diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
index 4b7761510..66474cb1d 100644
--- a/lib/checkcondition.cpp
+++ b/lib/checkcondition.cpp
@@ -1537,3 +1537,53 @@ void CheckCondition::pointerAdditionResultNotNullError(const Token *tok, const T
     const std::string s = calc ? calc->expressionString() : "ptr+1";
     reportError(tok, Severity::warning, "pointerAdditionResultNotNull", "Comparison is wrong. Result of '" + s + "' can't be 0 unless there is pointer overflow, and pointer overflow is undefined behaviour.");
 }
+
+void CheckCondition::checkDuplicateConditionalAssign()
+{
+    if (!mSettings->isEnabled(Settings::STYLE))
+        return;
+
+    const SymbolDatabase *symbolDatabase = mTokenizer->getSymbolDatabase();
+    for (const Scope *scope : symbolDatabase->functionScopes) {
+        for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
+            if (!Token::simpleMatch(tok, "if ("))
+                continue;
+            if (!Token::simpleMatch(tok->next()->link(), ") {"))
+                continue;
+            const Token *blockTok = tok->next()->link()->next();
+            const Token *condTok = tok->next()->astOperand2();
+            if (!Token::Match(condTok, "==|!="))
+                continue;
+            if (condTok->str() == "!=" && Token::simpleMatch(blockTok->link(), "} else {"))
+                continue;
+            if (!blockTok->next())
+                continue;
+            const Token *assignTok = blockTok->next()->astTop();
+            if (!Token::simpleMatch(assignTok, "="))
+                continue;
+            if (!isSameExpression(
+                    mTokenizer->isCPP(), true, condTok->astOperand1(), assignTok->astOperand1(), mSettings->library, true, true))
+                continue;
+            if (!isSameExpression(
+                    mTokenizer->isCPP(), true, condTok->astOperand2(), assignTok->astOperand2(), mSettings->library, true, true))
+                continue;
+            duplicateConditionalAssignError(condTok, assignTok);
+        }
+    }
+}
+
+void CheckCondition::duplicateConditionalAssignError(const Token *condTok, const Token* assignTok)
+{
+    ErrorPath errors;
+    if (condTok && assignTok) {
+        if (condTok->str() == "==") {
+            errors.emplace_back(condTok, "Condition '" + condTok->expressionString() + "'");
+            errors.emplace_back(assignTok, "Assignment '" + assignTok->expressionString() + "' is redundant");
+        } else {
+            errors.emplace_back(assignTok, "Assignment '" + assignTok->expressionString() + "'");
+            errors.emplace_back(condTok, "Condition '" + condTok->expressionString() + "' is redundant");
+        }
+    }
+    reportError(
+        errors, Severity::style, "duplicateConditionalAssign", "Duplicate expression for the condition and assignment.", CWE398, false);
+}
diff --git a/lib/checkcondition.h b/lib/checkcondition.h
index 421ac0688..bbbf04bdb 100644
--- a/lib/checkcondition.h
+++ b/lib/checkcondition.h
@@ -61,6 +61,7 @@ public:
         checkCondition.alwaysTrueFalse();
         checkCondition.duplicateCondition();
         checkCondition.checkPointerAdditionResultNotNull();
+        checkCondition.checkDuplicateConditionalAssign();
         checkCondition.assignIf();
         checkCondition.checkBadBitmaskCheck();
         checkCondition.comparison();
@@ -115,7 +116,9 @@ public:
     /** @brief Check if pointer addition result is NULL '(ptr + 1) == NULL' */
     void checkPointerAdditionResultNotNull();
 
-private:
+    void checkDuplicateConditionalAssign();
+
+  private:
     // The conditions that have been diagnosed
     std::set<const Token*> mCondDiags;
     bool diag(const Token* tok, bool insert=true);
@@ -151,6 +154,8 @@ private:
     void invalidTestForOverflow(const Token* tok, bool result);
     void pointerAdditionResultNotNullError(const Token *tok, const Token *calc);
 
+    void duplicateConditionalAssignError(const Token *condTok, const Token* assignTok);
+
     void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const OVERRIDE {
         CheckCondition c(nullptr, settings, errorLogger);
 
@@ -172,6 +177,7 @@ private:
         c.alwaysTrueFalseError(nullptr, nullptr);
         c.invalidTestForOverflow(nullptr, false);
         c.pointerAdditionResultNotNullError(nullptr, nullptr);
+        c.duplicateConditionalAssignError(nullptr, nullptr);
     }
 
     static std::string myName() {
@@ -183,6 +189,7 @@ private:
                "- Mismatching assignment and comparison => comparison is always true/false\n"
                "- Mismatching lhs and rhs in comparison => comparison is always true/false\n"
                "- Detect usage of | where & should be used\n"
+               "- Duplicate condition and assignment\n"
                "- Detect matching 'if' and 'else if' conditions\n"
                "- Mismatching bitand (a &= 0xf0; a &= 1; => a = 0)\n"
                "- Opposite inner condition is always false\n"
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index e9e8bce76..b858413e2 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -114,6 +114,7 @@ private:
         TEST_CASE(checkConditionIsAlwaysTrueOrFalseInsideIfWhile);
         TEST_CASE(alwaysTrueFalseInLogicalOperators);
         TEST_CASE(pointerAdditionResultNotNull);
+        TEST_CASE(duplicateConditionalAssign);
     }
 
     void check(const char code[], const char* filename = "test.cpp", bool inconclusive = false) {
@@ -3068,6 +3069,43 @@ private:
               "}");
         ASSERT_EQUALS("[test.cpp:2]: (warning) Comparison is wrong. Result of 'ptr+1' can't be 0 unless there is pointer overflow, and pointer overflow is undefined behaviour.\n", errout.str());
     }
+
+    void duplicateConditionalAssign()
+    {
+        check("void f(int& x, int y) {\n"
+              "    if (x == y)\n"
+              "        x = y;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Duplicate expression for the condition and assignment.\n", errout.str());
+
+        check("void f(int& x, int y) {\n"
+              "    if (x != y)\n"
+              "        x = y;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:2]: (style) Duplicate expression for the condition and assignment.\n", errout.str());
+
+        check("void f(int& x, int y) {\n"
+              "    if (x == y)\n"
+              "        x = y;\n"
+              "    else\n"
+              "        x = 1;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:2] -> [test.cpp:3]: (style) Duplicate expression for the condition and assignment.\n", errout.str());
+
+        check("void f(int& x, int y) {\n"
+              "    if (x != y)\n"
+              "        x = y;\n"
+              "    else\n"
+              "        x = 1;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("void f(int& x, int y) {\n"
+              "    if (x == y)\n"
+              "        x = y + 1;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
 };
 
 REGISTER_TEST(TestCondition)