contains a back-link to the Impl the witness is
for, allowing inst namer to name that interface in the textual semir,
and allowing the interface to be found when debugging from a witness.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
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.
Factor out logic to evaluate `EntityNameId` instead of duplicating it
between `BindSymbolicName` and `SymbolicBindingPattern`. Remove support
in `SymbolicBindingPattern` for evaluating a pattern to the constant
value of the corresponding binding, which doesn't really make any sense
given that patterns don't generally evaluate to the value that they
matched.
This results in the handling for `SymbolicBindingPattern` being simply
the default handling for an always-constant instruction, so remove the
special case for it entirely and change its constant kind to `Always`.
It's not entirely clear that it makes sense for `SymbolicBindingPattern`
to be treated as a constant when other patterns aren't, but we seem to
be relying on this in various places, so leave it as a constant for now.
Changing it to never be constant will be a smaller change now -- it just
requires changing the `constant_kind`.
The IR changes in the tests are fairly widespread, but mechanical, and
there are two kinds of things changing:
- `symbolic_binding_pattern`s in specifics now evaluate to
`symbolic_binding_pattern`s, not to the argument values. This means in a
few cases we end up with additional `symbolic_binding_pattern`
constants.
- We evaluate the type operand of `symbolic_binding_pattern` now, so an
error in the type will now properly be propagated into an error in the
pattern's constant value.
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>
- Explicitly document that `*Param` and `*ParamPattern` insts represent
`Call` parameters.
- Stop wrapping compile-time parameter patterns in `ValueParamPattern`
insts (because they aren't `Call` parameters).
- Document how `MatchContext::results_` relates to the `Call`
parameters, and be more consistent about when it's written to.
- Remove `RuntimeParamIndex::Unknown`: we no longer need to distinguish
"this `Param`'s runtime index is unknown" from "this `Param` isn't a
runtime param", because we no longer use `Param`s at all in the latter
case.
- Rename `RuntimeParamIndex` to `CallParamIndex`.
As a side effect of removing the `ValueParamPattern` insts, this fixes a
minor diagnostic bug where `NoteInitializingParam` didn't identify the
specific parameter that led to a deduction failure, because it expects
generic parameters to only be represented by `SymbolicBindingPattern`s,
but before this change they could be wrapped in `ValueParamPattern`s.
Add a full entity representation for associated constants, and build a
`Generic` object for them. This `Generic` is parameterized by the
enclosing `Self` type, allowing the use of `Self` within the type of the
associated constant to be supported.
When performing impl lookup for an associated constant, produce the type
with the provided self type substituted for its `Self` along with any
generic parameters of the interface.
Split the handling of associated constant declarations into two parts,
corresponding to the code before the `=`, and the code between the `=`
and `;` (if any). The former goes into the generic declaration region;
the latter into the generic definition region. This prepares us to
handle the default value for an associated constant, but for now we're
just storing the information and not actually using it.
Remove the entity type field from `assoc_entity_type`, because it's
almost unused and is an attractive nuisance -- it must necessarily be a
type in the generic scope of the associated constant rather than in the
scope of the instruction (because there is no `Self` anywhere else),
which means that it's hard to substitute into or derive meaning from.
See `toolchain/check/testdata/impl/assoc_const_self.carbon` for tests of
the new functionality; these used to cause the toolchain to crash.
High level, replacing `Id::Invalid` with `Id::None` and `Id::is_valid`
with `Id::has_value` for clarity, as discussed
[here](https://discord.com/channels/655572317891461132/655578254970716160/1331664574545395794).
The `IntId` refactoring is needed together with `AnyIdBase` because it's
also used with `ValueStore`.
Note, trying to be careful not to rewrite `EnumBase::InvalidIndex`, or
`is_valid` in general (e.g., `IdKind::is_valid`).
I've tried to sequence commits here:
1. Automatic replacements:
- `((?:Id|Index)(?: |::|\(|Base(?:\(|::)))Invalid((?:Index)?\W)` ->
`$1None$2`
- `<invalid>` -> `<none>`
- `InvalidNodeId` -> `NoneNodeId`
- `/\*invalid\*/` -> `/*none*/`
- `id((?:_|\(\))(?:\.|->))is_valid` -> `id$1has_value`
2. Manual edits:
- In `int.h` and `int_test.cpp`
- `IntT` has `is_value`, which I'm renaming to `is_embedded_value`.
- Manual edits to comments in this file.
- `AnyIdBase` and `IdBase`
- Declaration of `is_valid` -> `has_value`, `InvalidIndex` ->
`NoneIndex`.
- In `ids.h` and `ids.cpp`
- `is_valid` -> `has_value`
- `// An explicitly invalid ID.` -> `// An ID with no value.`; similar
for index
- Various math on `InvalidIndex` -> `NoneIndex`
- Various mentions of "valid" in comments
- In `value_store.h`, for `IdT::Invalid`, plus one comment
- In `impl.h` and `tokenized_buffer.h`, we had different initialization
of `::None` values (versus `ids.h` syntax) that I fixed manually.
- Spot checks to compile
- Particularly where `is_valid` replacements didn't catch spots due to
different naming.
3. Autoupdate tests
4. verbose.carbon (NOAUTOUPDATE)
5. Comment spot checks
Note there are probably other mentions of "Invalid" that should be swept
up, but I'd like to argue for merging and separating out remaining
cleanup since this is so sweeping (and likely to hit merge conflicts
from churn). We'll probably have lingering mentions of "invalid" for a
bit regardless, just because there are uses of "invalid" in non-Id APIs.
Include the index rather than the name in the fingerprint of a symbolic
binding. While both the index and the name contribute to the canonical
identity, using either one of them in the fingerprint is sufficient to
ensure that distinct entities get different fingerprints. Changing the
name of a symbolic binding should ideally not result in fingerprint
changes, so exclude the name from the fingerprint when we have an index.
Use the canonical type and constraint when fingerprinting an impl, so
that uses of names in `name_ref` instructions aren't considered, only
the entity the name resolves to, and different ways of spelling the same
type have the same fingerprint. This similarly allows compatible changes
to be made to impls without changing the fingerprint.
Exclude the declaration block when determining the fingerprint of a
declaration. The declaration block contains the declarations of
parameters of the declaration, which do affect whether two declarations
are identical, but not whether they denote the same entity, because it
would be invalid to have different declaration blocks for declarations
with the same name in the same scope. Therefore changes to the
declaration block are compatible, and it's useful for such changes to
not affect the fingerprint.
This is not easy to test in isolation with our current testing
machinery. However, a follow-on PR will change the name of a parameter
in the prelude, and with this in place, will not cause any changes to
occur elsewhere in the toolchain tests.
Use it in the instruction namer to make instruction names more stable
across unrelated changes to the toolchain or the prelude.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
* 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>
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>
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>
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>
- Do not include entities imported from files that we are not dumping.
- Do not include constants and import_refs that are not referenced by
something that we are including in the formatted output.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
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>
This is in particular to avoid churn from changes such as #4370. I think
the import list can be helpful (particularly to understand what the
library is aware of), but it's a different trade-off for the prelude
package due to the implicit imports.
This PR makes it so that types can implement the `IndexWith` interface
so that they can provide their custom indexing behavior.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
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>
Richard Smith
Chandler Carruth
Dana Jansens
Özgür T. ÖnsoyandDana Jansens
Geoff RomerandRichard Smith
Brymer MenesesandJon Ross-Perkins