[PATCH] D128745: [Sema] fix trailing parameter pack handling for function template partial ordering

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added reviewers: erichkeane, clang-language-wg.
aaron.ballman added a comment.

Thank you for working on this! Can you please add more details to the patch summary about the changes?



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Comment at: clang/lib/Sema/SemaTemplateDeduction.cpp:5184
 
-  // FIXME: This mimics what GCC implements, but doesn't match up with the
-  // proposed resolution for core issue 692. This area needs to be sorted out,
----------------
aaron.ballman wrote:
> We tend not to use top-level const on locals in the project as a matter of style.
Does GCC still implement it this way?

One concern I have is that this will be an ABI breaking change, and I'm not certain how disruptive it will be. If GCC already made that change, it may be reasonable for us to also break it without having to add ABI tags or something special. But if these changes diverge us from GCC, that may require some extra effort to mitigate.


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Comment at: clang/lib/Sema/SemaTemplateDeduction.cpp:5184-5185
 
-  // FIXME: This mimics what GCC implements, but doesn't match up with the
-  // proposed resolution for core issue 692. This area needs to be sorted out,
-  // but for now we attempt to maintain compatibility.
+  const unsigned NumParams1 = FT1->getTemplatedDecl()->getNumParams();
+  const unsigned NumParams2 = FT2->getTemplatedDecl()->getNumParams();
+
----------------
We tend not to use top-level const on locals in the project as a matter of style.


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Comment at: clang/test/CXX/drs/dr6xx.cpp:1084
 
 namespace dr692 { // dr692: no
   namespace temp_func_order_example2 {
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This DR is also about partial class specializations -- are changes not needed in `Sema::getMoreSpecializedPartialSpecialization()` as well?

It'd be helpful to add the examples from the DR here to make sure they're handled properly.


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https://reviews.llvm.org/D128745