Fixed #1105 (improve check: uninitialized variable not detected for 'a = a')

lib/checkother.cpp

@@ -1528,6 +1528,20 @@ private:
 
         if (tok.varId())
         {
+            if (Token::Match(tok.previous(), "[;{}] %var% ="))
+            {
+                // using same variable rhs?
+                for (const Token *tok2 = tok.tokAt(2); tok2; tok2 = tok2->next())
+                {
+                    if (Token::Match(tok2, ";|)|="))
+                        break;
+                    if (Token::Match(tok2, "%var% ("))
+                        break;
+                    if (tok2->varId() && !Token::simpleMatch(tok2->next(), "="))
+                        use(foundError, checks, tok2);
+                }
+            }
+
             if (Token::Match(tok.tokAt(-2), "[;{}] *"))
             {
                 if (Token::simpleMatch(tok.next(), "="))

lib/tokenize.cpp

@@ -3800,6 +3800,9 @@ bool Tokenizer::simplifyKnownVariables()
                 if (varid == 0)
                     continue;
 
+                if (tok2->str() == tok2->strAt(2))
+                    continue;
+
                 const bool pointeralias(tok2->tokAt(2)->isName());
 
                 std::string value(tok2->strAt(2));

test/testother.cpp

@@ -1027,6 +1027,13 @@ private:
                        "}\n");
         ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: ret\n", errout.str());
 
+        checkUninitVar("void f()\n"
+                       "{\n"
+                       "    int a;\n"
+                       "    a = 5 + a;\n"
+                       "}\n");
+        ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: a\n", errout.str());
+
         checkUninitVar("static void foo()\n"
                        "{\n"
                        "    int i;\n"

test/testtokenize.cpp

@@ -107,6 +107,7 @@ private:
         TEST_CASE(varid10);
         TEST_CASE(varid11);
         TEST_CASE(varid12);
+        TEST_CASE(varid13);
         TEST_CASE(varidStl);
         TEST_CASE(varid_delete);
         TEST_CASE(varid_functions);
@@ -1087,7 +1088,6 @@ private:
             Tokenizer tokenizer;
             std::istringstream istr(code);
             tokenizer.tokenize(istr, "test.cpp");
-            tokenizer.setVarId();
 
             // result..
             const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1120,7 +1120,6 @@ private:
             Tokenizer tokenizer;
             std::istringstream istr(code);
             tokenizer.tokenize(istr, "test.cpp");
-            tokenizer.setVarId();
 
             // result..
             const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1153,7 +1152,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1181,7 +1179,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1231,7 +1228,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
         tokenizer.simplifyTokenList();
 
         // result..
@@ -1285,7 +1281,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1340,7 +1335,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1362,7 +1356,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1384,7 +1377,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1406,7 +1398,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1427,7 +1418,6 @@ private:
         Tokenizer tokenizer;
         std::istringstream istr(code);
         tokenizer.tokenize(istr, "test.cpp");
-        tokenizer.setVarId();
 
         // result..
         const std::string actual(tokenizer.tokens()->stringifyList(true));
@@ -1440,6 +1430,32 @@ private:
         ASSERT_EQUALS(expected, actual);
     }
 
+    void varid13()
+    {
+        const std::string code("void f()\n"
+                               "{\n"
+                               "    int a; int b;\n"
+                               "    a = a;\n"
+                               "}\n");
+
+        // tokenize..
+        Tokenizer tokenizer;
+        std::istringstream istr(code);
+        tokenizer.tokenize(istr, "test.cpp");
+        tokenizer.simplifyTokenList();
+
+        // result..
+        const std::string actual(tokenizer.tokens()->stringifyList(true));
+        const std::string expected("\n\n##file 0\n"
+                                   "1: void f ( )\n"
+                                   "2: {\n"
+                                   "3: int a@1 ; int b@2 ;\n"
+                                   "4: a@1 = a@1 ;\n"
+                                   "5: }\n");
+
+        ASSERT_EQUALS(expected, actual);
+    }
+
     void varidStl()
     {
         const std::string code("list<int> ints;\n"