[clang] d982643 - [clang] Implement CWG 2397
Younan Zhang via cfe-commits
cfe-commits at lists.llvm.org
Wed Apr 12 07:30:32 PDT 2023
Author: Younan Zhang
Date: 2023-04-12T22:30:23+08:00
New Revision: d9826433f31cd081d0229d47d7982b5bf3c0055f
URL: https://github.com/llvm/llvm-project/commit/d9826433f31cd081d0229d47d7982b5bf3c0055f
DIFF: https://github.com/llvm/llvm-project/commit/d9826433f31cd081d0229d47d7982b5bf3c0055f.diff
LOG: [clang] Implement CWG 2397
This patch implements CWG 2397, allowing array of placeholder type
to be valid.
See also https://wg21.cmeerw.net/cwg/issue2397.
Reviewed By: aaron.ballman, #clang-language-wg
Differential Revision: https://reviews.llvm.org/D147909
Added:
clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/cwg2397.cpp
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaType.cpp
clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p1-cxx0x.cpp
clang/test/CXX/drs/dr23xx.cpp
clang/www/cxx_dr_status.html
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index dd66c71122999..e08aecfcc881f 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -103,6 +103,8 @@ C++2b Feature Support
Resolutions to C++ Defect Reports
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- Implemented `DR2397 <https://wg21.link/CWG2397>`_ which allows ``auto`` specifier for pointers
+ and reference to arrays.
C Language Changes
------------------
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index cd5930d385e69..18a0154b00411 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2314,8 +2314,6 @@ def err_auto_variable_cannot_appear_in_own_initializer : Error<
def err_binding_cannot_appear_in_own_initializer : Error<
"binding %0 cannot appear in the initializer of its own "
"decomposition declaration">;
-def err_illegal_decl_array_of_auto : Error<
- "'%0' declared as array of %1">;
def err_new_array_of_auto : Error<
"cannot allocate array of 'auto'">;
def err_auto_not_allowed : Error<
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index f557ff7b203fa..99e7ccfd88351 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -5130,17 +5130,6 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
D.setInvalidType(true);
}
}
- const AutoType *AT = T->getContainedAutoType();
- // Allow arrays of auto if we are a generic lambda parameter.
- // i.e. [](auto (&array)[5]) { return array[0]; }; OK
- if (AT && D.getContext() != DeclaratorContext::LambdaExprParameter) {
- // We've already diagnosed this for decltype(auto).
- if (!AT->isDecltypeAuto())
- S.Diag(DeclType.Loc, diag::err_illegal_decl_array_of_auto)
- << getPrintableNameForEntity(Name) << T;
- T = QualType();
- break;
- }
// Array parameters can be marked nullable as well, although it's not
// necessary if they're marked 'static'.
diff --git a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/cwg2397.cpp b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/cwg2397.cpp
new file mode 100644
index 0000000000000..f280d02a97513
--- /dev/null
+++ b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/cwg2397.cpp
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++14
+
+void f() {
+ int a[5];
+ auto (*b)[5] = &a;
+ auto (&c)[5] = a;
+ auto (&&d)[5] = static_cast<int(&&)[5]>(a);
+ auto e[] = {0}; // expected-error{{cannot deduce actual type for variable 'e' with type 'auto[]' from initializer list}}
+ static_assert(__is_same(decltype(b), int (*)[5]), "");
+ static_assert(__is_same(decltype(c), int (&)[5]), "");
+ static_assert(__is_same(decltype(d), int (&&)[5]), "");
+}
+
+#if __cplusplus >= 201402L
+
+constexpr int g() {
+ int a[] = {1, 2, 3};
+ auto (&b)[3] = a;
+ return b[1];
+}
+
+static_assert(g() == 2, "");
+
+#endif
diff --git a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p1-cxx0x.cpp b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p1-cxx0x.cpp
index 102746c3db292..a3482d58afa1f 100644
--- a/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p1-cxx0x.cpp
+++ b/clang/test/CXX/dcl.decl/dcl.meaning/dcl.array/p1-cxx0x.cpp
@@ -2,6 +2,6 @@
void f() {
int b[5];
- auto a[5] = b; // expected-error{{'a' declared as array of 'auto'}}
- auto *c[5] = b; // expected-error{{'c' declared as array of 'auto *'}}
+ auto a[5] = b; // expected-error{{variable 'a' with type 'auto[5]' has incompatible initializer of type 'int[5]'}}
+ auto *c[5] = b; // expected-error{{variable 'c' with type 'auto *[5]' has incompatible initializer of type 'int[5]'}}
}
diff --git a/clang/test/CXX/drs/dr23xx.cpp b/clang/test/CXX/drs/dr23xx.cpp
index 4f16746aad8be..51879e913c6ba 100644
--- a/clang/test/CXX/drs/dr23xx.cpp
+++ b/clang/test/CXX/drs/dr23xx.cpp
@@ -213,3 +213,14 @@ namespace dr2396 { // dr2396: no
// void g(A a) { a.operator decltype(B()) B::*(); }
// void g2(A a) { a.operator B decltype(B())::*(); }
}
+
+#if __cplusplus >= 201103L
+namespace dr2397 { // dr2397: 17
+ void foo() {
+ int a[5];
+
+ auto (&b)[5] = a;
+ auto (*c)[5] = &a;
+ }
+} // namespace dr2397
+#endif
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index bac8a52c2d5bd..5ee388f51f3ae 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -14189,7 +14189,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td><a href="https://wg21.link/cwg2397">2397</a></td>
<td>CD6</td>
<td><TT>auto</TT> specifier for pointers and references to arrays</td>
- <td class="none" align="center">Unknown</td>
+ <td class="unreleased" align="center">Clang 17</td>
</tr>
<tr class="open" id="2398">
<td><a href="https://wg21.link/cwg2398">2398</a></td>
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