Fix #14465 duplicated returnDanglingLifetime (#8184)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/checkautovariables.cpp

@@ -617,7 +617,8 @@ void CheckAutoVariables::checkVarLifetimeScope(const Token * start, const Token
                         if ((tokvalue->variable() && !isEscapedReference(tokvalue->variable()) &&
                              isInScope(tokvalue->variable()->nameToken(), scope)) ||
                             isDeadTemporary(tokvalue, nullptr, mSettings->library)) {
-                            errorReturnDanglingLifetime(tok, &val);
+                            if (!diag(tokvalue))
+                                errorReturnDanglingLifetime(tok, &val);
                             break;
                         }
                     } else if (tokvalue->variable() && isDeadScope(tokvalue->variable()->nameToken(), tok->scope())) {

test/testautovariables.cpp

@@ -2643,8 +2643,7 @@ class TestAutoVariables : public TestFixture {
               "    auto it = g().begin();\n"
               "    return it;\n"
               "}");
-        ASSERT_EQUALS("[test.cpp:3:24] -> [test.cpp:3:16] -> [test.cpp:4:5]: (error) Using iterator that is a temporary. [danglingTemporaryLifetime]\n"
-                      "[test.cpp:3:24] -> [test.cpp:4:12]: (error) Returning iterator that will be invalid when returning. [returnDanglingLifetime]\n",
+        ASSERT_EQUALS("[test.cpp:3:24] -> [test.cpp:3:16] -> [test.cpp:4:5]: (error) Using iterator that is a temporary. [danglingTemporaryLifetime]\n",
                       errout_str());
 
         check("std::vector<int> g();\n"
@@ -3142,6 +3141,14 @@ class TestAutoVariables : public TestFixture {
         ASSERT_EQUALS(
             "[test.cpp:3:12] -> [test.cpp:2:10] -> [test.cpp:3:12]: (error) Returning pointer to local variable 'a' that will be invalid when returning. [returnDanglingLifetime]\n",
             errout_str());
+
+        check("std::string_view f() {\n" // #14465
+              "    std::vector<std::string> v;\n"
+              "    return *v.begin();\n"
+              "}\n");
+        ASSERT_EQUALS(
+            "[test.cpp:3:12] -> [test.cpp:3:12]: (error) Returning object that will be invalid when returning. [returnDanglingLifetime]\n",
+            errout_str());
     }
 
     void danglingLifetimeUniquePtr()