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Fix #9997 False negative: variable is not used #4104

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Merged
danmar merged 4 commits into from
Jun 7, 2022
Merged

Fix #9997 False negative: variable is not used #4104

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27e1941
Fix #9997 False negative: variable is not used
chrchr-github May 11, 2022
db49b04
Fix dead store
chrchr-github May 11, 2022
2596af3
Fix dead store
chrchr-github May 11, 2022
a45fab6
Remove scope operator to avoid FP
chrchr-github May 11, 2022
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2 changes: 1 addition & 1 deletion lib/checkunusedvar.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1195,7 +1195,7 @@ void CheckUnusedVar::checkFunctionVariableUsage()
if (isIncrementOrDecrement && tok->astParent() && precedes(tok, tok->astOperand1()))
continue;

if (tok->str() == "=" && isRaiiClass(tok->valueType(), mTokenizer->isCPP(), false))
if (tok->str() == "=" && !(tok->valueType() && tok->valueType()->pointer) && isRaiiClass(tok->valueType(), mTokenizer->isCPP(), false))
continue;

if (tok->isName()) {
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1 change: 0 additions & 1 deletion lib/programmemory.cpp
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Expand Up @@ -360,7 +360,6 @@ static void fillProgramMemoryFromAssignments(ProgramMemory& pm, const Token* tok
++indentlevel;
continue;
}
tok2 = cond->astParent()->previous();
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@pfultz2 pfultz2 May 12, 2022

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Why is this changed? If the condition is false we should be skipping the entire block.

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@pfultz2 pfultz2 May 12, 2022

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Ah wait, I see, it's a dead store. Thats a bug. I think we need to continue here and not break. I think we can fix this in a later PR.

} else if (conditionIsTrue(cond, state)) {
if (inElse)
tok2 = tok2->link()->tokAt(-2);
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8 changes: 4 additions & 4 deletions test/testastutils.cpp
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Expand Up @@ -144,7 +144,7 @@ class TestAstUtils : public TestFixture {
const Token * const tok = (offset < 0)
? tokenizer.list.back()->tokAt(1+offset)
: tokenizer.tokens()->tokAt(offset);
return (::isReturnScope)(tok);
return (isReturnScope)(tok);
}

void isReturnScopeTest() {
Expand Down Expand Up @@ -176,7 +176,7 @@ class TestAstUtils : public TestFixture {
tokenizer.simplifyTokens1("");
const Token * const tok1 = Token::findsimplematch(tokenizer.tokens(), tokStr1, strlen(tokStr1));
const Token * const tok2 = Token::findsimplematch(tok1->next(), tokStr2, strlen(tokStr2));
return (::isSameExpression)(false, false, tok1, tok2, library, false, true, nullptr);
return (isSameExpression)(false, false, tok1, tok2, library, false, true, nullptr);
}

void isSameExpressionTest() {
Expand Down Expand Up @@ -214,7 +214,7 @@ class TestAstUtils : public TestFixture {
ASSERT_LOC(tokenizer.tokenize(istr, "test.cpp"), file, line);
const Token * const tok1 = Token::findsimplematch(tokenizer.tokens(), startPattern, strlen(startPattern));
const Token * const tok2 = Token::findsimplematch(tokenizer.tokens(), endPattern, strlen(endPattern));
return (::isVariableChanged)(tok1, tok2, 1, false, &settings, true);
return (isVariableChanged)(tok1, tok2, 1, false, &settings, true);
}

void isVariableChangedTest() {
Expand All @@ -236,7 +236,7 @@ class TestAstUtils : public TestFixture {
std::istringstream istr(code);
ASSERT_LOC(tokenizer.tokenize(istr, "test.cpp"), file, line);
const Token * const argtok = Token::findmatch(tokenizer.tokens(), pattern);
return (::isVariableChangedByFunctionCall)(argtok, 0, &settings, inconclusive);
return (isVariableChangedByFunctionCall)(argtok, 0, &settings, inconclusive);
}

void isVariableChangedByFunctionCallTest() {
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3 changes: 1 addition & 2 deletions test/testclangimport.cpp
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Expand Up @@ -1281,8 +1281,7 @@ class TestClangImport : public TestFixture {
const Token *tok = Token::findsimplematch(tokenizer.tokens(), "sizeof (");
ASSERT(!!tok);
tok = tok->next();
// TODO ASSERT(tok->hasKnownIntValue());
// TODO ASSERT_EQUALS(10, tok->getKnownIntValue());
TODO_ASSERT_EQUALS(true, false, tok->hasKnownIntValue() && tok->getKnownIntValue() == 10);
}

void valueType1() {
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23 changes: 23 additions & 0 deletions test/testunusedvar.cpp
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Expand Up @@ -131,6 +131,7 @@ class TestUnusedVar : public TestFixture {
TEST_CASE(localvar61); // #9407
TEST_CASE(localvar62); // #10824
TEST_CASE(localvar63); // #6928
TEST_CASE(localvar64); // #9997
TEST_CASE(localvarloops); // loops
TEST_CASE(localvaralias1);
TEST_CASE(localvaralias2); // ticket #1637
Expand Down Expand Up @@ -3484,6 +3485,28 @@ class TestUnusedVar : public TestFixture {
ASSERT_EQUALS("[test.cpp:2]: (style) Variable 'x' is assigned a value that is never used.\n", errout.str());
}

void localvar64() { // #9997
functionVariableUsage("class S {\n"
" ~S();\n"
" S* f();\n"
" S* g(int);\n"
"};\n"
"void h(S* s, bool b) {\n"
" S* p = nullptr;\n"
" S* q = nullptr;\n"
" if (b) {\n"
" p = s;\n"
" q = s->f()->g(-2);\n"
" }\n"
" else\n"
" q = s;\n"
"}\n");
ASSERT_EQUALS("[test.cpp:10]: (style) Variable 'p' is assigned a value that is never used.\n"
"[test.cpp:11]: (style) Variable 'q' is assigned a value that is never used.\n"
"[test.cpp:14]: (style) Variable 'q' is assigned a value that is never used.\n",
errout.str());
}

void localvarloops() {
// loops
functionVariableUsage("void fun(int c) {\n"
Expand Down