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Fix #15087 FP constParameterReference (returning reference to member in ternary) #8918

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Fix #15087 FP constParameterReference (returning reference to member in ternary) #8918

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8387608
Update testother.cpp
chrchr-github Oct 5, 2026
9de5bdd
Update checkother.cpp
chrchr-github Oct 5, 2026
a32896b
Format
chrchr-github Oct 5, 2026
6c6c205
Update checkother.cpp [skip ci]
chrchr-github Oct 7, 2026
9716105
Update testother.cpp
chrchr-github Oct 7, 2026
74b89d2
Merge branch 'main' into chr_15087
chrchr-github Oct 22, 2026
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37 changes: 25 additions & 12 deletions lib/checkother.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1825,18 +1825,31 @@ void CheckOtherImpl::checkConstVariable()
if (function && (Function::returnsReference(function) || Function::returnsPointer(function)) && !Function::returnsConst(function)) {
std::vector<const Token*> returns = Function::findReturns(function);
if (std::any_of(returns.cbegin(), returns.cend(), [&](const Token* retTok) {
if (retTok->varId() == var->declarationId())
return true;
while (retTok && retTok->isCast())
retTok = retTok->astOperand2() ? retTok->astOperand2() : retTok->astOperand1();
while (Token::simpleMatch(retTok, "."))
retTok = retTok->astOperand2();
if (Token::simpleMatch(retTok, "&"))
retTok = retTok->astOperand1();
ValueFlow::Value ltVal = ValueFlow::getLifetimeObjValue(retTok);
if (ltVal.isLifetimeValue() && ltVal.tokvalue->varId() == var->declarationId())
return true;
return ValueFlow::hasLifetimeToken(getParentLifetime(retTok), var->nameToken(), mSettings);
bool result = false;
visitAstNodes(retTok, [&result, &var, this](const Token* tok) {
if (tok->varId() == var->declarationId()) {
result = true;
return ChildrenToVisit::done;
}
ValueFlow::Value ltVal = ValueFlow::getLifetimeObjValue(tok);
if ((ltVal.isLifetimeValue() && ltVal.tokvalue->varId() == var->declarationId()) ||
ValueFlow::hasLifetimeToken(getParentLifetime(tok), var->nameToken(), mSettings)) {
result = true;
return ChildrenToVisit::done;
}
if (tok->isCast())
return tok->astOperand2() ? ChildrenToVisit::op2 : ChildrenToVisit::op1;
if (tok->str() == ".")
return ChildrenToVisit::op2;

@dmcppcheck dmcppcheck Oct 23, 2026

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AI review

This only follows the member side of ., so a ternary in the object expression is not reached. int& g(S& s, S& t, bool b) { return (b ? s : t).a; } still gives constParameterReference for both s and t, and both are wrong because the function returns a non-const int&. Visiting op1 of . as well (or both operands) would cover this case too.

if (tok->str() == "&")
return ChildrenToVisit::op1;
if (tok->str() == "?")
return ChildrenToVisit::op2;
if (tok->str() == ":")
return ChildrenToVisit::op1_and_op2;
return ChildrenToVisit::none;
});
return result;
}))
continue;
}
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11 changes: 11 additions & 0 deletions test/testother.cpp
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Expand Up @@ -4225,6 +4225,17 @@ class TestOther : public TestFixture {
" int select(DS &ds) { return select(ds, [](int) {}); }\n"
"};\n");
ASSERT_EQUALS("", errout_str());

check("struct S {\n" // #15087
" int a, b;\n"
"};\n"
"int& f(S& s, bool b) {\n"
" return b ? s.a : s.b;\n"
"}\n"
"int* g(U& u) {\n"

@dmcppcheck dmcppcheck Oct 23, 2026

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AI review

U is not declared here, and this function gives no warning on base either, so this part of the test does not cover the change. Consider replacing it with a case that only passes with the PR, e.g. int* g(S& s, bool b) { return b ? &s.a : &s.b; } or int& h(S& s, S& t, bool b) { return b ? s.a : t.a; }.

" return &(u.i);\n"
"}\n");
ASSERT_EQUALS("", errout_str());
}

void constParameterCallback() {
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