[clang-format] bit-field that has its size specified using a variable with `::` can be misformatted

[joelhock]

clang-format version 20.1.0 (https://github.com/llvm/llvm-project.git 24a30da) correctly formatted this code:

struct struct_with_constexpr {
  static constexpr unsigned int i_am_a_constexpr_lengthhhhh = 2;
};

struct foo {
  uint8_t i_am_a_bit_field_this_long
      : struct_with_constexpr::i_am_a_constexpr_lengthhhhh;
};

whereas clang-format version 21.1.0-rc3 (https://github.com/llvm/llvm-project.git 6096d35) misformats it, breaking on the ::

struct struct_with_constexpr {
  static constexpr unsigned int i_am_a_constexpr_lengthhhhh = 2;
};

struct foo {
  uint8_t i_am_a_bit_field_this_long : struct_with_constexpr::
      i_am_a_constexpr_lengthhhhh;
};

[llvmbot]

@llvm/issue-subscribers-clang-format

Author: Joel Hock (joelhock)

clang-format version 20.1.0 (https://github.com/llvm/llvm-project.git https://github.com/llvm/llvm-project/commit/24a30daaa559829ad079f2ff7f73eb4e18095f88) correctly formatted this code: ``` struct struct_with_constexpr { static constexpr unsigned int i_am_a_constexpr_lengthhhhh = 2; };

struct foo {
uint8_t i_am_a_bit_field_this_long
: struct_with_constexpr::i_am_a_constexpr_lengthhhhh;
};

whereas clang-format version 21.1.0-rc3 (https://github.com/llvm/llvm-project.git https://github.com/llvm/llvm-project/commit/6096d35ea93c75f648a253a00775b4d74915c819) misformats it, breaking on the `::`

struct struct_with_constexpr {
static constexpr unsigned int i_am_a_constexpr_lengthhhhh = 2;
};

struct foo {
uint8_t i_am_a_bit_field_this_long : struct_with_constexpr::
i_am_a_constexpr_lengthhhhh;
};

</details>

[owenca]

See #153443 (comment).