[clang] d933882 - [Clang] Add test for CWG2285 "Issues with structured bindings" (#126421)
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Thu Mar 6 22:16:55 PST 2025
Author: Yanzuo Liu
Date: 2025-03-07T07:16:51+01:00
New Revision: d933882ed369a68d118ca661488bb2c89028a2de
URL: https://github.com/llvm/llvm-project/commit/d933882ed369a68d118ca661488bb2c89028a2de
DIFF: https://github.com/llvm/llvm-project/commit/d933882ed369a68d118ca661488bb2c89028a2de.diff
LOG: [Clang] Add test for CWG2285 "Issues with structured bindings" (#126421)
The resolution of [CWG2285](https://wg21.link/cwg2285) adds the point of
declaration of a structured binding, and was implemented in
https://github.com/llvm/llvm-project/commit/bdb84f374cde7736ca68d5db2c2ecf5468346710
.
Drive-by changes: modify comment and diagnostic messages mentioned in
CWG2285.
Added:
Modified:
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/lib/Sema/SemaDeclCXX.cpp
clang/test/CXX/drs/cwg22xx.cpp
clang/test/Parser/cxx1z-decomposition.cpp
clang/www/cxx_dr_status.html
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index cf0e9846d4259..1b46920e09619 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -551,7 +551,7 @@ def err_decomp_decl_constraint : Error<
def err_decomp_decl_parens : Error<
"decomposition declaration cannot be declared with parentheses">;
def err_decomp_decl_template : Error<
- "decomposition declaration template not supported">;
+ "decomposition declaration cannot be a template">;
def err_decomp_decl_not_alone : Error<
"decomposition declaration must be the only declaration in its group">;
def err_decomp_decl_requires_init : Error<
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index a3a028b9485d6..fd5f0443fa894 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -733,8 +733,11 @@ Sema::ActOnDecompositionDeclarator(Scope *S, Declarator &D,
}
if (!TemplateParamLists.empty()) {
- // FIXME: There's no rule against this, but there are also no rules that
- // would actually make it usable, so we reject it for now.
+ // C++17 [temp]/1:
+ // A template defines a family of class, functions, or variables, or an
+ // alias for a family of types.
+ //
+ // Structured bindings are not included.
Diag(TemplateParamLists.front()->getTemplateLoc(),
diag::err_decomp_decl_template);
return nullptr;
diff --git a/clang/test/CXX/drs/cwg22xx.cpp b/clang/test/CXX/drs/cwg22xx.cpp
index d93070ef3804d..8c8ad9f7f74ee 100644
--- a/clang/test/CXX/drs/cwg22xx.cpp
+++ b/clang/test/CXX/drs/cwg22xx.cpp
@@ -1,10 +1,10 @@
// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify=expected -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++23 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++2c -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++23 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++2c -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
namespace cwg2211 { // cwg2211: 8
@@ -196,6 +196,17 @@ void g() {
#endif
} // namespace cwg2277
+namespace cwg2285 { // cwg2285: 4
+// Note: Clang 4 implements this DR but it set a wrong value of `__cplusplus`
+#if __cplusplus >= 201703L
+ void test() {
+ using T = int[1];
+ auto [a] = T{a};
+ // since-cxx17-error at -1 {{binding 'a' cannot appear in the initializer of its own decomposition declaration}}
+ }
+#endif
+} // namespace cwg2285
+
namespace cwg2292 { // cwg2292: 9
#if __cplusplus >= 201103L
template<typename T> using id = T;
diff --git a/clang/test/Parser/cxx1z-decomposition.cpp b/clang/test/Parser/cxx1z-decomposition.cpp
index acf3f99069185..f4a4dc5375bdc 100644
--- a/clang/test/Parser/cxx1z-decomposition.cpp
+++ b/clang/test/Parser/cxx1z-decomposition.cpp
@@ -136,8 +136,8 @@ namespace MultiDeclarator {
namespace Template {
int n[3];
- // FIXME: There's no actual rule against this...
- template<typename T> auto [a, b, c] = n; // expected-error {{decomposition declaration template not supported}}
+ // Structured binding template is not allowed.
+ template<typename T> auto [a, b, c] = n; // expected-error {{decomposition declaration cannot be a template}}
}
namespace Init {
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 919996bd700b4..b7888d2365acc 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -13537,7 +13537,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
<td><a href="https://cplusplus.github.io/CWG/issues/2285.html">2285</a></td>
<td>CD5</td>
<td>Issues with structured bindings</td>
- <td class="unknown" align="center">Unknown</td>
+ <td class="full" align="center">Clang 4</td>
</tr>
<tr id="2286">
<td><a href="https://cplusplus.github.io/CWG/issues/2286.html">2286</a></td>
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