qmllint: implement .qml warnings from qmljsstaticanalysismessage.cpp

Implement warnings in qmlls from QtC's codemodel for .qml files:

 
done to be done in progress won't do
 

• UnknownType not in use as warning
• ErrInvalidEnumValue
• ErrEnumValueMustBeStringOrNumber (Already covered by current parser)
  • complains about enum values (not keys)
• ErrNumberValueExpected (Already covered by qmllint)
  • complains about binding to properties expecting a number type
• ErrBooleanValueExpected (Already covered by qmllint)
  • complains about binding to properties expecting a boolean type
• ErrStringValueExpected (Already covered by qmllint)
  • complains about binding to properties expecting a string type
• ErrInvalidUrl (Already covered by qmllint)
  • is never triggered by QtC
  • seems to have complained in the past about binding to properties expecting an url type
• WarnFileOrDirectoryDoesNotExist
  • is never triggered by QtC
  • seems to have complained in the past about paths not existing locally
• ErrInvalidColor
  • uses the predecessor of "QColor::isValidColorName" to check the string value
• ErrAnchorLineExpected (Already covered by qmllint)
  • seems to have complained in the past about bindings to anchor lines
• ErrPropertiesCanOnlyHaveOneBinding Covered by QTBUG-118148.
• ErrIdExpected (Already covered by qmllint)
  • complains about ids not being strings or identifiers
• ErrInvalidId
  • complains about ids starting with an upper case letter
• ErrDuplicateId (Already covered by qmllint)
  • complains for ids already used in the document
• ErrInvalidPropertyName (Already covered by qmllint)
  • complains about properties that don't exist
• ErrDoesNotHaveMembers (Already covered by qmllint)
  • complains about member accesses "notAnObject.member" on non-objects
• ErrInvalidMember (Already covered by qmllint)
  • complains about member accesses on non-existing members "object.notAMember"
• WarnAssignmentInCondition
  • complains about if (x = 3), to avoid mismatches between = and ==
• WarnCaseWithoutFlowControl
  • complains about case statements that don't break/continue/return and also don't have a "fall through", "fall-through" or "fallthrough" comment
• WarnEval
  • complains of the usage of the eval function
• WarnUnreachable
  • complains about unreachable code (behind return statements for example)
• WarnWith (Already covered by qmllint)
  • complains about usage of "with" statements
• WarnComma
  • complains about the usage of "," comma expressions, except when inside a for-loop
• WarnUnnecessaryMessageSuppression (Not sure if really needed)
  • warn about comments that suppress warnings that actually don't suppress warnings, for example the eval warning is M23, but trying to suppress M25 (an unrelated warning) leads to WarnUnnecessaryMessageSuppression:

    // @disable-check M25
    eval("asdf")
    // @enable-check M25
    

  • maybe we should warn about qmllint comments that don't do anything? For example

    property string foo
    Item {
        property string bar: foo // qmllint disable syntax // this does not suppress any warning
    }
    

• WarnAlreadyFormalParameter
  • when trying to redeclarae a parameter of a function:

    function f(a) {
        const a = 3; // a already is a formal parameter
    }
    

• WarnAlreadyFunction
  • when trying to redeclare a function:

    function f() {
        function fff() {}
        const fff = 3
    }
    

• WarnVarUsedBeforeDeclaration (Already covered by qmllint)
• WarnAlreadyVar

  const fff = 123
  function fff(a,a,a) {} // already a var, can't be a function
  

• WarnDuplicateDeclaration same as QTBUG-127107
• WarnFunctionUsedBeforeDeclaration

  fff(a,a,a) // used before declaration
  function fff(a,a,a) {} 
  

• WarnBooleanConstructor
  • complains about new Boolean() usages
• WarnStringConstructor
  • complains about new String() usages
• WarnObjectConstructor (it seems that the linked explanation at https://doc.qt.io/qtcreator/creator-reference-js-and-qml-error-codes.html#javascript-and-qml-error-codes that points to https://github.com/jamesallardice/jslint-error-explanations/blob/master/message-articles/bad-constructor.md, https://github.com/jamesallardice/jslint-error-explanations/blob/master/message-articles/literal-constructor.md and https://github.com/jamesallardice/jslint-error-explanations/blob/master/message-articles/function-constructor.md does not seem to mention Object constructors
  • complains about new Object() usages
• WarnArrayConstructor
  • complains about new Array() usages
• WarnFunctionConstructor
  • complains about new Function() usages
• HintAnonymousFunctionSpacing (is disabled by default)
  • complains about function() I think, where the space is missing between function and ()
• WarnBlock
  • complains about blocks inside of JS code that contains a var-declaration

    {
        var xxx = 4
    }
    

• WarnVoid
  • complains about using void expressions

     void 5
    

• WarnConfusingPluses
  • warns about "+ +" and "- -", like:

    var xxx = 4 + ++x + // here once for `+ ++`
    x++ + 3 // here once of `++ +`
    

• WarnConfusingMinuses
  • see above
• HintDeclareVarsInOneLine (disabled by default + warning is never emitted)
• HintExtraParentheses (disabled by default)
  • complains about nested expressions inside of DeleteExpression, ThrowStatement, ReturnStatement and TypeOfExpression
• MaybeWarnEqualityTypeCoercion
  • complain about == and Unable to render embedded object: File ( they should be {{===}} and {{) not found.==
• WarnConfusingExpressionStatement
  • complains about expression statements without side-effects (like {{ 1 + 2; }} for example)
• StateCannotHaveChildItem
  • complains about children in States

    State {
        property var i: Item {}
    }
    

• ErrTypeIsInstantiatedRecursively
  • complain about

    // Main.qml
    import QtQuick
    Item { Main{} }
    

  • the QML engine complains about Main is instantiated recursively at runtime
• HintDeclarationsShouldBeAtStartOfFunction (disabled by default)
• HintOneStatementPerLine (disabled by default)
• ErrUnknownComponent (qmllint already complains about unresolved types)
• ErrCouldNotResolvePrototypeOf (qmllint already complains about unresolved base types)
• ErrCouldNotResolvePrototype (qmllint already complains about unresolved base types)
  • same as ErrCouldNotResolvePrototypeOf but for types without names
• ErrPrototypeCycle (qmllint already complains about cyclic inheritances)
• ErrInvalidPropertyType (not in use by Qt Creator)
• WarnEqualityTypeCoercion (not in use by Qt Creator)
  • to not be confused with MaybeWarnEqualityTypeCoercion
• WarnExpectedNewWithUppercaseFunction
  • complains about property var x: MyObject() (with "new" being missing)
• WarnNewWithLowercaseFunction
  • complains about property var x: new date() (with "date" being lowercase)
• WarnNumberConstructor
  • complains about using new Number, like property var x: new Number();
• HintBinaryOperatorSpacing (disabled by default)
• WarnUnintentinalEmptyBlock
  • complains about empty blocks like property var x: {}
• HintPreferNonVarPropertyType
  • complains about using "var" for certain types, like strings in property var x: "asfd" for example
• ErrMissingRequiredProperty (qmllint already complains about required properties not being bound/set)
• ErrObjectValueExpected (Unused in QtC)
• ErrArrayValueExpected (Unused in QtC)
• ErrDifferentValueExpected (Unused in QtC for qml, only used in the json linter)
• ErrSmallerNumberValueExpected (Unused in QtC for qml, only used in the json linter)
• ErrLargerNumberValueExpected (Unused in QtC for qml, only used in the json linter)
• ErrMaximumNumberValueIsExclusive (Unused in QtC for qml, only used in the json linter)
• ErrMinimumNumberValueIsExclusive (Unused in QtC for qml, only used in the json linter)
• ErrInvalidStringValuePattern (Unused in QtC for qml, only used in the json linter)
• ErrLongerStringValueExpected (Unused in QtC for qml, only used in the json linter)
• ErrShorterStringValueExpected (Unused in QtC for qml, only used in the json linter)
• ErrInvalidArrayValueLength (Unused in QtC for qml, only used in the json linter)
• ErrHitMaximumRecursion (qmllint already complains about too much recursion)
• ErrToManyComponentChildren
  • complains about components with more than one child: Component {Item{} Item {}}
• WarnComponentRequiresChildren
  • complains about components with no child: Component {}
• WarnDuplicateImport
  • complains about:

    import QtQuick
    import QtQuick
    Item {}
    

• ErrAliasReferRoot
  • see also https://codereview.qt-project.org/c/qt-creator/qt-creator/+/390841
• WarnAliasReferRootHierarchy
  • see also https://codereview.qt-project.org/c/qt-creator/qt-creator/+/390841

Also, you can find all qtc codemodel warnings in qmljsstaticanalysismessage.cpp's StaticAnalysisMessages::StaticAnalysisMessages() and qmljsstaticanalysismessage.h definition of Type enum (each enum value corresponds to a warning, see also their description in the StaticAnalysisMessages::StaticAnalysisMessages() constructor!)