[clang-format] return type can be split on namespace when member template has comment

[joelhock]

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

// ---
// IndentWidth:     4
// PenaltyReturnTypeOnItsOwnLine: 800

class MyClass {
    template <bool abool, // a comment
              bool anotherbool>
    static inline std::pair<size_t, MyCustomTypeeeeeeeee>
    myfunccccccccccccccccccccccc(const char *buf, const char *&err);
};

whereas clang-format version 21.1.0-rc3 (https://github.com/llvm/llvm-project.git 6096d35) splits the std:: from the rest of the return type:

// ---
// IndentWidth:     4
// PenaltyReturnTypeOnItsOwnLine: 800

class MyClass {
    template <bool abool, // a comment
              bool anotherbool>
    static inline std::
        pair<size_t, MyCustomTypeeeeeeeee> myfunccccccccccccccccccccccc(
            const char *buf, const char *&err);
};

i could see this being "as designed," but what's odd is that if the comment in the member template is removed, the formatting 21.1.0-rc3 does changes back to how clang version 20.1.0 did it:

// ---
// IndentWidth:     4
// PenaltyReturnTypeOnItsOwnLine: 800

class MyClass {
    template <bool abool, bool anotherbool>
    static inline std::pair<size_t, MyCustomTypeeeeeeeee>
    myfunccccccccccccccccccccccc(const char *buf, const char *&err);
};

[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) formatted code like this: ``` // --- // IndentWidth: 4 // PenaltyReturnTypeOnItsOwnLine: 800

class MyClass {
template <bool abool, // a comment
bool anotherbool>
static inline std::pair<size_t, MyCustomTypeeeeeeeee>
myfunccccccccccccccccccccccc(const char *buf, const char *&err);
};

whereas clang-format version 21.1.0-rc3 (https://github.com/llvm/llvm-project.git https://github.com/llvm/llvm-project/commit/6096d35ea93c75f648a253a00775b4d74915c819) splits the `std::` from the rest of the return type:

// ---
// IndentWidth: 4
// PenaltyReturnTypeOnItsOwnLine: 800

class MyClass {
template <bool abool, // a comment
bool anotherbool>
static inline std::
pair<size_t, MyCustomTypeeeeeeeee> myfunccccccccccccccccccccccc(
const char *buf, const char *&err);
};

i could see this being "as designed," but what's odd is that if the comment in the member template is removed, the formatting 21.1.0-rc3 does changes back to how clang version 20.1.0 did it:

// ---
// IndentWidth: 4
// PenaltyReturnTypeOnItsOwnLine: 800

class MyClass {
template <bool abool, bool anotherbool>
static inline std::pair<size_t, MyCustomTypeeeeeeeee>
myfunccccccccccccccccccccccc(const char *buf, const char *&err);
};

</details>

[owenca]

Bisected it to 2ca0855.