diff --git a/lib/checkunusedvar.cpp b/lib/checkunusedvar.cpp
index 0c55b32a1..7a75e60b1 100644
--- a/lib/checkunusedvar.cpp
+++ b/lib/checkunusedvar.cpp
@@ -1072,6 +1072,11 @@ void CheckUnusedVar::checkFunctionVariableUsage_iterateScopes(const Scope* const
         } else if (Token::Match(tok, "[(,] (") &&
                    Token::Match(tok->next()->link(), ") %var% [,)]")) {
             variables.use(tok->next()->link()->next()->varId(), tok);   // use = read + write
+        } else if (Token::Match(tok, "[(,] *| %var% =")) {
+            tok = tok->next();
+            if (tok->str() == "*")
+                tok = tok->next();
+            variables.use(tok->varId(), tok);
         }
 
         // function
diff --git a/test/testunusedvar.cpp b/test/testunusedvar.cpp
index c6bd4dde7..a4aa7255e 100644
--- a/test/testunusedvar.cpp
+++ b/test/testunusedvar.cpp
@@ -1779,6 +1779,25 @@ private:
                               "    x(a, b=2);\n"  // <- if param2 is passed-by-reference then b might be used in x
                               "}");
         ASSERT_EQUALS("", errout.str());
+
+        functionVariableUsage("int foo() {\n" // ticket #6147
+                              "    int a = 0;\n"
+                              "    bar(a=a+2);\n"
+                              "}");
+        ASSERT_EQUALS("", errout.str());
+
+        functionVariableUsage("int foo() {\n" // ticket #6147
+                              "    int a = 0;\n"
+                              "    bar(a=2);\n"
+                              "}");
+        TODO_ASSERT_EQUALS("error", "", errout.str());
+
+        functionVariableUsage("void bar(int);\n"
+                              "int foo() {\n"
+                              "    int a = 0;\n"
+                              "    bar(a=a+2);\n"
+                              "}");
+        TODO_ASSERT_EQUALS("error", "", errout.str());
     }
 
     void localvar37() { // ticket #3078