C++: Fix parsing designators vs lambdas

The introduction of C99 designators led to parsing problems with lambdas
that were passed in as a function arguments.

Fixed by prefering to parse without designators first. This will be
cleaner/clearer once the appropriate "LanguageFeatures" from the Project
Parts will be passed in.

Change-Id: Ia9cb7c4a4c9345e729cf2044e1e5411fe63e33ec
Reviewed-by: Wang Hoi <wanghoi@126.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/libs/3rdparty/cplusplus/Parser.cpp

@@ -2653,10 +2653,13 @@ bool Parser::parseBraceOrEqualInitializer0x(ExpressionAST *&node)
 
 bool Parser::parseInitializerClause0x(ExpressionAST *&node)
 {
+    DEBUG_THIS_RULE();
     if (LA() == T_LBRACE)
         return parseBracedInitList0x(node);
 
-    return parseAssignmentExpression(node);
+    if (parseAssignmentExpression(node))
+        return true;
+    return parseDesignatedInitializer(node);
 }
 
 bool Parser::parseInitializerList0x(ExpressionListAST *&node)
@@ -2664,7 +2667,7 @@ bool Parser::parseInitializerList0x(ExpressionListAST *&node)
     ExpressionListAST **expression_list_ptr = &node;
     ExpressionAST *expression = 0;
 
-    if (parseDesignatedInitializer(expression)) {
+    if (parseInitializerClause0x(expression)) {
         *expression_list_ptr = new (_pool) ExpressionListAST;
         (*expression_list_ptr)->value = expression;
         expression_list_ptr = &(*expression_list_ptr)->next;
@@ -2675,7 +2678,7 @@ bool Parser::parseInitializerList0x(ExpressionListAST *&node)
         while (LA() == T_COMMA && LA(2) != T_RBRACE) {
             consumeToken(); // consume T_COMMA
 
-            if (parseDesignatedInitializer(expression)) {
+            if (parseInitializerClause0x(expression)) {
                 *expression_list_ptr = new (_pool) ExpressionListAST;
                 (*expression_list_ptr)->value = expression;
 
@@ -2692,6 +2695,7 @@ bool Parser::parseInitializerList0x(ExpressionListAST *&node)
 
 bool Parser::parseBracedInitList0x(ExpressionAST *&node)
 {
+    DEBUG_THIS_RULE();
     if (LA() != T_LBRACE)
         return false;
 
@@ -5490,20 +5494,30 @@ bool Parser::parseDesignatedInitializer(ExpressionAST *&node)
 {
     DEBUG_THIS_RULE();
     if (!_languageFeatures.c99Enabled || (LA() != T_DOT && LA() != T_LBRACKET))
-        return parseInitializerClause0x(node);
+        return false;
 
     DesignatedInitializerAST *ast = new (_pool) DesignatedInitializerAST;
     DesignatorListAST **designator_list_ptr = &ast->designator_list;
     DesignatorAST *designator = 0;
+    const unsigned start = cursor();
     while (parseDesignator(designator)) {
         *designator_list_ptr = new (_pool) DesignatorListAST;
         (*designator_list_ptr)->value = designator;
         designator_list_ptr = &(*designator_list_ptr)->next;
     }
-    match(T_EQUAL, &ast->equal_token);
+    if (start == cursor())
-    parseInitializerClause0x(ast->initializer);
+        return false;
+
+    if (LA() == T_EQUAL) {
+        ast->equal_token = consumeToken();
+        if (parseAssignmentExpression(ast->initializer)) {
             node = ast;
             return true;
+        }
+    }
+
+    rewind(start);
+    return false;
 }
 
 // designator ::= T_DOT T_IDENTIFIER
@@ -5511,21 +5525,28 @@ bool Parser::parseDesignatedInitializer(ExpressionAST *&node)
 //
 bool Parser::parseDesignator(DesignatorAST *&node)
 {
-    DesignatorAST *ast = new (_pool) DesignatorAST;
+    DEBUG_THIS_RULE();
+    const unsigned start = cursor();
     if (LA() == T_DOT) {
+        DesignatorAST *ast = new (_pool) DesignatorAST;
         ast->type = DesignatorAST::Dot;
         ast->u.dot.dot_token = consumeToken();
         match(T_IDENTIFIER, &ast->u.dot.identifier_token);
-    } else if (LA() == T_LBRACKET) {
-        ast->type = DesignatorAST::Bracket;
-        ast->u.bracket.lbracket_token = consumeToken();
-        parseConstantExpression(ast->u.bracket.expression);
-        match(T_RBRACKET, &ast->u.bracket.rbracket_token);
-    } else {
-        return false;
-    }
         node = ast;
         return true;
+    } else if (LA() == T_LBRACKET) {
+        DesignatorAST *ast = new (_pool) DesignatorAST;
+        ast->type = DesignatorAST::Bracket;
+        ast->u.bracket.lbracket_token = consumeToken();
+        if (parseConditionalExpression(ast->u.bracket.expression)) {
+            match(T_RBRACKET, &ast->u.bracket.rbracket_token);
+            node = ast;
+            return true;
+        }
+    }
+
+    rewind(start);
+    return false;
 }
 
 // objc-class-declaraton ::= T_AT_CLASS (T_IDENTIFIER @ T_COMMA) T_SEMICOLON

tests/auto/cplusplus/cxx11/data/lambda.1.cpp

@@ -0,0 +1 @@
+Foo foo([&](int a) { ++a; });

tests/auto/cplusplus/cxx11/tst_cxx11.cpp

@@ -98,13 +98,14 @@ class tst_cxx11: public QObject
         }
     };
 
-    Document::Ptr document(const QString &fileName, QByteArray *errors = 0)
+    Document::Ptr document(const QString &fileName, QByteArray *errors = 0, bool c99Enabled = false)
     {
         Document::Ptr doc = Document::create(fileName);
         QFile file(testdata(fileName));
         if (file.open(QFile::ReadOnly)) {
             LanguageFeatures features;
             features.cxx11Enabled = true;
+            features.c99Enabled = c99Enabled;
             Client client(errors);
             doc->control()->setDiagnosticClient(&client);
             doc->setUtf8Source(QTextStream(&file).readAll().toUtf8());
@@ -124,6 +125,9 @@ private Q_SLOTS:
     void parse_data();
     void parse();
 
+    void parseWithC99Enabled_data();
+    void parseWithC99Enabled();
+
     //
     // checks for the semantic
     //
@@ -169,6 +173,29 @@ void tst_cxx11::parse()
     VERIFY_ERRORS();
 }
 
+void tst_cxx11::parseWithC99Enabled_data()
+{
+    QTest::addColumn<QString>("file");
+    QTest::addColumn<QString>("errorFile");
+
+    QTest::newRow("lambda.1") << "lambda.1.cpp" << "";
+}
+
+void tst_cxx11::parseWithC99Enabled()
+{
+    QFETCH(QString, file);
+    QFETCH(QString, errorFile);
+
+    const bool c99Enabled = true;
+    QByteArray errors;
+    Document::Ptr doc = document(file, &errors, c99Enabled);
+
+    if (! qgetenv("DEBUG").isNull())
+        printf("%s\n", errors.constData());
+
+    VERIFY_ERRORS();
+}
+
 //
 // check the visibility of symbols declared inside inline namespaces
 //