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Fix #14896: false positive: missing co_return in void function #8719

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Fix #14896: false positive: missing co_return in void function #8719

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5b2fbea
add test
ludviggunne Jul 13, 2026
3d3d39a
fix
ludviggunne Jul 13, 2026
1dfbe28
add language/standard check
ludviggunne Jul 13, 2026
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2 changes: 2 additions & 0 deletions lib/checkfunctions.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -329,6 +329,8 @@ void CheckFunctionsImpl::checkMissingReturn()
continue;
if (Function::returnsVoid(function, true))
continue;
if (Function::isCoroutine(function, mSettings.standards, *mTokenizer))
continue;
const Token *errorToken = checkMissingReturnScope(scope->bodyEnd, mSettings.library);
if (errorToken)
missingReturnError(errorToken);
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14 changes: 14 additions & 0 deletions lib/symboldatabase.cpp
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Expand Up @@ -3407,6 +3407,20 @@ bool Function::returnsVoid(const Function* function, bool unknown)
});
}

bool Function::isCoroutine(const Function* function, const Standards &standards, const Tokenizer &tokens)

@danmar danmar Jul 14, 2026

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hmm the name could say something like "isCoroutineCalled" or something like that.
the function is not a coroutine itself

@ludviggunne ludviggunne Jul 14, 2026

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I believe it is: https://en.cppreference.com/cpp/language/coroutines

{
if (!tokens.isCPP() || standards.cpp < Standards::CPP20)
return false;
if (!function->functionScope)
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return false;
const Scope *scope = function->functionScope;
for (const Token *tok = scope->bodyStart; tok != scope->bodyEnd; tok = tok->next()) {
if (Token::Match(tok, "co_return|co_await|co_yield"))
return true;
}
return false;
}

std::vector<const Token*> Function::findReturns(const Function* f)
{
std::vector<const Token*> result;
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1 change: 1 addition & 0 deletions lib/symboldatabase.h
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Expand Up @@ -945,6 +945,7 @@ class CPPCHECKLIB Function {
static bool returnsStandardType(const Function* function, bool unknown = false);

static bool returnsVoid(const Function* function, bool unknown = false);
static bool isCoroutine(const Function* function, const Standards &standards, const Tokenizer &tokens);

static std::vector<const Token*> findReturns(const Function* f);

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9 changes: 9 additions & 0 deletions test/testfunctions.cpp
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Expand Up @@ -86,6 +86,7 @@ class TestFunctions : public TestFixture {
TEST_CASE(checkMissingReturn5);
TEST_CASE(checkMissingReturn6); // #13180
TEST_CASE(checkMissingReturn7); // #14370 - FN try/catch
TEST_CASE(checkMissingReturn8);
TEST_CASE(checkMissingReturnStdInt); // #14482 - FN std::int32_t

// std::move for locar variable
Expand Down Expand Up @@ -1927,6 +1928,14 @@ class TestFunctions : public TestFixture {
ASSERT_EQUALS("[test.cpp:3:19]: (error) Found an exit path from function with non-void return type that has missing return statement [missingReturn]\n", errout_str());
}

void checkMissingReturn8() {
const Settings s = settingsBuilder(settings).cpp(Standards::CPP20).build();
check("boost::asio::awaitable<void> test() {\n"
" co_return;\n"
"}\n",s);
ASSERT_EQUALS("", errout_str());
}

void checkMissingReturnStdInt() {// #14482 - FN
check("std::int32_t f() {}\n");
ASSERT_EQUALS("[test.cpp:1:19]: (error) Found an exit path from function with non-void return type that has missing return statement [missingReturn]\n", errout_str());
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