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Fix #744 (Add regression tests for macro expansion) - #745
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C11 6.10.3.5 examples 3, 4, 5 and 7, the C23 __VA_OPT__ examples and invalid ## pastes. Known bugs are tested with the new TODO_ASSERT_EQUALS. Tests for Token::macro, the locations of expanded tokens and the macro usage, which are used by cppcheck. A new helper expandedTokens() writes each output token with its macro name and location; the tokenMacro tests use it. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…e an error gcc outputs the name, simplecpp reports wrong number of parameters. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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AI review
The PR only changes test.cpp. All tests pass, and I checked every TODO comment's claim against gcc and clang (the R/X name at the end of the file, the empty token from r(,)/t(,,), ==0 after the comment, a"s" should be an error). Each claim is correct, and every "wanted" value matches the reference preprocessors.
There is one new finding. tokenMacro10 uses ASSERT_EQUALS to lock in empty Token::macro for the results of # and ##, and its comment presents that as a general rule. It only holds for function-like macros. Object-like macros give the pasted token the macro name (#define XY x##y gives xy@XY). So does a function-like macro whose pasted token is built from body text, as in cat2(x) → xb with an empty name. cppcheck uses this field, so this looks like a known gap that should be a TODO, not a rule. I found no other problems.
Testing
Build and test suites
make -j8 testrunner simplecpp CXXOPTS=-Werrorbuilt without warnings../testrunnerpassed with exit code 0 and no failures.python3 run-tests.pypassed: 176 tests, 21 skipped, 15 todos with 0 fixed, 0 failed.python3 -m pytest integration_test.pypassed: 128 tests../selfcheck.shpassed with exit code 0.
The TODO claims, checked against gcc and clang
#define R()/R:gcc -E -PoutputsR, so the wanted value"\nR"with no error is right.cat(a,"s"): gcc (in both C and C++11 mode) reportspasting "a" and ""s"" does not give a valid preprocessing token, and clang reports a similar error. simplecpp outputsa"s"with no error.{ r(,) }: gcc outputs{ }. simplecpp outputs{ }, with an empty token between the braces.- The
str(strncmp(...) // this goes away\n == 0)example: gcc gives... '\\4') == 0". simplecpp gives'\\4') ==0".
Token::macro for # and ## results
I linked a small program against simplecpp.o and printed str@macro for each output token:
#define str(x) #x
#define XY x##y
#define cat(a,b) a##b
#define cat2(a) a##b
XY cat(x,y) cat2(x) str(z)Output: xy@XY xy@ xb@ "z"@. The object-like macro keeps its macro name on the pasted token. In the function-like macros the name is empty, even for xb, which is pasted with the body token b.
Automated review of 7ac04ea by Claude. The pull request was built and tested locally.
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