Uninitialized variables: better handling of initialization with >>. Ticket: #3369

lib/checkuninitvar.cpp

@@ -1130,10 +1130,6 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const unsigned int
 
         // variable is seen..
         if (tok->varId() == varid) {
-            // Assign variable
-            if (tok->previous()->str() == ">>" || tok->next()->str() == "=")
-                return true;
-
             // Use variable
             if (isVariableUsage(tok))
                 uninitvarError(tok, tok->str());
@@ -1156,6 +1152,11 @@ bool CheckUninitVar::isVariableUsage(const Token *vartok) const
         return true;
 
     if (Token::Match(vartok->previous(), "++|--|%op%")) {
+        if (vartok->previous()->str() == ">>" && _tokenizer->isCPP()) {
+            // assume that variable is initialized
+            return false;
+        }
+
         if (vartok->previous()->str() != "&" || !Token::Match(vartok->tokAt(-2), "[(,]")) {
             return true;
         }

test/testuninitvar.cpp

@@ -1682,7 +1682,7 @@ private:
 
 
     /** New checking that doesn't rely on ExecutionPath */
-    void checkUninitVar2(const char code[]) {
+    void checkUninitVar2(const char code[], const char fname[] = "test.cpp") {
         // Clear the error buffer..
         errout.str("");
 
@@ -1691,7 +1691,7 @@ private:
         // Tokenize..
         Tokenizer tokenizer(&settings, this);
         std::istringstream istr(code);
-        tokenizer.tokenize(istr, "test.cpp");
+        tokenizer.tokenize(istr, fname);
         tokenizer.simplifyTokenList();
 
         // Check for redundant code..
@@ -1732,6 +1732,20 @@ private:
                         "}");
         ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: x\n", errout.str());
 
+        // >> => initialization / usage
+        {
+            const char code[] = "void f() {\n"
+                                "    int x;\n"
+                                "    if (i >> x) { }\n"
+                                "}";
+
+            checkUninitVar2(code, "test.cpp");
+            ASSERT_EQUALS("", errout.str());
+
+            checkUninitVar2(code, "test.c");
+            ASSERT_EQUALS("[test.c:3]: (error) Uninitialized variable: x\n", errout.str());
+        }
+
         // conditional initialization
         checkUninitVar2("void f() {\n"
                         "    int x;\n"