diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 6556ff204..6354859ba 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -3508,6 +3508,21 @@ static void valueFlowContainerSize(TokenList *tokenlist, SymbolDatabase* symbold
         valueFlowContainerForward(var->nameToken()->next(), var->declarationId(), value, settings);
     }
 
+    // after assignment
+    for (const Scope *functionScope : symboldatabase->functionScopes) {
+        for (const Token *tok = functionScope->bodyStart; tok != functionScope->bodyEnd; tok = tok->next()) {
+            if (Token::Match(tok, "[;{}] %var% = %str% ;")) {
+                const Token *containerTok = tok->next();
+                if (containerTok && containerTok->valueType() && containerTok->valueType()->container && containerTok->valueType()->container->stdStringLike) {
+                    ValueFlow::Value value(Token::getStrLength(containerTok->tokAt(2)));
+                    value.valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
+                    value.setKnown();
+                    valueFlowContainerForward(containerTok->next(), containerTok->varId(), value, settings);
+                }
+            }
+        }
+    }
+
     // conditional conditionSize
     for (const Scope &scope : symboldatabase->scopeList) {
         if (scope.type != Scope::ScopeType::eIf) // TODO: while
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index f2b361cfb..8770fc6a0 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -3327,10 +3327,16 @@ private:
         ASSERT(tokenValues(code, "v [").empty());
 
         code = "void f() {\n"
-               "  std::list<int> ints;\n"
+               "  std::list<int> ints;\n"  // No value => ints is empty
                "  ints.front();\n"
                "}";
         ASSERT_EQUALS("", isKnownContainerSizeValue(tokenValues(code, "ints . front"), 0));
+
+        code = "void f() {\n"
+               "  std::string s=\"abc\";\n" // size of s is 3
+               "  s.size();\n"
+               "}";
+        ASSERT_EQUALS("", isKnownContainerSizeValue(tokenValues(code, "s . size"), 3));
     }
 };