diff --git a/src/plugins/clangcodemodel/clangdclient.h b/src/plugins/clangcodemodel/clangdclient.h
index 5a12c8f56d7..1b57ea4b66f 100644
--- a/src/plugins/clangcodemodel/clangdclient.h
+++ b/src/plugins/clangcodemodel/clangdclient.h
@@ -14,7 +14,10 @@
 
 #include <optional>
 
-namespace Core { class SearchResult; }
+namespace Core {
+class HelpItem;
+class SearchResult;
+}
 namespace CppEditor { class CppEditorWidget; }
 namespace LanguageServerProtocol { class Range; }
 namespace ProjectExplorer {
diff --git a/src/plugins/clangcodemodel/clangdlocatorfilters.cpp b/src/plugins/clangcodemodel/clangdlocatorfilters.cpp
index 5bf59150446..18fd250a982 100644
--- a/src/plugins/clangcodemodel/clangdlocatorfilters.cpp
+++ b/src/plugins/clangcodemodel/clangdlocatorfilters.cpp
@@ -6,6 +6,8 @@
 #include "clangdclient.h"
 #include "clangmodelmanagersupport.h"
 
+#include <coreplugin/editormanager/editormanager.h>
+
 #include <cppeditor/cppeditorconstants.h>
 #include <cppeditor/cppeditortr.h>
 #include <cppeditor/cpplocatorfilter.h>
diff --git a/src/plugins/clangcodemodel/clangtextmark.cpp b/src/plugins/clangcodemodel/clangtextmark.cpp
index c2c8c88801b..24edc0b954a 100644
--- a/src/plugins/clangcodemodel/clangtextmark.cpp
+++ b/src/plugins/clangcodemodel/clangtextmark.cpp
@@ -47,7 +47,7 @@ Project *projectForCurrentEditor()
         return nullptr;
 
     if (ProjectPart::ConstPtr projectPart = projectPartForFile(filePath))
-        return projectForProjectPart(*projectPart);
+        return projectPart->project();
 
     return nullptr;
 }
@@ -80,7 +80,7 @@ void disableDiagnosticInCurrentProjectConfig(const ClangDiagnostic &diagnostic)
 
     // Get config
     ClangDiagnosticConfig config = diagnosticConfig();
-    ClangDiagnosticConfigsModel configsModel = CppEditor::diagnosticConfigsModel();
+    ClangDiagnosticConfigsModel configsModel = ClangdSettings::diagnosticConfigsModel();
 
     // Create copy if needed
     if (config.isReadOnly()) {
diff --git a/src/plugins/clangcodemodel/clangutils.cpp b/src/plugins/clangcodemodel/clangutils.cpp
index b27117f056e..11e7398f372 100644
--- a/src/plugins/clangcodemodel/clangutils.cpp
+++ b/src/plugins/clangcodemodel/clangutils.cpp
@@ -5,6 +5,7 @@
 
 #include "clangcodemodeltr.h"
 
+#include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/icore.h>
 #include <coreplugin/idocument.h>
 #include <cppeditor/baseeditordocumentparser.h>
diff --git a/src/plugins/clangtools/diagnosticconfigswidget.cpp b/src/plugins/clangtools/diagnosticconfigswidget.cpp
index 81aa6fb2305..51aec7c0400 100644
--- a/src/plugins/clangtools/diagnosticconfigswidget.cpp
+++ b/src/plugins/clangtools/diagnosticconfigswidget.cpp
@@ -38,12 +38,12 @@
 #include <QSortFilterProxyModel>
 #include <QStackedWidget>
 #include <QStringListModel>
+#include <QTextEdit>
 #include <QTreeView>
 #include <QTreeWidget>
 #include <QTreeWidgetItem>
 #include <QUuid>
 
-
 using namespace CppEditor;
 using namespace Utils;
 
diff --git a/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp b/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp
index f3e512eebb0..0ab987d978a 100644
--- a/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp
+++ b/src/plugins/cmakeprojectmanager/cmakeprojectmanager.cpp
@@ -22,6 +22,7 @@
 #include <coreplugin/messagemanager.h>
 #include <coreplugin/modemanager.h>
 
+#include <cppeditor/cppprojectfile.h>
 #include <cppeditor/cpptoolsreuse.h>
 
 #include <debugger/analyzer/analyzerconstants.h>
diff --git a/src/plugins/cppeditor/baseeditordocumentparser.h b/src/plugins/cppeditor/baseeditordocumentparser.h
index dce82893848..fb7686f1470 100644
--- a/src/plugins/cppeditor/baseeditordocumentparser.h
+++ b/src/plugins/cppeditor/baseeditordocumentparser.h
@@ -6,8 +6,10 @@
 #include "cppeditor_global.h"
 #include "cpptoolsreuse.h"
 #include "cppworkingcopy.h"
+#include "projectpart.h"
 
 #include <projectexplorer/project.h>
+#include <utils/cpplanguage_details.h>
 
 #include <QObject>
 #include <QMutex>
diff --git a/src/plugins/cppeditor/builtincursorinfo.cpp b/src/plugins/cppeditor/builtincursorinfo.cpp
index 0bff4406e76..2b2acf82f1c 100644
--- a/src/plugins/cppeditor/builtincursorinfo.cpp
+++ b/src/plugins/cppeditor/builtincursorinfo.cpp
@@ -12,6 +12,7 @@
 
 #include <cplusplus/CppDocument.h>
 #include <cplusplus/Macro.h>
+#include <cplusplus/Overview.h>
 #include <cplusplus/TranslationUnit.h>
 
 #include <utils/async.h>
@@ -26,6 +27,51 @@ namespace CppEditor {
 using SemanticUses = QList<SemanticInfo::Use>;
 namespace {
 
+static bool isOwnershipRAIIName(const QString &name)
+{
+    static QSet<QString> knownNames;
+    if (knownNames.isEmpty()) {
+        // Qt
+        knownNames.insert(QLatin1String("QScopedPointer"));
+        knownNames.insert(QLatin1String("QScopedArrayPointer"));
+        knownNames.insert(QLatin1String("QMutexLocker"));
+        knownNames.insert(QLatin1String("QReadLocker"));
+        knownNames.insert(QLatin1String("QWriteLocker"));
+        // Standard C++
+        knownNames.insert(QLatin1String("auto_ptr"));
+        knownNames.insert(QLatin1String("unique_ptr"));
+        // Boost
+        knownNames.insert(QLatin1String("scoped_ptr"));
+        knownNames.insert(QLatin1String("scoped_array"));
+    }
+
+    return knownNames.contains(name);
+}
+
+static bool isOwnershipRAIIType(Symbol *symbol, const LookupContext &context)
+{
+    if (!symbol)
+        return false;
+
+    // This is not a "real" comparison of types. What we do is to resolve the symbol
+    // in question and then try to match its name with already known ones.
+    if (symbol->asDeclaration()) {
+        Declaration *declaration = symbol->asDeclaration();
+        const NamedType *namedType = declaration->type()->asNamedType();
+        if (namedType) {
+            ClassOrNamespace *clazz = context.lookupType(namedType->name(),
+                                                         declaration->enclosingScope());
+            if (clazz && !clazz->symbols().isEmpty()) {
+                Overview overview;
+                Symbol *symbol = clazz->symbols().at(0);
+                return isOwnershipRAIIName(overview.prettyName(symbol->name()));
+            }
+        }
+    }
+
+    return false;
+}
+
 CursorInfo::Range toRange(const SemanticInfo::Use &use)
 {
     return {use.line, use.column, use.length};
diff --git a/src/plugins/cppeditor/clangdiagnosticconfigsmodel.cpp b/src/plugins/cppeditor/clangdiagnosticconfigsmodel.cpp
index af63853edc5..8ebc5ffdb8e 100644
--- a/src/plugins/cppeditor/clangdiagnosticconfigsmodel.cpp
+++ b/src/plugins/cppeditor/clangdiagnosticconfigsmodel.cpp
@@ -4,6 +4,7 @@
 #include "clangdiagnosticconfigsmodel.h"
 
 #include "cppeditorconstants.h"
+#include "cppeditortr.h"
 #include "cpptoolsreuse.h"
 
 #include <utils/algorithm.h>
@@ -88,6 +89,34 @@ QStringList ClangDiagnosticConfigsModel::globalDiagnosticOptions()
     };
 }
 
+void ClangDiagnosticConfigsModel::addBuiltinConfigs()
+{
+    ClangDiagnosticConfig config;
+
+    // Questionable constructs
+    config = ClangDiagnosticConfig();
+    config.setId(Constants::CPP_CLANG_DIAG_CONFIG_QUESTIONABLE);
+    config.setDisplayName(Tr::tr("Checks for questionable constructs"));
+    config.setIsReadOnly(true);
+    config.setClangOptions({
+        "-Wall",
+        "-Wextra",
+    });
+    config.setClazyMode(ClangDiagnosticConfig::ClazyMode::UseCustomChecks);
+    config.setClangTidyMode(ClangDiagnosticConfig::TidyMode::UseCustomChecks);
+    appendOrUpdate(config);
+
+    // Warning flags from build system
+    config = ClangDiagnosticConfig();
+    config.setId(Constants::CPP_CLANG_DIAG_CONFIG_BUILDSYSTEM);
+    config.setDisplayName(Tr::tr("Build-system warnings"));
+    config.setIsReadOnly(true);
+    config.setClazyMode(ClangDiagnosticConfig::ClazyMode::UseCustomChecks);
+    config.setClangTidyMode(ClangDiagnosticConfig::TidyMode::UseCustomChecks);
+    config.setUseBuildSystemWarnings(true);
+    appendOrUpdate(config);
+}
+
 int ClangDiagnosticConfigsModel::indexOfConfig(const Utils::Id &id) const
 {
     return Utils::indexOf(m_diagnosticConfigs, [&](const ClangDiagnosticConfig &config) {
diff --git a/src/plugins/cppeditor/clangdiagnosticconfigsmodel.h b/src/plugins/cppeditor/clangdiagnosticconfigsmodel.h
index ba384630e76..ddac337f3f6 100644
--- a/src/plugins/cppeditor/clangdiagnosticconfigsmodel.h
+++ b/src/plugins/cppeditor/clangdiagnosticconfigsmodel.h
@@ -34,6 +34,8 @@ public:
                                                     const QString &displayName);
     static QStringList globalDiagnosticOptions();
 
+    void addBuiltinConfigs();
+
 private:
     ClangDiagnosticConfigs m_diagnosticConfigs;
 };
diff --git a/src/plugins/cppeditor/clangdsettings.cpp b/src/plugins/cppeditor/clangdsettings.cpp
index 78cce6df1c0..036dbeb41c3 100644
--- a/src/plugins/cppeditor/clangdsettings.cpp
+++ b/src/plugins/cppeditor/clangdsettings.cpp
@@ -11,6 +11,7 @@
 #include "cpptoolsreuse.h"
 
 #include <coreplugin/dialogs/ioptionspage.h>
+#include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/icore.h>
 #include <coreplugin/session.h>
 #include <projectexplorer/project.h>
@@ -201,6 +202,16 @@ void ClangdSettings::setCustomDiagnosticConfigs(const ClangDiagnosticConfigs &co
     instance().saveSettings();
 }
 
+ClangDiagnosticConfigsModel ClangdSettings::diagnosticConfigsModel()
+{
+    const ClangDiagnosticConfigs &customConfigs = instance().customDiagnosticConfigs();
+    ClangDiagnosticConfigsModel model;
+    model.addBuiltinConfigs();
+    for (const ClangDiagnosticConfig &config : customConfigs)
+        model.appendOrUpdate(config);
+    return model;
+}
+
 FilePath ClangdSettings::clangdFilePath() const
 {
     if (!m_data.executableFilePath.isEmpty())
@@ -237,7 +248,7 @@ Id ClangdSettings::diagnosticConfigId() const
 
 ClangDiagnosticConfig ClangdSettings::diagnosticConfig() const
 {
-    return diagnosticConfigsModel(customDiagnosticConfigs()).configWithId(diagnosticConfigId());
+    return diagnosticConfigsModel().configWithId(diagnosticConfigId());
 }
 
 ClangdSettings::Granularity ClangdSettings::granularity() const
@@ -761,7 +772,7 @@ ClangdSettingsWidget::ClangdSettingsWidget(const ClangdSettings::Data &settingsD
 
     m_configSelectionWidget = new ClangDiagnosticConfigsSelectionWidget(formLayout);
     m_configSelectionWidget->refresh(
-        diagnosticConfigsModel(settings.customDiagnosticConfigs()),
+        ClangdSettings::diagnosticConfigsModel(),
         settings.diagnosticConfigId(),
         [](const ClangDiagnosticConfigs &configs, const Utils::Id &configToSelect) {
             return new CppEditor::ClangDiagnosticConfigsWidget(configs, configToSelect);
diff --git a/src/plugins/cppeditor/clangdsettings.h b/src/plugins/cppeditor/clangdsettings.h
index e4fb22f5527..c5bf7052cea 100644
--- a/src/plugins/cppeditor/clangdsettings.h
+++ b/src/plugins/cppeditor/clangdsettings.h
@@ -13,6 +13,7 @@ namespace ProjectExplorer { class Project; }
 namespace Utils { class MacroExpander; }
 
 namespace CppEditor {
+class ClangDiagnosticConfigsModel;
 
 // TODO: Can we move this to ClangCodeModel?
 class CPPEDITOR_EXPORT ClangdSettings : public QObject
@@ -96,6 +97,8 @@ public:
 
     static void setDefaultClangdPath(const Utils::FilePath &filePath);
     static void setCustomDiagnosticConfigs(const ClangDiagnosticConfigs &configs);
+    static ClangDiagnosticConfigsModel diagnosticConfigsModel();
+
     Utils::FilePath clangdFilePath() const;
     IndexingPriority indexingPriority() const { return m_data.indexingPriority; }
     Utils::FilePath projectIndexPath(const Utils::MacroExpander &expander) const;
diff --git a/src/plugins/cppeditor/cppbuiltinmodelmanagersupport.cpp b/src/plugins/cppeditor/cppbuiltinmodelmanagersupport.cpp
index 3a82a411326..8944a52e7da 100644
--- a/src/plugins/cppeditor/cppbuiltinmodelmanagersupport.cpp
+++ b/src/plugins/cppeditor/cppbuiltinmodelmanagersupport.cpp
@@ -29,6 +29,7 @@ using namespace Utils;
 
 namespace CppEditor::Internal {
 namespace {
+
 class CppHoverHandler : public TextEditor::BaseHoverHandler
 {
 private:
diff --git a/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp b/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp
index 56c62dfca07..007a2c84cf7 100644
--- a/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp
+++ b/src/plugins/cppeditor/cppcodemodelinspectordialog.cpp
@@ -1913,7 +1913,7 @@ void CppCodeModelInspectorDialog::updateProjectPartData(const ProjectPart::Const
     QString projectFilePath = QLatin1String("<None>");
     if (part->hasProject()) {
         projectFilePath = part->topLevelProject.toUserOutput();
-        if (const ProjectExplorer::Project * const project = projectForProjectPart(*part))
+        if (const ProjectExplorer::Project * const project = part->project())
             projectName = project->displayName();
     }
     const QString callGroupId = part->callGroupId.isEmpty() ? QString::fromLatin1("<None>")
diff --git a/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp b/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp
index 4a9cff34542..a5bab99f121 100644
--- a/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp
+++ b/src/plugins/cppeditor/cppcodemodelinspectordumper.cpp
@@ -505,7 +505,7 @@ void Dumper::dumpProjectInfos(const QList<ProjectInfo::ConstPtr> &projectInfos)
             QString projectFilePath = "<None>";
             if (part->hasProject()) {
                 projectFilePath = part->topLevelProject.toUserOutput();
-                if (const ProjectExplorer::Project * const project = projectForProjectPart(*part))
+                if (const ProjectExplorer::Project * const project = part->project())
                     projectName = project->displayName();
             }
             if (!part->projectConfigFile.isEmpty())
diff --git a/src/plugins/cppeditor/cppheadersource.cpp b/src/plugins/cppeditor/cppheadersource.cpp
index 954158f5df9..0c586a4082e 100644
--- a/src/plugins/cppeditor/cppheadersource.cpp
+++ b/src/plugins/cppeditor/cppheadersource.cpp
@@ -250,7 +250,7 @@ FilePath correspondingHeaderOrSource(const FilePath &filePath, bool *wasHeader,
     } else {
         const QList<ProjectInfo::ConstPtr> projectInfos = CppModelManager::projectInfos();
         for (const ProjectInfo::ConstPtr &projectInfo : projectInfos) {
-            const Project *project = projectForProjectInfo(*projectInfo);
+            const Project *project = projectInfo->project();
             if (project == currentProject)
                 continue; // We have already checked the current project.
 
diff --git a/src/plugins/cppeditor/cpphighlighter.cpp b/src/plugins/cppeditor/cpphighlighter.cpp
index 952d74707a2..3b4345944e0 100644
--- a/src/plugins/cppeditor/cpphighlighter.cpp
+++ b/src/plugins/cppeditor/cpphighlighter.cpp
@@ -7,6 +7,7 @@
 #include "cpptoolsreuse.h"
 
 #include <texteditor/textdocumentlayout.h>
+#include <utils/algorithm.h>
 #include <utils/textutils.h>
 
 #include <cplusplus/SimpleLexer.h>
diff --git a/src/plugins/cppeditor/cppmodelmanager.cpp b/src/plugins/cppeditor/cppmodelmanager.cpp
index 6f2aebcca32..511094b48de 100644
--- a/src/plugins/cppeditor/cppmodelmanager.cpp
+++ b/src/plugins/cppeditor/cppmodelmanager.cpp
@@ -1573,7 +1573,7 @@ QFuture<void> CppModelManager::updateProjectInfo(const ProjectInfo::ConstPtr &ne
     QStringList removedProjectParts;
     bool filesRemoved = false;
 
-    Project * const project = projectForProjectInfo(*newProjectInfo);
+    Project * const project = newProjectInfo->project();
     if (!project)
         return {};
 
diff --git a/src/plugins/cppeditor/cppparsecontext.h b/src/plugins/cppeditor/cppparsecontext.h
index 6ced36f5346..9d65f6740ac 100644
--- a/src/plugins/cppeditor/cppparsecontext.h
+++ b/src/plugins/cppeditor/cppparsecontext.h
@@ -3,7 +3,7 @@
 
 #pragma once
 
-#include "cpptoolsreuse.h"
+#include "projectpart.h"
 
 #include <QAbstractListModel>
 #include <QComboBox>
diff --git a/src/plugins/cppeditor/cpptoolsreuse.cpp b/src/plugins/cppeditor/cpptoolsreuse.cpp
index 7be177c2c1b..109943123b1 100644
--- a/src/plugins/cppeditor/cpptoolsreuse.cpp
+++ b/src/plugins/cppeditor/cpptoolsreuse.cpp
@@ -3,20 +3,16 @@
 
 #include "cpptoolsreuse.h"
 
-#include "clangdiagnosticconfigsmodel.h"
 #include "clangdsettings.h"
 #include "cppautocompleter.h"
 #include "cppcanonicalsymbol.h"
 #include "cppcodemodelsettings.h"
 #include "cppcompletionassist.h"
-#include "cppeditorconstants.h"
 #include "cppeditorwidget.h"
 #include "cppeditortr.h"
 #include "cppfilesettingspage.h"
 #include "cpphighlighter.h"
 #include "cppqtstyleindenter.h"
-#include "cpprefactoringchanges.h"
-#include "projectinfo.h"
 #include "quickfixes/cppquickfixassistant.h"
 
 #include <coreplugin/documentmanager.h>
@@ -144,51 +140,6 @@ void moveCursorToStartOfIdentifier(QTextCursor *tc)
     skipCharsBackward(tc, isValidIdentifierChar);
 }
 
-static bool isOwnershipRAIIName(const QString &name)
-{
-    static QSet<QString> knownNames;
-    if (knownNames.isEmpty()) {
-        // Qt
-        knownNames.insert(QLatin1String("QScopedPointer"));
-        knownNames.insert(QLatin1String("QScopedArrayPointer"));
-        knownNames.insert(QLatin1String("QMutexLocker"));
-        knownNames.insert(QLatin1String("QReadLocker"));
-        knownNames.insert(QLatin1String("QWriteLocker"));
-        // Standard C++
-        knownNames.insert(QLatin1String("auto_ptr"));
-        knownNames.insert(QLatin1String("unique_ptr"));
-        // Boost
-        knownNames.insert(QLatin1String("scoped_ptr"));
-        knownNames.insert(QLatin1String("scoped_array"));
-    }
-
-    return knownNames.contains(name);
-}
-
-bool isOwnershipRAIIType(Symbol *symbol, const LookupContext &context)
-{
-    if (!symbol)
-        return false;
-
-    // This is not a "real" comparison of types. What we do is to resolve the symbol
-    // in question and then try to match its name with already known ones.
-    if (symbol->asDeclaration()) {
-        Declaration *declaration = symbol->asDeclaration();
-        const NamedType *namedType = declaration->type()->asNamedType();
-        if (namedType) {
-            ClassOrNamespace *clazz = context.lookupType(namedType->name(),
-                                                         declaration->enclosingScope());
-            if (clazz && !clazz->symbols().isEmpty()) {
-                Overview overview;
-                Symbol *symbol = clazz->symbols().at(0);
-                return isOwnershipRAIIName(overview.prettyName(symbol->name()));
-            }
-        }
-    }
-
-    return false;
-}
-
 bool isValidAsciiIdentifierChar(const QChar &ch)
 {
     return ch.isLetterOrNumber() || ch == QLatin1Char('_');
@@ -377,245 +328,6 @@ bool fileSizeExceedsLimit(const FilePath &filePath, int sizeLimitInMb)
     return false;
 }
 
-static void addBuiltinConfigs(ClangDiagnosticConfigsModel &model)
-{
-    ClangDiagnosticConfig config;
-
-    // Questionable constructs
-    config = ClangDiagnosticConfig();
-    config.setId(Constants::CPP_CLANG_DIAG_CONFIG_QUESTIONABLE);
-    config.setDisplayName(Tr::tr("Checks for questionable constructs"));
-    config.setIsReadOnly(true);
-    config.setClangOptions({
-        "-Wall",
-        "-Wextra",
-    });
-    config.setClazyMode(ClangDiagnosticConfig::ClazyMode::UseCustomChecks);
-    config.setClangTidyMode(ClangDiagnosticConfig::TidyMode::UseCustomChecks);
-    model.appendOrUpdate(config);
-
-    // Warning flags from build system
-    config = ClangDiagnosticConfig();
-    config.setId(Constants::CPP_CLANG_DIAG_CONFIG_BUILDSYSTEM);
-    config.setDisplayName(Tr::tr("Build-system warnings"));
-    config.setIsReadOnly(true);
-    config.setClazyMode(ClangDiagnosticConfig::ClazyMode::UseCustomChecks);
-    config.setClangTidyMode(ClangDiagnosticConfig::TidyMode::UseCustomChecks);
-    config.setUseBuildSystemWarnings(true);
-    model.appendOrUpdate(config);
-}
-
-ClangDiagnosticConfigsModel diagnosticConfigsModel(const ClangDiagnosticConfigs &customConfigs)
-{
-    ClangDiagnosticConfigsModel model;
-    addBuiltinConfigs(model);
-    for (const ClangDiagnosticConfig &config : customConfigs)
-        model.appendOrUpdate(config);
-    return model;
-}
-
-ClangDiagnosticConfigsModel diagnosticConfigsModel()
-{
-    return diagnosticConfigsModel(ClangdSettings::instance().customDiagnosticConfigs());
-}
-
-NSVisitor::NSVisitor(const CppRefactoringFile *file, const QStringList &namespaces, int symbolPos)
-    : ASTVisitor(file->cppDocument()->translationUnit()),
-      m_file(file),
-      m_remainingNamespaces(namespaces),
-      m_symbolPos(symbolPos)
-{}
-
-bool NSVisitor::preVisit(AST *ast)
-{
-    if (!m_firstToken)
-        m_firstToken = ast;
-    if (m_file->startOf(ast) >= m_symbolPos)
-        m_done = true;
-    return !m_done;
-}
-
-bool NSVisitor::visit(NamespaceAST *ns)
-{
-    if (!m_firstNamespace)
-        m_firstNamespace = ns;
-    if (m_remainingNamespaces.isEmpty()) {
-        m_done = true;
-        return false;
-    }
-
-    QString name;
-    const Identifier * const id = translationUnit()->identifier(ns->identifier_token);
-    if (id)
-        name = QString::fromUtf8(id->chars(), id->size());
-    if (name != m_remainingNamespaces.first())
-        return false;
-
-    if (!ns->linkage_body) {
-        m_done = true;
-        return false;
-    }
-
-    m_enclosingNamespace = ns;
-    m_remainingNamespaces.removeFirst();
-    return !m_remainingNamespaces.isEmpty();
-}
-
-void NSVisitor::postVisit(AST *ast)
-{
-    if (ast == m_enclosingNamespace)
-        m_done = true;
-}
-
-/**
- * @brief The NSCheckerVisitor class checks which namespaces are missing for a given list
- * of enclosing namespaces at a given position
- */
-NSCheckerVisitor::NSCheckerVisitor(const CppRefactoringFile *file, const QStringList &namespaces,
-                                   int symbolPos)
-    : ASTVisitor(file->cppDocument()->translationUnit())
-    , m_file(file)
-    , m_remainingNamespaces(namespaces)
-    , m_symbolPos(symbolPos)
-{}
-
-bool NSCheckerVisitor::preVisit(AST *ast)
-{
-    if (m_file->startOf(ast) >= m_symbolPos)
-        m_done = true;
-    return !m_done;
-}
-
-void NSCheckerVisitor::postVisit(AST *ast)
-{
-    if (!m_done && m_file->endOf(ast) > m_symbolPos)
-        m_done = true;
-}
-
-bool NSCheckerVisitor::visit(NamespaceAST *ns)
-{
-    if (m_remainingNamespaces.isEmpty())
-        return false;
-
-    QString name = getName(ns);
-    if (name != m_remainingNamespaces.first())
-        return false;
-
-    m_enteredNamespaces.push_back(ns);
-    m_remainingNamespaces.removeFirst();
-    // if we reached the searched namespace we don't have to search deeper
-    return !m_remainingNamespaces.isEmpty();
-}
-
-bool NSCheckerVisitor::visit(UsingDirectiveAST *usingNS)
-{
-    // example: we search foo::bar and get 'using namespace foo;using namespace foo::bar;'
-    const QString fullName = Overview{}.prettyName(usingNS->name->name);
-    const QStringList namespaces = fullName.split("::");
-    if (namespaces.length() > m_remainingNamespaces.length())
-        return false;
-
-    // from other using namespace statements
-    const auto curList = m_usingsPerNamespace.find(currentNamespace());
-    const bool isCurListValid = curList != m_usingsPerNamespace.end();
-
-    const bool startEqual = std::equal(namespaces.cbegin(),
-                                       namespaces.cend(),
-                                       m_remainingNamespaces.cbegin());
-    if (startEqual) {
-        if (isCurListValid) {
-            if (namespaces.length() > curList->second.length()) {
-                // eg. we already have 'using namespace foo;' and
-                // now get 'using namespace foo::bar;'
-                curList->second = namespaces;
-            }
-            // the other case: first 'using namespace foo::bar;' and now 'using namespace foo;'
-        } else
-            m_usingsPerNamespace.emplace(currentNamespace(), namespaces);
-    } else if (isCurListValid) {
-        // ex: we have already 'using namespace foo;' and get 'using namespace bar;' now
-        QStringList newlist = curList->second;
-        newlist.append(namespaces);
-        if (newlist.length() <= m_remainingNamespaces.length()) {
-            const bool startEqual = std::equal(newlist.cbegin(),
-                                               newlist.cend(),
-                                               m_remainingNamespaces.cbegin());
-            if (startEqual)
-                curList->second.append(namespaces);
-        }
-    }
-    return false;
-}
-
-void NSCheckerVisitor::endVisit(NamespaceAST *ns)
-{
-    // if the symbolPos was in the namespace and the
-    // namespace has no children, m_done should be true
-    postVisit(ns);
-    if (!m_done && currentNamespace() == ns) {
-        // we were not succesfull in this namespace, so undo all changes
-        m_remainingNamespaces.push_front(getName(currentNamespace()));
-        m_usingsPerNamespace.erase(currentNamespace());
-        m_enteredNamespaces.pop_back();
-    }
-}
-
-void NSCheckerVisitor::endVisit(TranslationUnitAST *)
-{
-    // the last node, create the final result
-    // we must handle like the following: We search for foo::bar and have:
-    // using namespace foo::bar;
-    // namespace foo {
-    //    // cursor/symbolPos here
-    // }
-    if (m_remainingNamespaces.empty()) {
-        // we are already finished
-        return;
-    }
-    // find the longest combination of normal namespaces + using statements
-    int longestNamespaceList = 0;
-    int enteredNamespaceCount = 0;
-    // check 'using namespace ...;' statements in the global scope
-    const auto namespaces = m_usingsPerNamespace.find(nullptr);
-    if (namespaces != m_usingsPerNamespace.end())
-        longestNamespaceList = namespaces->second.length();
-
-    for (auto ns : m_enteredNamespaces) {
-        ++enteredNamespaceCount;
-        const auto namespaces = m_usingsPerNamespace.find(ns);
-        int newListLength = enteredNamespaceCount;
-        if (namespaces != m_usingsPerNamespace.end())
-            newListLength += namespaces->second.length();
-        longestNamespaceList = std::max(newListLength, longestNamespaceList);
-    }
-    m_remainingNamespaces.erase(m_remainingNamespaces.begin(),
-                                m_remainingNamespaces.begin() + longestNamespaceList
-                                - m_enteredNamespaces.size());
-}
-
-QString NSCheckerVisitor::getName(NamespaceAST *ns)
-{
-    const Identifier *const id = translationUnit()->identifier(ns->identifier_token);
-    if (id)
-        return QString::fromUtf8(id->chars(), id->size());
-    return {};
-}
-
-NamespaceAST *NSCheckerVisitor::currentNamespace()
-{
-    return m_enteredNamespaces.empty() ? nullptr : m_enteredNamespaces.back();
-}
-
-ProjectExplorer::Project *projectForProjectPart(const ProjectPart &part)
-{
-    return ProjectExplorer::ProjectManager::projectWithProjectFilePath(part.topLevelProject);
-}
-
-ProjectExplorer::Project *projectForProjectInfo(const ProjectInfo &info)
-{
-    return ProjectExplorer::ProjectManager::projectWithProjectFilePath(info.projectFilePath());
-}
-
 void openEditor(const Utils::FilePath &filePath, bool inNextSplit, Utils::Id editorId)
 {
     using Core::EditorManager;
diff --git a/src/plugins/cppeditor/cpptoolsreuse.h b/src/plugins/cppeditor/cpptoolsreuse.h
index 71aabab08df..70349cacc37 100644
--- a/src/plugins/cppeditor/cpptoolsreuse.h
+++ b/src/plugins/cppeditor/cpptoolsreuse.h
@@ -5,25 +5,21 @@
 
 #include "cppeditor_global.h"
 
-#include "clangdiagnosticconfig.h"
-#include "projectpart.h"
-
-#include <texteditor/quickfix.h>
-#include <texteditor/texteditor.h>
-
-#include <utils/searchresultitem.h>
-
-#include <cplusplus/ASTVisitor.h>
 #include <cplusplus/CppDocument.h>
-#include <cplusplus/Token.h>
+#include <texteditor/quickfix.h>
+#include <utils/id.h>
+#include <utils/searchresultitem.h>
 
 namespace CPlusPlus {
 class Macro;
 class Symbol;
 class LookupContext;
 } // namespace CPlusPlus
-
-namespace TextEditor { class AssistInterface; }
+namespace ProjectExplorer { class Project; }
+namespace TextEditor {
+class AssistInterface;
+class TextEditorWidget;
+}
 namespace Utils { namespace Text { class Range; } }
 
 namespace CppEditor {
@@ -49,9 +45,6 @@ int CPPEDITOR_EXPORT activeArgumenForPrefix(const QString &prefix);
 QStringList CPPEDITOR_EXPORT identifierWordsUnderCursor(const QTextCursor &tc);
 QString CPPEDITOR_EXPORT identifierUnderCursor(QTextCursor *cursor);
 
-bool CPPEDITOR_EXPORT isOwnershipRAIIType(CPlusPlus::Symbol *symbol,
-                                         const CPlusPlus::LookupContext &context);
-
 const CPlusPlus::Macro CPPEDITOR_EXPORT *findCanonicalMacro(const QTextCursor &cursor,
                                                            CPlusPlus::Document::Ptr document);
 
@@ -89,114 +82,6 @@ QList<Utils::Text::Range> CPPEDITOR_EXPORT symbolOccurrencesInDeclarationComment
 
 bool fileSizeExceedsLimit(const Utils::FilePath &filePath, int sizeLimitInMb);
 
-ProjectExplorer::Project CPPEDITOR_EXPORT *projectForProjectInfo(const ProjectInfo &info);
-ProjectExplorer::Project CPPEDITOR_EXPORT *projectForProjectPart(const ProjectPart &part);
-
-class ClangDiagnosticConfigsModel;
-ClangDiagnosticConfigsModel CPPEDITOR_EXPORT diagnosticConfigsModel();
-ClangDiagnosticConfigsModel CPPEDITOR_EXPORT
-diagnosticConfigsModel(const ClangDiagnosticConfigs &customConfigs);
-
-class CPPEDITOR_EXPORT SymbolInfo
-{
-public:
-    int startLine = 0;
-    int startColumn = 0;
-    int endLine = 0;
-    int endColumn = 0;
-    QString fileName;
-    bool isResultOnlyForFallBack = false;
-};
-
-class ProjectPartInfo {
-public:
-    enum Hint {
-        NoHint = 0,
-        IsFallbackMatch  = 1 << 0,
-        IsAmbiguousMatch = 1 << 1,
-        IsPreferredMatch = 1 << 2,
-        IsFromProjectMatch = 1 << 3,
-        IsFromDependenciesMatch = 1 << 4,
-    };
-    Q_DECLARE_FLAGS(Hints, Hint)
-
-    ProjectPartInfo() = default;
-    ProjectPartInfo(const ProjectPart::ConstPtr &projectPart,
-                    const QList<ProjectPart::ConstPtr> &projectParts,
-                    Hints hints)
-        : projectPart(projectPart)
-        , projectParts(projectParts)
-        , hints(hints)
-    {
-    }
-
-public:
-    ProjectPart::ConstPtr projectPart;
-    QList<ProjectPart::ConstPtr> projectParts; // The one above as first plus alternatives.
-    Hints hints = NoHint;
-};
-
-QStringList CPPEDITOR_EXPORT getNamespaceNames(const CPlusPlus::Namespace *firstNamespace);
-QStringList CPPEDITOR_EXPORT getNamespaceNames(const CPlusPlus::Symbol *symbol);
-
-class CPPEDITOR_EXPORT NSVisitor : public CPlusPlus::ASTVisitor
-{
-public:
-    NSVisitor(const CppRefactoringFile *file, const QStringList &namespaces, int symbolPos);
-
-    const QStringList remainingNamespaces() const { return m_remainingNamespaces; }
-    const CPlusPlus::NamespaceAST *firstNamespace() const { return m_firstNamespace; }
-    const CPlusPlus::AST *firstToken() const { return m_firstToken; }
-    const CPlusPlus::NamespaceAST *enclosingNamespace() const { return m_enclosingNamespace; }
-
-private:
-    bool preVisit(CPlusPlus::AST *ast) override;
-    bool visit(CPlusPlus::NamespaceAST *ns) override;
-    void postVisit(CPlusPlus::AST *ast) override;
-
-    const CppRefactoringFile * const m_file;
-    const CPlusPlus::NamespaceAST *m_enclosingNamespace = nullptr;
-    const CPlusPlus::NamespaceAST *m_firstNamespace = nullptr;
-    const CPlusPlus::AST *m_firstToken = nullptr;
-    QStringList m_remainingNamespaces;
-    const int m_symbolPos;
-    bool m_done = false;
-};
-
-class CPPEDITOR_EXPORT NSCheckerVisitor : public CPlusPlus::ASTVisitor
-{
-public:
-    NSCheckerVisitor(const CppRefactoringFile *file, const QStringList &namespaces, int symbolPos);
-
-    /**
-     * @brief returns the names of the namespaces that are additionally needed at the symbolPos
-     * @return A list of namespace names, the outermost namespace at index 0 and the innermost
-     * at the last index
-     */
-    const QStringList remainingNamespaces() const { return m_remainingNamespaces; }
-
-private:
-    bool preVisit(CPlusPlus::AST *ast) override;
-    void postVisit(CPlusPlus::AST *ast) override;
-    bool visit(CPlusPlus::NamespaceAST *ns) override;
-    bool visit(CPlusPlus::UsingDirectiveAST *usingNS) override;
-    void endVisit(CPlusPlus::NamespaceAST *ns) override;
-    void endVisit(CPlusPlus::TranslationUnitAST *) override;
-
-    QString getName(CPlusPlus::NamespaceAST *ns);
-    CPlusPlus::NamespaceAST *currentNamespace();
-
-    const CppRefactoringFile *const m_file;
-    QStringList m_remainingNamespaces;
-    const int m_symbolPos;
-    std::vector<CPlusPlus::NamespaceAST *> m_enteredNamespaces;
-
-    // track 'using namespace ...' statements
-    std::unordered_map<CPlusPlus::NamespaceAST *, QStringList> m_usingsPerNamespace;
-
-    bool m_done = false;
-};
-
 namespace Internal {
 void decorateCppEditor(TextEditor::TextEditorWidget *editor);
 } // namespace Internal
diff --git a/src/plugins/cppeditor/insertionpointlocator.cpp b/src/plugins/cppeditor/insertionpointlocator.cpp
index 8b2b03698e2..d791ffc2203 100644
--- a/src/plugins/cppeditor/insertionpointlocator.cpp
+++ b/src/plugins/cppeditor/insertionpointlocator.cpp
@@ -11,6 +11,8 @@
 
 #include <cplusplus/ASTPath.h>
 #include <cplusplus/LookupContext.h>
+#include <cplusplus/Symbol.h>
+#include <cplusplus/Overview.h>
 
 #include <utils/qtcassert.h>
 
@@ -18,6 +20,7 @@ using namespace CPlusPlus;
 using namespace Utils;
 
 namespace CppEditor {
+using namespace Internal;
 namespace {
 
 static int ordering(InsertionPointLocator::AccessSpec xsSpec)
@@ -719,39 +722,6 @@ static QStringList getListOfMissingNamespacesForLocation(const CppRefactoringFil
     return visitor.remainingNamespaces();
 }
 
-/**
- * @brief getNamespaceNames Returns a list of namespaces for an enclosing namespaces of a
- * namespace (contains the namespace itself)
- * @param firstNamespace the starting namespace (included in the list)
- * @return the enclosing namespaces, the outermost namespace is at the first index, the innermost
- * at the last index
- */
-QStringList getNamespaceNames(const Namespace *firstNamespace)
-{
-    QStringList namespaces;
-    for (const Namespace *scope = firstNamespace; scope; scope = scope->enclosingNamespace()) {
-        if (scope->name() && scope->name()->identifier()) {
-            namespaces.prepend(QString::fromUtf8(scope->name()->identifier()->chars(),
-                                                 scope->name()->identifier()->size()));
-        } else {
-            namespaces.prepend(""); // an unnamed namespace
-        }
-    }
-    namespaces.pop_front(); // the "global namespace" is one namespace, but not an unnamed
-    return namespaces;
-}
-
-/**
- * @brief getNamespaceNames Returns a list of enclosing namespaces for a symbol
- * @param symbol a symbol from which we want the enclosing namespaces
- * @return the enclosing namespaces, the outermost namespace is at the first index, the innermost
- * at the last index
- */
-QStringList getNamespaceNames(const Symbol *symbol)
-{
-    return getNamespaceNames(symbol->enclosingNamespace());
-}
-
 InsertionLocation insertLocationForMethodDefinition(Symbol *symbol,
                                                     const bool useSymbolFinder,
                                                     NamespaceHandling namespaceHandling,
@@ -834,4 +804,226 @@ InsertionLocation insertLocationForMethodDefinition(Symbol *symbol,
     return InsertionLocation(filePath, prefix, suffix, line, column);
 }
 
+namespace Internal {
+NSVisitor::NSVisitor(const CppRefactoringFile *file, const QStringList &namespaces, int symbolPos)
+    : ASTVisitor(file->cppDocument()->translationUnit()),
+      m_file(file),
+      m_remainingNamespaces(namespaces),
+      m_symbolPos(symbolPos)
+{}
+
+bool NSVisitor::preVisit(AST *ast)
+{
+    if (!m_firstToken)
+        m_firstToken = ast;
+    if (m_file->startOf(ast) >= m_symbolPos)
+        m_done = true;
+    return !m_done;
+}
+
+bool NSVisitor::visit(NamespaceAST *ns)
+{
+    if (!m_firstNamespace)
+        m_firstNamespace = ns;
+    if (m_remainingNamespaces.isEmpty()) {
+        m_done = true;
+        return false;
+    }
+
+    QString name;
+    const Identifier * const id = translationUnit()->identifier(ns->identifier_token);
+    if (id)
+        name = QString::fromUtf8(id->chars(), id->size());
+    if (name != m_remainingNamespaces.first())
+        return false;
+
+    if (!ns->linkage_body) {
+        m_done = true;
+        return false;
+    }
+
+    m_enclosingNamespace = ns;
+    m_remainingNamespaces.removeFirst();
+    return !m_remainingNamespaces.isEmpty();
+}
+
+void NSVisitor::postVisit(AST *ast)
+{
+    if (ast == m_enclosingNamespace)
+        m_done = true;
+}
+
+/**
+ * @brief The NSCheckerVisitor class checks which namespaces are missing for a given list
+ * of enclosing namespaces at a given position
+ */
+NSCheckerVisitor::NSCheckerVisitor(const CppRefactoringFile *file, const QStringList &namespaces,
+                                   int symbolPos)
+    : ASTVisitor(file->cppDocument()->translationUnit())
+    , m_file(file)
+    , m_remainingNamespaces(namespaces)
+    , m_symbolPos(symbolPos)
+{}
+
+bool NSCheckerVisitor::preVisit(AST *ast)
+{
+    if (m_file->startOf(ast) >= m_symbolPos)
+        m_done = true;
+    return !m_done;
+}
+
+void NSCheckerVisitor::postVisit(AST *ast)
+{
+    if (!m_done && m_file->endOf(ast) > m_symbolPos)
+        m_done = true;
+}
+
+bool NSCheckerVisitor::visit(NamespaceAST *ns)
+{
+    if (m_remainingNamespaces.isEmpty())
+        return false;
+
+    QString name = getName(ns);
+    if (name != m_remainingNamespaces.first())
+        return false;
+
+    m_enteredNamespaces.push_back(ns);
+    m_remainingNamespaces.removeFirst();
+    // if we reached the searched namespace we don't have to search deeper
+    return !m_remainingNamespaces.isEmpty();
+}
+
+bool NSCheckerVisitor::visit(UsingDirectiveAST *usingNS)
+{
+    // example: we search foo::bar and get 'using namespace foo;using namespace foo::bar;'
+    const QString fullName = Overview{}.prettyName(usingNS->name->name);
+    const QStringList namespaces = fullName.split("::");
+    if (namespaces.length() > m_remainingNamespaces.length())
+        return false;
+
+    // from other using namespace statements
+    const auto curList = m_usingsPerNamespace.find(currentNamespace());
+    const bool isCurListValid = curList != m_usingsPerNamespace.end();
+
+    const bool startEqual = std::equal(namespaces.cbegin(),
+                                       namespaces.cend(),
+                                       m_remainingNamespaces.cbegin());
+    if (startEqual) {
+        if (isCurListValid) {
+            if (namespaces.length() > curList->second.length()) {
+                // eg. we already have 'using namespace foo;' and
+                // now get 'using namespace foo::bar;'
+                curList->second = namespaces;
+            }
+            // the other case: first 'using namespace foo::bar;' and now 'using namespace foo;'
+        } else
+            m_usingsPerNamespace.emplace(currentNamespace(), namespaces);
+    } else if (isCurListValid) {
+        // ex: we have already 'using namespace foo;' and get 'using namespace bar;' now
+        QStringList newlist = curList->second;
+        newlist.append(namespaces);
+        if (newlist.length() <= m_remainingNamespaces.length()) {
+            const bool startEqual = std::equal(newlist.cbegin(),
+                                               newlist.cend(),
+                                               m_remainingNamespaces.cbegin());
+            if (startEqual)
+                curList->second.append(namespaces);
+        }
+    }
+    return false;
+}
+
+void NSCheckerVisitor::endVisit(NamespaceAST *ns)
+{
+    // if the symbolPos was in the namespace and the
+    // namespace has no children, m_done should be true
+    postVisit(ns);
+    if (!m_done && currentNamespace() == ns) {
+        // we were not succesfull in this namespace, so undo all changes
+        m_remainingNamespaces.push_front(getName(currentNamespace()));
+        m_usingsPerNamespace.erase(currentNamespace());
+        m_enteredNamespaces.pop_back();
+    }
+}
+
+void NSCheckerVisitor::endVisit(TranslationUnitAST *)
+{
+    // the last node, create the final result
+    // we must handle like the following: We search for foo::bar and have:
+    // using namespace foo::bar;
+    // namespace foo {
+    //    // cursor/symbolPos here
+    // }
+    if (m_remainingNamespaces.empty()) {
+        // we are already finished
+        return;
+    }
+    // find the longest combination of normal namespaces + using statements
+    int longestNamespaceList = 0;
+    int enteredNamespaceCount = 0;
+    // check 'using namespace ...;' statements in the global scope
+    const auto namespaces = m_usingsPerNamespace.find(nullptr);
+    if (namespaces != m_usingsPerNamespace.end())
+        longestNamespaceList = namespaces->second.length();
+
+    for (auto ns : m_enteredNamespaces) {
+        ++enteredNamespaceCount;
+        const auto namespaces = m_usingsPerNamespace.find(ns);
+        int newListLength = enteredNamespaceCount;
+        if (namespaces != m_usingsPerNamespace.end())
+            newListLength += namespaces->second.length();
+        longestNamespaceList = std::max(newListLength, longestNamespaceList);
+    }
+    m_remainingNamespaces.erase(m_remainingNamespaces.begin(),
+                                m_remainingNamespaces.begin() + longestNamespaceList
+                                - m_enteredNamespaces.size());
+}
+
+QString NSCheckerVisitor::getName(NamespaceAST *ns)
+{
+    const Identifier *const id = translationUnit()->identifier(ns->identifier_token);
+    if (id)
+        return QString::fromUtf8(id->chars(), id->size());
+    return {};
+}
+
+NamespaceAST *NSCheckerVisitor::currentNamespace()
+{
+    return m_enteredNamespaces.empty() ? nullptr : m_enteredNamespaces.back();
+}
+
+/**
+ * @brief getNamespaceNames Returns a list of namespaces for an enclosing namespaces of a
+ * namespace (contains the namespace itself)
+ * @param firstNamespace the starting namespace (included in the list)
+ * @return the enclosing namespaces, the outermost namespace is at the first index, the innermost
+ * at the last index
+ */
+QStringList getNamespaceNames(const Namespace *firstNamespace)
+{
+    QStringList namespaces;
+    for (const Namespace *scope = firstNamespace; scope; scope = scope->enclosingNamespace()) {
+        if (scope->name() && scope->name()->identifier()) {
+            namespaces.prepend(QString::fromUtf8(scope->name()->identifier()->chars(),
+                                                 scope->name()->identifier()->size()));
+        } else {
+            namespaces.prepend(""); // an unnamed namespace
+        }
+    }
+    namespaces.pop_front(); // the "global namespace" is one namespace, but not an unnamed
+    return namespaces;
+}
+
+/**
+ * @brief getNamespaceNames Returns a list of enclosing namespaces for a symbol
+ * @param symbol a symbol from which we want the enclosing namespaces
+ * @return the enclosing namespaces, the outermost namespace is at the first index, the innermost
+ * at the last index
+ */
+QStringList getNamespaceNames(const Symbol *symbol)
+{
+    return getNamespaceNames(symbol->enclosingNamespace());
+}
+
+} // namespace Internal
 } // namespace CppEditor;
diff --git a/src/plugins/cppeditor/insertionpointlocator.h b/src/plugins/cppeditor/insertionpointlocator.h
index d6fd5d735cc..833adbd8ac9 100644
--- a/src/plugins/cppeditor/insertionpointlocator.h
+++ b/src/plugins/cppeditor/insertionpointlocator.h
@@ -113,4 +113,67 @@ insertLocationForMethodDefinition(CPlusPlus::Symbol *symbol,
                                   const Utils::FilePath &fileName,
                                   QStringList *insertedNamespaces = nullptr);
 
+namespace Internal {
+class NSVisitor : public CPlusPlus::ASTVisitor
+{
+public:
+    NSVisitor(const CppRefactoringFile *file, const QStringList &namespaces, int symbolPos);
+
+    const QStringList remainingNamespaces() const { return m_remainingNamespaces; }
+    const CPlusPlus::NamespaceAST *firstNamespace() const { return m_firstNamespace; }
+    const CPlusPlus::AST *firstToken() const { return m_firstToken; }
+    const CPlusPlus::NamespaceAST *enclosingNamespace() const { return m_enclosingNamespace; }
+
+private:
+    bool preVisit(CPlusPlus::AST *ast) override;
+    bool visit(CPlusPlus::NamespaceAST *ns) override;
+    void postVisit(CPlusPlus::AST *ast) override;
+
+    const CppRefactoringFile * const m_file;
+    const CPlusPlus::NamespaceAST *m_enclosingNamespace = nullptr;
+    const CPlusPlus::NamespaceAST *m_firstNamespace = nullptr;
+    const CPlusPlus::AST *m_firstToken = nullptr;
+    QStringList m_remainingNamespaces;
+    const int m_symbolPos;
+    bool m_done = false;
+};
+
+class NSCheckerVisitor : public CPlusPlus::ASTVisitor
+{
+public:
+    NSCheckerVisitor(const CppRefactoringFile *file, const QStringList &namespaces, int symbolPos);
+
+    /**
+     * @brief returns the names of the namespaces that are additionally needed at the symbolPos
+     * @return A list of namespace names, the outermost namespace at index 0 and the innermost
+     * at the last index
+     */
+    const QStringList remainingNamespaces() const { return m_remainingNamespaces; }
+
+private:
+    bool preVisit(CPlusPlus::AST *ast) override;
+    void postVisit(CPlusPlus::AST *ast) override;
+    bool visit(CPlusPlus::NamespaceAST *ns) override;
+    bool visit(CPlusPlus::UsingDirectiveAST *usingNS) override;
+    void endVisit(CPlusPlus::NamespaceAST *ns) override;
+    void endVisit(CPlusPlus::TranslationUnitAST *) override;
+
+    QString getName(CPlusPlus::NamespaceAST *ns);
+    CPlusPlus::NamespaceAST *currentNamespace();
+
+    const CppRefactoringFile *const m_file;
+    QStringList m_remainingNamespaces;
+    const int m_symbolPos;
+    std::vector<CPlusPlus::NamespaceAST *> m_enteredNamespaces;
+
+    // track 'using namespace ...' statements
+    std::unordered_map<CPlusPlus::NamespaceAST *, QStringList> m_usingsPerNamespace;
+
+    bool m_done = false;
+};
+
+QStringList getNamespaceNames(const CPlusPlus::Namespace *firstNamespace);
+QStringList getNamespaceNames(const CPlusPlus::Symbol *symbol);
+
+} // namespace Internal
 } // namespace CppEditor
diff --git a/src/plugins/cppeditor/projectinfo.cpp b/src/plugins/cppeditor/projectinfo.cpp
index 9561310f323..e25070044bd 100644
--- a/src/plugins/cppeditor/projectinfo.cpp
+++ b/src/plugins/cppeditor/projectinfo.cpp
@@ -6,6 +6,7 @@
 #include <projectexplorer/abi.h>
 #include <projectexplorer/kitaspects.h>
 #include <projectexplorer/projectexplorerconstants.h>
+#include <projectexplorer/projectmanager.h>
 #include <projectexplorer/rawprojectpart.h>
 #include <projectexplorer/toolchain.h>
 
@@ -25,6 +26,11 @@ ProjectInfo::ConstPtr ProjectInfo::cloneWithNewSettings(const ConstPtr &pi,
     return ConstPtr(new ProjectInfo(pi, settings));
 }
 
+ProjectExplorer::Project *ProjectInfo::project() const
+{
+    return ProjectExplorer::ProjectManager::projectWithProjectFilePath(projectFilePath());
+}
+
 bool ProjectInfo::operator ==(const ProjectInfo &other) const
 {
     return m_projectName == other.m_projectName
diff --git a/src/plugins/cppeditor/projectinfo.h b/src/plugins/cppeditor/projectinfo.h
index 3b18c7ae6fd..43afd6cbefd 100644
--- a/src/plugins/cppeditor/projectinfo.h
+++ b/src/plugins/cppeditor/projectinfo.h
@@ -36,6 +36,7 @@ public:
     const QSet<Utils::FilePath> &sourceFiles() const { return m_sourceFiles; }
     QString projectName() const { return m_projectName; }
     Utils::FilePath projectFilePath() const { return m_projectFilePath; }
+    ProjectExplorer::Project *project() const;
     Utils::FilePath projectRoot() const { return m_projectFilePath.parentDir(); }
     Utils::FilePath buildRoot() const { return m_buildRoot; }
     const CppCodeModelSettings &settings() const { return m_settings; }
diff --git a/src/plugins/cppeditor/projectpart.cpp b/src/plugins/cppeditor/projectpart.cpp
index 24f9dc42e85..8e4bd1c4fe5 100644
--- a/src/plugins/cppeditor/projectpart.cpp
+++ b/src/plugins/cppeditor/projectpart.cpp
@@ -4,6 +4,7 @@
 #include "projectpart.h"
 
 #include <projectexplorer/project.h>
+#include <projectexplorer/projectmanager.h>
 
 #include <utils/algorithm.h>
 
@@ -44,6 +45,11 @@ bool ProjectPart::belongsToProject(const Utils::FilePath &project) const
     return topLevelProject == project;
 }
 
+Project *ProjectPart::project() const
+{
+    return ProjectManager::projectWithProjectFilePath(topLevelProject);
+}
+
 QByteArray ProjectPart::readProjectConfigFile(const QString &projectConfigFile)
 {
     QByteArray result;
diff --git a/src/plugins/cppeditor/projectpart.h b/src/plugins/cppeditor/projectpart.h
index a55adb2a0c3..d3a96ab60c6 100644
--- a/src/plugins/cppeditor/projectpart.h
+++ b/src/plugins/cppeditor/projectpart.h
@@ -30,7 +30,6 @@ class CPPEDITOR_EXPORT ProjectPart
 public:
     using ConstPtr = QSharedPointer<const ProjectPart>;
 
-public:
     static ConstPtr create(const Utils::FilePath &topLevelProject,
                       const ProjectExplorer::RawProjectPart &rpp = {},
                       const QString &displayName = {},
@@ -49,10 +48,10 @@ public:
     bool hasProject() const { return !topLevelProject.isEmpty(); }
     bool belongsToProject(const ProjectExplorer::Project *project) const;
     bool belongsToProject(const Utils::FilePath &project) const;
+    ProjectExplorer::Project *project() const;
 
     static QByteArray readProjectConfigFile(const QString &projectConfigFile);
 
-public:
     const Utils::FilePath topLevelProject;
     const QString displayName;
     const QString projectFile;
@@ -117,4 +116,31 @@ public:
     const CPlusPlus::LanguageFeatures languageFeatures;
 };
 
+class ProjectPartInfo {
+public:
+    enum Hint {
+        NoHint = 0,
+        IsFallbackMatch  = 1 << 0,
+        IsAmbiguousMatch = 1 << 1,
+        IsPreferredMatch = 1 << 2,
+        IsFromProjectMatch = 1 << 3,
+        IsFromDependenciesMatch = 1 << 4,
+    };
+    Q_DECLARE_FLAGS(Hints, Hint)
+
+    ProjectPartInfo() = default;
+    ProjectPartInfo(const ProjectPart::ConstPtr &projectPart,
+                    const QList<ProjectPart::ConstPtr> &projectParts,
+                    Hints hints)
+        : projectPart(projectPart)
+        , projectParts(projectParts)
+        , hints(hints)
+    {
+    }
+
+    ProjectPart::ConstPtr projectPart;
+    QList<ProjectPart::ConstPtr> projectParts; // The one above as first plus alternatives.
+    Hints hints = NoHint;
+};
+
 } // namespace CppEditor
diff --git a/src/plugins/cppeditor/quickfixes/bringidentifierintoscope.cpp b/src/plugins/cppeditor/quickfixes/bringidentifierintoscope.cpp
index 6a85c95dfc9..157f48894d1 100644
--- a/src/plugins/cppeditor/quickfixes/bringidentifierintoscope.cpp
+++ b/src/plugins/cppeditor/quickfixes/bringidentifierintoscope.cpp
@@ -8,6 +8,7 @@
 #include "../cppprojectfile.h"
 #include "../cpprefactoringchanges.h"
 #include "../indexitem.h"
+#include "../insertionpointlocator.h"
 #include "cppquickfix.h"
 #include "cppquickfixhelpers.h"
 
diff --git a/src/plugins/modeleditor/elementtasks.cpp b/src/plugins/modeleditor/elementtasks.cpp
index 7bbdd7b3e0b..039964ccb83 100644
--- a/src/plugins/modeleditor/elementtasks.cpp
+++ b/src/plugins/modeleditor/elementtasks.cpp
@@ -27,12 +27,13 @@
 #include "qmt/project_controller/projectcontroller.h"
 #include "qmt/project/project.h"
 
-#include <extensionsystem/pluginmanager.h>
+#include <coreplugin/editormanager/editormanager.h>
+#include <coreplugin/editormanager/ieditorfactory.h>
+#include <coreplugin/icore.h>
 #include <cppeditor/cpplocatordata.h>
 #include <cppeditor/indexitem.h>
 #include <cppeditor/searchsymbols.h>
-#include <coreplugin/editormanager/editormanager.h>
-#include <coreplugin/icore.h>
+#include <extensionsystem/pluginmanager.h>
 #include <utils/qtcassert.h>
 
 #include <QMenu>