From 8579feb3aa49d846e1feaea83bf292d4671ec49f Mon Sep 17 00:00:00 2001
From: chrchr-github <78114321+chrchr-github@users.noreply.github.com>
Date: Sat, 11 Jun 2022 11:01:23 +0200
Subject: [PATCH] Fix  #10545 FP redundantCopyLocalConst with modified object
 [inconclusive] (#4197)

* Fix  #10545 FP redundantCopyLocalConst with modified object [inconclusive]

* Comment
---
 lib/checkother.cpp |  4 ++++
 test/testother.cpp | 15 ++++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 3800b9251..f78401158 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -2757,6 +2757,10 @@ void CheckOther::checkRedundantCopy()
         if (!Token::Match(tok->link(), ") )| ;")) // bailout for usage like "const A a = getA()+3"
             continue;
 
+        const Token* dot = tok->astOperand1();
+        if (Token::simpleMatch(dot, ".") && dot->astOperand1() && isVariableChanged(dot->astOperand1()->variable(), mSettings, mTokenizer->isCPP()))
+            continue;
+
         const Function* func = tok->previous()->function();
         if (func && func->tokenDef->strAt(-1) == "&") {
             redundantCopyError(startTok, startTok->str());
diff --git a/test/testother.cpp b/test/testother.cpp
index 11d4dd482..187707b89 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -7521,7 +7521,7 @@ private:
                                "    }\n"
                                "}";
         check(code5618, nullptr, false, true);
-        TODO_ASSERT_EQUALS("", "[test.cpp:7]: (performance, inconclusive) Use const reference for 'temp' to avoid unnecessary data copying.\n", errout.str());
+        ASSERT_EQUALS("", errout.str());
         check(code5618, nullptr, false, false);
         ASSERT_EQUALS("", errout.str());
 
@@ -7544,6 +7544,19 @@ private:
               "  const CD cd(CD::getOne());\n"
               "}", nullptr, false, true);
         ASSERT_EQUALS("", errout.str());
+
+        check("struct S {\n" // #10545
+              "    int modify();\n"
+              "    const std::string& get() const;\n"
+              "};\n"
+              "std::string f(S& s) {\n"
+              "    const std::string old = s.get();\n"
+              "    int i = s.modify();\n"
+              "    if (i != 0)\n"
+              "        return old;\n"
+              "    return {};\n"
+              "}", nullptr, /*experimental*/ false, /*inconclusive*/ true);
+        ASSERT_EQUALS("", errout.str());
     }
 
     void checkNegativeShift() {