From 02ae71917a8b8f7890ef5e950243b987a8a43892 Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Wed, 1 Apr 2020 15:35:41 -0500
Subject: [PATCH] Fix issue 9536: False positive: Reference to temporary
 returned when using operator() (#2582)

* Fix issue 9536: False positive: Reference to temporary returned when using operator()

* Add more test cases
---
 lib/astutils.cpp           |  5 +++++
 test/testautovariables.cpp | 29 +++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index 80a752fb2..befd66053 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -254,6 +254,11 @@ bool isTemporary(bool cpp, const Token* tok, const Library* library, bool unknow
             return unknown;
         }
     }
+    if (tok->isCast())
+        return false;
+    // Currying a function is unknown in cppcheck
+    if (Token::simpleMatch(tok, "(") && Token::simpleMatch(tok->astOperand1(), "("))
+        return unknown;
     return true;
 }
 
diff --git a/test/testautovariables.cpp b/test/testautovariables.cpp
index 49bd45770..2b4560de7 100644
--- a/test/testautovariables.cpp
+++ b/test/testautovariables.cpp
@@ -114,6 +114,7 @@ private:
         TEST_CASE(returnReference17); // #9461
         TEST_CASE(returnReference18); // #9482
         TEST_CASE(returnReference19); // #9597
+        TEST_CASE(returnReference20); // #9536
         TEST_CASE(returnReferenceFunction);
         TEST_CASE(returnReferenceContainer);
         TEST_CASE(returnReferenceLiteral);
@@ -1316,6 +1317,34 @@ private:
         ASSERT_EQUALS("", errout.str());
     }
 
+    // #9536
+    void returnReference20() {
+        check("struct a {\n"
+              "    int& operator()() const;\n"
+              "};\n"
+              "int& b() {\n"
+              "    return a()();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("auto a() {\n"
+              "    return []() -> int& {\n"
+              "        static int b;\n"
+              "        return b;\n"
+              "    };\n"
+              "}\n"
+              "const int& c() {\n"
+              "    return a()();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        check("std::function<int&()> a();\n"
+              "int& b() {\n"
+              "    return a()();\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
+    }
+
     void returnReferenceFunction() {
         check("int& f(int& a) {\n"
               "    return a;\n"