[all-commits] [llvm/llvm-project] bfb4af: [clang-format] Avoid inserting space after C++ casts.

[Marek Kurdej via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bfb4afee74c8d6e3b1d020564bfe163073f07a04
      https://github.com/llvm/llvm-project/commit/bfb4afee74c8d6e3b1d020564bfe163073f07a04
  Author: Marek Kurdej <marek.kurdej+llvm.org at gmail.com>
  Date:   2022-02-24 (Thu, 24 Feb 2022)

  Changed paths:
    M clang/lib/Format/FormatToken.h
    M clang/lib/Format/TokenAnnotator.cpp
    M clang/unittests/Format/FormatTest.cpp

  Log Message:
  -----------
  [clang-format] Avoid inserting space after C++ casts.

Fixes https://github.com/llvm/llvm-project/issues/53876.

This is a solution for standard C++ casts: const_cast, dynamic_cast, reinterpret_cast, static_cast.

A general approach handling all possible casts is not possible without semantic information.
Consider the code:
```
static_cast<T>(*function_pointer_variable)(arguments);
```
vs.
```
some_return_type<T> (*function_pointer_variable)(parameters);
// Later used as:
function_pointer_variable = &some_function;
return function_pointer_variable(args);
```
In the latter case, it's not a cast but a variable declaration of a pointer to function.
Without knowing what `some_return_type<T>` is (and clang-format does not know it), it's hard to distinguish between the two cases. Theoretically, one could check whether "parameters" are types (not a cast) and "arguments" are value/expressions (a cast), but that might be inefficient (needs lots of lookahead).

Reviewed By: MyDeveloperDay, HazardyKnusperkeks, owenpan

Differential Revision: https://reviews.llvm.org/D120140