[PATCH] D128619: [Clang] Implement P0848 (Conditionally Trivial Special Member Functions)

Sun Aug 21 14:12:25 PDT 2022

royjacobson marked 11 inline comments as done.
royjacobson added inline comments.

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Comment at: clang/lib/Frontend/InitPreprocessor.cpp:677
     //Builder.defineMacro("__cpp_aggregate_paren_init", "201902L");
-    Builder.defineMacro("__cpp_concepts", "201907L");
+    Builder.defineMacro("__cpp_concepts", "202002L");
     Builder.defineMacro("__cpp_conditional_explicit", "201806L");
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aaron.ballman wrote:
> Does any of the not-yet-implemented bits (including from the DRs) impact the ability to use conditionally trivial special member functions? If so, we might want to be careful about aggressively bumping this value. (It's more palatable for us to come back and bump the value later than it is for us to claim we implement something fully when we know we don't -- the goal of the feature test macros is so that users don't have to resort to compiler version checks, which is what users have to use when they fall into that "not fully implemented" space.)
I don't think they're very significant, and the benefits of enabling it seem large enough for me - for example, std::expected works with libstdc++ and passes their unit tests but is gated by this macro.

We still have a non-trivial amount of concept bugs to go over, but I support enabling this.

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Comment at: clang/www/cxx_status.html:930
         <td><a href="https://wg21.link/p0848r3">P0848R3</a></td>
-        <td rowspan="1" class="none" align="center">No</td>
+        <td rowspan="1" class="unreleased" align="center">Clang 16 <a href="#p0848">(12)</a></td>
       </tr>
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aaron.ballman wrote:
> FWIW, the way we've started handling this in recent history is to use "partial" and a details tag instead of a footnote, as in: https://github.com/llvm/llvm-project/blob/main/clang/www/cxx_status.html#L915.
It felt a bit too long of an explanation to put in the tiny table box, but I don't feel very strongly about it either way.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D128619/new/

https://reviews.llvm.org/D128619