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fix #12944: False positive: uninitvar reported in lambda #6975

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fix #12944: False positive: uninitvar reported in lambda #6975

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233eb5c
fix #12944
ludviggunne Oct 30, 2024
ed6f54b
move test
ludviggunne Oct 30, 2024
0cc4aaa
remove empty line
ludviggunne Oct 30, 2024
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2 changes: 2 additions & 0 deletions lib/checkuninitvar.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1671,6 +1671,8 @@ void CheckUninitVar::valueFlowUninit()
const bool isleaf = isLeafDot(tok) || uninitderef;
if (!isleaf && Token::Match(tok->astParent(), ". %name%") && (tok->astParent()->next()->varId() || tok->astParent()->next()->isEnumerator()))
continue;
if (isWithinScope(tok, tok->variable(), Scope::ScopeType::eLambda))
continue;
}
const ExprUsage usage = getExprUsage(tok, v->indirect, *mSettings);
if (usage == ExprUsage::NotUsed || usage == ExprUsage::Inconclusive)
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12 changes: 12 additions & 0 deletions test/testuninitvar.cpp
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Expand Up @@ -63,6 +63,7 @@ class TestUninitVar : public TestFixture {
TEST_CASE(valueFlowUninit2_value);
TEST_CASE(valueFlowUninit_uninitvar2);
TEST_CASE(valueFlowUninit_functioncall);
TEST_CASE(valueFlowUninit_lambda); // #12944
TEST_CASE(uninitStructMember); // struct members
TEST_CASE(uninitvar2_while);
TEST_CASE(uninitvar2_4494); // #4494
Expand Down Expand Up @@ -4389,6 +4390,17 @@ class TestUninitVar : public TestFixture {
ASSERT_EQUALS("[test.cpp:8] -> [test.cpp:4]: (warning) Uninitialized variable: i\n", errout_str());
}

void valueFlowUninit_lambda() { // #12944
valueFlowUninit( "void Fun()\n"
"{\n"
" int var;\n"
" auto lam = [&]() { int x = var; };\n"
" var = 5;\n"

@danmar danmar Oct 30, 2024

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I assume after your changes that no error will be written if var = 5; is removed?

It feels like a better fix would be in valueflow? I assume it "executes" the lambda when it is defined. It should probably skip the lambda first and then when lam() is called it can "execute" the lambda.

" lam();\n"
"}\n");
ASSERT_EQUALS("", errout_str());
}

void uninitStructMember() { // struct members
checkUninitVar("struct AB { int a; int b; };\n"
"void f(void) {\n"
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