treewide: automatic rewriting of all comment-style type annotations

Performed using https://github.com/ilevkivskyi/com2ann

This has no actual effect on the codebase as type checkers (still)
support both and negligible effect on runtime performance since
__future__ annotations ameliorates that. Technically, the bytecode would
be bigger for non function-local annotations, of which we have many
either way.

So if it doesn't really matter, why do a large-scale refactor? Simple:
because people keep wanting to, but it's getting nickle-and-dimed. If
we're going to do this we might as well do it consistently in one shot,
using tooling that guarantees repeatability and correctness.

Repeat with:

```
com2ann mesonbuild/
```

5 files changed, 25 insertions, 25 deletions

diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index 72e9f44..fa94f87 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -566,7 +566,7 @@ def strip_system_includedirs(environment: 'Environment', for_machine: MachineCho
     return [i for i in include_args if i not in exclude]
 
 def process_method_kw(possible: T.Iterable[DependencyMethods], kwargs: T.Dict[str, T.Any]) -> T.List[DependencyMethods]:
-    method = kwargs.get('method', 'auto')  # type: T.Union[DependencyMethods, str]
+    method: T.Union[DependencyMethods, str] = kwargs.get('method', 'auto')
     if isinstance(method, DependencyMethods):
         return [method]
     # TODO: try/except?
diff --git a/mesonbuild/dependencies/boost.py b/mesonbuild/dependencies/boost.py
index 648c8d2..788ccbb 100644
--- a/mesonbuild/dependencies/boost.py
+++ b/mesonbuild/dependencies/boost.py
@@ -248,7 +248,7 @@ class BoostLibraryFile():
         # Handle the boost_python naming madness.
         # See https://github.com/mesonbuild/meson/issues/4788 for some distro
         # specific naming variations.
-        other_tags = []  # type: T.List[str]
+        other_tags: T.List[str] = []
 
         # Split the current modname into the base name and the version
         m_cur = BoostLibraryFile.reg_python_mod_split.match(self.mod_name)
@@ -331,7 +331,7 @@ class BoostLibraryFile():
         return True
 
     def get_compiler_args(self) -> T.List[str]:
-        args = []  # type: T.List[str]
+        args: T.List[str] = []
         if self.mod_name in boost_libraries:
             libdef = boost_libraries[self.mod_name]
             if self.static:
@@ -355,19 +355,19 @@ class BoostDependency(SystemDependency):
         self.debug = buildtype.startswith('debug')
         self.multithreading = kwargs.get('threading', 'multi') == 'multi'
 
-        self.boost_root = None  # type: T.Optional[Path]
+        self.boost_root: T.Optional[Path] = None
         self.explicit_static = 'static' in kwargs
 
         # Extract and validate modules
-        self.modules = mesonlib.extract_as_list(kwargs, 'modules')  # type: T.List[str]
+        self.modules: T.List[str] = mesonlib.extract_as_list(kwargs, 'modules')
         for i in self.modules:
             if not isinstance(i, str):
                 raise DependencyException('Boost module argument is not a string.')
             if i.startswith('boost_'):
                 raise DependencyException('Boost modules must be passed without the boost_ prefix')
 
-        self.modules_found = []    # type: T.List[str]
-        self.modules_missing = []  # type: T.List[str]
+        self.modules_found: T.List[str] = []
+        self.modules_missing: T.List[str] = []
 
         # Do we need threads?
         if 'thread' in self.modules:
@@ -450,7 +450,7 @@ class BoostDependency(SystemDependency):
         mlog.debug('  - potential include dirs: {}'.format([x.path.as_posix() for x in inc_dirs]))
 
         #   2. Find all boost libraries
-        libs = []  # type: T.List[BoostLibraryFile]
+        libs: T.List[BoostLibraryFile] = []
         for i in lib_dirs:
             libs = self.detect_libraries(i)
             if libs:
@@ -471,8 +471,8 @@ class BoostDependency(SystemDependency):
                 mlog.debug(f'    - {j}')
 
             #   3. Select the libraries matching the requested modules
-            not_found = []  # type: T.List[str]
-            selected_modules = []  # type: T.List[BoostLibraryFile]
+            not_found: T.List[str] = []
+            selected_modules: T.List[BoostLibraryFile] = []
             for mod in modules:
                 found = False
                 for l in f_libs:
@@ -485,8 +485,8 @@ class BoostDependency(SystemDependency):
 
             # log the result
             mlog.debug('  - found:')
-            comp_args = []  # type: T.List[str]
-            link_args = []  # type: T.List[str]
+            comp_args: T.List[str] = []
+            link_args: T.List[str] = []
             for j in selected_modules:
                 c_args = j.get_compiler_args()
                 l_args = j.get_link_args()
@@ -524,7 +524,7 @@ class BoostDependency(SystemDependency):
         return False
 
     def detect_inc_dirs(self, root: Path) -> T.List[BoostIncludeDir]:
-        candidates = []  # type: T.List[Path]
+        candidates: T.List[Path] = []
         inc_root = root / 'include'
 
         candidates += [root / 'boost']
@@ -555,8 +555,8 @@ class BoostDependency(SystemDependency):
 
         # No system include paths were found --> fall back to manually looking
         # for library dirs in root
-        dirs = []     # type: T.List[Path]
-        subdirs = []  # type: T.List[Path]
+        dirs: T.List[Path] = []
+        subdirs: T.List[Path] = []
         for i in root.iterdir():
             if i.is_dir() and i.name.startswith('lib'):
                 dirs += [i]
@@ -578,7 +578,7 @@ class BoostDependency(SystemDependency):
         raw_list = dirs + subdirs
         no_arch = [x for x in raw_list if not any(y in x.name for y in arch_list_32 + arch_list_64)]
 
-        matching_arch = []  # type: T.List[Path]
+        matching_arch: T.List[Path] = []
         if '32' in self.arch:
             matching_arch = [x for x in raw_list if any(y in x.name for y in arch_list_32)]
         elif '64' in self.arch:
@@ -624,7 +624,7 @@ class BoostDependency(SystemDependency):
         return libs
 
     def detect_libraries(self, libdir: Path) -> T.List[BoostLibraryFile]:
-        libs = set()  # type: T.Set[BoostLibraryFile]
+        libs: T.Set[BoostLibraryFile] = set()
         for i in libdir.iterdir():
             if not i.is_file():
                 continue
@@ -655,7 +655,7 @@ class BoostDependency(SystemDependency):
         self.is_found = self.run_check([boost_inc_dir], [lib_dir])
 
     def detect_roots(self) -> None:
-        roots = []  # type: T.List[Path]
+        roots: T.List[Path] = []
 
         # Try getting the BOOST_ROOT from a boost.pc if it exists. This primarily
         # allows BoostDependency to find boost from Conan. See #5438
@@ -686,7 +686,7 @@ class BoostDependency(SystemDependency):
             # Where boost prebuilt binaries are
             local_boost = Path('C:/local')
 
-            candidates = []  # type: T.List[Path]
+            candidates: T.List[Path] = []
             if prog_files.is_dir():
                 candidates += [*prog_files.iterdir()]
             if local_boost.is_dir():
@@ -694,7 +694,7 @@ class BoostDependency(SystemDependency):
 
             roots += [x for x in candidates if x.name.lower().startswith('boost') and x.is_dir()]
         else:
-            tmp = []  # type: T.List[Path]
+            tmp: T.List[Path] = []
 
             # Add some default system paths
             tmp += [Path('/opt/local')]
diff --git a/mesonbuild/dependencies/cmake.py b/mesonbuild/dependencies/cmake.py
index 8827c9a..11d3564 100644
--- a/mesonbuild/dependencies/cmake.py
+++ b/mesonbuild/dependencies/cmake.py
@@ -80,7 +80,7 @@ class CMakeDependency(ExternalDependency):
 
     def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any], language: T.Optional[str] = None, force_use_global_compilers: bool = False) -> None:
         # Gather a list of all languages to support
-        self.language_list = []  # type: T.List[str]
+        self.language_list: T.List[str] = []
         if language is None or force_use_global_compilers:
             compilers = None
             if kwargs.get('native', False):
@@ -312,7 +312,7 @@ class CMakeDependency(ExternalDependency):
                 return True
 
         # Check PATH
-        system_env = []  # type: T.List[str]
+        system_env: T.List[str] = []
         for i in os.environ.get('PATH', '').split(os.pathsep):
             if i.endswith('/bin') or i.endswith('\\bin'):
                 i = i[:-4]
diff --git a/mesonbuild/dependencies/hdf5.py b/mesonbuild/dependencies/hdf5.py
index 501e89d..a437e84 100644
--- a/mesonbuild/dependencies/hdf5.py
+++ b/mesonbuild/dependencies/hdf5.py
@@ -48,7 +48,7 @@ class HDF5PkgConfigDependency(PkgConfigDependency):
             return
 
         # some broken pkgconfig don't actually list the full path to the needed includes
-        newinc = []  # type: T.List[str]
+        newinc: T.List[str] = []
         for arg in self.compile_args:
             if arg.startswith('-I'):
                 stem = 'static' if self.static else 'shared'
@@ -56,7 +56,7 @@ class HDF5PkgConfigDependency(PkgConfigDependency):
                     newinc.append('-I' + str(Path(arg[2:]) / stem))
         self.compile_args += newinc
 
-        link_args = []  # type: T.List[str]
+        link_args: T.List[str] = []
         for larg in self.get_link_args():
             lpath = Path(larg)
             # some pkg-config hdf5.pc (e.g. Ubuntu) don't include the commonly-used HL HDF5 libraries,
diff --git a/mesonbuild/dependencies/mpi.py b/mesonbuild/dependencies/mpi.py
index 240e6fd..d9a1585 100644
--- a/mesonbuild/dependencies/mpi.py
+++ b/mesonbuild/dependencies/mpi.py
@@ -74,7 +74,7 @@ def mpi_factory(env: 'Environment',
             elif language == 'fortran':
                 tool_names = [os.environ.get('I_MPI_F90'), 'mpiifort']
 
-            cls = IntelMPIConfigToolDependency  # type: T.Type[ConfigToolDependency]
+            cls: T.Type[ConfigToolDependency] = IntelMPIConfigToolDependency
         else: # OpenMPI, which doesn't work with intel
             #
             # We try the environment variables for the tools first, but then