LSP: Add type hierarchy support

Fixes: QTCREATORBUG-28116
Change-Id: Ibaed23144f63fa84fa97ae9106d0f0baf8f53118
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

16 files changed, 674 insertions, 326 deletions

diff --git a/src/libs/languageserverprotocol/CMakeLists.txt b/src/libs/languageserverprotocol/CMakeLists.txt
index a3031413a4..0261046016 100644
--- a/src/libs/languageserverprotocol/CMakeLists.txt
+++ b/src/libs/languageserverprotocol/CMakeLists.txt
@@ -22,5 +22,6 @@ add_qtc_library(LanguageServerProtocol
     servercapabilities.cpp servercapabilities.h
     shutdownmessages.cpp shutdownmessages.h
     textsynchronization.cpp textsynchronization.h
+    typehierarchy.cpp typehierarchy.h
     workspace.cpp workspace.h
 )
diff --git a/src/libs/languageserverprotocol/clientcapabilities.h b/src/libs/languageserverprotocol/clientcapabilities.h
index b2311d7e72..91c9954cd7 100644
--- a/src/libs/languageserverprotocol/clientcapabilities.h
+++ b/src/libs/languageserverprotocol/clientcapabilities.h
@@ -529,6 +529,12 @@ public:
     void setCallHierarchy(const DynamicRegistrationCapabilities &callHierarchy)
     { insert(callHierarchyKey, callHierarchy); }
     void clearCallHierarchy() { remove(callHierarchyKey); }
+
+    std::optional<DynamicRegistrationCapabilities> typeHierarchy() const
+    { return optionalValue<DynamicRegistrationCapabilities>(typeHierarchyKey); }
+    void setTypeHierarchy(const DynamicRegistrationCapabilities &typeHierarchy)
+    { insert(typeHierarchyKey, typeHierarchy); }
+    void clearTypeHierarchy() { remove(typeHierarchyKey); }
 };
 
 class LANGUAGESERVERPROTOCOL_EXPORT SemanticTokensWorkspaceClientCapabilities : public JsonObject
diff --git a/src/libs/languageserverprotocol/jsonkeys.h b/src/libs/languageserverprotocol/jsonkeys.h
index c2b5e545f2..37894f166e 100644
--- a/src/libs/languageserverprotocol/jsonkeys.h
+++ b/src/libs/languageserverprotocol/jsonkeys.h
@@ -218,6 +218,8 @@ constexpr Key trimTrailingWhitespaceKey{"trimTrailingWhitespace"};
 constexpr Key typeDefinitionKey{"typeDefinition"};
 constexpr Key typeDefinitionProviderKey{"typeDefinitionProvider"};
 constexpr Key typeKey{"type"};
+constexpr Key typeHierarchyKey{"typeHierarchy"};
+constexpr Key typeHierarchyProviderKey{"typeHierarchyProvider"};
 constexpr Key unregistrationsKey{"unregistrations"};
 constexpr Key uriKey{"uri"};
 constexpr Key valueKey{"value"};
diff --git a/src/libs/languageserverprotocol/languageserverprotocol.qbs b/src/libs/languageserverprotocol/languageserverprotocol.qbs
index 0368ceafee..2bf717c293 100644
--- a/src/libs/languageserverprotocol/languageserverprotocol.qbs
+++ b/src/libs/languageserverprotocol/languageserverprotocol.qbs
@@ -44,6 +44,8 @@ QtcLibrary {
         "shutdownmessages.h",
         "textsynchronization.cpp",
         "textsynchronization.h",
+        "typehierarchy.cpp",
+        "typehierarchy.h",
         "workspace.cpp",
         "workspace.h",
     ]
diff --git a/src/libs/languageserverprotocol/servercapabilities.cpp b/src/libs/languageserverprotocol/servercapabilities.cpp
index 885198d12e..0c57f47131 100644
--- a/src/libs/languageserverprotocol/servercapabilities.cpp
+++ b/src/libs/languageserverprotocol/servercapabilities.cpp
@@ -196,6 +196,28 @@ void ServerCapabilities::setCallHierarchyProvider(
     insert(callHierarchyProviderKey, val);
 }
 
+std::optional<std::variant<bool, WorkDoneProgressOptions>> ServerCapabilities::typeHierarchyProvider()
+    const
+{
+    const QJsonValue &provider = value(typeHierarchyProviderKey);
+    if (provider.isBool())
+        return provider.toBool();
+    else if (provider.isObject())
+        return WorkDoneProgressOptions(provider.toObject());
+    return std::nullopt;
+}
+
+void ServerCapabilities::setTypeHierarchyProvider(
+    const std::variant<bool, WorkDoneProgressOptions> &typeHierarchyProvider)
+{
+    QJsonValue val;
+    if (std::holds_alternative<bool>(typeHierarchyProvider))
+        val = std::get<bool>(typeHierarchyProvider);
+    else if (std::holds_alternative<WorkDoneProgressOptions>(typeHierarchyProvider))
+        val = QJsonObject(std::get<WorkDoneProgressOptions>(typeHierarchyProvider));
+    insert(typeHierarchyProviderKey, val);
+}
+
 std::optional<std::variant<bool, WorkDoneProgressOptions>>
 ServerCapabilities::workspaceSymbolProvider() const
 {
diff --git a/src/libs/languageserverprotocol/servercapabilities.h b/src/libs/languageserverprotocol/servercapabilities.h
index c3b50dd590..32598d2afa 100644
--- a/src/libs/languageserverprotocol/servercapabilities.h
+++ b/src/libs/languageserverprotocol/servercapabilities.h
@@ -330,6 +330,10 @@ public:
     void setCallHierarchyProvider(const std::variant<bool, WorkDoneProgressOptions> &callHierarchyProvider);
     void clearCallHierarchyProvider() { remove(callHierarchyProviderKey); }
 
+    std::optional<std::variant<bool, WorkDoneProgressOptions>> typeHierarchyProvider() const;
+    void setTypeHierarchyProvider(const std::variant<bool, WorkDoneProgressOptions> &typeHierarchyProvider);
+    void clearTypeHierarchyProvider() { remove(typeHierarchyProviderKey); }
+
     // The server provides workspace symbol support.
     std::optional<std::variant<bool, WorkDoneProgressOptions>> workspaceSymbolProvider() const;
     void setWorkspaceSymbolProvider(std::variant<bool, WorkDoneProgressOptions> workspaceSymbolProvider);
diff --git a/src/libs/languageserverprotocol/typehierarchy.cpp b/src/libs/languageserverprotocol/typehierarchy.cpp
new file mode 100644
index 0000000000..1734e25a6b
--- /dev/null
+++ b/src/libs/languageserverprotocol/typehierarchy.cpp
@@ -0,0 +1,28 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "typehierarchy.h"
+
+namespace LanguageServerProtocol {
+
+bool TypeHierarchyItem::isValid() const
+{
+    return contains(nameKey) && contains(kindKey) && contains(uriKey) && contains(rangeKey)
+           && contains(selectionRangeKey);
+}
+std::optional<QList<SymbolTag>> TypeHierarchyItem::symbolTags() const
+{
+    return Internal::getSymbolTags(*this);
+}
+
+PrepareTypeHierarchyRequest::PrepareTypeHierarchyRequest(const TextDocumentPositionParams &params)
+    : Request(methodName, params)
+{}
+TypeHierarchySupertypesRequest::TypeHierarchySupertypesRequest(const TypeHierarchyParams &params)
+    : Request(methodName, params)
+{}
+TypeHierarchySubtypesRequest::TypeHierarchySubtypesRequest(const TypeHierarchyParams &params)
+    : Request(methodName, params)
+{}
+
+} // namespace LanguageServerProtocol
diff --git a/src/libs/languageserverprotocol/typehierarchy.h b/src/libs/languageserverprotocol/typehierarchy.h
new file mode 100644
index 0000000000..d5e88c8cfd
--- /dev/null
+++ b/src/libs/languageserverprotocol/typehierarchy.h
@@ -0,0 +1,85 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include "jsonrpcmessages.h"
+
+namespace LanguageServerProtocol {
+
+class LANGUAGESERVERPROTOCOL_EXPORT TypeHierarchyItem : public JsonObject
+{
+public:
+    using JsonObject::JsonObject;
+
+    QString name() const { return typedValue<QString>(nameKey); }
+    void setName(const QString &name) { insert(nameKey, name); }
+
+    SymbolKind symbolKind() const { return SymbolKind(typedValue<int>(kindKey)); }
+    void setSymbolKind(const SymbolKind &symbolKind) { insert(kindKey, int(symbolKind)); }
+
+    std::optional<QList<SymbolTag>> symbolTags() const;
+
+    std::optional<QString> detail() const { return optionalValue<QString>(detailKey); }
+    void setDetail(const QString &detail) { insert(detailKey, detail); }
+    void clearDetail() { remove(detailKey); }
+
+    DocumentUri uri() const { return DocumentUri::fromProtocol(typedValue<QString>(uriKey)); }
+    void setUri(const DocumentUri &uri) { insert(uriKey, uri); }
+
+    Range range() const { return typedValue<Range>(rangeKey); }
+    void setRange(const Range &range) { insert(rangeKey, range); }
+
+    Range selectionRange() const { return typedValue<Range>(selectionRangeKey); }
+    void setSelectionRange(Range selectionRange) { insert(selectionRangeKey, selectionRange); }
+
+    /*
+     * A data entry field that is preserved between a type hierarchy prepare and
+     * supertypes or subtypes requests. It could also be used to identify the
+     * type hierarchy in the server, helping improve the performance on
+     * resolving supertypes and subtypes.
+     */
+    std::optional<QJsonValue> data() const { return optionalValue<QJsonValue>(dataKey); }
+
+    bool isValid() const override;
+};
+
+class LANGUAGESERVERPROTOCOL_EXPORT PrepareTypeHierarchyRequest : public Request<
+        LanguageClientArray<TypeHierarchyItem>, std::nullptr_t, TextDocumentPositionParams>
+{
+public:
+    explicit PrepareTypeHierarchyRequest(const TextDocumentPositionParams &params);
+    using Request::Request;
+    constexpr static const char methodName[] = "textDocument/prepareTypeHierarchy";
+};
+
+class LANGUAGESERVERPROTOCOL_EXPORT TypeHierarchyParams : public JsonObject
+{
+public:
+    using JsonObject::JsonObject;
+
+    TypeHierarchyItem item() const { return typedValue<TypeHierarchyItem>(itemKey); }
+    void setItem(const TypeHierarchyItem &item) { insert(itemKey, item); }
+
+    bool isValid() const override { return contains(itemKey); }
+};
+
+class LANGUAGESERVERPROTOCOL_EXPORT TypeHierarchySupertypesRequest : public Request<
+        LanguageClientArray<TypeHierarchyItem>, std::nullptr_t, TypeHierarchyParams>
+{
+public:
+    explicit TypeHierarchySupertypesRequest(const TypeHierarchyParams &params);
+    using Request::Request;
+    constexpr static const char methodName[] = "typeHierarchy/supertypes";
+};
+
+class LANGUAGESERVERPROTOCOL_EXPORT TypeHierarchySubtypesRequest
+    : public Request<LanguageClientArray<TypeHierarchyItem>, std::nullptr_t, TypeHierarchyParams>
+{
+public:
+    explicit TypeHierarchySubtypesRequest(const TypeHierarchyParams &params);
+    using Request::Request;
+    constexpr static const char methodName[] = "typeHierarchy/subtypes";
+};
+
+} // namespace LanguageServerProtocol
diff --git a/src/plugins/cppeditor/cpptypehierarchy.cpp b/src/plugins/cppeditor/cpptypehierarchy.cpp
index d0a523ce13..ab4bc0525e 100644
--- a/src/plugins/cppeditor/cpptypehierarchy.cpp
+++ b/src/plugins/cppeditor/cpptypehierarchy.cpp
@@ -420,7 +420,7 @@ class CppTypeHierarchyFactory final : public TextEditor::TypeHierarchyWidgetFact
         if (!textEditor)
             return nullptr;
         const auto cppDoc = qobject_cast<CppEditorDocument *>(textEditor->textDocument());
-        if (!cppDoc /* || cppDoc->usesClangd() */)
+        if (!cppDoc || cppDoc->usesClangd())
             return nullptr;
 
         return new CppTypeHierarchyWidget;
diff --git a/src/plugins/languageclient/CMakeLists.txt b/src/plugins/languageclient/CMakeLists.txt
index a74bc33026..e098168a1c 100644
--- a/src/plugins/languageclient/CMakeLists.txt
+++ b/src/plugins/languageclient/CMakeLists.txt
@@ -8,7 +8,7 @@ add_qtc_plugin(LanguageClient
   PUBLIC_DEPENDS LanguageServerProtocol Qt::Core
   PLUGIN_DEPENDS ProjectExplorer Core TextEditor
   SOURCES
-    callhierarchy.cpp callhierarchy.h
+    callandtypehierarchy.cpp callandtypehierarchy.h
     client.cpp client.h
     clientrequest.cpp clientrequest.h
     currentdocumentsymbolsrequest.cpp currentdocumentsymbolsrequest.h
diff --git a/src/plugins/languageclient/callandtypehierarchy.cpp b/src/plugins/languageclient/callandtypehierarchy.cpp
new file mode 100644
index 0000000000..14e5935c6a
--- /dev/null
+++ b/src/plugins/languageclient/callandtypehierarchy.cpp
@@ -0,0 +1,508 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "callandtypehierarchy.h"
+
+#include "languageclientmanager.h"
+#include "languageclienttr.h"
+
+#include <coreplugin/editormanager/editormanager.h>
+#include <coreplugin/inavigationwidgetfactory.h>
+
+#include <languageserverprotocol/callhierarchy.h>
+#include <languageserverprotocol/typehierarchy.h>
+
+#include <texteditor/texteditor.h>
+#include <texteditor/typehierarchy.h>
+
+#include <utils/delegates.h>
+#include <utils/navigationtreeview.h>
+#include <utils/treemodel.h>
+#include <utils/utilsicons.h>
+
+#include <QLayout>
+#include <QToolButton>
+
+using namespace Utils;
+using namespace TextEditor;
+using namespace LanguageServerProtocol;
+
+namespace LanguageClient {
+
+namespace {
+enum {
+    AnnotationRole = Qt::UserRole + 1,
+    LinkRole
+};
+}
+
+template<class Item, class Params, class Request, class Result>
+class HierarchyItem : public TreeItem
+{
+public:
+    HierarchyItem(const Item &item, Client *client)
+        : m_item(item)
+        , m_client(client)
+    {}
+
+protected:
+    QVariant data(int column, int role) const override
+    {
+        switch (role) {
+        case Qt::DecorationRole:
+            if (hasTag(SymbolTag::Deprecated))
+                return Utils::Icons::WARNING.icon();
+            return symbolIcon(int(m_item.symbolKind()));
+        case Qt::DisplayRole:
+            return m_item.name();
+        case Qt::ToolTipRole:
+            if (hasTag(SymbolTag::Deprecated))
+                return Tr::tr("Deprecated");
+            return {};
+        case LinkRole: {
+            if (!m_client)
+                return QVariant();
+            const Position start = m_item.selectionRange().start();
+            return QVariant::fromValue(
+                Link(m_client->serverUriToHostPath(m_item.uri()), start.line() + 1, start.character()));
+        }
+        case AnnotationRole:
+            if (const std::optional<QString> detail = m_item.detail())
+                return *detail;
+            return {};
+        default:
+            return TreeItem::data(column, role);
+        }
+    }
+
+private:
+    bool canFetchMore() const override { return m_client && !m_fetchedChildren; }
+
+    void fetchMore() override
+    {
+        m_fetchedChildren = true;
+        if (!m_client)
+            return;
+
+        Params params;
+        params.setItem(m_item);
+        Request request(params);
+        request.setResponseCallback(
+            [this](const typename Request::Response &response) {
+                const std::optional<LanguageClientArray<Result>> result = response.result();
+                if (result && !result->isNull()) {
+                    for (const Result &item : result->toList()) {
+                        if (item.isValid())
+                            appendChild(new HierarchyItem(getSourceItem(item), m_client));
+                    }
+                }
+                if (!hasChildren())
+                    update();
+            });
+        m_client->sendMessage(request);
+    }
+
+    Item getSourceItem(const Result &result)
+    {
+        if constexpr (std::is_same_v<Result, CallHierarchyIncomingCall>)
+            return result.from();
+        if constexpr (std::is_same_v<Result, CallHierarchyOutgoingCall>)
+            return result.to();
+        if constexpr (std::is_same_v<Result, TypeHierarchyItem>)
+            return result;
+    }
+
+    bool hasTag(const SymbolTag tag) const
+    {
+        if (const std::optional<QList<SymbolTag>> tags = m_item.symbolTags())
+            return tags->contains(tag);
+        return false;
+    }
+
+    const Item m_item;
+    bool m_fetchedChildren = false;
+    QPointer<Client> m_client;
+};
+
+class CallHierarchyIncomingItem : public HierarchyItem<CallHierarchyItem,
+                                                       CallHierarchyCallsParams,
+                                                       CallHierarchyIncomingCallsRequest,
+                                                       CallHierarchyIncomingCall>
+{
+public:
+    CallHierarchyIncomingItem(const LanguageServerProtocol::CallHierarchyItem &item, Client *client)
+        : HierarchyItem(item, client)
+    {}
+
+private:
+    QVariant data(int column, int role) const override
+    {
+        if (role == Qt::DisplayRole)
+            return Tr::tr("Incoming");
+        if (role == Qt::DecorationRole)
+            return {};
+        return HierarchyItem::data(column, role);
+    }
+};
+
+class CallHierarchyOutgoingItem : public HierarchyItem<CallHierarchyItem,
+                                                       CallHierarchyCallsParams,
+                                                       CallHierarchyOutgoingCallsRequest,
+                                                       CallHierarchyOutgoingCall>
+{
+public:
+    CallHierarchyOutgoingItem(const LanguageServerProtocol::CallHierarchyItem &item, Client *client)
+        : HierarchyItem(item, client)
+    {}
+
+private:
+    QVariant data(int column, int role) const override
+    {
+        if (role == Qt::DisplayRole)
+            return Tr::tr("Outgoing");
+        if (role == Qt::DecorationRole)
+            return {};
+        return HierarchyItem::data(column, role);
+    }
+};
+
+template<class Item> class HierarchyRootItem : public TreeItem
+{
+public:
+    HierarchyRootItem(const Item &item)
+        : m_item(item)
+    {}
+
+private:
+    QVariant data(int column, int role) const override
+    {
+        switch (role) {
+        case Qt::DecorationRole:
+            if (m_item.symbolTags().value_or(QList<SymbolTag>()).contains(SymbolTag::Deprecated))
+                return Utils::Icons::WARNING.icon();
+            return symbolIcon(int(m_item.symbolKind()));
+        case Qt::DisplayRole:
+            return m_item.name();
+        default:
+            return TreeItem::data(column, role);
+        }
+    }
+
+    const Item m_item;
+};
+
+
+class CallHierarchyRootItem : public HierarchyRootItem<LanguageServerProtocol::CallHierarchyItem>
+{
+public:
+    CallHierarchyRootItem(const LanguageServerProtocol::CallHierarchyItem &item, Client *client)
+        : HierarchyRootItem(item)
+    {
+        appendChild(new CallHierarchyIncomingItem(item, client));
+        appendChild(new CallHierarchyOutgoingItem(item, client));
+    }
+};
+
+class TypeHierarchyBasesItem : public HierarchyItem<TypeHierarchyItem,
+                                                    TypeHierarchyParams,
+                                                    TypeHierarchySupertypesRequest,
+                                                    TypeHierarchyItem>
+{
+public:
+    TypeHierarchyBasesItem(const LanguageServerProtocol::TypeHierarchyItem &item, Client *client)
+        : HierarchyItem(item, client)
+    {}
+
+private:
+    QVariant data(int column, int role) const override
+    {
+        if (role == Qt::DisplayRole)
+            return Tr::tr("Bases");
+        if (role == Qt::DecorationRole)
+            return {};
+        return HierarchyItem::data(column, role);
+    }
+};
+
+class TypeHierarchyDerivedItem : public HierarchyItem<TypeHierarchyItem,
+                                                      TypeHierarchyParams,
+                                                      TypeHierarchySubtypesRequest,
+                                                      TypeHierarchyItem>
+{
+public:
+    TypeHierarchyDerivedItem(const LanguageServerProtocol::TypeHierarchyItem &item, Client *client)
+        : HierarchyItem(item, client)
+    {}
+
+private:
+    QVariant data(int column, int role) const override
+    {
+        if (role == Qt::DisplayRole)
+            return Tr::tr("Derived");
+        if (role == Qt::DecorationRole)
+            return {};
+        return HierarchyItem::data(column, role);
+    }
+};
+
+class TypeHierarchyRootItem : public HierarchyRootItem<LanguageServerProtocol::TypeHierarchyItem>
+{
+public:
+    TypeHierarchyRootItem(const LanguageServerProtocol::TypeHierarchyItem &item, Client *client)
+        : HierarchyRootItem(item)
+    {
+        appendChild(new TypeHierarchyBasesItem(item, client));
+        appendChild(new TypeHierarchyDerivedItem(item, client));
+    }
+};
+
+class HierarchyWidgetHelper
+{
+public:
+    HierarchyWidgetHelper(QWidget *theWidget) : m_view(new NavigationTreeView(theWidget))
+    {
+        m_delegate.setDelimiter(" ");
+        m_delegate.setAnnotationRole(AnnotationRole);
+
+        m_view->setModel(&m_model);
+        m_view->setActivationMode(SingleClickActivation);
+        m_view->setItemDelegate(&m_delegate);
+
+        theWidget->setLayout(new QVBoxLayout);
+        theWidget->layout()->addWidget(m_view);
+        theWidget->layout()->setContentsMargins(0, 0, 0, 0);
+        theWidget->layout()->setSpacing(0);
+
+        QObject::connect(m_view, &NavigationTreeView::activated,
+                         theWidget, [this](const QModelIndex &index) { onItemActivated(index); });
+        QObject::connect(m_view, &QTreeView::doubleClicked,
+                         theWidget, [this](const QModelIndex &index) { onItemDoubleClicked(index); });
+    }
+
+    void updateHierarchyAtCursorPosition()
+    {
+        m_model.clear();
+
+        BaseTextEditor *editor = BaseTextEditor::currentTextEditor();
+        if (!editor)
+            return;
+
+        Core::IDocument *document = editor->document();
+
+        Client *client = LanguageClientManager::clientForFilePath(document->filePath());
+        if (!client)
+            return;
+
+        TextDocumentPositionParams params;
+        params.setTextDocument(TextDocumentIdentifier(client->hostPathToServerUri(document->filePath())));
+        params.setPosition(Position(editor->editorWidget()->textCursor()));
+        sendRequest(client, params, document);
+    }
+
+protected:
+    void addItem(TreeItem *item)
+    {
+        m_model.rootItem()->appendChild(item);
+        m_view->expand(item->index());
+        item->forChildrenAtLevel(1, [&](const TreeItem *child) { m_view->expand(child->index()); });
+    }
+
+private:
+    virtual void sendRequest(Client *client, const TextDocumentPositionParams &params,
+                             const Core::IDocument *document) = 0;
+
+    virtual void onItemDoubleClicked(const QModelIndex &index) { Q_UNUSED(index) }
+
+    void onItemActivated(const QModelIndex &index)
+    {
+        const auto link = index.data(LinkRole).value<Utils::Link>();
+        if (link.hasValidTarget())
+            Core::EditorManager::openEditorAt(link);
+    }
+
+    AnnotatedItemDelegate m_delegate;
+    NavigationTreeView * const m_view;
+    TreeModel<TreeItem> m_model;
+};
+
+class CallHierarchy : public QWidget, public HierarchyWidgetHelper
+{
+public:
+    CallHierarchy() : HierarchyWidgetHelper(this)
+    {
+        connect(LanguageClientManager::instance(), &LanguageClientManager::openCallHierarchy,
+                this, [this] { updateHierarchyAtCursorPosition(); });
+    }
+
+private:
+    void sendRequest(Client *client, const TextDocumentPositionParams &params,
+                     const Core::IDocument *document) override
+    {
+        if (!supportsCallHierarchy(client, document))
+            return;
+
+        PrepareCallHierarchyRequest request(params);
+        request.setResponseCallback([this, client = QPointer<Client>(client)](
+                                        const PrepareCallHierarchyRequest::Response &response) {
+            handlePrepareResponse(client, response);
+        });
+        client->sendMessage(request);
+    }
+
+    void handlePrepareResponse(Client *client,
+                               const PrepareCallHierarchyRequest::Response &response)
+    {
+        if (!client)
+            return;
+        const std::optional<PrepareCallHierarchyRequest::Response::Error> error = response.error();
+        if (error)
+            client->log(*error);
+
+        const std::optional<LanguageClientArray<LanguageServerProtocol::CallHierarchyItem>>
+            result = response.result();
+        if (result && !result->isNull()) {
+            for (const LanguageServerProtocol::CallHierarchyItem &item : result->toList())
+                addItem(new CallHierarchyRootItem(item, client));
+        }
+    }
+};
+
+class TypeHierarchy : public TypeHierarchyWidget, public HierarchyWidgetHelper
+{
+public:
+    TypeHierarchy() : HierarchyWidgetHelper(this) {}
+
+private:
+    void reload() override
+    {
+        updateHierarchyAtCursorPosition();
+    }
+
+    void sendRequest(Client *client, const TextDocumentPositionParams &params,
+                     const Core::IDocument *document) override
+    {
+        if (!supportsTypeHierarchy(client, document))
+            return;
+
+        PrepareTypeHierarchyRequest request(params);
+        request.setResponseCallback([this, client = QPointer<Client>(client)](
+                                        const PrepareTypeHierarchyRequest::Response &response) {
+            handlePrepareResponse(client, response);
+        });
+        client->sendMessage(request);
+    }
+
+    void onItemDoubleClicked(const QModelIndex &index) override
+    {
+        if (const auto link = index.data(LinkRole).value<Link>(); link.hasValidTarget())
+            reload();
+    }
+
+    void handlePrepareResponse(Client *client,
+                               const PrepareTypeHierarchyRequest::Response &response)
+    {
+        if (!client)
+            return;
+        const std::optional<PrepareTypeHierarchyRequest::Response::Error> error = response.error();
+        if (error)
+            client->log(*error);
+
+        const std::optional<LanguageClientArray<LanguageServerProtocol::TypeHierarchyItem>>
+            result = response.result();
+        if (result && !result->isNull()) {
+            for (const LanguageServerProtocol::TypeHierarchyItem &item : result->toList())
+                addItem(new TypeHierarchyRootItem(item, client));
+        }
+    }
+};
+
+class CallHierarchyFactory : public Core::INavigationWidgetFactory
+{
+public:
+    CallHierarchyFactory()
+    {
+        setDisplayName(Tr::tr("Call Hierarchy"));
+        setPriority(650);
+        setId(Constants::CALL_HIERARCHY_FACTORY_ID);
+    }
+
+    Core::NavigationView createWidget() final
+    {
+        auto h = new CallHierarchy;
+        h->updateHierarchyAtCursorPosition();
+
+        Icons::RELOAD_TOOLBAR.icon();
+        auto button = new QToolButton;
+        button->setIcon(Icons::RELOAD_TOOLBAR.icon());
+        button->setToolTip(LanguageClient::Tr::tr(
+            "Reloads the call hierarchy for the symbol under cursor position."));
+        connect(button, &QToolButton::clicked, this, [h] { h->updateHierarchyAtCursorPosition(); });
+        return {h, {button}};
+    }
+};
+
+class TypeHierarchyFactory final : public TypeHierarchyWidgetFactory
+{
+    TypeHierarchyWidget *createWidget(Core::IEditor *editor) final
+    {
+        const auto textEditor = qobject_cast<BaseTextEditor *>(editor);
+        if (!textEditor)
+            return nullptr;
+
+        Client *const client = LanguageClientManager::clientForFilePath(
+            textEditor->document()->filePath());
+        if (!client || !supportsTypeHierarchy(client, textEditor->document()))
+            return nullptr;
+
+        return new TypeHierarchy;
+    }
+};
+
+void setupCallHierarchyFactory()
+{
+    static CallHierarchyFactory theCallHierarchyFactory;
+}
+
+static bool supportsHierarchy(
+    Client *client,
+    const Core::IDocument *document,
+    const QString &methodName,
+    const std::optional<std::variant<bool, WorkDoneProgressOptions>> &provider)
+{
+    std::optional<bool> registered = client->dynamicCapabilities().isRegistered(methodName);
+    bool supported = registered.value_or(false);
+    if (registered) {
+        if (supported) {
+            const QJsonValue &options = client->dynamicCapabilities().option(methodName);
+            const TextDocumentRegistrationOptions docOptions(options);
+            supported = docOptions.filterApplies(document->filePath(),
+                                                 Utils::mimeTypeForName(document->mimeType()));
+        }
+    } else {
+        supported = provider.has_value();
+    }
+    return supported;
+}
+
+bool supportsCallHierarchy(Client *client, const Core::IDocument *document)
+{
+    return supportsHierarchy(client,
+                             document,
+                             PrepareCallHierarchyRequest::methodName,
+                             client->capabilities().callHierarchyProvider());
+}
+
+void setupTypeHierarchyFactory()
+{
+    static TypeHierarchyFactory theTypeHierarchyFactory;
+}
+
+bool supportsTypeHierarchy(Client *client, const Core::IDocument *document)
+{
+    return supportsHierarchy(client,
+                             document,
+                             PrepareTypeHierarchyRequest::methodName,
+                             client->capabilities().typeHierarchyProvider());
+}
+
+} // namespace LanguageClient
diff --git a/src/plugins/languageclient/callhierarchy.h b/src/plugins/languageclient/callandtypehierarchy.h
index 860919b2b9..b49684d65a 100644
--- a/src/plugins/languageclient/callhierarchy.h
+++ b/src/plugins/languageclient/callandtypehierarchy.h
@@ -1,4 +1,4 @@
-// Copyright (C) 2022 The Qt Company Ltd.
+// Copyright (C) 2024 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0 WITH Qt-GPL-exception-1.0
 
 #pragma once
@@ -12,4 +12,7 @@ class Client;
 void setupCallHierarchyFactory();
 bool supportsCallHierarchy(Client *client, const Core::IDocument *document);
 
+void setupTypeHierarchyFactory();
+bool supportsTypeHierarchy(Client *client, const Core::IDocument *document);
+
 } // namespace LanguageClient
diff --git a/src/plugins/languageclient/callhierarchy.cpp b/src/plugins/languageclient/callhierarchy.cpp
deleted file mode 100644
index 2f53a120eb..0000000000
--- a/src/plugins/languageclient/callhierarchy.cpp
+++ /dev/null
@@ -1,318 +0,0 @@
-// Copyright (C) 2022 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0 WITH Qt-GPL-exception-1.0
-
-#include "callhierarchy.h"
-
-#include "languageclientmanager.h"
-#include "languageclienttr.h"
-
-#include <coreplugin/editormanager/editormanager.h>
-#include <coreplugin/inavigationwidgetfactory.h>
-
-#include <languageserverprotocol/callhierarchy.h>
-
-#include <texteditor/texteditor.h>
-
-#include <utils/delegates.h>
-#include <utils/navigationtreeview.h>
-#include <utils/treemodel.h>
-#include <utils/utilsicons.h>
-
-#include <QLayout>
-#include <QToolButton>
-
-using namespace Utils;
-using namespace TextEditor;
-using namespace LanguageServerProtocol;
-
-namespace LanguageClient {
-
-namespace {
-enum Direction { Incoming, Outgoing };
-
-enum {
-    AnnotationRole = Qt::UserRole + 1,
-    LinkRole
-};
-}
-
-class CallHierarchyRootItem : public TreeItem
-{
-public:
-    CallHierarchyRootItem(const CallHierarchyItem &item)
-        : m_item(item)
-    {}
-
-    QVariant data(int column, int role) const override
-    {
-        switch (role) {
-        case Qt::DecorationRole:
-            if (hasTag(SymbolTag::Deprecated))
-                return Utils::Icons::WARNING.icon();
-            return symbolIcon(int(m_item.symbolKind()));
-        case Qt::DisplayRole:
-            return m_item.name();
-        case Qt::ToolTipRole:
-            if (hasTag(SymbolTag::Deprecated))
-                return Tr::tr("Deprecated");
-            break;
-        default:
-            break;
-        }
-        return TreeItem::data(column, role);
-    }
-
-protected:
-    const CallHierarchyItem m_item;
-
-    bool hasTag(const SymbolTag tag) const
-    {
-        if (const std::optional<QList<SymbolTag>> tags = m_item.symbolTags())
-            return tags->contains(tag);
-        return false;
-    }
-};
-
-class CallHierarchyTreeItem : public CallHierarchyRootItem
-{
-public:
-    CallHierarchyTreeItem(const CallHierarchyItem &item, const Direction direction, Client *client)
-        : CallHierarchyRootItem(item)
-        , m_direction(direction)
-        , m_client(client)
-    {
-    }
-
-    QVariant data(int column, int role) const override
-    {
-        switch (role) {
-        case LinkRole: {
-            if (!m_client)
-                return QVariant();
-            const Position start = m_item.selectionRange().start();
-            return QVariant::fromValue(
-                Link(m_client->serverUriToHostPath(m_item.uri()), start.line() + 1, start.character()));
-        }
-        case AnnotationRole:
-            if (const std::optional<QString> detail = m_item.detail())
-                return *detail;
-            return {};
-        default:
-            break;
-        }
-        return CallHierarchyRootItem::data(column, role);
-    }
-    bool canFetchMore() const override
-    {
-        return m_client && !m_fetchedChildren;
-    }
-
-    void fetchMore() override
-    {
-        m_fetchedChildren = true;
-        if (!m_client)
-            return;
-
-        CallHierarchyCallsParams params;
-        params.setItem(m_item);
-
-        if (m_direction == Incoming) {
-            CallHierarchyIncomingCallsRequest request(params);
-            request.setResponseCallback(
-                        [this](const CallHierarchyIncomingCallsRequest::Response &response) {
-                const std::optional<LanguageClientArray<CallHierarchyIncomingCall>> result
-                        = response.result();
-                if (result && !result->isNull()) {
-                    for (const CallHierarchyIncomingCall &item : result->toList()) {
-                        if (item.isValid())
-                            appendChild(new CallHierarchyTreeItem(item.from(), m_direction, m_client));
-                    }
-                }
-                if (!hasChildren())
-                    update();
-            });
-            m_client->sendMessage(request);
-        } else {
-            CallHierarchyOutgoingCallsRequest request(params);
-            request.setResponseCallback(
-                        [this](const CallHierarchyOutgoingCallsRequest::Response &response) {
-                const std::optional<LanguageClientArray<CallHierarchyOutgoingCall>> result
-                        = response.result();
-                if (result && !result->isNull()) {
-                    for (const CallHierarchyOutgoingCall &item : result->toList()) {
-                        if (item.isValid())
-                            appendChild(new CallHierarchyTreeItem(item.to(), m_direction, m_client));
-                    }
-                }
-                if (!hasChildren())
-                    update();
-                });
-            m_client->sendMessage(request);
-        }
-    }
-
-protected:
-    const Direction m_direction;
-    bool m_fetchedChildren = false;
-    QPointer<Client> m_client;
-};
-
-class CallHierarchyDirectionItem : public CallHierarchyTreeItem
-{
-public:
-    CallHierarchyDirectionItem(const CallHierarchyItem &item,
-                               const Direction direction,
-                               Client *client)
-        : CallHierarchyTreeItem(item, direction, client)
-    {}
-
-    QVariant data(int column, int role) const override
-    {
-        if (role == Qt::DisplayRole)
-            return m_direction == Incoming ? Tr::tr("Incoming") : Tr::tr("Outgoing");
-        return TreeItem::data(column, role);
-    }
-};
-
-class CallHierarchy : public QWidget
-{
-public:
-    CallHierarchy() : m_view(new NavigationTreeView(this))
-    {
-        m_delegate.setDelimiter(" ");
-        m_delegate.setAnnotationRole(AnnotationRole);
-
-        m_view->setModel(&m_model);
-        m_view->setActivationMode(SingleClickActivation);
-        m_view->setItemDelegate(&m_delegate);
-
-        setLayout(new QVBoxLayout);
-        layout()->addWidget(m_view);
-        layout()->setContentsMargins(0, 0, 0, 0);
-        layout()->setSpacing(0);
-
-        connect(m_view, &NavigationTreeView::activated, this, &CallHierarchy::onItemActivated);
-
-        connect(LanguageClientManager::instance(), &LanguageClientManager::openCallHierarchy,
-                this, &CallHierarchy::updateHierarchyAtCursorPosition);
-    }
-
-    void onItemActivated(const QModelIndex &index)
-    {
-        const auto link = index.data(LinkRole).value<Utils::Link>();
-        if (link.hasValidTarget())
-            Core::EditorManager::openEditorAt(link);
-    }
-
-    void updateHierarchyAtCursorPosition();
-    void handlePrepareResponse(Client *client,
-                               const PrepareCallHierarchyRequest::Response &response);
-
-    AnnotatedItemDelegate m_delegate;
-    NavigationTreeView *m_view;
-    TreeModel<TreeItem, CallHierarchyRootItem, CallHierarchyTreeItem> m_model;
-};
-
-void CallHierarchy::updateHierarchyAtCursorPosition()
-{
-    m_model.clear();
-
-    BaseTextEditor *editor = BaseTextEditor::currentTextEditor();
-    if (!editor)
-        return;
-
-    Core::IDocument *document = editor->document();
-
-    Client *client = LanguageClientManager::clientForFilePath(document->filePath());
-    if (!client)
-        return;
-
-    if (!supportsCallHierarchy(client, document))
-        return;
-
-    TextDocumentPositionParams params;
-    params.setTextDocument(TextDocumentIdentifier(client->hostPathToServerUri(document->filePath())));
-    params.setPosition(Position(editor->editorWidget()->textCursor()));
-
-    PrepareCallHierarchyRequest request(params);
-    request.setResponseCallback([this, client = QPointer<Client>(client)](
-                                    const PrepareCallHierarchyRequest::Response &response) {
-        handlePrepareResponse(client, response);
-    });
-
-    client->sendMessage(request);
-}
-
-void CallHierarchy::handlePrepareResponse(Client *client,
-                                          const PrepareCallHierarchyRequest::Response &response)
-{
-    if (!client)
-        return;
-    const std::optional<PrepareCallHierarchyRequest::Response::Error> error = response.error();
-    if (error)
-        client->log(*error);
-
-    const std::optional<LanguageClientArray<CallHierarchyItem>>
-        result = response.result();
-    if (result && !result->isNull()) {
-        for (const CallHierarchyItem &item : result->toList()) {
-            auto newItem = new CallHierarchyRootItem(item);
-            newItem->appendChild(new CallHierarchyDirectionItem(item, Incoming, client));
-            newItem->appendChild(new CallHierarchyDirectionItem(item, Outgoing, client));
-            m_model.rootItem()->appendChild(newItem);
-            m_view->expand(newItem->index());
-            newItem->forChildrenAtLevel(1, [&](const TreeItem *child) {
-                m_view->expand(child->index());
-            });
-        }
-    }
-}
-
-class CallHierarchyFactory final : public Core::INavigationWidgetFactory
-{
-public:
-    CallHierarchyFactory()
-    {
-        setDisplayName(Tr::tr("Call Hierarchy"));
-        setPriority(650);
-        setId(Constants::CALL_HIERARCHY_FACTORY_ID);
-    }
-
-    Core::NavigationView createWidget() final
-    {
-        auto h = new CallHierarchy;
-        h->updateHierarchyAtCursorPosition();
-
-        Icons::RELOAD_TOOLBAR.icon();
-        auto button = new QToolButton;
-        button->setIcon(Icons::RELOAD_TOOLBAR.icon());
-        button->setToolTip(::LanguageClient::Tr::tr("Reloads the call hierarchy for the symbol under cursor position."));
-        connect(button, &QToolButton::clicked, this, [h] { h->updateHierarchyAtCursorPosition(); });
-        return {h, {button}};
-    }
-};
-
-void setupCallHierarchyFactory()
-{
-    static CallHierarchyFactory theCallHierarchyFactory;
-}
-
-bool supportsCallHierarchy(Client *client, const Core::IDocument *document)
-{
-    const QString methodName = PrepareCallHierarchyRequest::methodName;
-    std::optional<bool> registered = client->dynamicCapabilities().isRegistered(methodName);
-    bool supported = registered.value_or(false);
-    if (registered) {
-        if (supported) {
-            const QJsonValue &options = client->dynamicCapabilities().option(methodName);
-            const TextDocumentRegistrationOptions docOptions(options);
-            supported = docOptions.filterApplies(document->filePath(),
-                                                 Utils::mimeTypeForName(document->mimeType()));
-        }
-    } else {
-        supported = client->capabilities().callHierarchyProvider().has_value();
-    }
-    return supported;
-}
-
-} // namespace LanguageClient
diff --git a/src/plugins/languageclient/client.cpp b/src/plugins/languageclient/client.cpp
index 15a71adae3..5e3d240f8c 100644
--- a/src/plugins/languageclient/client.cpp
+++ b/src/plugins/languageclient/client.cpp
@@ -3,7 +3,7 @@
 
 #include "client.h"
 
-#include "callhierarchy.h"
+#include "callandtypehierarchy.h"
 #include "diagnosticmanager.h"
 #include "documentsymbolcache.h"
 #include "languageclientcompletionassist.h"
@@ -527,6 +527,7 @@ static ClientCapabilities generateClientCapabilities()
     tokens.setFormats({"relative"});
     documentCapabilities.setSemanticTokens(tokens);
     documentCapabilities.setCallHierarchy(allowDynamicRegistration);
+    documentCapabilities.setTypeHierarchy(allowDynamicRegistration);
     capabilities.setTextDocument(documentCapabilities);
 
     WindowClientClientCapabilities window;
@@ -1013,6 +1014,8 @@ void Client::activateEditor(Core::IEditor *editor)
             optionalActions |= TextEditor::TextEditorActionHandler::FollowTypeUnderCursor;
         if (supportsCallHierarchy(this, textEditor->document()))
             optionalActions |= TextEditor::TextEditorActionHandler::CallHierarchy;
+        if (supportsTypeHierarchy(this, textEditor->document()))
+            optionalActions |= TextEditor::TextEditorActionHandler::TypeHierarchy;
         widget->setOptionalActions(optionalActions);
     }
 }
diff --git a/src/plugins/languageclient/languageclient.qbs b/src/plugins/languageclient/languageclient.qbs
index 96a88629f0..04c2f0f326 100644
--- a/src/plugins/languageclient/languageclient.qbs
+++ b/src/plugins/languageclient/languageclient.qbs
@@ -15,8 +15,8 @@ QtcPlugin {
     Depends { name: "TextEditor" }
 
     files: [
-        "callhierarchy.cpp",
-        "callhierarchy.h",
+        "callandtypehierarchy.cpp",
+        "callandtypehierarchy.h",
         "client.cpp",
         "client.h",
         "clientrequest.cpp",
@@ -30,7 +30,8 @@ QtcPlugin {
         "dynamiccapabilities.cpp",
         "dynamiccapabilities.h",
         "languageclient.qrc",
-        "languageclient_global.h", "languageclienttr.h",
+        "languageclient_global.h",
+        "languageclienttr.h",
         "languageclientformatter.cpp",
         "languageclientformatter.h",
         "languageclienthoverhandler.cpp",
diff --git a/src/plugins/languageclient/languageclientplugin.cpp b/src/plugins/languageclient/languageclientplugin.cpp
index 83a1512253..985f00da1e 100644
--- a/src/plugins/languageclient/languageclientplugin.cpp
+++ b/src/plugins/languageclient/languageclientplugin.cpp
@@ -1,7 +1,7 @@
 // Copyright (C) 2018 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
-#include "callhierarchy.h"
+#include "callandtypehierarchy.h"
 #include "languageclientmanager.h"
 #include "languageclientoutline.h"
 #include "languageclientsettings.h"
@@ -43,6 +43,7 @@ void LanguageClientPlugin::initialize()
     using namespace Core;
 
     setupCallHierarchyFactory();
+    setupTypeHierarchyFactory();
     setupLanguageClientProjectPanel();
     setupLanguageClientManager(this);