QmlCompiler: Don't warn for ValueTypeBehavior: Assertable

We don't use the attribute so far, but we should certainly welcome its
usage.

Pick-to: 6.8
Fixes: QTBUG-144585
Change-Id: Iaa69c9401d411a4ad986d4c46ace0bad049b9881
Reviewed-by: Olivier De Cannière <olivier.decanniere@qt.io>
(cherry picked from commit 9c8a2dab276a10064bd4ac608b5ba886fc492558)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 0fe39fca4edee70b90726090bfe0d986b834ba07)

5 files changed, 83 insertions, 0 deletions

diff --git a/src/qmlcompiler/qqmljsimportvisitor.cpp b/src/qmlcompiler/qqmljsimportvisitor.cpp
index 86f38bd9d7..4552960b19 100644
--- a/src/qmlcompiler/qqmljsimportvisitor.cpp
+++ b/src/qmlcompiler/qqmljsimportvisitor.cpp
@@ -2917,6 +2917,10 @@ bool QQmlJSImportVisitor::visit(QQmlJS::AST::UiPragma *pragma)
                 m_scopesById.setValueTypesAreAddressable(true);
             } else if (value == u"Inaddressable") {
                 m_scopesById.setValueTypesAreAddressable(false);
+            } else if (value == u"Assertable") {
+                m_scopesById.setValueTypesAreAssertable(true);
+            } else if (value == u"Inassertable") {
+                m_scopesById.setValueTypesAreAssertable(false);
             } else {
                 m_logger->log(u"Unknown argument \"%1\" to pragma ValueTypeBehavior"_s.arg(value),
                               qmlSyntax, pragma->firstSourceLocation());
diff --git a/src/qmlcompiler/qqmljsscopesbyid_p.h b/src/qmlcompiler/qqmljsscopesbyid_p.h
index 2f17f0c95d..b28dd8fb99 100644
--- a/src/qmlcompiler/qqmljsscopesbyid_p.h
+++ b/src/qmlcompiler/qqmljsscopesbyid_p.h
@@ -78,6 +78,9 @@ public:
     void setValueTypesAreAddressable(bool addressable) { m_valueTypesAreAddressable = addressable; }
     bool valueTypesAreAddressable() const { return m_valueTypesAreAddressable; }
 
+    void setValueTypesAreAssertable(bool assertable) { m_valueTypesAreAssertable = assertable; }
+    bool valueTypesAreAssertable() const { return m_valueTypesAreAssertable; }
+
     /*!
         \internal
         Find the possible IDs for \a scope as seen by \a referrer. There can be at most one
@@ -315,6 +318,7 @@ private:
     bool m_componentsAreBound = false;
     bool m_signaturesAreEnforced = true;
     bool m_valueTypesAreAddressable = false;
+    bool m_valueTypesAreAssertable = false;
 };
 
 QT_END_NAMESPACE
diff --git a/tests/auto/qml/qmllint/data/asCast.qml b/tests/auto/qml/qmllint/data/asCast.qml
new file mode 100644
index 0000000000..c6201aa6f8
--- /dev/null
+++ b/tests/auto/qml/qmllint/data/asCast.qml
@@ -0,0 +1,41 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+
+pragma Strict
+pragma ValueTypeBehavior: Assertable
+
+import QtQuick
+import QtQml as QQ
+
+Item {
+    QtObject { id: object }
+    Item { id: item }
+    Rectangle { id: rectangle }
+
+    property string string: "a"
+    property url url: "http://example.com"
+    property date date: new Date(1996, 2, 3)
+
+    property QtObject objectAsObject: object as QtObject
+    property QtObject objectAsItem: object as Item
+    property QtObject objectAsRectangle: object as Rectangle
+
+    property QtObject itemAsObject: item as QtObject
+    property QtObject itemAsItem: item as Item
+    property QtObject itemAsRectangle: item as Rectangle
+
+    property QtObject rectangleAsObject: rectangle as QtObject
+    property QtObject rectangleAsItem: rectangle as Item
+    property QtObject rectangleAsRectangle: rectangle as Rectangle
+
+    property QtObject nullAsObject: null as QtObject
+    property QtObject nullAsItem: null as Item
+    property QtObject nullAsRectangle: null as Rectangle
+
+    property QtObject undefinedAsObject: undefined as QtObject
+    property QtObject undefinedAsItem: undefined as Item
+    property QtObject undefinedAsRectangle: undefined as Rectangle
+
+    property var stringAsString: string as QQ.string
+    property var urlAsUrl: url as QQ.url
+    property var dateAsDate: date as QQ.date
+}
diff --git a/tests/auto/qml/qmllint/data/asValueTypeGood.qml b/tests/auto/qml/qmllint/data/asValueTypeGood.qml
new file mode 100644
index 0000000000..c5441ca09d
--- /dev/null
+++ b/tests/auto/qml/qmllint/data/asValueTypeGood.qml
@@ -0,0 +1,32 @@
+pragma ValueTypeBehavior: Assertable
+import QtQml as Q
+
+Q.QtObject {
+    property var a
+    property rect b: a as Q.rect
+    property bool c: a instanceof Q.rect
+    property bool d: ({x: 10, y: 20}) instanceof Q.point
+    property var e: ({x: 10, y: 20}) as Q.point
+    property var g: "green" as Q.string
+
+    property var i: {
+        let p = new Q.point;
+        p.x = 10
+        p.y = 20
+        return p
+    }
+
+    property var j: 4.0 as Q.int
+    property var k: (4.5 / 1.5) as Q.int
+    property var l: 5 as Q.double
+    property var m: "something" as Q.var
+    property var n: 1 as Q.bool
+    property var o: Infinity as Q.int
+
+    property var p: b as Q.size;
+    property var q: this as Q.size;
+    property var r: ({}) as Q.size;
+    property var s: 11 as Q.size;
+    property var t: Q.Component as Q.size;
+    property var u: Q.Qt as Q.size;
+}
diff --git a/tests/auto/qml/qmllint/tst_qmllint.cpp b/tests/auto/qml/qmllint/tst_qmllint.cpp
index b9ab17d35a..aef02664fa 100644
--- a/tests/auto/qml/qmllint/tst_qmllint.cpp
+++ b/tests/auto/qml/qmllint/tst_qmllint.cpp
@@ -2193,6 +2193,8 @@ void TestQmllint::cleanQmlCode_data()
             << QStringLiteral("aliasToRequiredPropertyIsNotRequiredItself.qml");
     QTest::newRow("anchors1") << QStringLiteral("anchors1.qml");
     QTest::newRow("anchors2") << QStringLiteral("anchors2.qml");
+    QTest::newRow("asCast") << QStringLiteral("asCast.qml");
+    QTest::newRow("asValueTypeGood") << QStringLiteral("asValueTypeGood.qml");
     QTest::newRow("attached") << QStringLiteral("attached.qml");
     QTest::newRow("attachedImportUse") << QStringLiteral("attachedImportUse.qml");
     QTest::newRow("attachedPropertyAssignments")