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Fix #12773 FP accessMoved using try_emplace() together with std::move() #8421

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Merged
chrchr-github merged 4 commits into from
Apr 11, 2026
Merged

Fix #12773 FP accessMoved using try_emplace() together with std::move() #8421

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914aa16
Update valueflow.cpp
chrchr-github Apr 7, 2026
5e769b3
Update testother.cpp
chrchr-github Apr 7, 2026
57029cb
Update valueflow.cpp
chrchr-github Apr 7, 2026
3381360
Merge branch 'main' into chr_12773
chrchr-github Apr 9, 2026
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16 changes: 15 additions & 1 deletion lib/valueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3223,6 +3223,14 @@
return nextAfterAstRightmostLeaf(parent);
}

static bool isTryEmplace(const Token* tok)
{
if (tok->str() != "(" || !Token::simpleMatch(tok->astOperand1(), ".") || !tok->astOperand1()->astOperand1() || !Token::simpleMatch(tok->astOperand1()->astOperand2(), "try_emplace"))
return false;
const ValueType* vt = tok->astOperand1()->astOperand1()->valueType();
return vt && vt->container && vt->container->stdAssociativeLike;
}

static void valueFlowAfterMove(const TokenList& tokenlist, const SymbolDatabase& symboldatabase, ErrorLogger& errorLogger, const Settings& settings)
{
if (!tokenlist.isCPP() || settings.standards.cpp < Standards::CPP11)
Expand Down Expand Up @@ -3265,9 +3273,15 @@
const nonneg int varId = varTok->varId();
// x is not MOVED after assignment if code is: x = ... std::move(x) .. ;
const Token *parent = tok->astParent();
bool bail = false;

Check warning

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The scope of the variable 'bail' can be reduced. Warning

The scope of the variable 'bail' can be reduced.
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Fixed
while (parent && parent->str() != "=" && parent->str() != "return" &&
!(parent->str() == "(" && isOpenParenthesisMemberFunctionCallOfVarId(parent, varId)))
!(parent->str() == "(" && isOpenParenthesisMemberFunctionCallOfVarId(parent, varId))) {
if (isTryEmplace(parent)) {
bail = true;
break;
}
parent = parent->astParent();
}
if (parent &&
(parent->str() == "return" || // MOVED in return statement
parent->str() == "(")) // MOVED in self assignment, isOpenParenthesisMemberFunctionCallOfVarId == true
Expand Down
12 changes: 12 additions & 0 deletions test/testother.cpp
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Expand Up @@ -304,6 +304,7 @@ class TestOther : public TestFixture {
TEST_CASE(moveForRange);
TEST_CASE(moveTernary);
TEST_CASE(movePointerAlias);
TEST_CASE(moveTryEmplace);

TEST_CASE(funcArgNamesDifferent);
TEST_CASE(funcArgOrderDifferent);
Expand Down Expand Up @@ -12730,6 +12731,17 @@ class TestOther : public TestFixture {
ASSERT_EQUALS("[test.cpp:5:8]: (warning) Access of moved variable '.'. [accessMoved]\n", errout_str());
}

void moveTryEmplace()
{
check("void f(std::map<std::string, std::string>& m, std::string& s) {\n" // #12773
" bool b = m.try_emplace(\"a\", std::move(s)).second;\n"
" if (!b) {\n"
" std::cout << s;\n"
" }\n"
"}\n");
ASSERT_EQUALS("", errout_str());
}

void funcArgNamesDifferent() {
check("void func1(int a, int b, int c);\n"
"void func1(int a, int b, int c) { }\n"
Expand Down
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