Index: src/script/data/indentation/cstyle.js
===================================================================
--- src/script/data/indentation/cstyle.js
+++ src/script/data/indentation/cstyle.js
@@ -514,6 +514,8 @@
                 if (currentString.search(/^\s*(if\b|[}]?\s*else|do\b|while\b|for)[^{]*$/) != -1)
                     indentation = firstPosVirtual;
                 break;
+            } else if (currentLine == 0 || lineDelimiter == 0) {
+                return indentation;
             }
         }
     }
Index: src/script/katecommandlinescript.cpp
===================================================================
--- src/script/katecommandlinescript.cpp
+++ src/script/katecommandlinescript.cpp
@@ -55,6 +55,7 @@
         errorMessage = i18n("Function '%1' not found in script: %2", cmd, url());
         return false;
     }
+    V4JITDisabler maybeDisableQMLJITCompiler;
 
     // add the arguments that we are going to pass to the function
     QJSValueList arguments;
@@ -123,6 +124,7 @@
     if (!helpFunction.isCallable()) {
         return false;
     }
+    V4JITDisabler maybeDisableQMLJITCompiler;
 
     // add the arguments that we are going to pass to the function
     QJSValueList arguments;
Index: src/script/kateindentscript.cpp
===================================================================
--- src/script/kateindentscript.cpp
+++ src/script/kateindentscript.cpp
@@ -69,6 +69,8 @@
     if (!indentFunction.isCallable()) {
         return qMakePair(-2, -2);
     }
+    V4JITDisabler maybeDisableQMLJITCompiler;
+
     // add the arguments that we are going to pass to the function
     QJSValueList arguments;
     arguments << QJSValue(position.line());
Index: src/script/katescript.h
===================================================================
--- src/script/katescript.h
+++ src/script/katescript.h
@@ -188,6 +188,23 @@
     /** Return the general header */
     KateScriptHeader &generalHeader();
 
+    /**
+     * Helper class to disable the JIT during its scope. Kate's scripts have been known
+     * to trigger a bug in JIT-compiled QML that would crash the application.
+     * Creating a V4JITDisabler instance disables the JIT in affected Qt versions, and
+     * restores the setting before going out of scope.
+     */
+    class V4JITDisabler
+    {
+    public:
+        V4JITDisabler();
+        ~V4JITDisabler();
+    private:
+        QByteArray m_cachedValue;
+        bool m_hasCache;
+        static bool s_infoPrinted;
+    };
+
 protected:
     /** Checks for exception and gives feedback on the console. */
     bool hasException(const QJSValue &object, const QString &file);
Index: src/script/katescript.cpp
===================================================================
--- src/script/katescript.cpp
+++ src/script/katescript.cpp
@@ -40,6 +40,43 @@
 
 //END
 
+KateScript::V4JITDisabler::V4JITDisabler()
+    : m_hasCache(false)
+{
+#if QT_VERSION < QT_VERSION_CHECK(5, 9, 1)
+    if (qEnvironmentVariableIsSet("QV4_FORCE_INTERPRETER")) {
+        m_cachedValue = qgetenv("QV4_FORCE_INTERPRETER");
+        m_hasCache = true;
+    }
+    // disable the JIT for this call as it may trigger a bug in QML
+    // that would crash the application. Crude but effective.
+    qputenv("QV4_FORCE_INTERPRETER", QByteArrayLiteral("1"));
+    qCDebug(LOG_KTE) << "QV4_FORCE_INTERPRETER set to" << qgetenv("QV4_FORCE_INTERPRETER");
+#endif
+}
+
+KateScript::V4JITDisabler::~V4JITDisabler()
+{
+#if QT_VERSION < QT_VERSION_CHECK(5, 9, 1)
+    if (m_hasCache) {
+        // restore
+        qputenv("QV4_FORCE_INTERPRETER", m_cachedValue);
+        qCWarning(LOG_KTE) << "QV4_FORCE_INTERPRETER reset to" << qgetenv("QV4_FORCE_INTERPRETER");
+    } else {
+        qunsetenv("QV4_FORCE_INTERPRETER");
+        qCDebug(LOG_KTE) << "QV4_FORCE_INTERPRETER unset";
+        if (!s_infoPrinted) {
+            QTextStream info(stderr);
+            info << i18n("Please disregard any warnings about JIT being disabled for QML; "
+                "this applies only to KTextEditor scripts.\n");
+            s_infoPrinted = true;
+        }
+    }
+#endif
+}
+
+bool KateScript::V4JITDisabler::s_infoPrinted = false;
+
 KateScript::KateScript(const QString &urlOrScript, enum InputType inputType)
     : m_loaded(false)
     , m_loadSuccessful(false)
@@ -118,6 +155,11 @@
     m_loaded = true;
     m_loadSuccessful = false; // here set to false, and at end of function to true
 
+    // disable the JIT for this call as it may trigger a bug in QML
+    // that would crash the application. V4JITDisabler disables the JIT
+    // in affected Qt versions, and restores it before exitting from this function.
+    V4JITDisabler maybeDisableQMLJITCompiler;
+
     // read the script file into memory
     QString source;
     if (m_inputType == InputURL) {
@@ -202,6 +244,7 @@
         qWarning() << "load of script failed:" << program;
         return QJSValue();
     }
+    V4JITDisabler maybeDisableQMLJITCompiler;
 
     // Wrap the arguments in a function to avoid poluting the global object
     QString programWithContext = QStringLiteral("function(") +
Index: src/script/katescripthelpers.cpp
===================================================================
--- src/script/katescripthelpers.cpp
+++ src/script/katescripthelpers.cpp
@@ -116,6 +116,7 @@
 {
     QStringList files;
     files << file;
+    KateScript::V4JITDisabler maybeDisableQMLJITCompiler;
     /**
      * just search for all given scripts and eval them
      */