qmllint: Warn about too many or mismatched signal parameters

It's easy to mess this up when you transform your signal handlers into
functions.

Task-number: QTBUG-89943
Pick-to: 6.1
Change-Id: If35be2f6828a0e19aada19abb41d8135b0c6ab45
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

3 files changed, 33 insertions, 0 deletions

diff --git a/tests/auto/qml/qmllint/data/namedSignalParameters.qml b/tests/auto/qml/qmllint/data/namedSignalParameters.qml
new file mode 100644
index 0000000000..00746d5d83
--- /dev/null
+++ b/tests/auto/qml/qmllint/data/namedSignalParameters.qml
@@ -0,0 +1,15 @@
+import QtQuick 2.0
+Window {
+    width: 800
+    height: 600
+    visible: true
+    signal sig(string arg, int argarg)
+    signal sig2(int foo, bool bar)
+
+    onSig: function(argarg) {
+        print("SIG", argarg);
+    }
+
+    onSig2: (foo, bar)=> { sig(foo, bar); }
+}
+
diff --git a/tests/auto/qml/qmllint/data/tooManySignalParameters.qml b/tests/auto/qml/qmllint/data/tooManySignalParameters.qml
new file mode 100644
index 0000000000..f5d5977a99
--- /dev/null
+++ b/tests/auto/qml/qmllint/data/tooManySignalParameters.qml
@@ -0,0 +1,8 @@
+import QtQml
+QtObject {
+    signal sig(string arg, int argarg)
+    onSig: function(arg, b, c, d) {
+        print("SIG", arg, b, c, d);
+    }
+}
+
diff --git a/tests/auto/qml/qmllint/tst_qmllint.cpp b/tests/auto/qml/qmllint/tst_qmllint.cpp
index 6e2a41263e..fe6996d6d9 100644
--- a/tests/auto/qml/qmllint/tst_qmllint.cpp
+++ b/tests/auto/qml/qmllint/tst_qmllint.cpp
@@ -288,6 +288,16 @@ void TestQmllint::dirtyQmlCode_data()
             << QStringLiteral("Variable \"argq\" is used before its declaration at 5:9. "
                               "The declaration is at 6:13.")
             << QString();
+    QTest::newRow("SignalParameterMismatch")
+            << QStringLiteral("namedSignalParameters.qml")
+            << QStringLiteral("Parameter 1 to signal handler for \"onSig\" is called \"argarg\". "
+                              "The signal has a parameter of the same name in position 2.")
+            << QStringLiteral("onSig2");
+    QTest::newRow("TooManySignalParameters")
+            << QStringLiteral("tooManySignalParameters.qml")
+            << QStringLiteral("Signal handler for \"onSig\" has more formal parameters "
+                              "than the signal it handles.")
+            << QString();
 }
 
 void TestQmllint::dirtyQmlCode()