QmlJS checks: Hint about extra parentheses.

Migrated from QtChecker.

Change-Id: I85f7dd039ac858b103dfe0af257f66031540c5de
Reviewed-on: http://codereview.qt-project.org/5969
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@nokia.com>

src/libs/qmljs/qmljscheck.cpp

@@ -525,6 +525,7 @@ Check::Check(Document::Ptr doc, const ContextPtr &context)
     disableMessage(HintDeclarationsShouldBeAtStartOfFunction);
     disableMessage(HintBinaryOperatorSpacing);
     disableMessage(HintOneStatementPerLine);
+    disableMessage(HintExtraParentheses);
 }
 
 Check::~Check()
@@ -1104,6 +1105,13 @@ void Check::checkBindingRhs(Statement *statement)
     addMessages(unreachableCheck(statement));
 }
 
+void Check::checkExtraParentheses(ExpressionNode *expression)
+{
+    if (NestedExpression *nested = cast<NestedExpression *>(expression)) {
+        addMessage(HintExtraParentheses, nested->lparenToken);
+    }
+}
+
 void Check::addMessages(const QList<Message> &messages)
 {
     foreach (const Message &msg, messages)
@@ -1199,6 +1207,30 @@ bool Check::visit(StatementList *ast)
     return true;
 }
 
+bool Check::visit(ReturnStatement *ast)
+{
+    checkExtraParentheses(ast->expression);
+    return true;
+}
+
+bool Check::visit(ThrowStatement *ast)
+{
+    checkExtraParentheses(ast->expression);
+    return true;
+}
+
+bool Check::visit(DeleteExpression *ast)
+{
+    checkExtraParentheses(ast->expression);
+    return true;
+}
+
+bool Check::visit(TypeOfExpression *ast)
+{
+    checkExtraParentheses(ast->expression);
+    return true;
+}
+
 /// When something is changed here, also change ReadingContext::lookupProperty in
 /// texttomodelmerger.cpp
 /// ### Maybe put this into the context as a helper method.

src/libs/qmljs/qmljscheck.h

@@ -96,6 +96,10 @@ protected:
     virtual bool visit(AST::NewMemberExpression *ast);
     virtual bool visit(AST::CallExpression *ast);
     virtual bool visit(AST::StatementList *ast);
+    virtual bool visit(AST::ReturnStatement *ast);
+    virtual bool visit(AST::ThrowStatement *ast);
+    virtual bool visit(AST::DeleteExpression *ast);
+    virtual bool visit(AST::TypeOfExpression *ast);
 
     virtual void endVisit(QmlJS::AST::UiObjectInitializer *);
 
@@ -108,6 +112,7 @@ private:
     void checkProperty(QmlJS::AST::UiQualifiedId *);
     void checkNewExpression(AST::ExpressionNode *node);
     void checkBindingRhs(AST::Statement *statement);
+    void checkExtraParentheses(AST::ExpressionNode *expression);
 
     void addMessages(const QList<StaticAnalysis::Message> &messages);
     void addMessage(const StaticAnalysis::Message &message);

src/libs/qmljs/qmljsstaticanalysismessage.cpp

@@ -150,9 +150,8 @@ StaticAnalysisMessages::StaticAnalysisMessages()
            tr("confusing minuses"));
     newMsg(HintDeclareVarsInOneLine, Hint,
            tr("declare all function vars on a single line"));
-    // unused
-//    newMsg(HintExtraParentheses, Hint,
-//           tr(""));
+    newMsg(HintExtraParentheses, Hint,
+           tr("unnecessary parentheses"));
     newMsg(MaybeWarnEqualityTypeCoercion, MaybeWarning,
            tr("== and != may perform type coercion, use === or !== to avoid"));
     newMsg(WarnConfusingExpressionStatement, Warning,