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Fix #15150 Duplicate accessMoved (passed by value to subfunction) #8969

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Fix #15150 Duplicate accessMoved (passed by value to subfunction) #8969

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7e345b3
Update valueflow.cpp
chrchr-github Oct 27, 2026
9d0880c
Update testother.cpp
chrchr-github Oct 27, 2026
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4 changes: 2 additions & 2 deletions lib/valueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5738,11 +5738,11 @@ static void valueFlowSubFunction(const TokenList& tokenlist,
// passing value(s) to function
std::list<ValueFlow::Value> argvalues(getFunctionArgumentValues(argtok));

// Remove non-local lifetimes
// Remove non-local lifetimes and moved values
argvalues.remove_if([](const ValueFlow::Value& v) {
if (v.isLifetimeValue())
return !v.isLocalLifetimeValue() && !v.isSubFunctionLifetimeValue();
return false;
return v.isMovedValue();

@dmcppcheck dmcppcheck Oct 29, 2026

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AI review

This removes moved values for every parameter kind, so it loses true positives when a moved-from object is passed by non-const reference. The caller does not warn in that case, because the callee could reinitialize the object, so before this PR the callee was the only place where the warning came from:

void g1(std::vector<int>& v) { int x = v[0]; (void)x; }
void f1() { std::vector<int> v; auto w = std::move(v); g1(v); }

base: accessMoved at v[0]. PR: no warning.

Restricting the removal to by-value parameters would fix #15150 and keep these warnings, e.g. return v.isMovedValue() && !argvar->isReference(); (the lambda would need to capture argvar). A test with a reference parameter would also help.

});
// Remove uninit values if argument is passed by value
if (argtok->variable() && !argtok->variable()->isPointer() && argvalues.size() == 1 &&
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15 changes: 15 additions & 0 deletions test/testother.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -312,6 +312,7 @@ class TestOther : public TestFixture {
TEST_CASE(movePointerAlias);
TEST_CASE(moveOutparam);
TEST_CASE(moveTryEmplace);
TEST_CASE(moveSubFunction);

TEST_CASE(funcArgNamesDifferent);
TEST_CASE(funcArgOrderDifferent);
Expand Down Expand Up @@ -13342,6 +13343,20 @@ class TestOther : public TestFixture {
ASSERT_EQUALS("", errout_str());
}

void moveSubFunction()
{
check("struct T {\n" // #15150
" void set(std::string a) { m = std::move(a); }\n"
" std::string m;\n"
"};\n"
"void f(std::string s) {\n"
" T t;\n"
" t.set(std::move(s));\n"
" t.set(s);\n"
"}\n");
ASSERT_EQUALS("[test.cpp:8:11]: (warning) Access of moved variable 's'. [accessMoved]\n", 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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