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https://github.com/carbon-language/carbon-lang.git
synced 2026-10-01 15:56:01 +01:00
Richard Smith
74aae0911f
Add basic support for `match_first` declarations to explorer, as described in https://github.com/carbon-language/carbon-lang/blob/trunk/docs/design/generics/details.md#prioritization-rule. The concrete syntax here is not yet approved, so `match_first` is renamed to `__match_first` for now, but the semantics are necessary to implement other approved features in explorer so we're intentionally getting a little ahead of the design here.
37 lines
1.0 KiB
Plaintext
37 lines
1.0 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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// AUTOUPDATE
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// RUN: %{not} %{explorer-run}
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// RUN: %{not} %{explorer-run-trace}
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package ExplorerTest api;
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class A(T:! type) {}
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interface B(T:! type) {}
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// This match_first doesn't affect the ambiguity between
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// these impls and the one below.
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// TODO: Once we order by type structure, the second impl
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// in this block should win.
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__match_first {
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external impl A(i32) as B(i32) {}
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external impl forall [T:! type] A(i32) as B(T) {}
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}
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external impl forall [T:! type] A(T) as B(i32) {}
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fn F[T:! B(i32)](x: T) {}
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fn G[T:! B(bool)](x: T) {}
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fn Main() -> i32 {
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let a: A(bool) = {};
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let b: A(i32) = {};
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F(a);
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G(b);
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// CHECK:STDERR: COMPILATION ERROR: {{.*}}/explorer/testdata/impl/fail_ambiguous_impl_match_first.carbon:[[@LINE+1]]: ambiguous implementations of interface B(T = i32) for class A(T = i32)
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F(b);
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return 0;
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}
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