clang-format: hangs when a CASE macro is defined and used

[nickie]

The following simple .clang-format file, defining a CASE macro, results in a hang when trying to format the following simple poc.cc file.

$ cat .clang-format
Macros:
  - CASE=case

$ cat poc.cc
int f() {
  switch (42) {
#define CASE(kind)
    CASE(1)
    CASE(2)
#undef CASE
  }
}

$ ./clang-format -version
clang-format version 21.1.3 (https://github.com/llvm/llvm-project 450f52eec88f728c89a9efd667dbeaf2dad93826)

$ ./clang-format poc.cc
^Cinterrupted

[llvmbot]

@llvm/issue-subscribers-clang-format

Author: Nikolaos S. Papaspyrou (nickie)

The following simple `.clang-format` file, defining a `CASE` macro, results in a hang when trying to format the following simple `poc.cc` file. ``` $ cat .clang-format Macros: - CASE=case

$ cat poc.cc
int f() {
switch (42) {
#define CASE(kind)
CASE(1)
CASE(2)
#undef CASE
}
}

$ ./clang-format -version
clang-format version 21.1.3 (https://github.com/llvm/llvm-project 450f52e)

$ ./clang-format poc.cc
^Cinterrupted

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