BranchWatchTableModel: Assume Unreachable Code Truly Is

Source/Core/Common/CMakeLists.txt

@@ -143,6 +143,7 @@ add_library(common
   TraversalClient.h
   TraversalProto.h
   TypeUtils.h
+  Unreachable.h
   UPnP.cpp
   UPnP.h
   VariantUtil.h

Source/Core/Common/Unreachable.h

@@ -0,0 +1,21 @@
+// Copyright 2024 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "Common/CommonFuncs.h"
+
+namespace Common
+{
+// TODO C++23: Replace with std::unreachable.
+[[noreturn]] inline void Unreachable()
+{
+#ifdef _DEBUG
+  Crash();
+#elif defined(_MSC_VER) && !defined(__clang__)
+  __assume(false);
+#else
+  __builtin_unreachable();
+#endif
+}
+}  // namespace Common

Source/Core/DolphinLib.props

@@ -165,6 +165,7 @@
     <ClInclude Include="Common\TraversalClient.h" />
     <ClInclude Include="Common\TraversalProto.h" />
     <ClInclude Include="Common\TypeUtils.h" />
+    <ClInclude Include="Common\Unreachable.h" />
     <ClInclude Include="Common\UPnP.h" />
     <ClInclude Include="Common\VariantUtil.h" />
     <ClInclude Include="Common\Version.h" />

Source/Core/DolphinQt/Debugger/BranchWatchTableModel.cpp

@@ -11,6 +11,7 @@
 
 #include "Common/Assert.h"
 #include "Common/GekkoDisassembler.h"
+#include "Common/Unreachable.h"
 #include "Core/Debugger/BranchWatch.h"
 #include "Core/PowerPC/PPCSymbolDB.h"
 
@@ -355,7 +356,8 @@ QVariant BranchWatchTableModel::DisplayRoleData(const QModelIndex& index) const
   case Column::TotalHits:
     return QString::number(kv->second.total_hits);
   }
-  return QVariant();
+  static_assert(Column::NumberOfColumns == 8);
+  Common::Unreachable();
 }
 
 QVariant BranchWatchTableModel::FontRoleData(const QModelIndex& index) const
@@ -400,7 +402,8 @@ QVariant BranchWatchTableModel::TextAlignmentRoleData(const QModelIndex& index)
   case Column::DestinSymbol:
     return QVariant::fromValue(Qt::AlignLeft | Qt::AlignVCenter);
   }
-  return QVariant();
+  static_assert(Column::NumberOfColumns == 8);
+  Common::Unreachable();
 }
 
 QVariant BranchWatchTableModel::ForegroundRoleData(const QModelIndex& index) const
@@ -498,5 +501,6 @@ QVariant BranchWatchTableModel::SortRoleData(const QModelIndex& index) const
   case Column::TotalHits:
     return qulonglong{kv->second.total_hits};
   }
-  return QVariant();
+  static_assert(Column::NumberOfColumns == 8);
+  Common::Unreachable();
 }