diff --git a/messagecomposer/src/attachment/attachmentmodel.h b/messagecomposer/src/attachment/attachmentmodel.h
--- a/messagecomposer/src/attachment/attachmentmodel.h
+++ b/messagecomposer/src/attachment/attachmentmodel.h
@@ -94,7 +94,7 @@
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
     Q_REQUIRED_RESULT bool setData(const QModelIndex &index, const QVariant &value, int role = Qt::EditRole) override;
 
-    Q_REQUIRED_RESULT bool addAttachment(const MessageCore::AttachmentPart::Ptr &part);
+    void addAttachment(const MessageCore::AttachmentPart::Ptr &part);
     Q_REQUIRED_RESULT bool updateAttachment(const MessageCore::AttachmentPart::Ptr &part);
     Q_REQUIRED_RESULT bool replaceAttachment(const MessageCore::AttachmentPart::Ptr &oldPart, const MessageCore::AttachmentPart::Ptr &newPart);
     Q_REQUIRED_RESULT bool removeAttachment(const MessageCore::AttachmentPart::Ptr &part);
diff --git a/messagecomposer/src/attachment/attachmentmodel.cpp b/messagecomposer/src/attachment/attachmentmodel.cpp
--- a/messagecomposer/src/attachment/attachmentmodel.cpp
+++ b/messagecomposer/src/attachment/attachmentmodel.cpp
@@ -369,19 +369,18 @@
     return true;
 }
 
-bool AttachmentModel::addAttachment(const AttachmentPart::Ptr &part)
+void AttachmentModel::addAttachment(const AttachmentPart::Ptr &part)
 {
     Q_ASSERT(!d->parts.contains(part));
     for (const AttachmentPart::Ptr &partElement : qAsConst(d->parts)) {
         if (partElement->url() == part->url()) {
-            return true;
+            return;
         }
     }
 
     beginInsertRows(QModelIndex(), rowCount(), rowCount());
     d->parts.append(part);
     endInsertRows();
-    return true;
 }
 
 bool AttachmentModel::updateAttachment(const AttachmentPart::Ptr &part)
diff --git a/messagecomposer/src/composer-ng/autotests/richtextcomposersignaturestest.cpp b/messagecomposer/src/composer-ng/autotests/richtextcomposersignaturestest.cpp
--- a/messagecomposer/src/composer-ng/autotests/richtextcomposersignaturestest.cpp
+++ b/messagecomposer/src/composer-ng/autotests/richtextcomposersignaturestest.cpp
@@ -50,12 +50,12 @@
     richtextComposerNg.insertSignature(signature1, KIdentityManagement::Signature::Start, KIdentityManagement::Signature::AddNewLines);
     composerSignature->cleanWhitespace(signature2);
 
-    composerSignature->replaceSignature(signature1, signature2);
+    QVERIFY( !composerSignature->replaceSignature(signature1, signature2));
     QCOMPARE(richtextComposerNg.toPlainText(), QStringLiteral("\n\nbla Bla "));
 
     for (int i = 0; i < 10; i++) {
-        composerSignature->replaceSignature(signature2, signature1);
-        composerSignature->replaceSignature(signature1, signature2);
+        QVERIFY( !composerSignature->replaceSignature(signature2, signature1));
+        QVERIFY( !composerSignature->replaceSignature(signature1, signature2));
     }
     QCOMPARE(richtextComposerNg.toPlainText(), QStringLiteral("\n\nbla Bla "));
 }
@@ -81,13 +81,13 @@
     richtextComposerNg.insertSignature(signature1, KIdentityManagement::Signature::End, KIdentityManagement::Signature::AddSeparator);
     composerSignature->cleanWhitespace(signature2);
 
-    composerSignature->replaceSignature(signature1, signature2);
+    QVERIFY( !composerSignature->replaceSignature(signature1, signature2));
     const QString result = QStringLiteral("foo\nbla\nfoo--\nbla Bla ");
     QCOMPARE(richtextComposerNg.toPlainText(), result);
 
     for (int i = 0; i < 10; i++) {
-        composerSignature->replaceSignature(signature2, signature1);
-        composerSignature->replaceSignature(signature1, signature2);
+        QVERIFY( !composerSignature->replaceSignature(signature2, signature1));
+        QVERIFY( !composerSignature->replaceSignature(signature1, signature2));
     }
     QCOMPARE(richtextComposerNg.toPlainText(), result);
 }
diff --git a/messagelist/src/core/item.h b/messagelist/src/core/item.h
--- a/messagelist/src/core/item.h
+++ b/messagelist/src/core/item.h
@@ -382,7 +382,7 @@
     * Appends an Item to this item's child list.
     * The Model is used for beginInsertRows()/endInsertRows() calls.
     */
-    Q_REQUIRED_RESULT int appendChildItem(Model *model, Item *child);
+    int appendChildItem(Model *model, Item *child);
 
     /**
     * Appends a child item without inserting it via the model.