mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-10-03 17:45:49 +01:00
Richard Smith
e0c90767be
The strategy that we use for now to support template instantiation is to check the impl declaration as if it were a generic, but to defer all checking of the impl definition until we see a use in which all template parameters have arguments. At that point, we clone the impl definition and type-check the whole thing, with constant values set on the template parameters corresponding to the given arguments. No caching of template instantiations is performed yet; each time we form a reference to a template instantiation, we instantiate it afresh. We also don't implement the name lookup rule from #949 yet; lookups during template instantiation look only in the actual type and not in the constraint. Depends on #2699
78 lines
1.9 KiB
Plaintext
78 lines
1.9 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: %{explorer-run}
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// RUN: %{explorer-run-trace}
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// CHECK:STDOUT: MemberF.F
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// CHECK:STDOUT: ImplF.(HasF.F)
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// CHECK:STDOUT: BothFs.(HasF.F)
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// CHECK:STDOUT: BothFs.F
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// CHECK:STDOUT: BothFs.F
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// CHECK:STDOUT: result: 0
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package ExplorerTest api;
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choice ImplKind {
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Checked,
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ConstrainedTemplate,
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UnconstrainedTemplate
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}
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interface CallF(K:! ImplKind) {
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fn DoIt[self: Self]();
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}
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interface HasF {
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fn F[self: Self]();
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}
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impl forall [T:! HasF] T as CallF(ImplKind.Checked) {
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fn DoIt[self: Self]() { self.F(); }
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}
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impl forall [template T:! HasF] T as CallF(ImplKind.ConstrainedTemplate) {
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fn DoIt[self: Self]() { self.F(); }
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}
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impl forall [template T:! type] T as CallF(ImplKind.UnconstrainedTemplate) {
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fn DoIt[self: Self]() { self.F(); }
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}
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class MemberF {
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fn F[self: Self]() { Print("MemberF.F"); }
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}
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class ImplF {}
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external impl ImplF as HasF {
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fn F[self: Self]() { Print("ImplF.(HasF.F)"); }
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}
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class BothFs {
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fn F[self: Self]() { Print("BothFs.F"); }
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}
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external impl BothFs as HasF {
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fn F[self: Self]() { Print("BothFs.(HasF.F)"); }
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}
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fn Main() -> i32 {
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var mem: MemberF = {};
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var imp: ImplF = {};
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var both: BothFs = {};
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mem.(CallF(ImplKind.UnconstrainedTemplate).DoIt)();
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imp.(CallF(ImplKind.Checked).DoIt)();
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// TODO: Should be valid, but currently fails during instantiation.
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//imp.(CallF(ImplKind.ConstrainedTemplate).DoIt)();
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both.(CallF(ImplKind.Checked).DoIt)();
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// TODO: Should be rejected, but currently incorrectly accepted.
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// This line can be deleted once it starts failing; we test that this is
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// rejected in fail_name_lookup.carbon.
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both.(CallF(ImplKind.ConstrainedTemplate).DoIt)();
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both.(CallF(ImplKind.UnconstrainedTemplate).DoIt)();
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return 0;
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}
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