Fix #13057 FP: Returning pointer to local variable (danmar#6739)

Author: chrchr-github

lib/valueflow.cpp

@@ -3017,6 +3017,8 @@ static void valueFlowLifetimeFunction(Token *tok, const TokenList &tokenlist, Er
         // TODO: Propagate lifetimes with library functions
         if (settings.library.getFunction(tok->previous()))
             return;
+        if (Token::simpleMatch(tok->astParent(), "."))
+            return;
         // Assume constructing the valueType
         valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings);
         valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings);

test/testautovariables.cpp

@@ -3504,6 +3504,13 @@ class TestAutoVariables : public TestFixture {
               "    return par;\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("struct S { int* (*ptr)(const int*); };\n" // #13057
+              "int* f(S* s) {\n"
+              "    int x = 0;\n"
+              "    return s->ptr(&x);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
     }
 
     void danglingLifetimeUserConstructor()