From 0a718694afae837010f68a2bdbb8f158e1ea81aa Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Tue, 1 Sep 2020 04:21:29 -0500
Subject: [PATCH] Fix issue 9852: False positive: danglingTemporaryLifetime
 when returning a vector of vectors (#2766)

---
 lib/checkautovariables.cpp | 13 +++++++++++--
 test/testautovariables.cpp |  7 +++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/lib/checkautovariables.cpp b/lib/checkautovariables.cpp
index 889b22569..f36694b32 100644
--- a/lib/checkautovariables.cpp
+++ b/lib/checkautovariables.cpp
@@ -445,8 +445,17 @@ static bool isDeadTemporary(bool cpp, const Token* tok, const Token* expr, const
 {
     if (!isTemporary(cpp, tok, library))
         return false;
-    if (expr && !precedes(nextAfterAstRightmostLeaf(tok->astTop()), nextAfterAstRightmostLeaf(expr->astTop())))
-        return false;
+    if (expr) {
+        if (!precedes(nextAfterAstRightmostLeaf(tok->astTop()), nextAfterAstRightmostLeaf(expr->astTop())))
+            return false;
+        const Token* parent = tok->astParent();
+        // Is in a for loop
+        if (astIsRHS(tok) && Token::simpleMatch(parent, ":") && Token::simpleMatch(parent->astParent(), "(") && Token::simpleMatch(parent->astParent()->previous(), "for (")) {
+            const Token* braces = parent->astParent()->link()->next();
+            if (precedes(braces, expr) && precedes(expr, braces->link()))
+                return false;
+        }
+    }
     return true;
 }
 
diff --git a/test/testautovariables.cpp b/test/testautovariables.cpp
index 34bb9c0be..8748b85e8 100644
--- a/test/testautovariables.cpp
+++ b/test/testautovariables.cpp
@@ -2142,6 +2142,13 @@ private:
               "    return std::vector<char*>{&a};\n"
               "}\n");
         ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:3] -> [test.cpp:2] -> [test.cpp:3]: (error) Returning object that points to local variable 'a' that will be invalid when returning.\n", errout.str());
+
+        check("std::vector<std::vector<int>> g();\n"
+              "void f() {\n"
+              "    for(auto& x:g())\n"
+              "        std::sort(x.begin(), x.end());\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void danglingLifetime() {