[clang] [clang][test] Avoid some C++14 warnings in discrim-union.cpp (PR #146829)
Timm Baeder via cfe-commits
cfe-commits at lists.llvm.org
Thu Jul 3 01:03:43 PDT 2025
https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/146829
Before this patch, we emitted a bunch of irrelevant (to this test) warnings:
```
../clang/test/SemaCXX/discrim-union.cpp:49:24: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
49 | constexpr const T &get(select<0>) { return val; }
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:50:104: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
50 | template<unsigned N> constexpr const decltype(static_cast<const rest_t&>(rest).get(select<N-1>{})) get(select<N>) {
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:82:22: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
82 | constexpr unsigned index() noexcept { return elem; }
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:88:33: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
88 | constexpr const_get_result<N> get() {
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:96:22: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
96 | constexpr const U &get() {
| ^
| const
5 warnings generated.
```
>From 8f95d47d40b20d25074cbcf7597f8e233472f4ac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Thu, 3 Jul 2025 09:57:40 +0200
Subject: [PATCH] [clang][test] Avoid some C++14 warnings in discrim-union.cpp
Before this patch, we emitted a bunch of irrelevant (to this test)
warnings:
../clang/test/SemaCXX/discrim-union.cpp:49:24: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
49 | constexpr const T &get(select<0>) { return val; }
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:50:104: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
50 | template<unsigned N> constexpr const decltype(static_cast<const rest_t&>(rest).get(select<N-1>{})) get(select<N>) {
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:82:22: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
82 | constexpr unsigned index() noexcept { return elem; }
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:88:33: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
88 | constexpr const_get_result<N> get() {
| ^
| const
../clang/test/SemaCXX/discrim-union.cpp:96:22: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in behavior [-Wconstexpr-not-const]
96 | constexpr const U &get() {
| ^
| const
5 warnings generated.
---
clang/test/SemaCXX/discrim-union.cpp | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/clang/test/SemaCXX/discrim-union.cpp b/clang/test/SemaCXX/discrim-union.cpp
index 15c9a225ed9a9..9877b70205104 100644
--- a/clang/test/SemaCXX/discrim-union.cpp
+++ b/clang/test/SemaCXX/discrim-union.cpp
@@ -46,8 +46,8 @@ namespace detail {
val.~T();
}
- constexpr const T &get(select<0>) { return val; }
- template<unsigned N> constexpr const decltype(static_cast<const rest_t&>(rest).get(select<N-1>{})) get(select<N>) {
+ constexpr const T &get(select<0>) const { return val; }
+ template<unsigned N> constexpr const decltype(static_cast<const rest_t&>(rest).get(select<N-1>{})) get(select<N>) const {
return rest.get(select<N-1>{});
}
};
@@ -79,13 +79,13 @@ class either {
// FIXME: declare a destructor iff any element has a nontrivial destructor
//~either() { impl.destroy(elem); }
- constexpr unsigned index() noexcept { return elem; }
+ constexpr unsigned index() const noexcept { return elem; }
template<unsigned N> using const_get_result =
decltype(static_cast<const impl_t&>(impl).get(detail::select<N>{}));
template<unsigned N>
- constexpr const_get_result<N> get() {
+ constexpr const_get_result<N> get() const {
// Can't just use throw here, since that makes the conditional a prvalue,
// which means we return a reference to a temporary.
return (elem != N ? throw_<const_get_result<N>>("bad_either_get")
@@ -93,7 +93,7 @@ class either {
}
template<typename U>
- constexpr const U &get() {
+ constexpr const U &get() const {
return get<impl_t::index(detail::type<U>())>();
}
};
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