C++: Discard comments in macro definitions

Task-number: QTCREATORBUG-7815

Change-Id: Id3e6b018bfd58b0f0072c637d69721a4bde1603a
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/libs/cplusplus/pp-engine.cpp

@@ -1542,7 +1542,9 @@ void Preprocessor::handleDefineDirective(PPToken *tk)
         previousOffset = tk->offset;
         previousLine = tk->lineno;
 
-        bodyTokens.push_back(*tk);
+        // Discard comments in macro definitions (keep comments flag doesn't apply here).
+        if (!tk->isComment())
+            bodyTokens.push_back(*tk);
 
         lex(tk);
     }

tests/auto/cplusplus/preprocessor/tst_preprocessor.cpp

@@ -1076,7 +1076,6 @@ void tst_Preprocessor::comments_within()
 {
     compare_input_output();
 }
-
 void tst_Preprocessor::comments_within_data()
 {
     QTest::addColumn<QByteArray>("input");
@@ -1219,6 +1218,26 @@ void tst_Preprocessor::comments_within_data()
             "# expansion end\n"
             "# 8 \"<stdin>\"\n";
     QTest::newRow("case 6") << original << expected;
+
+    original =
+            "#define FOO 0 //coment\n"
+            "#define BAR (1 == FOO)\n"
+            "void foo() {\n"
+            "    if (BAR) {}\n"
+            "}\n";
+    expected =
+            "# 1 \"<stdin>\"\n"
+            "\n"
+            "\n"
+            "void foo() {\n"
+            "    if (\n"
+            "# expansion begin 67,3 ~5\n"
+            "(1 == 0)\n"
+            "# expansion end\n"
+            "# 4 \"<stdin>\"\n"
+            "           ) {}\n"
+            "}\n";
+    QTest::newRow("case 7") << original << expected;
 }
 
 void tst_Preprocessor::comments_within2()
@@ -1373,6 +1392,26 @@ void tst_Preprocessor::comments_within2_data()
             "# expansion end\n"
             "# 8 \"<stdin>\"\n";
     QTest::newRow("case 6") << original << expected;
+
+    original =
+            "#define FOO 0 //coment\n"
+            "#define BAR (1 == FOO)\n"
+            "void foo() {\n"
+            "    if (BAR) {}\n"
+            "}\n";
+    expected =
+            "# 1 \"<stdin>\"\n"
+            "\n"
+            "\n"
+            "void foo() {\n"
+            "    if (\n"
+            "# expansion begin 67,3 ~5\n"
+            "(1 == 0)\n"
+            "# expansion end\n"
+            "# 4 \"<stdin>\"\n"
+            "           ) {}\n"
+            "}\n";
+    QTest::newRow("case 7") << original << expected;
 }
 
 void tst_Preprocessor::multiline_strings()