Fixed #8195 (False positive uninitvar (regression) - valueflow misses variable initialization via istringstream >>)

lib/astutils.cpp

@@ -458,6 +458,15 @@ bool isVariableChanged(const Token *start, const Token *end, const unsigned int
         if (Token::Match(tok->previous(), "++|-- %name%"))
             return true;
 
+        if (Token::simpleMatch(tok->previous(), ">>")) {
+            const Token *shr = tok->previous();
+            if (Token::simpleMatch(shr->astParent(), ">>"))
+                return true;
+            const Token *lhs = shr->astOperand1();
+            if (!lhs->valueType() || !lhs->valueType()->isIntegral())
+                return true;
+        }
+
         const Token *ftok = tok;
         while (ftok && !Token::Match(ftok, "[({[]"))
             ftok = ftok->astParent();

test/testvalueflow.cpp

@@ -2625,6 +2625,16 @@ private:
                "    f(x=3), return x+3;\n"
                "}";
         ASSERT_EQUALS(0U, tokenValues(code, "x +").size());
+
+        // #8195
+        code = "void foo(std::istream &is) {\n"
+               "  int x;\n"
+               "  if (is >> x) {\n"
+               "    a = x;\n"
+               "  }\n"
+               "}";
+        values = tokenValues(code, "x ; }");
+        ASSERT_EQUALS(true, values.empty());
     }
 };