diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
index c8fcca48f1a..72664c6a954 100644
--- a/lib/checkstl.cpp
+++ b/lib/checkstl.cpp
@@ -637,12 +637,14 @@ void CheckStlImpl::iterators()
 void CheckStlImpl::mismatchingContainerIteratorError(const Token* containerTok, const Token* iterTok, const Token* containerTok2)
 {
     const std::string container(containerTok ? containerTok->expressionString() : std::string("v1"));
+    const std::string containerTemp(isTemporary(containerTok, &mSettings.library) ? " temporary " : " ");
     const std::string container2(containerTok2 ? containerTok2->expressionString() : std::string("v2"));
+    const std::string containerTemp2(isTemporary(containerTok2, &mSettings.library) ? " temporary " : " ");
     const std::string iter(iterTok ? iterTok->expressionString() : std::string("it"));
     reportError(containerTok,
                 Severity::error,
                 "mismatchingContainerIterator",
-                "Iterator '" + iter + "' referring to container '" + container2 + "' is used with container '" + container + "'.",
+                "Iterator '" + iter + "' referring to" + containerTemp2 + "container '" + container2 + "' is used with" + containerTemp + "container '" + container + "'.",
                 CWE664,
                 Certainty::normal);
 }
@@ -884,7 +886,7 @@ void CheckStlImpl::mismatchingContainerIterator()
             const std::vector<const Token *> args = getArguments(ftok);
 
             const Library::Container * c = tok->valueType()->container;
-            const Library::Container::Action action = c->getAction(tok->strAt(2));
+            const Library::Container::Action action = c->getAction(ftok->str());
             const Token* iterTok = nullptr;
             if (action == Library::Container::Action::INSERT && args.size() == 2) {
                 // Skip if iterator pair
diff --git a/test/teststl.cpp b/test/teststl.cpp
index 2060a5cfd2b..50ad9297e87 100644
--- a/test/teststl.cpp
+++ b/test/teststl.cpp
@@ -2345,6 +2345,15 @@ class TestStl : public TestFixture {
               "    }   \n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("std::string g1();\n" // #12520
+              "const std::string& g2();\n"
+              "void f() {\n"
+              "    g1().erase(g1().begin());\n"
+              "    g2().erase(g2().begin());\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:4:7]: (error) Iterator 'g1().begin()' referring to temporary container 'g1()' is used with temporary container 'g1()'. [mismatchingContainerIterator]\n",
+                      errout_str());
     }
 
     void eraseIteratorOutOfBounds() {