Fix #12874 FP redundantAssignment with offset (#6555)

danmar · Jun 29, 2024 · fc9bd28 · fc9bd28
1 parent a8ee10a
commit fc9bd28
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Showing 3 changed files with 14 additions and 5 deletions.
diff --git a/lib/checkother.cpp b/lib/checkother.cpp
@@ -520,7 +520,9 @@ void CheckOther::checkRedundantAssignment()
                 }
 
                 if (start->hasKnownSymbolicValue(tokenToCheck) && Token::simpleMatch(start->astParent(), "=") && !diag(tok)) {
-                    redundantAssignmentSameValueError(start, tokenToCheck, tok->astOperand1()->expressionString());
+                    const ValueFlow::Value* val = start->getKnownValue(ValueFlow::Value::ValueType::SYMBOLIC);
+                    if (val->intvalue == 0) // no offset
+                        redundantAssignmentSameValueError(tokenToCheck, val, tok->astOperand1()->expressionString());
                 }
 
                 // Get next assignment..
@@ -593,11 +595,10 @@ void CheckOther::redundantAssignmentInSwitchError(const Token *tok1, const Token
                 "Variable '$symbol' is reassigned a value before the old one has been used. 'break;' missing?", CWE563, Certainty::normal);
 }
 
-void CheckOther::redundantAssignmentSameValueError(const Token *tok1, const Token* tok2, const std::string &var)
+void CheckOther::redundantAssignmentSameValueError(const Token *tok, const ValueFlow::Value* val, const std::string &var)
 {
-    const ValueFlow::Value* val = tok1->getKnownValue(ValueFlow::Value::ValueType::SYMBOLIC);
     auto errorPath = val->errorPath;
-    errorPath.emplace_back(tok2, "");
+    errorPath.emplace_back(tok, "");
     reportError(errorPath, Severity::style, "redundantAssignment",
                 "$symbol:" + var + "\n"
                 "Variable '$symbol' is assigned an expression that holds the same value.", CWE563, Certainty::normal);

diff --git a/lib/checkother.h b/lib/checkother.h
@@ -254,7 +254,7 @@ class CPPCHECKLIB CheckOther : public Check {
     void redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive);
     void redundantInitializationError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive);
     void redundantAssignmentInSwitchError(const Token *tok1, const Token *tok2, const std::string &var);
-    void redundantAssignmentSameValueError(const Token *tok1, const Token *tok2, const std::string &var);
+    void redundantAssignmentSameValueError(const Token* tok, const ValueFlow::Value* val, const std::string& var);
     void redundantCopyError(const Token *tok1, const Token* tok2, const std::string& var);
     void redundantBitwiseOperationInSwitchError(const Token *tok, const std::string &varname);
     void suspiciousCaseInSwitchError(const Token* tok, const std::string& operatorString);

diff --git a/test/testother.cpp b/test/testother.cpp
@@ -10217,6 +10217,14 @@ class TestOther : public TestFixture {
               "    return a * b * c;\n"
               "}\n");
         ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:5]: (style) Redundant initialization for 'b'. The initialized value is overwritten before it is read.\n", errout_str());
+
+        check("int f(int i) {\n" // #12874
+              "    int j = i + 1;\n"
+              "    if (i > 5)\n"
+              "        j = i;\n"
+              "    return j;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
     }
 
     void varFuncNullUB() { // #4482