Clarify error message when using eval in signal handlers

Task-number: QTBUG-64024
Change-Id: If8f749ef9ec072928cb352ad7cd4dcf140b6ed53
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

2 files changed, 8 insertions, 6 deletions

diff --git a/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp b/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
index 6dc54a323e..48eb694167 100644
--- a/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
+++ b/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
@@ -253,7 +253,7 @@ void tst_qmlcachegen::errorOnArgumentsInSignalHandler()
 
     QByteArray errorOutput;
     QVERIFY(!generateCache(testFilePath, &errorOutput));
-    QVERIFY2(errorOutput.contains("error: The use of the arguments object in signal handlers is"), errorOutput);
+    QVERIFY2(errorOutput.contains("error: The use of eval() or the use of the arguments object in signal handlers is"), errorOutput);
 }
 
 void tst_qmlcachegen::aheadOfTimeCompilation()
diff --git a/tools/qmlcachegen/qmlcachegen.cpp b/tools/qmlcachegen/qmlcachegen.cpp
index adc9def590..8a2776e808 100644
--- a/tools/qmlcachegen/qmlcachegen.cpp
+++ b/tools/qmlcachegen/qmlcachegen.cpp
@@ -147,11 +147,13 @@ static bool checkArgumentsObjectUseInSignalHandlers(const QmlIR::Document &doc,
                 if (compiledFunction->column > 0)
                     error->message += QString::number(compiledFunction->column) + QLatin1Char(':');
 
-                error->message += QLatin1String(" error: The use of the arguments object in signal handlers is\n"
-                                                "not supported when compiling qml files ahead of time, because it may be ambiguous if\n"
-                                                "any signal parameter is called \"arguments\". Unfortunately we cannot distinguish\n"
-                                                "between it being a parameter or the JavaScript arguments object at this point.\n"
-                                                "Consider renaming the parameter of the signal if applicable.");
+                error->message += QLatin1String(" error: The use of eval() or the use of the arguments object in signal handlers is\n"
+                                                "not supported when compiling qml files ahead of time. That is because it's ambiguous if \n"
+                                                "any signal parameter is called \"arguments\". Similarly the string passed to eval might use\n"
+                                                "\"arguments\". Unfortunately we cannot distinguish between it being a parameter or the\n"
+                                                "JavaScript arguments object at this point.\n"
+                                                "Consider renaming the parameter of the signal if applicable or moving the code into a\n"
+                                                "helper function.");
                 return false;
             }
         }