Address a constexpr template point of instantiation issue

...that hits at least when building with Clang and --with-latest-c++ against
recent libc++ or MSVC standard library (where C++20 and esp. C++23 made more and
more class template member functions constexpr).  My understanding is that there
is some leeway at what point a compiler should instantiate such function
specializations, and Clang decides to instantiate constexpr ones early (cf.
<https://github.com/llvm/llvm-project/commit/242ad89a15d5466d166d47978bfff983d40ab511>
"C++11 half of r147023: In C++11, additionally eagerly instantiate:" and its "Do
not defer instantiations of constexpr functions" comment, and the discussion at
<https://discourse.llvm.org/t/point-of-instantiation-of-constexpr-function-template/65129>).

> In file included from cui/source/dialogs/cuihyperdlg.cxx:23:
> In file included from include/comphelper/lok.hxx:14:
> In file included from include/rtl/ustring.hxx:34:
> In file included from ~/llvm/inst/bin/../include/c++/v1/ostream:168:
> ~/llvm/inst/bin/../include/c++/v1/__memory/unique_ptr.h:47:19: error: invalid application of 'sizeof' to an incomplete type 'IconChoicePage'
>     static_assert(sizeof(_Tp) >= 0, "cannot delete an incomplete type");
>                   ^~~~~~~~~~~
> ~/llvm/inst/bin/../include/c++/v1/__memory/unique_ptr.h:281:7: note: in instantiation of member function 'std::default_delete<IconChoicePage>::operator()' requested here
>       __ptr_.second()(__tmp);
>       ^
> ~/llvm/inst/bin/../include/c++/v1/__memory/unique_ptr.h:247:75: note: in instantiation of member function 'std::unique_ptr<IconChoicePage>::reset' requested here
>   _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX23 ~unique_ptr() { reset(); }
>                                                                           ^
> cui/source/inc/iconcdlg.hxx:43:5: note: in instantiation of member function 'std::unique_ptr<IconChoicePage>::~unique_ptr' requested here
>     IconChoicePageData(OString aId, std::unique_ptr<IconChoicePage> xInPage)
>     ^
> cui/source/inc/iconcdlg.hxx:28:7: note: forward declaration of 'IconChoicePage'
> class IconChoicePage;
>       ^

Change-Id: I789c85e0661969679c88fea1dfc7a65475fb3037
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/141811
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 15 insertions, 15 deletions

diff --git a/cui/source/inc/iconcdlg.hxx b/cui/source/inc/iconcdlg.hxx
index 1803a9a633e2..6367016fe8b5 100644
--- a/cui/source/inc/iconcdlg.hxx
+++ b/cui/source/inc/iconcdlg.hxx
@@ -32,21 +32,6 @@ class SfxItemSet;
 // Create-Function
 typedef std::unique_ptr<IconChoicePage> (*CreatePage)(weld::Container* pParent, SvxHpLinkDlg* pDlg, const SfxItemSet* pAttrSet);
 
-/// Data-structure for pages in dialog
-struct IconChoicePageData
-{
-    OString sId;
-    std::unique_ptr<IconChoicePage> xPage;      ///< the TabPage itself
-    bool bRefresh;          ///< Flag: page has to be newly initialized
-
-    // constructor
-    IconChoicePageData(OString aId, std::unique_ptr<IconChoicePage> xInPage)
-        : sId(std::move(aId))
-        , xPage(std::move(xInPage))
-        , bRefresh(false)
-    {}
-};
-
 class IconChoicePage
 {
 protected:
@@ -79,4 +64,19 @@ public:
     virtual bool        QueryClose();
 };
 
+/// Data-structure for pages in dialog
+struct IconChoicePageData
+{
+    OString sId;
+    std::unique_ptr<IconChoicePage> xPage;      ///< the TabPage itself
+    bool bRefresh;          ///< Flag: page has to be newly initialized
+
+    // constructor
+    IconChoicePageData(OString aId, std::unique_ptr<IconChoicePage> xInPage)
+        : sId(std::move(aId))
+        , xPage(std::move(xInPage))
+        , bRefresh(false)
+    {}
+};
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */