C++: fix macro calls with comment before arguments

When in 'keep comments' mode, the preprocessor does not properly handle macro calls with
comments between the macro name and the opening parenthesis: "FOO /*something to say*/
(45)".

Change-Id: I6fe733242e4d2ccff2985d17399d0a084917415a
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/libs/cplusplus/pp-engine.cpp

@@ -1330,6 +1330,13 @@ bool Preprocessor::collectActualArguments(PPToken *tk, QVector<QVector<PPToken>
 
     lex(tk); // consume the identifier
 
+    // consume comments
+    while (tk->isComment()) {
+        lex(tk);
+        if (!tk)
+            return false;
+    }
+
     if (tk->isNot(T_LPAREN))
         //### TODO: error message
         return false;

tests/auto/cplusplus/preprocessor/tst_preprocessor.cpp

@@ -329,6 +329,7 @@ private slots:
     void dont_eagerly_expand_data();
     void comparisons_data();
     void comparisons();
+    void comments_before_args();
     void comments_within();
     void comments_within_data();
     void comments_within2();
@@ -1239,6 +1240,28 @@ void tst_Preprocessor::comments_within_data()
     QTest::newRow("case 7") << original << expected;
 }
 
+void tst_Preprocessor::comments_before_args()
+{
+    Client *client = 0; // no client.
+    Environment env;
+
+    Preprocessor preprocess(client, &env);
+    preprocess.setKeepComments(true);
+    QByteArray preprocessed = preprocess.run(QLatin1String("<stdin>"),
+                                                "\n#define foo(a,b) int a = b;"
+                                                "\nfoo/*C comment*/(a,1)\n"
+                                                "\nfoo/**Doxygen comment*/(b,2)\n"
+                                                "\nfoo//C++ comment\n(c,3)\n"
+                                                "\nfoo///Doxygen C++ comment\n(d,4)\n"
+                                                "\nfoo/*multiple*///comments\n/**as well*/(e,5)\n",
+                                             true, false);
+
+    preprocessed = preprocessed.simplified();
+//    DUMP_OUTPUT(preprocessed);
+    QCOMPARE(simplified(preprocessed),
+             QString("int a=1;int b=2;int c=3;int d=4;int e=5;"));
+}
+
 void tst_Preprocessor::comments_within2()
 {
     compare_input_output(true);