Disable deprecated-enum-enum-conversion (#3040, #2983)

imgui_widgets.cpp

@@ -68,6 +68,9 @@ Index of this file:
 #if __has_warning("-Wdouble-promotion")
 #pragma clang diagnostic ignored "-Wdouble-promotion"       // warning: implicit conversion from 'float' to 'double' when passing argument to function  // using printf() is a misery with this as C++ va_arg ellipsis changes float to double.
 #endif
+#if __has_warning("-Wdeprecated-enum-enum-conversion")
+#pragma clang diagnostic ignored "-Wdeprecated-enum-enum-conversion" // warning: bitwise operation between different enumeration types ('XXXFlags_' and 'XXXFlagsPrivate_') is deprecated
+#endif
 #elif defined(__GNUC__)
 #pragma GCC diagnostic ignored "-Wpragmas"                  // warning: unknown option after '#pragma GCC diagnostic' kind
 #pragma GCC diagnostic ignored "-Wformat-nonliteral"        // warning: format not a string literal, format string not checked
@@ -5573,7 +5576,9 @@ bool ImGui::CollapsingHeader(const char* label, bool* p_open, ImGuiTreeNodeFlags
         return false;
 
     ImGuiID id = window->GetID(label);
-    flags |= ImGuiTreeNodeFlags_CollapsingHeader | (p_open ? ImGuiTreeNodeFlags_AllowItemOverlap | ImGuiTreeNodeFlags_ClipLabelForTrailingButton : 0);
+    flags |= ImGuiTreeNodeFlags_CollapsingHeader;
+    if (p_open)
+        flags |= ImGuiTreeNodeFlags_AllowItemOverlap | ImGuiTreeNodeFlags_ClipLabelForTrailingButton;
     bool is_open = TreeNodeBehavior(id, flags, label);
     if (p_open)
     {