diff --git a/src/plugins/clangcodemodel/clangdclient.cpp b/src/plugins/clangcodemodel/clangdclient.cpp
index 07e8956f0a0..48cb1bf13bd 100644
--- a/src/plugins/clangcodemodel/clangdclient.cpp
+++ b/src/plugins/clangcodemodel/clangdclient.cpp
@@ -2576,7 +2576,8 @@ static QList<BlockRange> cleanupDisabledCode(HighlightingResults &results, const
         }
 
         if (wasIfdefedOut && (it + 1 == results.end()
-                || (it + 1)->textStyles.mainStyle != C_DISABLED_CODE)) {
+                || (it + 1)->textStyles.mainStyle != C_DISABLED_CODE
+                || (it + 1)->line != it->line + 1)) {
             // The #else or #endif that ends disabled code should not be disabled.
             const QTextBlock block = doc->findBlockByNumber(it->line - 1);
             ifdefedOutRanges << BlockRange(rangeStartPos, block.position());
diff --git a/src/plugins/clangcodemodel/test/clangdtests.cpp b/src/plugins/clangcodemodel/test/clangdtests.cpp
index 36217ad8d76..6ed6163a6bd 100644
--- a/src/plugins/clangcodemodel/test/clangdtests.cpp
+++ b/src/plugins/clangcodemodel/test/clangdtests.cpp
@@ -675,6 +675,8 @@ void ClangdTestHighlighting::initTestCase()
 {
     ClangdTest::initTestCase();
 
+    connect(document("highlighting.cpp"), &TextDocument::ifdefedOutBlocksChanged, this,
+            [this](const QList<BlockRange> &ranges) { m_ifdefedOutBlocks = ranges; });
     QTimer timer;
     timer.setSingleShot(true);
     QEventLoop loop;
@@ -1380,6 +1382,17 @@ void ClangdTestHighlighting::test()
     QCOMPARE(result.kind, expectedKind);
 }
 
+void ClangdTestHighlighting::testIfdefedOutBlocks()
+{
+    QCOMPARE(m_ifdefedOutBlocks.size(), 3);
+    QCOMPARE(m_ifdefedOutBlocks.at(0).first(), 12033);
+    QCOMPARE(m_ifdefedOutBlocks.at(0).last(), 12050);
+    QCOMPARE(m_ifdefedOutBlocks.at(1).first(), 13351);
+    QCOMPARE(m_ifdefedOutBlocks.at(1).last(), 13364);
+    QCOMPARE(m_ifdefedOutBlocks.at(2).first(), 13390);
+    QCOMPARE(m_ifdefedOutBlocks.at(2).last(), 13402);
+}
+
 
 class Manipulator : public TextDocumentManipulatorInterface
 {
diff --git a/src/plugins/clangcodemodel/test/clangdtests.h b/src/plugins/clangcodemodel/test/clangdtests.h
index b6399a9c59f..66f41cfa156 100644
--- a/src/plugins/clangcodemodel/test/clangdtests.h
+++ b/src/plugins/clangcodemodel/test/clangdtests.h
@@ -27,6 +27,7 @@
 
 #include <cppeditor/cpptoolstestcase.h>
 #include <coreplugin/find/searchresultitem.h>
+#include <texteditor/blockrange.h>
 #include <texteditor/codeassist/genericproposal.h>
 #include <texteditor/semantichighlighter.h>
 #include <utils/fileutils.h>
@@ -141,9 +142,11 @@ private slots:
     void initTestCase() override;
     void test_data();
     void test();
+    void testIfdefedOutBlocks();
 
 private:
     TextEditor::HighlightingResults m_results;
+    QList<TextEditor::BlockRange> m_ifdefedOutBlocks;
 };
 
 class ClangdTestCompletion : public ClangdTest
diff --git a/src/plugins/clangcodemodel/test/data/highlighting/highlighting.cpp b/src/plugins/clangcodemodel/test/data/highlighting/highlighting.cpp
index 46112c2f136..7ebc39d433f 100644
--- a/src/plugins/clangcodemodel/test/data/highlighting/highlighting.cpp
+++ b/src/plugins/clangcodemodel/test/data/highlighting/highlighting.cpp
@@ -869,3 +869,14 @@ void constMemberAsFunctionArg()
         const Foo &constMember;
     };
 }
+
+# if 0
+#define FOO
+
+#endif
+
+// comment
+
+#if 0
+#define BAR
+# endif
diff --git a/src/plugins/texteditor/textdocument.cpp b/src/plugins/texteditor/textdocument.cpp
index 4376cc17398..696e4caf0a2 100644
--- a/src/plugins/texteditor/textdocument.cpp
+++ b/src/plugins/texteditor/textdocument.cpp
@@ -532,6 +532,10 @@ void TextDocument::setIfdefedOutBlocks(const QList<BlockRange> &blocks)
 
     if (needUpdate)
         documentLayout->requestUpdate();
+
+#ifdef WITH_TESTS
+    emit ifdefedOutBlocksChanged(blocks);
+#endif
 }
 
 const ExtraEncodingSettings &TextDocument::extraEncodingSettings() const
diff --git a/src/plugins/texteditor/textdocument.h b/src/plugins/texteditor/textdocument.h
index 71a9a120a6c..0385bb2463f 100644
--- a/src/plugins/texteditor/textdocument.h
+++ b/src/plugins/texteditor/textdocument.h
@@ -172,6 +172,10 @@ signals:
     void fontSettingsChanged();
     void markRemoved(TextMark *mark);
 
+#ifdef WITH_TESTS
+    void ifdefedOutBlocksChanged(const QList<BlockRange> &blocks);
+#endif
+
 protected:
     virtual void applyFontSettings();