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Jon Ross-PerkinsandDana Jansens
5e3bb523f8
This is in support of a goal of changing the blanket `destroy` impl to
use (roughly):
```
private fn CanAggregateDestroy() -> type = "type.can_aggregate_destroy";
// Handles aggregate type destruction.
impl forall [AggregateDestroyT:! CanAggregateDestroy()] AggregateDestroyT as Destroy {
fn Op[addr self: Self*]() = "type.aggregate_destroy";
}
```
That isn't done here because there's still other issues that migrating
raises. What this *does* do is add the builtin functions, and in
particular, support to `FacetTypeInfo` to make `CanAggregateDestroy`
work.
The "special requirement" approach in `FacetTypeInfo` allows us to
support restricting a blanket impl under the current approach of impls.
Maybe we'll find a cleaner approach that can work in the future, but
this fits into the current model by propagating similar to other
requirements. I'm using an enum mask because we have a number of similar
things to add (e.g. copy, move) but I'm not sure we need a full vector.
A few alternatives considered were:
- Supporting syntax more like `where .Self impls
TypeCanAggregateDestroy(.Self, SupportedInterface,
UnsupportedInterface)`. I think it'd be a little cleaner, but requires
better compile-time evaluation in order to assess the type of the call.
Right now it's expected to be a `FacetType` too early to make this work,
and I was concerned about pouring too much more time down this route.
- Providing an actual interface, in particular doing name lookup back
into `Core.` for an interface. This would've added name lookup overhead,
and the question of whether an `impl` exists.
- Generating an interface. This avoids the name lookup, but would still
raise the question of whether an `impl` should also be generated. Work
I've previously done generating interfaces for class destruction also
feels complex to both write and understand (an unfortunate issue).
- Still modeling as an `ImplsConstraint`, for example by defining a
special `InterfaceId::CanAggregateDestroy = -2` similar to what we do on
other ids. I was hesitant because of how this expands the number of
modes of `InterfaceId`, and things for consuming code to watch out for,
for what feels like a relatively niche set of use-cases that are only
interface-like.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
94 lines
4.1 KiB
Plaintext
94 lines
4.1 KiB
Plaintext
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/none.carbon
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// TODO: Add ranges and switch to "--dump-sem-ir-ranges=only".
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// EXTRA-ARGS: --dump-sem-ir-ranges=if-present
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//
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// AUTOUPDATE
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// TIP: To test this file alone, run:
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// TIP: bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/check/testdata/impl/fail_alias.carbon
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// TIP: To dump output, run:
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// TIP: bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/check/testdata/impl/fail_alias.carbon
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interface I {}
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class C {}
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alias AI = I;
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alias AC = C;
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impl AC as AI {}
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// CHECK:STDERR: fail_alias.carbon:[[@LINE+7]]:1: error: redefinition of `impl AC as AI` [ImplRedefinition]
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// CHECK:STDERR: impl AC as AI {}
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// CHECK:STDERR: ^~~~~~~~~~~~~~~
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// CHECK:STDERR: fail_alias.carbon:[[@LINE-5]]:1: note: previous definition was here [ImplPreviousDefinition]
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// CHECK:STDERR: impl AC as AI {}
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// CHECK:STDERR: ^~~~~~~~~~~~~~~
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// CHECK:STDERR:
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impl AC as AI {}
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// CHECK:STDOUT: --- fail_alias.carbon
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// CHECK:STDOUT:
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// CHECK:STDOUT: constants {
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// CHECK:STDOUT: %I.type: type = facet_type <@I> [concrete]
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// CHECK:STDOUT: %Self: %I.type = bind_symbolic_name Self, 0 [symbolic]
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// CHECK:STDOUT: %C: type = class_type @C [concrete]
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// CHECK:STDOUT: %empty_struct_type: type = struct_type {} [concrete]
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// CHECK:STDOUT: %complete_type: <witness> = complete_type_witness %empty_struct_type [concrete]
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// CHECK:STDOUT: %I.impl_witness: <witness> = impl_witness file.%I.impl_witness_table [concrete]
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: file {
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// CHECK:STDOUT: package: <namespace> = namespace [concrete] {
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// CHECK:STDOUT: .I = %I.decl
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// CHECK:STDOUT: .C = %C.decl
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// CHECK:STDOUT: .AI = %AI
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// CHECK:STDOUT: .AC = %AC
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// CHECK:STDOUT: }
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// CHECK:STDOUT: %I.decl: type = interface_decl @I [concrete = constants.%I.type] {} {}
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// CHECK:STDOUT: %C.decl: type = class_decl @C [concrete = constants.%C] {} {}
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// CHECK:STDOUT: %I.ref: type = name_ref I, %I.decl [concrete = constants.%I.type]
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// CHECK:STDOUT: %AI: type = bind_alias AI, %I.decl [concrete = constants.%I.type]
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// CHECK:STDOUT: %C.ref: type = name_ref C, %C.decl [concrete = constants.%C]
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// CHECK:STDOUT: %AC: type = bind_alias AC, %C.decl [concrete = constants.%C]
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// CHECK:STDOUT: impl_decl @C.as.I.impl.7de31e.1 [concrete] {} {
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// CHECK:STDOUT: %AC.ref: type = name_ref AC, file.%AC [concrete = constants.%C]
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// CHECK:STDOUT: %AI.ref: type = name_ref AI, file.%AI [concrete = constants.%I.type]
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// CHECK:STDOUT: }
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// CHECK:STDOUT: %I.impl_witness_table = impl_witness_table (), @C.as.I.impl.7de31e.1 [concrete]
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// CHECK:STDOUT: %I.impl_witness: <witness> = impl_witness %I.impl_witness_table [concrete = constants.%I.impl_witness]
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// CHECK:STDOUT: impl_decl @C.as.I.impl.7de31e.2 [concrete] {} {
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// CHECK:STDOUT: %AC.ref: type = name_ref AC, file.%AC [concrete = constants.%C]
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// CHECK:STDOUT: %AI.ref: type = name_ref AI, file.%AI [concrete = constants.%I.type]
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// CHECK:STDOUT: }
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: interface @I {
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// CHECK:STDOUT: %Self: %I.type = bind_symbolic_name Self, 0 [symbolic = constants.%Self]
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// CHECK:STDOUT:
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// CHECK:STDOUT: !members:
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// CHECK:STDOUT: .Self = %Self
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// CHECK:STDOUT: witness = ()
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: impl @C.as.I.impl.7de31e.1: %AC.ref as %AI.ref {
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// CHECK:STDOUT: !members:
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// CHECK:STDOUT: witness = file.%I.impl_witness
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: impl @C.as.I.impl.7de31e.2: %AC.ref as %AI.ref {
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// CHECK:STDOUT: !members:
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// CHECK:STDOUT: witness = <error>
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: class @C {
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// CHECK:STDOUT: %complete_type: <witness> = complete_type_witness constants.%empty_struct_type [concrete = constants.%complete_type]
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// CHECK:STDOUT: complete_type_witness = %complete_type
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// CHECK:STDOUT:
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// CHECK:STDOUT: !members:
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// CHECK:STDOUT: .Self = constants.%C
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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