Clang C++20 Feature: P1814R0 - Wording for Class Template Argument Deduction for Alias Templates #54051
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@llvm/issue-subscribers-c-20 |
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Friendly ping, any updates on this? |
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@alanzhao1 sorry, I haven't had the time to work on this. |
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It turned out this and #54050 are both parts of https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p1021r6.html which I'm currently working on. |
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@yuanfang-chen, I've been looking at this for the past few days, but I saw that you've been pretty active with https://reviews.llvm.org/D139837, which addresses #54050 which is related to this bug. Have you made any progress on this bug? If so, I'll abandon my efforts, as I'm sure you'll have something out before I do and I'd prefer to avoid duplicating work. |
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Hi @alanzhao1, I'm still working on this. However, P2582R0 is yet to be picked up AFAIK. |
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Thanks for the update! Since you're working on it, I'll abandon my efforts, as you're more experienced in this area. Feel free to add me as a reviewer to the patch (I'm ayzhao on LLVM's phabricator) |
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Ran into this pothole today. So uh... Any news here? |
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Ran into again today; just for another voice / raised hand. |
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Hi @yuanfang-chen, I wonder what's the status now, are you still working on it? If not, I'm happy to pick it up. |
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Reassign this issue to me. I'm working on it. |
Fixes #54051 This patch implements the C++20 feature -- CTAD for alias templates (P1814R0, specified in https://eel.is/c++draft/over.match.class.deduct#3). It is an initial patch: - it cover major pieces, thus it works for most cases; - the big missing piece is to implement the associated constraints (over.match.class.deduct#3.3) for the synthesized deduction guides, see the FIXME in code and tests; - Some enhancements on the TreeTransform&TemplateInstantiator to allow performing instantiation on `BuildingDeductionGuides` mode;
EugeneZelenko
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clang:frontend
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@llvm/issue-subscribers-clang-frontend Author: Tom Stellard (tstellar)
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id: P1814R0
paper: https://wg21.link/p1814r0
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Fix the following compilation error: ``` | ../../pdf/pdfium/pdfium_api_wrappers.cc:150:32: error: alias template 'PDFiumAPIStringBufferAdapter' requires template arguments; argument deduction only allowed for class templates | 150 | PDFiumAPIStringBufferAdapter adapter(&name, expected_size, | | ^ | ../../pdf/pdfium/pdfium_api_string_buffer_adapter.h:173:1: note: template is declared here | 173 | using PDFiumAPIStringBufferAdapter = | | ^ | 1 error generated. ``` This patch will be dropped once clang >= 19.1.0 is available, which includes support for class template argument deduction (CTAD) for type alias templates (P1814R0 [0]) (#54051 [1]). Note that currently meta-clang [2] provides the clang version `18.1.6`. [0] https://wg21.link/p1814r0 [1] llvm/llvm-project#54051 [2] https://github.com/kraj/meta-clang Signed-off-by: Ariel D'Alessandro <[email protected]>
Fix the following compilation error: ``` | ../../pdf/pdfium/pdfium_api_wrappers.cc:150:32: error: alias template 'PDFiumAPIStringBufferAdapter' requires template arguments; argument deduction only allowed for class templates | 150 | PDFiumAPIStringBufferAdapter adapter(&name, expected_size, | | ^ | ../../pdf/pdfium/pdfium_api_string_buffer_adapter.h:173:1: note: template is declared here | 173 | using PDFiumAPIStringBufferAdapter = | | ^ | 1 error generated. ``` This patch will be dropped once clang >= 19.1.0 is available, which includes support for class template argument deduction (CTAD) for type alias templates (P1814R0 [0]) (#54051 [1]). Note that currently meta-clang [2] provides the clang version `18.1.6`. [0] https://wg21.link/p1814r0 [1] llvm/llvm-project#54051 [2] https://github.com/kraj/meta-clang Signed-off-by: Ariel D'Alessandro <[email protected]>
id: P1814R0
paper: https://wg21.link/p1814r0
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