Fixed #4320 (False positives 'unassignedVariable' and 'uninitvar')

lib/checkuninitvar.cpp

@@ -574,7 +574,8 @@ private:
                     return tok.tokAt(3);
             }
 
-            else if ((!isC && Token::Match(tok.previous(), "<<|>>")) || Token::simpleMatch(tok.next(), "=")) {
+            else if ((!isC && (Token::Match(tok.previous(), "<<|>>") || Token::Match(tok.previous(), "[;{}] %var% <<"))) ||
+                     Token::simpleMatch(tok.next(), "=")) {
                 // TODO: Don't bail out for "<<" and ">>" if these are
                 // just computations
                 ExecutionPath::bailOutVar(checks, tok.varId());
@@ -1328,12 +1329,17 @@ bool CheckUninitVar::isVariableUsage(const Token *vartok, bool pointer) const
     }
 
     if (_tokenizer->isCPP() && Token::Match(vartok->next(), "<<|>>")) {
+        // Is this calculation done in rhs?
+        const Token *tok = vartok;
+        while (tok && Token::Match(tok, "%var%|.|::"))
+            tok = tok->previous();
+        if (Token::Match(tok, "[;{}]"))
+            return false;
+
         // 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;
+        return (var && var->typeStartToken()->isStandardType());
     }
 
     if (Token::Match(vartok->next(), "++|--|%op%"))

lib/checkunusedvar.cpp

@@ -954,6 +954,10 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
             }
         }
 
+        else if (_tokenizer->isCPP() && Token::Match(tok, "[;{}] %var% <<")) {
+            variables.erase(tok->next()->varId());
+        }
+
         else if (Token::Match(tok, "& %var%")) {
             if (tok->previous()->isName() || tok->previous()->isNumber()) { // bitop
                 variables.read(tok->next()->varId(), tok);

test/testuninitvar.cpp

@@ -377,6 +377,14 @@ private:
                            "}\n",
                            "test.c");
             ASSERT_EQUALS("[test.c:3]: (error) Uninitialized variable: ret\n", errout.str());
+
+            // #4320
+            checkUninitVar("void f() {\n"
+                           "    int a;\n"
+                           "    a << 1;\n"
+                           "    return a;\n"
+                           "}\n");
+            ASSERT_EQUALS("", errout.str());
         }
 
         checkUninitVar("void a() {\n"   // asm
@@ -2341,6 +2349,13 @@ private:
                         "    char a = c << 2;\n"
                         "}");
         ASSERT_EQUALS("[test.cpp:3]: (error) Uninitialized variable: c\n", errout.str());
+
+        // #4320
+        checkUninitVar2("void f() {\n"
+                        "    int a;\n"
+                        "    a << 1;\n"  // there might be a operator<<
+                        "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     // Handling of unknown types. Assume they are POD in C.

test/testunusedvar.cpp

@@ -3005,6 +3005,13 @@ private:
                               "    ints << 1;\n"
                               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        functionVariableUsage("int foo() {\n" // #4320
+                              "    int x;\n"
+                              "    x << 1;\n"
+                              "    return x;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void localvarCast() {