3 files changed, 28 insertions, 18 deletions

diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index b6bc48c833..c7343e709c 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -501,6 +501,25 @@ bool IRBuilder::isSignalPropertyName(const QString &name)
     return false; // consists solely of underscores - invalid.
 }
 
+QString IRBuilder::signalNameFromSignalPropertyName(const QString &signalPropertyName)
+{
+    Q_ASSERT(signalPropertyName.startsWith(QLatin1String("on")));
+    QString signalNameCandidate = signalPropertyName;
+    signalNameCandidate.remove(0, 2);
+
+    // Note that the property name could start with any alpha or '_' or '$' character,
+    // so we need to do the lower-casing of the first alpha character.
+    for (int firstAlphaIndex = 0; firstAlphaIndex < signalNameCandidate.size(); ++firstAlphaIndex) {
+        if (signalNameCandidate.at(firstAlphaIndex).isUpper()) {
+            signalNameCandidate[firstAlphaIndex] = signalNameCandidate.at(firstAlphaIndex).toLower();
+            return signalNameCandidate;
+        }
+    }
+
+    Q_UNREACHABLE();
+    return QString();
+}
+
 bool IRBuilder::visit(QQmlJS::AST::UiArrayMemberList *ast)
 {
     return QQmlJS::AST::Visitor::visit(ast);
diff --git a/src/qml/compiler/qqmlirbuilder_p.h b/src/qml/compiler/qqmlirbuilder_p.h
index e755694335..99c1af6cbf 100644
--- a/src/qml/compiler/qqmlirbuilder_p.h
+++ b/src/qml/compiler/qqmlirbuilder_p.h
@@ -461,6 +461,7 @@ public:
     bool generateFromQml(const QString &code, const QString &url, Document *output);
 
     static bool isSignalPropertyName(const QString &name);
+    static QString signalNameFromSignalPropertyName(const QString &signalPropertyName);
 
     using QQmlJS::AST::Visitor::visit;
     using QQmlJS::AST::Visitor::endVisit;
diff --git a/src/qml/qml/qqmltypecompiler.cpp b/src/qml/qml/qqmltypecompiler.cpp
index f04272e5b9..3be3c6fc0e 100644
--- a/src/qml/qml/qqmltypecompiler.cpp
+++ b/src/qml/qml/qqmltypecompiler.cpp
@@ -356,30 +356,20 @@ bool SignalHandlerConverter::convertSignalHandlerExpressionsToFunctionDeclaratio
 
         QQmlPropertyResolver resolver(propertyCache);
 
-        Q_ASSERT(bindingPropertyName.startsWith(QLatin1String("on")));
-        QString signalNameCandidate = bindingPropertyName;
-        signalNameCandidate.remove(0, 2);
-
-        // Note that the property name could start with any alpha or '_' or '$' character,
-        // so we need to do the lower-casing of the first alpha character.
-        for (int firstAlphaIndex = 0; firstAlphaIndex < signalNameCandidate.size(); ++firstAlphaIndex) {
-            if (signalNameCandidate.at(firstAlphaIndex).isUpper()) {
-                signalNameCandidate[firstAlphaIndex] = signalNameCandidate.at(firstAlphaIndex).toLower();
-                break;
-            }
-        }
+        const QString signalName = QmlIR::IRBuilder::signalNameFromSignalPropertyName(
+                    bindingPropertyName);
 
         QString qPropertyName;
-        if (signalNameCandidate.endsWith(QLatin1String("Changed")))
-            qPropertyName = signalNameCandidate.mid(0, signalNameCandidate.length() - static_cast<int>(strlen("Changed")));
+        if (signalName.endsWith(QLatin1String("Changed")))
+            qPropertyName = signalName.mid(0, signalName.length() - static_cast<int>(strlen("Changed")));
 
         QList<QString> parameters;
 
         bool notInRevision = false;
-        QQmlPropertyData * const signal = resolver.signal(signalNameCandidate, &notInRevision);
-        QQmlPropertyData * const signalPropertyData = resolver.property(signalNameCandidate, /*notInRevision ptr*/nullptr);
+        QQmlPropertyData * const signal = resolver.signal(signalName, &notInRevision);
+        QQmlPropertyData * const signalPropertyData = resolver.property(signalName, /*notInRevision ptr*/nullptr);
         QQmlPropertyData * const qPropertyData = !qPropertyName.isEmpty() ? resolver.property(qPropertyName) : nullptr;
-        QString finalSignalHandlerPropertyName = signalNameCandidate;
+        QString finalSignalHandlerPropertyName = signalName;
         uint flags = QV4::CompiledData::Binding::IsSignalHandlerExpression;
 
         const bool isPropertyObserver = !signalPropertyData && qPropertyData && qPropertyData->isBindable();
@@ -439,7 +429,7 @@ bool SignalHandlerConverter::convertSignalHandlerExpressionsToFunctionDeclaratio
                 }
             }
 
-            QHash<QString, QStringList>::ConstIterator entry = customSignals.constFind(signalNameCandidate);
+            QHash<QString, QStringList>::ConstIterator entry = customSignals.constFind(signalName);
             if (entry == customSignals.constEnd() && !qPropertyName.isEmpty())
                 entry = customSignals.constFind(qPropertyName);