Fixed #7049 (valueflow: value is not known after case)

lib/valueflow.cpp

@@ -1105,7 +1105,7 @@ static bool valueFlowForward(Token * const               startToken,
             }
         }
 
-        if (Token::Match(tok2, "[;{}] %name% :")) {
+        if (Token::Match(tok2, "[;{}] %name% :") || tok2->str() == "case") {
             for (std::list<ValueFlow::Value>::iterator it = values.begin(); it != values.end(); ++it)
                 it->changeKnownToPossible();
             tok2 = tok2->tokAt(2);

test/testvalueflow.cpp

@@ -1729,6 +1729,17 @@ private:
                "}";
         ASSERT(isNotKnownValues(code, "!"));
 
+        code = "void f() {\n" // #7049
+               "  int x = 0;\n"
+               "  switch (a) {\n"
+               "  case 1:\n"
+               "    x = 1;\n"
+               "  case 2:\n"
+               "    if (!x) {}\n" // <- possible value
+               "  }\n"
+               "}";
+        ASSERT(isNotKnownValues(code, "!"));
+
         code = "void f() {\n"
                "  int x = 0;\n"
                "  while (!x) {\n" // <- possible value