QmlJS checks: Add hint about not using multiple statements per line.

Migrated from QtChecker.

Change-Id: Ia76067a5f0e443a61a7b78ca9081f5a1bb51b471
Reviewed-on: http://codereview.qt-project.org/5861
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@nokia.com>

src/libs/qmljs/qmljscheck.cpp

@@ -519,6 +519,7 @@ Check::Check(Document::Ptr doc, const ContextPtr &context)
     disableMessage(HintDeclareVarsInOneLine);
     disableMessage(HintDeclarationsShouldBeAtStartOfFunction);
     disableMessage(HintBinaryOperatorSpacing);
+    disableMessage(HintOneStatementPerLine);
 }
 
 Check::~Check()
@@ -1165,6 +1166,32 @@ bool Check::visit(CallExpression *ast)
     return true;
 }
 
+bool Check::visit(StatementList *ast)
+{
+    SourceLocation warnStart;
+    SourceLocation warnEnd;
+    unsigned currentLine = 0;
+    for (StatementList *it = ast; it; it = it->next) {
+        if (!it->statement)
+            continue;
+        const SourceLocation itLoc = it->statement->firstSourceLocation();
+        if (itLoc.startLine != currentLine) { // first statement on a line
+            if (warnStart.isValid())
+                addMessage(HintOneStatementPerLine, locationFromRange(warnStart, warnEnd));
+            warnStart = SourceLocation();
+            currentLine = itLoc.startLine;
+        } else { // other statements on the same line
+            if (!warnStart.isValid())
+                warnStart = itLoc;
+            warnEnd = it->statement->lastSourceLocation();
+        }
+    }
+    if (warnStart.isValid())
+        addMessage(HintOneStatementPerLine, locationFromRange(warnStart, warnEnd));
+
+    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

@@ -95,6 +95,7 @@ protected:
     virtual bool visit(AST::NewExpression *ast);
     virtual bool visit(AST::NewMemberExpression *ast);
     virtual bool visit(AST::CallExpression *ast);
+    virtual bool visit(AST::StatementList *ast);
 
     virtual void endVisit(QmlJS::AST::UiObjectInitializer *);