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Fix #11538: Fix syntax error on C++23 'if consteval' / 'if !consteval' #8733

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Fix #11538: Fix syntax error on C++23 'if consteval' / 'if !consteval' #8733

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17 changes: 16 additions & 1 deletion lib/tokenize.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5721,7 +5721,22 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])

// if MACRO
for (Token *tok = list.front(); tok; tok = tok->next()) {
if (Token::Match(tok, "if|for|while %name% (")) {
if (Token::simpleMatch(tok, "if consteval {")) {

@ludviggunne ludviggunne Jul 30, 2026

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I think this has to be done after Tokenizer::simplifyCAlternativeTokens is called. Suggested test case (from https://en.cppreference.com/cpp/language/if#Consteval_if):

constexpr bool is_runtime_evaluated() noexcept
{
    if not consteval { return true; } else { return false; }
}

@ludviggunne ludviggunne Jul 30, 2026

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Or just match with "not" as well.

@danmar danmar Aug 4, 2026

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it sounds good to me if it can be moved until after simplifyCAlternativeTokens.. is that a working solution?

@ludviggunne ludviggunne Aug 5, 2026

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I think it's simpler to just match with not as well. It's replaced later anyway:

cppcheck $ cat tmp/consteval.cpp
void f(void)
{
    if consteval {} else {}
    if !consteval {} else {}
    if not consteval {} else {}
}
cppcheck $ ./cppcheck --debug tmp/consteval.cpp
Checking tmp/consteval.cpp ...


##file tmp/consteval.cpp
1: void f ( )
2: {
3: if ( __cppcheck_consteval__@expr2 ) { } else { }
4: if ( !@expr3 __cppcheck_consteval__@expr2 ) { } else { }
5: if ( !@expr3 __cppcheck_consteval__@expr2 ) { } else { }
6: }

@autoantwort autoantwort Aug 11, 2026

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I have kept the current implementation, or should I move it after simplifyCAlternativeTokens?

// 'if consteval { ... }' -> 'if ( __cppcheck_consteval__ ) { ... }'
Token *parTok = tok->next();
parTok->str("(");
Token *evalTok = parTok->insertToken("__cppcheck_consteval__");
evalTok->originalName("consteval");
evalTok->insertToken(")");
} else if (Token::Match(tok, "if !|not consteval {")) {
// 'if !consteval { ... }' / 'if not consteval { ... }' -> 'if ( ! __cppcheck_consteval__ ) { ... }'
Token *notTok = tok->next();
notTok->insertTokenBefore("(");
Token *evalTok = notTok->next();
evalTok->str("__cppcheck_consteval__");
evalTok->originalName("consteval");
evalTok->insertToken(")");
} else if (Token::Match(tok, "if|for|while %name% (")) {
if (Token::simpleMatch(tok, "for each")) {
// 'for each (x in y )' -> 'for (x : y)'
if (Token* in = Token::findsimplematch(tok->tokAt(2), "in", tok->linkAt(2)))
Expand Down
17 changes: 17 additions & 0 deletions test/testtokenize.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -104,6 +104,7 @@ class TestTokenizer : public TestFixture {

TEST_CASE(foreach); // #3690
TEST_CASE(ifconstexpr);
TEST_CASE(ifconsteval);

TEST_CASE(combineOperators);

Expand Down Expand Up @@ -1042,6 +1043,22 @@ class TestTokenizer : public TestFixture {
filter_valueflow(errout_str()));
}

void ifconsteval() {
ASSERT_EQUALS("void f ( ) { if ( __cppcheck_consteval__ ) { bar ( ) ; } }", tokenizeAndStringify("void f() { if consteval { bar(); } }"));
filter_valueflow(errout_str());

ASSERT_EQUALS("void f ( ) { if ( ! __cppcheck_consteval__ ) { bar ( ) ; } }", tokenizeAndStringify("void f() { if !consteval { bar(); } }"));
filter_valueflow(errout_str());

ASSERT_EQUALS("void f ( ) { if ( __cppcheck_consteval__ ) { bar ( ) ; } else { baz ( ) ; } }",
tokenizeAndStringify("void f() { if consteval { bar(); } else { baz(); } }"));
filter_valueflow(errout_str());

ASSERT_EQUALS("constexpr bool is_runtime_evaluated ( ) noexcept ( true ) { if ( ! __cppcheck_consteval__ ) { return true ; } else { return false ; } }",
tokenizeAndStringify("constexpr bool is_runtime_evaluated() noexcept { if not consteval { return true; } else { return false; } }"));
filter_valueflow(errout_str());
}

void combineOperators() {
ASSERT_EQUALS("; private: ;", tokenizeAndStringify(";private:;"));
ASSERT_EQUALS("; protected: ;", tokenizeAndStringify(";protected:;"));
Expand Down
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