diff --git a/src/libs/qmljs/qmljscheck.cpp b/src/libs/qmljs/qmljscheck.cpp
index c97fc10c55b..53796d0acdd 100644
--- a/src/libs/qmljs/qmljscheck.cpp
+++ b/src/libs/qmljs/qmljscheck.cpp
@@ -953,6 +953,13 @@ bool Check::visit(UiObjectBinding *ast)
         //addMessage(ErrBehavioursNotSupportedInQmlUi, locationFromRange(ast->firstSourceLocation(), ast->lastSourceLocation()));
     }
 
+    if (!m_typeStack.isEmpty() && m_typeStack.last() == "State"
+        && toString(ast->qualifiedId) == "when") {
+        addMessage(
+            ErrWhenConditionCannotBeObject,
+            locationFromRange(ast->firstSourceLocation(), ast->lastSourceLocation()));
+    }
+
     visitQmlObject(ast, ast->qualifiedTypeNameId, ast->initializer);
     return false;
 }
diff --git a/src/libs/qmljs/qmljsstaticanalysismessage.cpp b/src/libs/qmljs/qmljsstaticanalysismessage.cpp
index a58bf43765b..fc4579245db 100644
--- a/src/libs/qmljs/qmljsstaticanalysismessage.cpp
+++ b/src/libs/qmljs/qmljsstaticanalysismessage.cpp
@@ -238,6 +238,7 @@ StaticAnalysisMessages::StaticAnalysisMessages()
            Tr::tr("Do not reference the root item as alias."));
     newMsg(WarnAliasReferRootHierarchy, Warning,
            Tr::tr("Avoid referencing the root item in a hierarchy."));
+    newMsg(ErrWhenConditionCannotBeObject, Error, Tr::tr("When condtion cannot contain an object."));
 }
 
 } // anonymous namespace
diff --git a/src/libs/qmljs/qmljsstaticanalysismessage.h b/src/libs/qmljs/qmljsstaticanalysismessage.h
index 97dd95c5eb9..b26eab2bd25 100644
--- a/src/libs/qmljs/qmljsstaticanalysismessage.h
+++ b/src/libs/qmljs/qmljsstaticanalysismessage.h
@@ -113,7 +113,8 @@ enum Type {
     WarnComponentRequiresChildren = 327,
     WarnDuplicateImport = 400,
     ErrAliasReferRoot = 401,
-    WarnAliasReferRootHierarchy = 402
+    WarnAliasReferRootHierarchy = 402,
+    ErrWhenConditionCannotBeObject = 403,
 };
 
 class QMLJS_EXPORT PrototypeMessageData {