Fixed #3861 (uninitialized variables)

lib/checkuninitvar.cpp

@@ -1275,6 +1275,15 @@ bool CheckUninitVar::isVariableUsage(const Token *vartok, bool pointer) const
             return true;
     }
 
+    if (_tokenizer->isCPP() && Token::Match(vartok->next(), "<<|>>")) {
+        // Is variable a known POD type then this is a variable usage,
+        // otherwise we assume it's not.
+        const Variable *var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(vartok->varId());
+        if (var && var->typeStartToken()->isStandardType())
+            return true;
+        return false;
+    }
+
     if (Token::Match(vartok->next(), "++|--|%op%"))
         return true;
 

test/testuninitvar.cpp

@@ -54,6 +54,7 @@ private:
         TEST_CASE(uninitvar2);
         TEST_CASE(uninitvar3);          // #3844
         TEST_CASE(uninitvar4);          // #3869 (reference)
+        TEST_CASE(uninitvar5);          // #3861
     }
 
     void checkUninitVar(const char code[]) {
@@ -2161,6 +2162,23 @@ private:
                         "}");
         ASSERT_EQUALS("", errout.str());
     }
+
+    // #3861
+    void uninitvar5() {
+        // ensure there is no false positive
+        checkUninitVar2("void f() {\n"
+                        "    x<char> c;\n"
+                        "    c << 2345;\n"
+                        "}");
+        ASSERT_EQUALS("", errout.str());
+
+        // ensure there is no false negative
+        checkUninitVar2("void f() {\n"
+                        "    char c;\n"
+                        "    char a = c << 2;\n"
+                        "}");
+        ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: c\n", errout.str());
+    }
 };
 
 REGISTER_TEST(TestUninitVar)