[clang-format] AlignConsecutiveDeclarations is not respected in `.h` file for variable whose name is a C++ keyword such as `new`

[miEsMar]

It seems that clangd formatting style is messed up in structs definition (I do not know if this is reflected somewhere else) if fields are named with lexical keywords.

See images below:

The thing is that new/delete are not C keywords, yet recognised as such, messing the formatting.

Expected behaviour:

[llvmbot]

@llvm/issue-subscribers-clangd

Author: mEm (miEsMar)

It seems that `clangd` formatting style is messed up in `struct`s definition (I do not know if this is reflected somewhere else) if fields are named with lexical keywords.

See images below:

<img width="646" height="186" alt="Image" src="https://github.com/user-attachments/assets/f8a5df57-6208-4883-8208-35a2576137ba" />

<img width="646" height="186" alt="Image" src="https://github.com/user-attachments/assets/0e9ef370-8c08-4b0f-b935-21ddb6e60838" />

<img width="646" height="186" alt="Image" src="https://github.com/user-attachments/assets/fca32c9d-1284-4e99-b19d-12b5e7bb48bb" />

The thing is that new/delete are not C keywords, yet recognised as such, messing the formatting.

Expected behaviour:

<img width="683" height="185" alt="Image" src="https://github.com/user-attachments/assets/40812cff-3980-40c1-bda2-a7992dde7715" />

[HighCommander4]

Please provide the following information:

• The contents of an affected source file in text form, including the file name extension.
• The contents of your .clang-format file if any.

[miEsMar]

Sample affected source file test.h:

struct a {
    double dval;
    int new;
};

.clang-format:

BasedOnStyle: LLVM
IndentWidth: 4
ColumnLimit: 100
BreakBeforeBraces: Custom
BraceWrapping:
  AfterCaseLabel: false
  AfterClass: true
  AfterControlStatement: false
  AfterEnum: false
  AfterExternBlock: false
  AfterFunction: true
  AfterNamespace: true
  AfterStruct: false
  BeforeElse: false
  BeforeLambdaBody: true
  BeforeWhile: false
  SplitEmptyFunction: true
  SplitEmptyNamespace: true
AlignConsecutiveAssignments:
  Enabled: true
  AcrossEmptyLines: false
  AcrossComments: false
AlignConsecutiveDeclarations:
  Enabled: true
  AcrossEmptyLines: false
  AcrossComments: false
AlignConsecutiveMacros:
  Enabled: true
  AcrossEmptyLines: false
  AcrossComments: false
MaxEmptyLinesToKeep: 2
IndentPPDirectives: AfterHash
PPIndentWidth: 1

[HighCommander4]

Thanks. I can reproduce this. The issue occurs when using clang-format on the command line as well, it's not specific to clangd.

The issue does not occur in a file with extension *.c. My guess is that for *.h files, since they are used for both C and C++ code, clang-format has to guess the language, and guesses C++, thereby causing the apperance of C++ keywords to have an effect on the formatting.

[llvmbot]

@llvm/issue-subscribers-clang-format

Author: mEm (miEsMar)

It seems that `clangd` formatting style is messed up in `struct`s definition (I do not know if this is reflected somewhere else) if fields are named with lexical keywords.

See images below:

<img width="646" height="186" alt="Image" src="https://github.com/user-attachments/assets/f8a5df57-6208-4883-8208-35a2576137ba" />

<img width="646" height="186" alt="Image" src="https://github.com/user-attachments/assets/0e9ef370-8c08-4b0f-b935-21ddb6e60838" />

<img width="646" height="186" alt="Image" src="https://github.com/user-attachments/assets/fca32c9d-1284-4e99-b19d-12b5e7bb48bb" />

The thing is that new/delete are not C keywords, yet recognised as such, messing the formatting.

Expected behaviour:

<img width="683" height="185" alt="Image" src="https://github.com/user-attachments/assets/40812cff-3980-40c1-bda2-a7992dde7715" />

[owenca]

clang-format treats C/C++ .h files as C++ unless you add // clang-format Language: C at the top. See the note in Language.