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Fix #14098 FN nullPointer constructing std::string from known function result (regression) #8141

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Fix #14098 FN nullPointer constructing std::string from known function result (regression) #8141

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0bf9b25
Update checknullpointer.cpp
chrchr-github Jan 21, 2026
09c92f0
Update testnullpointer.cpp
chrchr-github Jan 21, 2026
6df17ac
Format [skip ci]
chrchr-github Jan 21, 2026
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6 changes: 3 additions & 3 deletions lib/checknullpointer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -223,10 +223,10 @@ bool CheckNullPointer::isPointerDeRef(const Token *tok, bool &unknown, const Set
return true;

// std::string dereferences nullpointers
if (Token::Match(parent->tokAt(-3), "std :: string|wstring (|{ %name% )|}"))
if (Token::Match(parent->tokAt(-3), "std :: string|wstring (|{"))
return true;
if (Token::Match(parent->previous(), "%name% (|{ %name% )|}")) {
const Variable* var = tok->tokAt(-2)->variable();
if (Token::Match(parent->previous(), "%name% (|{")) {
const Variable* var = parent->previous()->variable();
if (var && !var->isPointer() && !var->isArray() && var->isStlStringType())
return true;
}
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9 changes: 9 additions & 0 deletions test/testnullpointer.cpp
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Expand Up @@ -3944,6 +3944,15 @@ class TestNullPointer : public TestFixture {
"void f() { std::string s = g(0L); }\n");
ASSERT_EQUALS("[test.cpp:2:29]: (error) Null pointer dereference: g(0L) [nullPointer]\n",
errout_str());

check("const char* g() { return nullptr; }\n" // #14098
"std::string f() {\n"
" std::string s{ g() };\n"
" return s + std::string(g());\n"
"}\n");
ASSERT_EQUALS("[test.cpp:3:21]: (error) Null pointer dereference: g() [nullPointer]\n"
"[test.cpp:4:29]: (error) Null pointer dereference: g() [nullPointer]\n",
errout_str());
}

void nullpointerStdStream() {
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