[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
https://github.com/mizvekov edited https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
https://github.com/mizvekov edited https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
https://github.com/mizvekov closed https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
jyknight wrote: Heads up: this commit has triggered some weird errors for a compile, but only when clang header modules are enabled. A std::vector, that's built through a large amount of template gunk that definitely involves template template parameter matching, ends up failing vector's "Allocator::value_type must be same type as value_type" static assertion -- the vector's allocator's value_type seems to be some unrelated type. But, only when modules are enabled. That seems to _probably_ indicate a bug in this commit (presumably related to AST serialization or deserialization?), but I don't have a test-case, and, that's harder to get for issues that only arise with modules enabled... If this very vague and unhelpful description makes you think "oh, I see where the problem likely is!", then great! But, otherwise, I'll see if I can create a test case... https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
dcci wrote: I am seeing something similar in vector (without modules). I'm reducing a test case now. https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
dcci wrote:
Example error while I reduce:
```
fbcode/third-party-buck/platform010/build/libgcc/include/c++/trunk/bits/stl_vector.h:404:21:
error: static assertion failed due to requirement
'is_same, std::allocator>,
quic::Interval>::value': std::vector must have the same
value_type as its allocator
404 | static_assert(is_same::value,
| ^~~~
buck-out/v2/gen/fbcode/21eca57c08ba71f9/quic/common/__interval_set__/buck-headers/quic/common/IntervalSet.h:61:29:
note: in instantiation of template class 'std::vector>' requested here
61 | class IntervalSet : private Container> {
| ^
buck-out/v2/gen/fbcode/21eca57c08ba71f9/quic/state/__quic_state_machine__/buck-headers/quic/state/QuicStreamManager.h:79:41:
note: in instantiation of template class 'quic::IntervalSet' requested here
79 | IntervalSet streams_;
| ^
```
https://github.com/llvm/llvm-project/pull/92855
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[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
mizvekov wrote: Thanks for the heads up, this does look like a problem. I am reverting it for now. https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
mizvekov wrote: > Heads up: this commit has triggered some weird errors for a compile, but only > when clang header modules are enabled. > That seems to _probably_ indicate a bug in this commit (presumably related to > AST serialization or deserialization?), but I don't have a test-case, and, > that's harder to get for issues that only arise with modules enabled... Thanks for the heads-up, James. Indeed, and it's not only modules, our tooling for reducing test cases is getting less and less effective. https://github.com/llvm/llvm-project/pull/92855 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #92855)
mizvekov wrote:
I figured a reproducer based on your hints:
```C++
template struct A {};
template class TT> auto f(TT a) { return a; }
A v1;
A v2;
using X = decltype(f(v1));
using Y = decltype(f(v2));
```
Fails with:
```
t.cc:9:20: error: no matching function for call to 'f'
9 | using Y = decltype(f(v2));
|^
t.cc:3:41: note: candidate template ignored: deduced type 'A<[...], (default)
float>' of 1st parameter does not match adjusted type 'A<[...], double>' of
argument [with TT = A]
3 | template class TT> auto f(TT a) { return a; }
| ^
```
This shows we are not properly canonicalizing the synthesized template
declaration.
The problem does not show up with class template partial specializations due to
a pre-existing issue, but otherwise this was an oversight on my part.
No need to keep reducing on your end, I already have enough to go with.
https://github.com/llvm/llvm-project/pull/92855
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