From 4dbbae62a7a3ccd95aceba68d6daf5a4feb14bf4 Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Thu, 8 Jun 2023 07:45:59 +0200
Subject: [PATCH] Fix #11753 FN: invalidLifetime (#5128)

* Fix #11753 FN: invalidLifetime

* Format

* Format

* Only forward for local variables

* Format

* Format
---
 lib/valueflow.cpp          | 17 +++++++++++++++++
 test/testautovariables.cpp | 17 +++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 04bddf20e..60446f315 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -4490,6 +4490,23 @@ static void valueFlowLifetimeFunction(Token *tok, TokenList *tokenlist, ErrorLog
         // Assume constructing the valueType
         valueFlowLifetimeConstructor(tok->next(), tokenlist, errorLogger, settings);
         valueFlowForwardLifetime(tok->next(), tokenlist, errorLogger, settings);
+    } else {
+        const std::string& retVal = settings->library.returnValue(tok);
+        if (retVal.compare(0, 3, "arg") == 0) {
+            std::size_t iArg{};
+            try {
+                iArg = strToInt<std::size_t>(retVal.substr(3));
+            } catch (...) {
+                return;
+            }
+            std::vector<const Token*> args = getArguments(tok);
+            if (iArg > 0 && iArg <= args.size()) {
+                const Token* varTok = args[iArg - 1];
+                if (varTok->variable() && varTok->variable()->isLocal())
+                    LifetimeStore{ varTok, "Passed to '" + tok->str() + "'.", ValueFlow::Value::LifetimeKind::Address }.byRef(
+                    tok->next(), tokenlist, errorLogger, settings);
+            }
+        }
     }
 }
 
diff --git a/test/testautovariables.cpp b/test/testautovariables.cpp
index a05fca0c5..8694c14e7 100644
--- a/test/testautovariables.cpp
+++ b/test/testautovariables.cpp
@@ -4413,6 +4413,23 @@ private:
               "    return 0;\n"
               "}");
         ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:4] -> [test.cpp:8]: (error) Using pointer to local variable 'x' that is out of scope.\n", errout.str());
+
+        // #11753
+        check("int main(int argc, const char *argv[]) {\n"
+              "    const char* s = \"\";\n"
+              "    if (argc > 0) {\n"
+              "        char buff[32]{};\n"
+              "        s = std::strncpy(buff, argv[0], 31);\n"
+              "    }\n"
+              "    std::cout << s;\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:4] -> [test.cpp:7]: (error) Using pointer to local variable 'buff' that is out of scope.\n", errout.str());
+
+        check("char* f(char* dst) {\n"
+              "    const char* src = \"abc\";\n"
+              "    return strcpy(dst, src);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void splitNamespaceAuto() { // #10473