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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
9704dc670e
The main direction of this change is the edits to `destroy.carbon` (matching in both prelude and min_prelude). Previously there was a no-op blanket impl for `Destroy`, which hid all missing implementations of `Destroy`. This does a few things: - Sets up builtin aggregate destruction for struct and tuple types as before, but also adds C++ class types and array types to the same handling. (all as a TODO for actual implementation) - Also maybe-unformed destruction, for now at least. (there's a chance I may try a different approach on this, but the impl lookup wasn't working as I'd hope in order to write it in code) - Adds handlers for simple things that are easy to do in code: `type`, `bool`, pointers. (because these are no-op destruction) - Redirect `const T` destruction to `T` destruction. This leaves as future issues: - `partial T` destruction. (this can't be done similar to `const` because it only works for non-`final` class types; I think `class` definitions should just generate what's needed) - Destruction of other prelude-provided types. (will probably come up as we implement class destruction, that the adapted builtin type doesn't implement `Destroy` -- but may end up special-casing that in a way that moots it) This moves the `&` operator from `facet_types.carbon` to `convert.carbon` because more things need to handle type and now that we're getting separate copy and destroy interfaces. It should be low-cost (an interface and builtin) so hopefully this is the right balance for complexity and re-use. A few tests are also edited in order to focus them more on what they intend to test, and avoid a `Destroy` dependency.
129 lines
3.4 KiB
Plaintext
129 lines
3.4 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/convert.carbon
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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/lookup/find_in_final.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/lookup/find_in_final.carbon
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// --- final_impl_precedence_over_facet.carbon
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library "[[@TEST_NAME]]";
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interface I {
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let T:! type;
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}
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final impl forall [U:! type] U as I where .T = () {}
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fn F(V:! I) -> V.T {
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// Even though we have a witness that `V impls I` from the constraint on `I`,
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// we should do an impl lookup to see if any effectively final impl applies
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// when we find an unknown value in that witness. In this case, that lookup
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// would find an impl with more specific values for associated constants that
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// we should merge.
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return ();
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}
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// --- final_impl_precedence_over_facet_with_where.carbon
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library "[[@TEST_NAME]]";
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interface Z {
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let X:! type;
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let Y:! type;
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}
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final impl forall [T:! type] T as Z where .X = () and .Y = () {}
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fn F(ZZ:! Z where .X = ()) {
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// Z.Y is unspecified on `ZZ` so it's found on the final impl where it's known
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// to be the concrete type (), which can then be used in this generic
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// function.
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let a: ZZ.Y = ();
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}
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// --- final_impl_precedence_over_facet_access_type_with_where.carbon
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library "[[@TEST_NAME]]";
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interface Z {
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let X:! type;
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let Y:! type;
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}
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final impl forall [T:! type] T as Z where .X = () and .Y = () {}
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fn F[T:! Z where .X = ()](z: T) {
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// z.Y is unspecified on `ZZ` so it's found on the final impl where it's known
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// to be the concrete type (), which can then be used in this generic
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// function.
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let a: z.Y = ();
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}
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// --- final_impl_makes_compatible_facet_values.carbon
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library "[[@TEST_NAME]]";
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interface I { let X:! type; }
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interface J {}
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final impl forall [T:! J] T as I where .X = () {}
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class C(T:! I) {
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var b: T.X;
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}
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class D(T:! J) {
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var c: C(T)*;
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}
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fn F(T:! I & J) -> () {
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// The witness for `I` found here directly, and inside `D` from a FacetValue
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// come from the same facet, the `T` binding in the params of F, so they
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// should be compatible.
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var x: C(T);
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var y: D(T);
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y.c = &x;
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return (*y.c).b;
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}
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// --- non_final_impl_makes_compatible_facet_values.carbon
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library "[[@TEST_NAME]]";
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interface I { let X:! type; }
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interface J {}
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impl forall [T:! J] T as I where .X = () {}
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class C(T:! I) {
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var b: T.X;
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}
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class D(T:! J) {
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var c: C(T)*;
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}
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fn F(T:! I & J) -> T.(I.X)* {
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var x: C(T);
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var y: D(T);
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// The witness for `I` found here directly, and inside `D` from a FacetValue
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// come from the same facet, the `T` binding in the params of F, so they
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// should be compatible.
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y.c = &x;
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return &(*y.c).b;
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}
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// --- todo_fail_facet_value_rewrite_incompatible_with_final_impl.carbon
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library "[[@TEST_NAME]]";
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interface Z {
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let X:! type;
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}
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final impl forall [T:! type] T as Z where .X = () {}
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// TODO: This should be diagnosed as there is a final impl defining `.X = ()`,
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// which makes the LHS of this rewrite constraint concrete. And since the RHS is
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// not the same (or convertible from), the rewrite is impossible.
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fn F(ZZ:! Z where .X = {.r: ()}) {}
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