Clang: Add semantic C++ operator-token styling

We used to style overloaded operators in the same way
as C++'s built-in operators. There was no way to tell
if a + token would call a operator+() function or not.

Now, if an operator is overloaded (redefined),
we give it the "Overloaded Operator"-mixin so users
can style it differently.

Note: Calls to overloaded 'new' and 'delete' are not
highlighted by "Overloaded Operator". This is because
clang today always maps these to CXCursor_CXXNewExpr
and CXCursor_CXXDeleteExpr with cursor.spelling == ""
(empty string). So there is no (?) quick way for us
to tell if a new/delete-token was overloaded or not.

After follow-ups, follow symbol will work for operator
overload usages in current translation unit.
Commit is appended by Ivan Donchevskii.

Task-number: QTCREATORBUG-19659
Change-Id: I157855d482a61ad2059642a1ee982089fcb7d312
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

15 files changed, 518 insertions, 74 deletions

diff --git a/src/libs/clangsupport/clangsupport_global.h b/src/libs/clangsupport/clangsupport_global.h
index 03f4528ee9..8c5b5f57b8 100644
--- a/src/libs/clangsupport/clangsupport_global.h
+++ b/src/libs/clangsupport/clangsupport_global.h
@@ -82,6 +82,7 @@ enum class HighlightingType : quint8
     GlobalVariable,
     Enumeration,
     Operator,
+    OverloadedOperator,
     Preprocessor,
     PreprocessorDefinition,
     PreprocessorExpansion,
diff --git a/src/libs/clangsupport/tokeninfocontainer.cpp b/src/libs/clangsupport/tokeninfocontainer.cpp
index 01485ce66a..157f93746c 100644
--- a/src/libs/clangsupport/tokeninfocontainer.cpp
+++ b/src/libs/clangsupport/tokeninfocontainer.cpp
@@ -46,6 +46,7 @@ static const char *highlightingTypeToCStringLiteral(HighlightingType type)
         RETURN_TEXT_FOR_CASE(Field);
         RETURN_TEXT_FOR_CASE(Enumeration);
         RETURN_TEXT_FOR_CASE(Operator);
+        RETURN_TEXT_FOR_CASE(OverloadedOperator);
         RETURN_TEXT_FOR_CASE(Preprocessor);
         RETURN_TEXT_FOR_CASE(Label);
         RETURN_TEXT_FOR_CASE(FunctionDefinition);
@@ -67,6 +68,8 @@ static const char *highlightingTypeToCStringLiteral(HighlightingType type)
         RETURN_TEXT_FOR_CASE(ObjectiveCImplementation);
         RETURN_TEXT_FOR_CASE(ObjectiveCProperty);
         RETURN_TEXT_FOR_CASE(ObjectiveCMethod);
+        RETURN_TEXT_FOR_CASE(PrimitiveType);
+        RETURN_TEXT_FOR_CASE(Declaration);
         default: return "UnhandledHighlightingType";
     }
 }
diff --git a/src/plugins/clangcodemodel/clanghighlightingresultreporter.cpp b/src/plugins/clangcodemodel/clanghighlightingresultreporter.cpp
index 54a3a39488..ef1b905a8d 100644
--- a/src/plugins/clangcodemodel/clanghighlightingresultreporter.cpp
+++ b/src/plugins/clangcodemodel/clanghighlightingresultreporter.cpp
@@ -70,6 +70,8 @@ TextEditor::TextStyle toTextStyle(ClangBackEnd::HighlightingType type)
         return TextEditor::C_OUTPUT_ARGUMENT;
     case HighlightingType::Operator:
         return TextEditor::C_OPERATOR;
+    case HighlightingType::OverloadedOperator:
+        return TextEditor::C_OVERLOADED_OPERATOR;
     case HighlightingType::Comment:
         return TextEditor::C_COMMENT;
     case HighlightingType::StringLiteral:
diff --git a/src/plugins/clangcodemodel/clangutils.cpp b/src/plugins/clangcodemodel/clangutils.cpp
index 799bc99e88..0b82c90f00 100644
--- a/src/plugins/clangcodemodel/clangutils.cpp
+++ b/src/plugins/clangcodemodel/clangutils.cpp
@@ -255,7 +255,8 @@ CPlusPlus::Icons::IconType iconTypeForToken(const ClangBackEnd::TokenInfoContain
 
     ClangBackEnd::StorageClass storageClass = extraInfo.storageClass;
     if (mainType == ClangBackEnd::HighlightingType::VirtualFunction
-            || mainType == ClangBackEnd::HighlightingType::Function) {
+            || mainType == ClangBackEnd::HighlightingType::Function
+            || mainType == ClangBackEnd::HighlightingType::Operator) {
         if (storageClass != ClangBackEnd::StorageClass::Static) {
             switch (access) {
             case ClangBackEnd::AccessSpecifier::Public:
diff --git a/src/plugins/texteditor/texteditorconstants.cpp b/src/plugins/texteditor/texteditorconstants.cpp
index 0715275be5..4e2f0e9d9d 100644
--- a/src/plugins/texteditor/texteditorconstants.cpp
+++ b/src/plugins/texteditor/texteditorconstants.cpp
@@ -63,6 +63,7 @@ const char *nameForStyle(TextStyle style)
     case C_KEYWORD:             return "Keyword";
     case C_PRIMITIVE_TYPE:      return "PrimitiveType";
     case C_OPERATOR:            return "Operator";
+    case C_OVERLOADED_OPERATOR: return "Overloaded Operator";
     case C_PREPROCESSOR:        return "Preprocessor";
     case C_LABEL:               return "Label";
     case C_COMMENT:             return "Comment";
diff --git a/src/plugins/texteditor/texteditorconstants.h b/src/plugins/texteditor/texteditorconstants.h
index 3101912e35..504a6d8ea2 100644
--- a/src/plugins/texteditor/texteditorconstants.h
+++ b/src/plugins/texteditor/texteditorconstants.h
@@ -59,6 +59,7 @@ enum TextStyle : quint8 {
     C_KEYWORD,
     C_PRIMITIVE_TYPE,
     C_OPERATOR,
+    C_OVERLOADED_OPERATOR,
     C_PREPROCESSOR,
     C_LABEL,
     C_COMMENT,
diff --git a/src/plugins/texteditor/texteditorsettings.cpp b/src/plugins/texteditor/texteditorsettings.cpp
index 9ab2bfb98b..64a618f6fb 100644
--- a/src/plugins/texteditor/texteditorsettings.cpp
+++ b/src/plugins/texteditor/texteditorsettings.cpp
@@ -226,7 +226,8 @@ TextEditorSettings::TextEditorSettings()
                              tr("Reserved keywords of the programming language except "
                                 "keywords denoting primitive types."), Qt::darkYellow);
     formatDescr.emplace_back(C_OPERATOR, tr("Operator"),
-                             tr("Operators (for example operator++ or operator-=)."));
+                             tr("Non user-defined language operators.\n"
+                                "To style user-defined operators, use Overloaded Operator."));
     formatDescr.emplace_back(C_PREPROCESSOR, tr("Preprocessor"),
                              tr("Preprocessor directives."), Qt::darkBlue);
     formatDescr.emplace_back(C_LABEL, tr("Label"), tr("Labels for goto statements."),
@@ -313,6 +314,10 @@ TextEditorSettings::TextEditorSettings()
                              QColor(255, 190, 0),
                              QTextCharFormat::DotLine,
                              FormatDescription::ShowUnderlineControl);
+    formatDescr.emplace_back(C_OVERLOADED_OPERATOR,
+                             tr("Overloaded Operators"),
+                             tr("Calls and declarations of overloaded (user-defined) operators."),
+                             Format::createMixinFormat());
     Format declarationFormat = Format::createMixinFormat();
     declarationFormat.setBold(true);
     formatDescr.emplace_back(C_DECLARATION,
diff --git a/src/tools/clangbackend/source/clangstring.h b/src/tools/clangbackend/source/clangstring.h
index 685055cff0..ad8373c837 100644
--- a/src/tools/clangbackend/source/clangstring.h
+++ b/src/tools/clangbackend/source/clangstring.h
@@ -91,6 +91,11 @@ public:
         return !isNull() && std::strlen(cString()) > 0;
     }
 
+    bool startsWith(const char* str) const
+    {
+        return std::strncmp(cString(), str, strlen(str)) == 0;
+    }
+
     friend bool operator==(const ClangString &first, const ClangString &second)
     {
         return std::strcmp(first.cString(), second.cString()) == 0;
@@ -107,6 +112,7 @@ public:
     {
         return second == first;
     }
+
     template<typename Type,
              typename = typename std::enable_if<std::is_pointer<Type>::value>::type
              >
@@ -123,6 +129,39 @@ public:
         return second == first;
     }
 
+    friend bool operator!=(const ClangString &first, const ClangString &second)
+    {
+        return !(first == second);
+    }
+
+    template<std::size_t Size>
+    friend bool operator!=(const ClangString &first, const char(&second)[Size])
+    {
+        return !(first == second);
+    }
+
+    template<std::size_t Size>
+    friend bool operator!=(const char(&first)[Size], const ClangString &second)
+    {
+        return second != first;
+    }
+
+    template<typename Type,
+             typename = typename std::enable_if<std::is_pointer<Type>::value>::type
+             >
+    friend bool operator!=(const ClangString &first, Type second)
+    {
+        return !(first == second);
+    }
+
+    template<typename Type,
+             typename = typename std::enable_if<std::is_pointer<Type>::value>::type
+             >
+    friend bool operator!=(Type first, const ClangString &second)
+    {
+        return !(first == second);
+    }
+
     friend std::ostream &operator<<(std::ostream &os, const ClangString &string)
     {
         return os << string.cString();
diff --git a/src/tools/clangbackend/source/fulltokeninfo.cpp b/src/tools/clangbackend/source/fulltokeninfo.cpp
index 36fabc6cd2..d539138ce9 100644
--- a/src/tools/clangbackend/source/fulltokeninfo.cpp
+++ b/src/tools/clangbackend/source/fulltokeninfo.cpp
@@ -216,16 +216,16 @@ void FullTokenInfo::memberReferenceKind(const Cursor &cursor)
     }
 }
 
-void FullTokenInfo::keywordKind(const Cursor &cursor)
+void FullTokenInfo::keywordKind()
 {
-    TokenInfo::keywordKind(cursor);
+    TokenInfo::keywordKind();
 
-    CXCursorKind cursorKind = cursor.kind();
+    CXCursorKind cursorKind = m_originalCursor.kind();
     bool anonymous = false;
-    if (clang_Cursor_isAnonymous(cursor.cx())) {
+    if (clang_Cursor_isAnonymous(m_originalCursor.cx())) {
         anonymous = true;
     } else {
-        const Utf8String type = fullyQualifiedType(cursor);
+        const Utf8String type = fullyQualifiedType(m_originalCursor);
         if (type.endsWith(Utf8StringLiteral(")"))
                 && static_cast<const QByteArray &>(type).indexOf("(anonymous") >= 0) {
             anonymous = true;
@@ -242,11 +242,33 @@ void FullTokenInfo::keywordKind(const Cursor &cursor)
             m_types.mixinHighlightingTypes.push_back(HighlightingType::Namespace);
         m_extraInfo.declaration = m_extraInfo.definition = true;
         m_extraInfo.token = Utf8StringLiteral("anonymous");
-        updateTypeSpelling(cursor);
-        m_extraInfo.cursorRange = cursor.sourceRange();
+        updateTypeSpelling(m_originalCursor);
+        m_extraInfo.cursorRange = m_originalCursor.sourceRange();
     }
 }
 
+void FullTokenInfo::overloadedOperatorKind()
+{
+    TokenInfo::overloadedOperatorKind();
+
+    if (m_types.mixinHighlightingTypes.front() != HighlightingType::OverloadedOperator)
+        return;
+
+    // Overloaded operator
+    m_extraInfo.identifier = true;
+    if (!m_originalCursor.isDeclaration())
+        return;
+
+    // Overloaded operator declaration
+    m_extraInfo.declaration = true;
+    m_extraInfo.definition = m_originalCursor.isDefinition();
+
+    updateTypeSpelling(m_originalCursor, true);
+    m_extraInfo.cursorRange = m_originalCursor.sourceRange();
+    m_extraInfo.accessSpecifier = m_originalCursor.accessSpecifier();
+    m_extraInfo.storageClass = m_originalCursor.storageClass();
+}
+
 void FullTokenInfo::evaluate()
 {
     m_extraInfo.token = ClangString(clang_getTokenSpelling(m_cxTranslationUnit, *m_cxToken));
diff --git a/src/tools/clangbackend/source/fulltokeninfo.h b/src/tools/clangbackend/source/fulltokeninfo.h
index 1544b47a80..a0ebb81005 100644
--- a/src/tools/clangbackend/source/fulltokeninfo.h
+++ b/src/tools/clangbackend/source/fulltokeninfo.h
@@ -48,7 +48,8 @@ protected:
     void variableKind(const Cursor &cursor) override;
     void fieldKind(const Cursor &cursor) override;
     void memberReferenceKind(const Cursor &cursor) override;
-    void keywordKind(const Cursor &cursor) override;
+    void keywordKind() override;
+    void overloadedOperatorKind() override;
 private:
     void updateTypeSpelling(const Cursor &cursor, bool functionLike = false);
     void updatePropertyData();
diff --git a/src/tools/clangbackend/source/tokeninfo.cpp b/src/tools/clangbackend/source/tokeninfo.cpp
index 5da41a30d3..0638a3c6ea 100644
--- a/src/tools/clangbackend/source/tokeninfo.cpp
+++ b/src/tools/clangbackend/source/tokeninfo.cpp
@@ -98,9 +98,7 @@ TokenInfo::operator TokenInfoContainer() const
     return TokenInfoContainer(m_line, m_column, m_length, m_types);
 }
 
-namespace {
-
-bool isFinalFunction(const Cursor &cursor)
+static bool isFinalFunction(const Cursor &cursor)
 {
     auto referencedCursor = cursor.referenced();
     if (referencedCursor.hasFinalFunctionAttribute())
@@ -109,7 +107,7 @@ bool isFinalFunction(const Cursor &cursor)
         return false;
 }
 
-bool isFunctionInFinalClass(const Cursor &cursor)
+static bool isFunctionInFinalClass(const Cursor &cursor)
 {
     auto functionBase = cursor.functionBaseDeclaration();
     if (functionBase.isValid() && functionBase.hasFinalClassAttribute())
@@ -117,7 +115,6 @@ bool isFunctionInFinalClass(const Cursor &cursor)
 
     return false;
 }
-}
 
 void TokenInfo::memberReferenceKind(const Cursor &cursor)
 {
@@ -196,12 +193,11 @@ bool TokenInfo::isVirtualMethodDeclarationOrDefinition(const Cursor &cursor) con
         && (m_originalCursor.isDeclaration() || m_originalCursor.isDefinition());
 }
 
-namespace {
-bool isNotFinalFunction(const Cursor &cursor)
+static bool isNotFinalFunction(const Cursor &cursor)
 {
     return !cursor.hasFinalFunctionAttribute();
 }
-}
+
 bool TokenInfo::isRealDynamicCall(const Cursor &cursor) const
 {
     return m_originalCursor.isDynamicCall() && isNotFinalFunction(cursor);
@@ -246,9 +242,7 @@ void TokenInfo::collectOutputArguments(const Cursor &cursor)
     filterOutPreviousOutputArguments();
 }
 
-namespace {
-
-uint getEnd(CXSourceRange cxSourceRange)
+static uint getEnd(CXSourceRange cxSourceRange)
 {
     CXSourceLocation startSourceLocation = clang_getRangeEnd(cxSourceRange);
 
@@ -258,7 +252,6 @@ uint getEnd(CXSourceRange cxSourceRange)
 
     return endOffset;
 }
-}
 
 void TokenInfo::filterOutPreviousOutputArguments()
 {
@@ -456,8 +449,7 @@ void TokenInfo::identifierKind(const Cursor &cursor, Recursion recursion)
     }
 }
 
-namespace {
-HighlightingType literalKind(const Cursor &cursor)
+static HighlightingType literalKind(const Cursor &cursor)
 {
     switch (cursor.kind()) {
         case CXCursor_CharacterLiteral:
@@ -476,32 +468,86 @@ HighlightingType literalKind(const Cursor &cursor)
     Q_UNREACHABLE();
 }
 
-bool hasOperatorName(const char *operatorString)
+static bool isTokenPartOfOperator(const Cursor &declarationCursor, CXToken *token)
 {
-    return std::strncmp(operatorString, "operator", 8) == 0;
+    Q_ASSERT(declarationCursor.isDeclaration());
+    const CXTranslationUnit cxTranslationUnit = declarationCursor.cxTranslationUnit();
+    const ClangString tokenName = clang_getTokenSpelling(cxTranslationUnit, *token);
+    if (tokenName == "operator")
+        return true;
+
+    if (tokenName == "(") {
+        // Valid operator declarations have at least one token after '(' so
+        // it's safe to proceed to token + 1 without extra checks.
+        const ClangString nextToken = clang_getTokenSpelling(cxTranslationUnit, *(token + 1));
+        if (nextToken != ")") {
+            // Argument lists' parentheses are not operator tokens.
+            // This '('-token opens a (non-empty) argument list.
+            return false;
+        }
+    }
+
+    // It's safe to evaluate the preceding token because we will at least have
+    // the 'operator'-keyword's token to the left.
+    CXToken *prevToken = token - 1;
+    if (clang_getTokenKind(*prevToken) == CXToken_Punctuation) {
+        if (tokenName == "(") {
+            // In an operator declaration, when a '(' follows another punctuation
+            // then this '(' opens an argument list. Ex: operator*()|operator()().
+            return false;
+        }
+
+        // This token is preceded by another punctuation token so this token
+        // could be the second token of a two-tokened operator such as
+        // operator+=|-=|*=|/=|<<|==|<=|++ or the third token of operator
+        // new[]|delete[]. We decrement one more time to hit one of the keywords:
+        // "operator" / "delete" / "new".
+        --prevToken;
+    }
+
+    const ClangString precedingKeyword =
+            clang_getTokenSpelling(cxTranslationUnit, *prevToken);
+
+    return precedingKeyword == "operator" ||
+           precedingKeyword == "new" ||
+           precedingKeyword == "delete";
 }
 
-HighlightingType operatorKind(const Cursor &cursor)
+void TokenInfo::overloadedOperatorKind()
 {
-    if (hasOperatorName(cursor.spelling().cString()))
-        return HighlightingType::Operator;
-    else
-        return HighlightingType::Invalid;
-}
+    bool inOperatorDeclaration = m_originalCursor.isDeclaration();
+    Cursor declarationCursor =
+            inOperatorDeclaration ? m_originalCursor :
+                                    m_originalCursor.referenced();
+    if (!declarationCursor.displayName().startsWith("operator"))
+        return;
+
+    if (inOperatorDeclaration && !isTokenPartOfOperator(declarationCursor, m_cxToken))
+        return;
 
+    if (m_types.mainHighlightingType == HighlightingType::Invalid)
+        m_types.mainHighlightingType = HighlightingType::Operator;
+    m_types.mixinHighlightingTypes.push_back(HighlightingType::OverloadedOperator);
 }
 
-HighlightingType TokenInfo::punctuationKind(const Cursor &cursor)
+void TokenInfo::punctuationOrOperatorKind()
 {
-    HighlightingType highlightingType = HighlightingType::Invalid;
-
-    switch (cursor.kind()) {
+    auto kind = m_originalCursor.kind();
+    switch (kind) {
+        case CXCursor_CallExpr:
+            collectOutputArguments(m_originalCursor);
+            Q_FALLTHROUGH();
+        case CXCursor_FunctionDecl:
+        case CXCursor_CXXMethod:
         case CXCursor_DeclRefExpr:
-            highlightingType = operatorKind(cursor);
+            // TODO(QTCREATORBUG-19948): Mark calls to overloaded new and delete.
+            // Today we can't because libclang sets these cursors' spelling to "".
+            // case CXCursor_CXXNewExpr:
+            // case CXCursor_CXXDeleteExpr:
+            overloadedOperatorKind();
             break;
         case CXCursor_Constructor:
-        case CXCursor_CallExpr:
-            collectOutputArguments(cursor);
+            collectOutputArguments(m_originalCursor);
             break;
         default:
             break;
@@ -509,8 +555,6 @@ HighlightingType TokenInfo::punctuationKind(const Cursor &cursor)
 
     if (isOutputArgument())
         m_types.mixinHighlightingTypes.push_back(HighlightingType::OutputArgument);
-
-    return highlightingType;
 }
 
 enum class PropertyPart
@@ -582,17 +626,20 @@ void TokenInfo::invalidFileKind()
     }
 }
 
-static HighlightingType highlightingTypeForKeyword(CXTranslationUnit cxTranslationUnit,
-                                                   CXToken *cxToken,
-                                                   const Cursor &cursor)
+void TokenInfo::keywordKind()
 {
-    switch (cursor.kind()) {
-        case CXCursor_PreprocessingDirective: return HighlightingType::Preprocessor;
-        case CXCursor_InclusionDirective: return HighlightingType::StringLiteral;
-        default: break;
+    switch (m_originalCursor.kind()) {
+        case CXCursor_PreprocessingDirective:
+            m_types.mainHighlightingType = HighlightingType::Preprocessor;
+            return;
+        case CXCursor_InclusionDirective:
+            m_types.mainHighlightingType = HighlightingType::StringLiteral;
+            return;
+        default:
+            break;
     }
 
-    const ClangString spelling = clang_getTokenSpelling(cxTranslationUnit, *cxToken);
+    const ClangString spelling = clang_getTokenSpelling(m_cxTranslationUnit, *m_cxToken);
     if (spelling == "bool"
             || spelling == "char"
             || spelling == "char16_t"
@@ -606,17 +653,14 @@ static HighlightingType highlightingTypeForKeyword(CXTranslationUnit cxTranslati
             || spelling == "unsigned"
             || spelling == "void"
             || spelling == "wchar_t") {
-        return HighlightingType::PrimitiveType;
+        m_types.mainHighlightingType =  HighlightingType::PrimitiveType;
+        return;
     }
 
-    return HighlightingType::Keyword;
-}
+    m_types.mainHighlightingType = HighlightingType::Keyword;
 
-void TokenInfo::keywordKind(const Cursor &cursor)
-{
-    m_types.mainHighlightingType = highlightingTypeForKeyword(m_cxTranslationUnit,
-                                                              m_cxToken,
-                                                              cursor);
+    if (spelling == "new" || spelling == "delete" || spelling == "operator")
+        overloadedOperatorKind();
 }
 
 void TokenInfo::evaluate()
@@ -627,10 +671,10 @@ void TokenInfo::evaluate()
 
     switch (cxTokenKind) {
         case CXToken_Keyword:
-            keywordKind(m_originalCursor);
+            keywordKind();
             break;
         case CXToken_Punctuation:
-            m_types.mainHighlightingType = punctuationKind(m_originalCursor);
+            punctuationOrOperatorKind();
             break;
         case CXToken_Identifier:
             identifierKind(m_originalCursor, Recursion::FirstPass);
diff --git a/src/tools/clangbackend/source/tokeninfo.h b/src/tools/clangbackend/source/tokeninfo.h
index 03aea72fd2..7cd0d48086 100644
--- a/src/tools/clangbackend/source/tokeninfo.h
+++ b/src/tools/clangbackend/source/tokeninfo.h
@@ -93,10 +93,11 @@ protected:
     virtual void fieldKind(const Cursor &cursor);
     virtual void functionKind(const Cursor &cursor, Recursion recursion);
     virtual void memberReferenceKind(const Cursor &cursor);
-    virtual HighlightingType punctuationKind(const Cursor &cursor);
     virtual void typeKind(const Cursor &cursor);
-    virtual void keywordKind(const Cursor &cursor);
+    virtual void keywordKind();
     virtual void invalidFileKind();
+    virtual void overloadedOperatorKind();
+    virtual void punctuationOrOperatorKind();
 
     Cursor m_originalCursor;
     CXToken *m_cxToken = nullptr;
diff --git a/tests/unit/unittest/clangstring-test.cpp b/tests/unit/unittest/clangstring-test.cpp
index bea70a7ab0..8e30da93e2 100644
--- a/tests/unit/unittest/clangstring-test.cpp
+++ b/tests/unit/unittest/clangstring-test.cpp
@@ -105,9 +105,9 @@ TEST(ClangString, NotEqualBetweenClangStrings)
     ClangString text(CXString{"text", 0});
     ClangString text2(CXString{"text ", 0});
 
-    bool textIsEqual = text == text2;
+    bool textIsNotEqual = text != text2;
 
-    ASSERT_FALSE(textIsEqual);
+    ASSERT_TRUE(textIsNotEqual);
 }
 
 TEST(ClangString, EqualClangStringAndCString)
@@ -123,9 +123,9 @@ TEST(ClangString, NotEqualClangStringAndCString)
 {
     ClangString text(CXString{"text", 0});
 
-    bool textIsEqual = text == "text ";
+    bool textIsNotEqual = text != "text ";
 
-    ASSERT_FALSE(textIsEqual);
+    ASSERT_TRUE(textIsNotEqual);
 }
 
 TEST(ClangString, EqualCStringAndClangString)
@@ -137,6 +137,15 @@ TEST(ClangString, EqualCStringAndClangString)
     ASSERT_TRUE(textIsEqual);
 }
 
+TEST(ClangString, NotEqualCStringAndClangString)
+{
+    ClangString text(CXString{"text", 0});
+
+    bool textIsNotEqual = "text " != text;
+
+    ASSERT_TRUE(textIsNotEqual);
+}
+
 TEST(ClangString, EqualClangStringPointerAndCString)
 {
     ClangString text(CXString{"text", 0});
@@ -152,9 +161,9 @@ TEST(ClangString, NotEqualClangStringPointerAndCString)
     ClangString text(CXString{"text", 0});
     const char *cString = "text ";
 
-    bool textIsEqual = cString == text;
+    bool textIsNotEqual = cString != text;
 
-    ASSERT_FALSE(textIsEqual);
+    ASSERT_TRUE(textIsNotEqual);
 }
 
 TEST(ClangString, EqualCStringAndClangStringPointer)
@@ -167,6 +176,16 @@ TEST(ClangString, EqualCStringAndClangStringPointer)
     ASSERT_TRUE(textIsEqual);
 }
 
+TEST(ClangString, NotEqualCStringAndClangStringPointer)
+{
+    ClangString text(CXString{"text", 0});
+    const char *cString = "text ";
+
+    bool textIsNotEqual = text != cString;
+
+    ASSERT_TRUE(textIsNotEqual);
+}
+
 TEST(ClangString, NullStringHasNoContent)
 {
     ClangString text(CXString{nullptr, 0});
diff --git a/tests/unit/unittest/data/highlightingmarks.cpp b/tests/unit/unittest/data/highlightingmarks.cpp
index c4e18d65d1..edbe0a14c2 100644
--- a/tests/unit/unittest/data/highlightingmarks.cpp
+++ b/tests/unit/unittest/data/highlightingmarks.cpp
@@ -600,6 +600,44 @@ class Property {
     Q_PROPERTY(const QString str READ getStr)
 };
 
+struct X {
+    void operator*(int) {}
+};
+
+void operator*(X, float) {}
+
+void CallSite() {
+    X x;
+    int y = 10;
+    float z = 10;
+    x * y;
+    x * z;
+}
+
+struct Dummy {
+    Dummy operator<<=(int key);
+    Dummy operator()(int a);
+    int& operator[] (unsigned index);
+    void* operator new(unsigned size);
+    void operator delete(void* ptr);
+    void* operator new[](unsigned size);
+    void operator delete[](void* ptr);
+};
+
+void TryOverloadedOperators(Dummy object)
+{
+    object <<= 3;
+
+    Dummy stacked;
+    stacked(4);
+    stacked[1];
+    int *i = new int;
+    Dummy* use_new = new Dummy();
+    delete use_new;
+    Dummy* many = new Dummy[10];
+    delete [] many;
+}
+
 enum {
     Test = 0
 };
@@ -611,3 +649,17 @@ class B {
     };
 };
 }
+
+struct Dummy2 {
+    Dummy2 operator()();
+    int operator*();
+    Dummy2 operator=(int foo);
+};
+
+void TryOverloadedOperators2(Dummy object)
+{
+    Dummy2 dummy2;
+    dummy2();
+    *dummy2;
+    dummy2 = 3;
+}
diff --git a/tests/unit/unittest/tokenprocessor-test.cpp b/tests/unit/unittest/tokenprocessor-test.cpp
index ac202d8fd1..51daef634e 100644
--- a/tests/unit/unittest/tokenprocessor-test.cpp
+++ b/tests/unit/unittest/tokenprocessor-test.cpp
@@ -584,18 +584,270 @@ TEST_F(TokenProcessor, NonFinalVirtualFunctionCallPointer)
     ASSERT_THAT(infos[2], HasOnlyType(HighlightingType::VirtualFunction));
 }
 
-TEST_F(TokenProcessor, PlusOperator)
+TEST_F(TokenProcessor, OverriddenPlusOperatorDeclaration)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(220, 67));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, CallToOverriddenPlusOperator)
 {
     const auto infos = translationUnit.tokenInfosInRange(sourceRange(224, 49));
 
-    ASSERT_THAT(infos[6], HasOnlyType(HighlightingType::Operator));
+    ASSERT_THAT(infos[6], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
 }
 
-TEST_F(TokenProcessor, PlusAssignOperator)
+TEST_F(TokenProcessor, CallToOverriddenPlusAssignOperator)
 {
     const auto infos = translationUnit.tokenInfosInRange(sourceRange(226, 24));
 
-    ASSERT_THAT(infos[1], HasOnlyType(HighlightingType::Operator));
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, OverriddenStarOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(604, 26));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, OverriddenStarOperatorNonMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(607, 29));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, IntegerCallToOverriddenBinaryOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(613, 9));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, FloatCallToOverriddenBinaryOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(614, 9));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, LeftShiftAssignmentOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(618, 32));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledLeftShiftAssignmentOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(629, 18));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[2], HasOnlyType(HighlightingType::NumberLiteral));
+}
+
+TEST_F(TokenProcessor, FunctionCallOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(619, 29));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[4], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledFunctionCallOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(632, 16));
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, AccessOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(620, 38));
+
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[4], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[5], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledAccessOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(633, 16));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));
+}
+
+TEST_F(TokenProcessor, NewOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(621, 39));
+
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));
+    ASSERT_THAT(infos[4], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledNewOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(635, 34));
+
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid));  // = is not marked.
+    // CLANG-UPGRADE-CHECK: Check if 'new' keyword usage cursor correctly returns referenced() cursor
+    // and uncomment this test in that case.
+    // ASSERT_THAT(infos[4], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // new
+}
+
+TEST_F(TokenProcessor, DeleteOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(622, 37));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // delete
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledDeleteOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(636, 20));
+
+    // CLANG-UPGRADE-CHECK: Check if 'delete' keyword usage cursor correctly returns referenced() cursor
+    // and uncomment this test in that case.
+    // ASSERT_THAT(infos[0], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // delete
+    ASSERT_THAT(infos[1], HasOnlyType(HighlightingType::LocalVariable));
+    ASSERT_THAT(infos[2], HasOnlyType(HighlightingType::Invalid));  // ; is a punctuation.
+}
+
+TEST_F(TokenProcessor, NewArrayOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(623, 41));
+
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // new
+    ASSERT_THAT(infos[4], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));  // [
+    ASSERT_THAT(infos[5], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));  // ]
+    ASSERT_THAT(infos[6], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledNewArrayOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(637, 34));
+
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid));  // = is not marked.
+    // CLANG-UPGRADE-CHECK: Check if 'new' keyword usage cursor correctly returns referenced() cursor
+    // and uncomment this test in that case.
+    // ASSERT_THAT(infos[4], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // new
+}
+
+TEST_F(TokenProcessor, DeleteArrayOperatorMemberDefinition)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(624, 39));
+
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // delete
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));  // [
+    ASSERT_THAT(infos[4], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator));  // ]
+    ASSERT_THAT(infos[5], HasOnlyType(HighlightingType::Invalid));  // ( is a punctuation.
+}
+
+TEST_F(TokenProcessor, CalledDeleteArrayOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(638, 20));
+
+    // CLANG-UPGRADE-CHECK: Check if 'delete' keyword usage cursor correctly returns referenced() cursor
+    // and uncomment this test in that case.
+    // ASSERT_THAT(infos[0], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator));  // delete
+}
+
+TEST_F(TokenProcessor, CalledNotOverloadedOperator)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(634, 22));
+
+    ASSERT_THAT(infos[4], HasOnlyType(HighlightingType::Keyword)); // new
+}
+
+TEST_F(TokenProcessor, ParenthesisOperatorWithoutArguments)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(654, 25));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator)); // operator
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // '('
+    ASSERT_THAT(infos[3], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // ')'
+    ASSERT_THAT(infos[4], HasOnlyType(HighlightingType::Invalid)); // second '(' is a punctuation
+}
+
+TEST_F(TokenProcessor, CalledParenthesisOperatorWithoutArguments)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(662, 14));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // '('
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // ')'
+}
+
+TEST_F(TokenProcessor, OperatorWithOnePunctuationTokenWithoutArguments)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(655, 25));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator)); // operator
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // '*'
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid)); // ( is a punctuation
+}
+
+TEST_F(TokenProcessor, CalledOperatorWithOnePunctuationTokenWithoutArguments)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(663, 13));
+
+    ASSERT_THAT(infos[0], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // '*'
+}
+
+TEST_F(TokenProcessor, EqualsOperatorOverload)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(656, 43));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Keyword, HighlightingType::OverloadedOperator)); // operator
+    ASSERT_THAT(infos[2], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // '='
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid)); // ( is a punctuation
+}
+
+TEST_F(TokenProcessor, CalledEqualsOperatorOverload)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(664, 23));
+
+    ASSERT_THAT(infos[1], HasTwoTypes(HighlightingType::Operator, HighlightingType::OverloadedOperator)); // '='
+}
+
+TEST_F(TokenProcessor, LeftParenthesisIsAPunctuation)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(607, 29));
+
+    ASSERT_THAT(infos[3], HasOnlyType(HighlightingType::Invalid));
+}
+
+TEST_F(TokenProcessor, SeparatingCommaIsAPunctuation)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(607, 29));
+
+    ASSERT_THAT(infos[5], HasOnlyType(HighlightingType::Invalid));
+}
+
+TEST_F(TokenProcessor, RightParenthesisIsAPunctuation)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(607, 29));
+
+    ASSERT_THAT(infos[7], HasOnlyType(HighlightingType::Invalid));
+}
+
+TEST_F(TokenProcessor, CurlyLeftParenthesisIsAPunctuation)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(607, 29));
+
+    ASSERT_THAT(infos[8], HasOnlyType(HighlightingType::Invalid));
+}
+
+TEST_F(TokenProcessor, CurlyRightParenthesisIsAPunctuation)
+{
+    const auto infos = translationUnit.tokenInfosInRange(sourceRange(607, 29));
+
+    ASSERT_THAT(infos[9], HasOnlyType(HighlightingType::Invalid));
 }
 
 TEST_F(TokenProcessor, Comment)
@@ -1326,7 +1578,7 @@ TEST_F(TokenProcessor, CursorRange)
 
 TEST_F(TokenProcessor, AnonymousEnum)
 {
-    const auto infos = translationUnit.fullTokenInfosInRange(sourceRange(603, 7));
+    const auto infos = translationUnit.fullTokenInfosInRange(sourceRange(641, 7));
 
     ClangBackEnd::TokenInfoContainer container(infos[0]);
 
@@ -1336,7 +1588,7 @@ TEST_F(TokenProcessor, AnonymousEnum)
 
 TEST_F(TokenProcessor, AnonymousNamespace)
 {
-    const auto infos = translationUnit.fullTokenInfosInRange(sourceRange(607, 12));
+    const auto infos = translationUnit.fullTokenInfosInRange(sourceRange(645, 12));
 
     ClangBackEnd::TokenInfoContainer container(infos[0]);
 
@@ -1346,7 +1598,7 @@ TEST_F(TokenProcessor, AnonymousNamespace)
 
 TEST_F(TokenProcessor, AnonymousStruct)
 {
-    const auto infos = translationUnit.fullTokenInfosInRange(sourceRange(609, 13));
+    const auto infos = translationUnit.fullTokenInfosInRange(sourceRange(647, 13));
 
     ClangBackEnd::TokenInfoContainer container(infos[0]);