QmlJS: Add check for duplicated import

Add a soft check for duplicated Qml/JS imports which
adds a warning when a file contains imports that
duplicate the same URI / version or file path.

Change-Id: Ib9a1f8a90dd3cf469d90e83abc1d748901b1e353
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

doc/src/editors/creator-code-syntax.qdoc

@@ -669,6 +669,11 @@
             \l{http://linterrors.com/js/the-array-literal-notation-is-preferrable}
             {The array literal notation [] is preferable}.
 
+    \row
+        \li M400
+        \li Warning
+        \li Duplicate import
+
     \endtable
 
     \section1 Resetting the Code Model

src/libs/qmljs/qmljscheck.cpp

@@ -764,6 +764,26 @@ bool Check::visit(UiProgram *)
     return true;
 }
 
+bool Check::visit(UiImport *ast)
+{
+    ShortImportInfo info;
+    if (auto ver = ast->version)
+        info.second = LanguageUtils::ComponentVersion(ver->majorVersion, ver->minorVersion);
+
+    if (!ast->fileName.isNull())  // it must be a file import
+        info.first = ast->fileName.toString();
+    else                          // no file import - construct full uri
+        info.first = toString(ast->importUri);
+
+    if (m_importInfo.contains(info)) {
+        SourceLocation location = ast->firstSourceLocation();
+        location.length = ast->lastSourceLocation().end();
+        addMessage(WarnDuplicateImport, location, info.first);
+    }
+    m_importInfo.append(info);
+    return true;
+}
+
 bool Check::visit(UiObjectInitializer *)
 {
     QString typeName;

src/libs/qmljs/qmljscheck.h

@@ -65,6 +65,7 @@ protected:
     void postVisit(AST::Node *ast) override;
 
     bool visit(AST::UiProgram *ast) override;
+    bool visit(AST::UiImport *ast) override;
     bool visit(AST::UiObjectDefinition *ast) override;
     bool visit(AST::UiObjectBinding *ast) override;
     bool visit(AST::UiScriptBinding *ast) override;
@@ -136,6 +137,9 @@ private:
     QStack<StringSet> m_propertyStack;
     QStack<QString> m_typeStack;
 
+    using ShortImportInfo = QPair<QString, LanguageUtils::ComponentVersion>;
+    QList<ShortImportInfo> m_importInfo;
+
     class MessageTypeAndSuppression
     {
     public:

src/libs/qmljs/qmljsstaticanalysismessage.cpp

@@ -240,6 +240,8 @@ StaticAnalysisMessages::StaticAnalysisMessages()
             tr("Referencing the parent of the root item is not supported in a Qt Quick UI form."));
     newMsg(StateCannotHaveChildItem, Error,
             tr("A State cannot have a child item (%1)."), 1);
+    newMsg(WarnDuplicateImport, Warning,
+           tr("Duplicate import (%1)."), 1);
 }
 
 } // anonymous namespace

src/libs/qmljs/qmljsstaticanalysismessage.h

@@ -43,7 +43,7 @@ enum Type
 {
     // Changing the numbers can break user code.
     // When adding a new check, also add it to the documentation, currently
-    // in creator-editors.qdoc.
+    // in creator-code-syntax.qdoc.
     UnknownType = 0,
     ErrInvalidEnumValue = 1,
     ErrEnumValueMustBeStringOrNumber = 2,
@@ -128,7 +128,8 @@ enum Type
     ErrInvalidStringValuePattern = 320,
     ErrLongerStringValueExpected = 321,
     ErrShorterStringValueExpected = 322,
-    ErrInvalidArrayValueLength = 323
+    ErrInvalidArrayValueLength = 323,
+    WarnDuplicateImport = 400
 };
 
 class QMLJS_EXPORT PrototypeMessageData {