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/
```

38 files changed, 214 insertions, 214 deletions

diff --git a/mesonbuild/arglist.py b/mesonbuild/arglist.py
index dfb3dcd..f50d54e 100644
--- a/mesonbuild/arglist.py
+++ b/mesonbuild/arglist.py
@@ -82,23 +82,23 @@ class CompilerArgs(T.MutableSequence[str]):
 
     '''
     # Arg prefixes that override by prepending instead of appending
-    prepend_prefixes = ()  # type: T.Tuple[str, ...]
+    prepend_prefixes: T.Tuple[str, ...] = ()
 
     # Arg prefixes and args that must be de-duped by returning 2
-    dedup2_prefixes = ()   # type: T.Tuple[str, ...]
-    dedup2_suffixes = ()   # type: T.Tuple[str, ...]
-    dedup2_args = ()       # type: T.Tuple[str, ...]
+    dedup2_prefixes: T.Tuple[str, ...] = ()
+    dedup2_suffixes: T.Tuple[str, ...] = ()
+    dedup2_args: T.Tuple[str, ...] = ()
 
     # Arg prefixes and args that must be de-duped by returning 1
     #
     # NOTE: not thorough. A list of potential corner cases can be found in
     # https://github.com/mesonbuild/meson/pull/4593#pullrequestreview-182016038
-    dedup1_prefixes = ()  # type: T.Tuple[str, ...]
+    dedup1_prefixes: T.Tuple[str, ...] = ()
     dedup1_suffixes = ('.lib', '.dll', '.so', '.dylib', '.a')
     # Match a .so of the form path/to/libfoo.so.0.1.0
     # Only UNIX shared libraries require this. Others have a fixed extension.
     dedup1_regex = re.compile(r'([\/\\]|\A)lib.*\.so(\.[0-9]+)?(\.[0-9]+)?(\.[0-9]+)?$')
-    dedup1_args = ()  # type: T.Tuple[str, ...]
+    dedup1_args: T.Tuple[str, ...] = ()
     # In generate_link() we add external libs without de-dup, but we must
     # *always* de-dup these because they're special arguments to the linker
     # TODO: these should probably move too
@@ -107,19 +107,19 @@ class CompilerArgs(T.MutableSequence[str]):
     def __init__(self, compiler: T.Union['Compiler', 'StaticLinker'],
                  iterable: T.Optional[T.Iterable[str]] = None):
         self.compiler = compiler
-        self._container = list(iterable) if iterable is not None else []  # type: T.List[str]
-        self.pre = collections.deque()    # type: T.Deque[str]
-        self.post = collections.deque()   # type: T.Deque[str]
+        self._container: T.List[str] = list(iterable) if iterable is not None else []
+        self.pre: T.Deque[str] = collections.deque()
+        self.post: T.Deque[str] = collections.deque()
 
     # Flush the saved pre and post list into the _container list
     #
     # This correctly deduplicates the entries after _can_dedup definition
     # Note: This function is designed to work without delete operations, as deletions are worsening the performance a lot.
     def flush_pre_post(self) -> None:
-        new = []                          # type: T.List[str]
-        pre_flush_set = set()             # type: T.Set[str]
-        post_flush = collections.deque()  # type: T.Deque[str]
-        post_flush_set = set()            # type: T.Set[str]
+        new: T.List[str] = []
+        pre_flush_set: T.Set[str] = set()
+        post_flush: T.Deque[str] = collections.deque()
+        post_flush_set: T.Set[str] = set()
 
         #The two lists are here walked from the front to the back, in order to not need removals for deduplication
         for a in self.pre:
@@ -285,7 +285,7 @@ class CompilerArgs(T.MutableSequence[str]):
         Add two CompilerArgs while taking into account overriding of arguments
         and while preserving the order of arguments as much as possible
         '''
-        tmp_pre = collections.deque()  # type: T.Deque[str]
+        tmp_pre: T.Deque[str] = collections.deque()
         if not isinstance(args, collections.abc.Iterable):
             raise TypeError(f'can only concatenate Iterable[str] (not "{args}") to CompilerArgs')
         for arg in args:
diff --git a/mesonbuild/ast/interpreter.py b/mesonbuild/ast/interpreter.py
index 68e2b6e..70a4f1f 100644
--- a/mesonbuild/ast/interpreter.py
+++ b/mesonbuild/ast/interpreter.py
@@ -97,10 +97,10 @@ class AstInterpreter(InterpreterBase):
     def __init__(self, source_root: str, subdir: str, subproject: str, visitors: T.Optional[T.List[AstVisitor]] = None):
         super().__init__(source_root, subdir, subproject)
         self.visitors = visitors if visitors is not None else []
-        self.processed_buildfiles = set() # type: T.Set[str]
-        self.assignments = {}             # type: T.Dict[str, BaseNode]
-        self.assign_vals = {}             # type: T.Dict[str, T.Any]
-        self.reverse_assignment = {}      # type: T.Dict[str, BaseNode]
+        self.processed_buildfiles: T.Set[str] = set()
+        self.assignments: T.Dict[str, BaseNode] = {}
+        self.assign_vals: T.Dict[str, T.Any] = {}
+        self.reverse_assignment: T.Dict[str, BaseNode] = {}
         self.funcs.update({'project': self.func_do_nothing,
                            'test': self.func_do_nothing,
                            'benchmark': self.func_do_nothing,
@@ -274,7 +274,7 @@ class AstInterpreter(InterpreterBase):
                 duplicate_key_error: T.Optional[str] = None,
             ) -> T.Tuple[T.List[TYPE_nvar], TYPE_nkwargs]:
         if isinstance(args, ArgumentNode):
-            kwargs = {}  # type: T.Dict[str, TYPE_nvar]
+            kwargs: T.Dict[str, TYPE_nvar] = {}
             for key, val in args.kwargs.items():
                 kwargs[key_resolver(key)] = val
             if args.incorrect_order():
@@ -383,7 +383,7 @@ class AstInterpreter(InterpreterBase):
         elif isinstance(node, MethodNode):
             src = quick_resolve(node.source_object)
             margs = self.flatten_args(node.args.arguments, include_unknown_args, id_loop_detect)
-            mkwargs = {} # type: T.Dict[str, TYPE_nvar]
+            mkwargs: T.Dict[str, TYPE_nvar] = {}
             try:
                 if isinstance(src, str):
                     result = StringHolder(src, T.cast('Interpreter', self)).method_call(node.name, margs, mkwargs)
@@ -402,7 +402,7 @@ class AstInterpreter(InterpreterBase):
         if isinstance(result, BaseNode):
             result = self.resolve_node(result, include_unknown_args, id_loop_detect)
         elif isinstance(result, list):
-            new_res = []  # type: T.List[TYPE_nvar]
+            new_res: T.List[TYPE_nvar] = []
             for i in result:
                 if isinstance(i, BaseNode):
                     resolved = self.resolve_node(i, include_unknown_args, id_loop_detect)
@@ -421,7 +421,7 @@ class AstInterpreter(InterpreterBase):
         else:
             args = [args_raw]
 
-        flattened_args = []  # type: T.List[TYPE_nvar]
+        flattened_args: T.List[TYPE_nvar] = []
 
         # Resolve the contents of args
         for i in args:
diff --git a/mesonbuild/ast/introspection.py b/mesonbuild/ast/introspection.py
index d31b29f..e8055c5 100644
--- a/mesonbuild/ast/introspection.py
+++ b/mesonbuild/ast/introspection.py
@@ -47,8 +47,8 @@ class IntrospectionHelper(argparse.Namespace):
     def __init__(self, cross_file: str):
         super().__init__()
         self.cross_file = cross_file
-        self.native_file = None       # type: str
-        self.cmd_line_options = {}    # type: T.Dict[str, str]
+        self.native_file: str = None
+        self.cmd_line_options: T.Dict[str, str] = {}
 
     def __eq__(self, other: object) -> bool:
         return NotImplemented
@@ -78,10 +78,10 @@ class IntrospectionInterpreter(AstInterpreter):
         self.coredata = self.environment.get_coredata()
         self.backend = backend
         self.default_options = {OptionKey('backend'): self.backend}
-        self.project_data = {}    # type: T.Dict[str, T.Any]
-        self.targets = []         # type: T.List[T.Dict[str, T.Any]]
-        self.dependencies = []    # type: T.List[T.Dict[str, T.Any]]
-        self.project_node = None  # type: BaseNode
+        self.project_data: T.Dict[str, T.Any] = {}
+        self.targets: T.List[T.Dict[str, T.Any]] = []
+        self.dependencies: T.List[T.Dict[str, T.Any]] = []
+        self.project_node: BaseNode = None
 
         self.funcs.update({
             'add_languages': self.func_add_languages,
@@ -170,7 +170,7 @@ class IntrospectionInterpreter(AstInterpreter):
                 self._add_languages(args, required, for_machine)
 
     def _add_languages(self, raw_langs: T.List[TYPE_nvar], required: bool, for_machine: MachineChoice) -> None:
-        langs = []  # type: T.List[str]
+        langs: T.List[str] = []
         for l in self.flatten_args(raw_langs):
             if isinstance(l, str):
                 langs.append(l)
@@ -238,7 +238,7 @@ class IntrospectionInterpreter(AstInterpreter):
         kwargs = self.flatten_kwargs(kwargs_raw, True)
 
         def traverse_nodes(inqueue: T.List[BaseNode]) -> T.List[BaseNode]:
-            res = []  # type: T.List[BaseNode]
+            res: T.List[BaseNode] = []
             while inqueue:
                 curr = inqueue.pop(0)
                 arg_node = None
@@ -277,8 +277,8 @@ class IntrospectionInterpreter(AstInterpreter):
         kwargs_reduced = {k: v.value if isinstance(v, ElementaryNode) else v for k, v in kwargs_reduced.items()}
         kwargs_reduced = {k: v for k, v in kwargs_reduced.items() if not isinstance(v, BaseNode)}
         for_machine = MachineChoice.HOST
-        objects = []        # type: T.List[T.Any]
-        empty_sources = []  # type: T.List[T.Any]
+        objects: T.List[T.Any] = []
+        empty_sources: T.List[T.Any] = []
         # Passing the unresolved sources list causes errors
         kwargs_reduced['_allow_no_sources'] = True
         target = targetclass(name, self.subdir, self.subproject, for_machine, empty_sources, [], objects,
diff --git a/mesonbuild/ast/postprocess.py b/mesonbuild/ast/postprocess.py
index 09c339d..7d2036e 100644
--- a/mesonbuild/ast/postprocess.py
+++ b/mesonbuild/ast/postprocess.py
@@ -80,7 +80,7 @@ class AstIndentationGenerator(AstVisitor):
 
 class AstIDGenerator(AstVisitor):
     def __init__(self) -> None:
-        self.counter = {}  # type: T.Dict[str, int]
+        self.counter: T.Dict[str, int] = {}
 
     def visit_default_func(self, node: mparser.BaseNode) -> None:
         name = type(node).__name__
diff --git a/mesonbuild/ast/printer.py b/mesonbuild/ast/printer.py
index 579a83d..ebf63af 100644
--- a/mesonbuild/ast/printer.py
+++ b/mesonbuild/ast/printer.py
@@ -240,12 +240,12 @@ class AstPrinter(AstVisitor):
 
 class AstJSONPrinter(AstVisitor):
     def __init__(self) -> None:
-        self.result = {}  # type: T.Dict[str, T.Any]
+        self.result: T.Dict[str, T.Any] = {}
         self.current = self.result
 
     def _accept(self, key: str, node: mparser.BaseNode) -> None:
         old = self.current
-        data = {}  # type: T.Dict[str, T.Any]
+        data: T.Dict[str, T.Any] = {}
         self.current = data
         node.accept(self)
         self.current = old
@@ -253,7 +253,7 @@ class AstJSONPrinter(AstVisitor):
 
     def _accept_list(self, key: str, nodes: T.Sequence[mparser.BaseNode]) -> None:
         old = self.current
-        datalist = []  # type: T.List[T.Dict[str, T.Any]]
+        datalist: T.List[T.Dict[str, T.Any]] = []
         for i in nodes:
             self.current = {}
             i.accept(self)
@@ -388,10 +388,10 @@ class AstJSONPrinter(AstVisitor):
 
     def visit_ArgumentNode(self, node: mparser.ArgumentNode) -> None:
         self._accept_list('positional', node.arguments)
-        kwargs_list = []  # type: T.List[T.Dict[str, T.Dict[str, T.Any]]]
+        kwargs_list: T.List[T.Dict[str, T.Dict[str, T.Any]]] = []
         for key, val in node.kwargs.items():
-            key_res = {}  # type: T.Dict[str, T.Any]
-            val_res = {}  # type: T.Dict[str, T.Any]
+            key_res: T.Dict[str, T.Any] = {}
+            val_res: T.Dict[str, T.Any] = {}
             self._raw_accept(key, key_res)
             self._raw_accept(val, val_res)
             kwargs_list += [{'key': key_res, 'val': val_res}]
diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index a0a38d0..e5cdfea 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -723,7 +723,7 @@ class BuildTarget(Target):
             kwargs):
         super().__init__(name, subdir, subproject, True, for_machine, environment, install=kwargs.get('install', False))
         self.all_compilers = compilers
-        self.compilers = OrderedDict() # type: OrderedDict[str, Compiler]
+        self.compilers: OrderedDict[str, Compiler] = OrderedDict()
         self.objects: T.List[ObjectTypes] = []
         self.structured_sources = structured_sources
         self.external_deps: T.List[dependencies.Dependency] = []
@@ -1539,7 +1539,7 @@ class BuildTarget(Target):
 
         See: https://github.com/mesonbuild/meson/issues/1653
         '''
-        langs = [] # type: T.List[str]
+        langs: T.List[str] = []
 
         # Check if any of the external libraries were written in this language
         for dep in self.external_deps:
diff --git a/mesonbuild/cmake/common.py b/mesonbuild/cmake/common.py
index 002cda7..415937e 100644
--- a/mesonbuild/cmake/common.py
+++ b/mesonbuild/cmake/common.py
@@ -123,7 +123,7 @@ def cmake_get_generator_args(env: 'Environment') -> T.List[str]:
     return ['-G', backend_generator_map[backend_name]]
 
 def cmake_defines_to_args(raw: T.List[T.Dict[str, TYPE_var]], permissive: bool = False) -> T.List[str]:
-    res = []  # type: T.List[str]
+    res: T.List[str] = []
 
     for i in raw:
         for key, val in i.items():
@@ -144,7 +144,7 @@ def cmake_defines_to_args(raw: T.List[T.Dict[str, TYPE_var]], permissive: bool =
 
 # TODO: this function will become obsolete once the `cmake_args` kwarg is dropped
 def check_cmake_args(args: T.List[str]) -> T.List[str]:
-    res = []  # type: T.List[str]
+    res: T.List[str] = []
     dis = ['-D' + x for x in blacklist_cmake_defs]
     assert dis  # Ensure that dis is not empty.
     for i in args:
@@ -166,14 +166,14 @@ class CMakeInclude:
 
 class CMakeFileGroup:
     def __init__(self, data: T.Dict[str, T.Any]) -> None:
-        self.defines = data.get('defines', '')                       # type: str
+        self.defines: str = data.get('defines', '')
         self.flags = _flags_to_list(data.get('compileFlags', ''))
-        self.is_generated = data.get('isGenerated', False)                # type: bool
-        self.language = data.get('language', 'C')                     # type: str
+        self.is_generated: bool = data.get('isGenerated', False)
+        self.language: str = data.get('language', 'C')
         self.sources = [Path(x) for x in data.get('sources', [])]
 
         # Fix the include directories
-        self.includes = []  # type: T.List[CMakeInclude]
+        self.includes: T.List[CMakeInclude] = []
         for i in data.get('includePath', []):
             if isinstance(i, dict) and 'path' in i:
                 isSystem = i.get('isSystem', False)
@@ -199,18 +199,18 @@ class CMakeTarget:
         self.artifacts = [Path(x) for x in data.get('artifacts', [])]
         self.src_dir = Path(data.get('sourceDirectory', ''))
         self.build_dir = Path(data.get('buildDirectory', ''))
-        self.name = data.get('name', '')                                            # type: str
-        self.full_name = data.get('fullName', '')                                   # type: str
-        self.install = data.get('hasInstallRule', False)                            # type: bool
+        self.name: str = data.get('name', '')
+        self.full_name: str = data.get('fullName', '')
+        self.install: bool = data.get('hasInstallRule', False)
         self.install_paths = [Path(x) for x in set(data.get('installPaths', []))]
-        self.link_lang = data.get('linkerLanguage', '')                             # type: str
+        self.link_lang: str = data.get('linkerLanguage', '')
         self.link_libraries = _flags_to_list(data.get('linkLibraries', ''))
         self.link_flags = _flags_to_list(data.get('linkFlags', ''))
         self.link_lang_flags = _flags_to_list(data.get('linkLanguageFlags', ''))
         # self.link_path = Path(data.get('linkPath', ''))
-        self.type = data.get('type', 'EXECUTABLE')                                  # type: str
+        self.type: str = data.get('type', 'EXECUTABLE')
         # self.is_generator_provided = data.get('isGeneratorProvided', False)         # type: bool
-        self.files = []                                                             # type: T.List[CMakeFileGroup]
+        self.files: T.List[CMakeFileGroup] = []
 
         for i in data.get('fileGroups', []):
             self.files += [CMakeFileGroup(i)]
@@ -239,8 +239,8 @@ class CMakeProject:
     def __init__(self, data: T.Dict[str, T.Any]) -> None:
         self.src_dir = Path(data.get('sourceDirectory', ''))
         self.build_dir = Path(data.get('buildDirectory', ''))
-        self.name = data.get('name', '')                        # type: str
-        self.targets = []                                       # type: T.List[CMakeTarget]
+        self.name: str = data.get('name', '')
+        self.targets: T.List[CMakeTarget] = []
 
         for i in data.get('targets', []):
             self.targets += [CMakeTarget(i)]
@@ -256,8 +256,8 @@ class CMakeProject:
 
 class CMakeConfiguration:
     def __init__(self, data: T.Dict[str, T.Any]) -> None:
-        self.name = data.get('name', '')        # type: str
-        self.projects = []                      # type: T.List[CMakeProject]
+        self.name: str = data.get('name', '')
+        self.projects: T.List[CMakeProject] = []
         for i in data.get('projects', []):
             self.projects += [CMakeProject(i)]
 
@@ -270,9 +270,9 @@ class CMakeConfiguration:
 
 class SingleTargetOptions:
     def __init__(self) -> None:
-        self.opts = {}       # type: T.Dict[str, str]
-        self.lang_args = {}  # type: T.Dict[str, T.List[str]]
-        self.link_args = []  # type: T.List[str]
+        self.opts: T.Dict[str, str] = {}
+        self.lang_args: T.Dict[str, T.List[str]] = {}
+        self.link_args: T.List[str] = []
         self.install = 'preserve'
 
     def set_opt(self, opt: str, val: str) -> None:
@@ -290,7 +290,7 @@ class SingleTargetOptions:
         self.install = 'true' if install else 'false'
 
     def get_override_options(self, initial: T.List[str]) -> T.List[str]:
-        res = []  # type: T.List[str]
+        res: T.List[str] = []
         for i in initial:
             opt = i[:i.find('=')]
             if opt not in self.opts:
@@ -312,7 +312,7 @@ class SingleTargetOptions:
 class TargetOptions:
     def __init__(self) -> None:
         self.global_options = SingleTargetOptions()
-        self.target_options = {}  # type: T.Dict[str, SingleTargetOptions]
+        self.target_options: T.Dict[str, SingleTargetOptions] = {}
 
     def __getitem__(self, tgt: str) -> SingleTargetOptions:
         if tgt not in self.target_options:
diff --git a/mesonbuild/cmake/executor.py b/mesonbuild/cmake/executor.py
index c22c0ca..7958baf 100644
--- a/mesonbuild/cmake/executor.py
+++ b/mesonbuild/cmake/executor.py
@@ -39,9 +39,9 @@ if T.TYPE_CHECKING:
 class CMakeExecutor:
     # The class's copy of the CMake path. Avoids having to search for it
     # multiple times in the same Meson invocation.
-    class_cmakebin = PerMachine(None, None)   # type: PerMachine[T.Optional[ExternalProgram]]
-    class_cmakevers = PerMachine(None, None)  # type: PerMachine[T.Optional[str]]
-    class_cmake_cache = {}  # type: T.Dict[T.Any, TYPE_result]
+    class_cmakebin: PerMachine[T.Optional[ExternalProgram]] = PerMachine(None, None)
+    class_cmakevers: PerMachine[T.Optional[str]] = PerMachine(None, None)
+    class_cmake_cache: T.Dict[T.Any, TYPE_result] = {}
 
     def __init__(self, environment: 'Environment', version: str, for_machine: MachineChoice, silent: bool = False):
         self.min_version = version
@@ -50,8 +50,8 @@ class CMakeExecutor:
         self.cmakebin, self.cmakevers = self.find_cmake_binary(self.environment, silent=silent)
         self.always_capture_stderr = True
         self.print_cmout = False
-        self.prefix_paths = []      # type: T.List[str]
-        self.extra_cmake_args = []  # type: T.List[str]
+        self.prefix_paths: T.List[str] = []
+        self.extra_cmake_args: T.List[str] = []
 
         if self.cmakebin is None:
             return
diff --git a/mesonbuild/cmake/fileapi.py b/mesonbuild/cmake/fileapi.py
index 9605f92..baf499f 100644
--- a/mesonbuild/cmake/fileapi.py
+++ b/mesonbuild/cmake/fileapi.py
@@ -28,8 +28,8 @@ class CMakeFileAPI:
         self.api_base_dir = self.build_dir / '.cmake' / 'api' / 'v1'
         self.request_dir = self.api_base_dir / 'query' / 'client-meson'
         self.reply_dir = self.api_base_dir / 'reply'
-        self.cmake_sources = []   # type: T.List[CMakeBuildFile]
-        self.cmake_configurations = []   # type: T.List[CMakeConfiguration]
+        self.cmake_sources: T.List[CMakeBuildFile] = []
+        self.cmake_configurations: T.List[CMakeConfiguration] = []
         self.kind_resolver_map = {
             'codemodel': self._parse_codemodel,
             'cmakeFiles': self._parse_cmakeFiles,
diff --git a/mesonbuild/cmake/generator.py b/mesonbuild/cmake/generator.py
index f47625c..750e4c2 100644
--- a/mesonbuild/cmake/generator.py
+++ b/mesonbuild/cmake/generator.py
@@ -98,7 +98,7 @@ def parse_generator_expressions(
             return ';'.join([x for x in tgt.properties['IMPORTED_LOCATION'] if x])
         return ''
 
-    supported = {
+    supported: T.Dict[str, T.Callable[[str], str]] = {
         # Boolean functions
         'BOOL': lambda x: '0' if x.upper() in {'', '0', 'FALSE', 'OFF', 'N', 'NO', 'IGNORE', 'NOTFOUND'} or x.endswith('-NOTFOUND') else '1',
         'AND': lambda x: '1' if all(y == '1' for y in x.split(',')) else '0',
@@ -140,7 +140,7 @@ def parse_generator_expressions(
         'TARGET_NAME_IF_EXISTS': lambda x: x if x in trace.targets else '',
         'TARGET_PROPERTY': target_property,
         'TARGET_FILE': target_file,
-    }  # type: T.Dict[str, T.Callable[[str], str]]
+    }
 
     # Recursively evaluate generator expressions
     def eval_generator_expressions() -> str:
diff --git a/mesonbuild/cmake/toolchain.py b/mesonbuild/cmake/toolchain.py
index 477629e..be5bd66 100644
--- a/mesonbuild/cmake/toolchain.py
+++ b/mesonbuild/cmake/toolchain.py
@@ -144,7 +144,7 @@ class CMakeToolchain:
         return res
 
     def get_defaults(self) -> T.Dict[str, T.List[str]]:
-        defaults = {}  # type: T.Dict[str, T.List[str]]
+        defaults: T.Dict[str, T.List[str]] = {}
 
         # Do nothing if the user does not want automatic defaults
         if not self.properties.get_cmake_defaults():
@@ -153,13 +153,13 @@ class CMakeToolchain:
         # Best effort to map the meson system name to CMAKE_SYSTEM_NAME, which
         # is not trivial since CMake lacks a list of all supported
         # CMAKE_SYSTEM_NAME values.
-        SYSTEM_MAP = {
+        SYSTEM_MAP: T.Dict[str, str] = {
             'android': 'Android',
             'linux': 'Linux',
             'windows': 'Windows',
             'freebsd': 'FreeBSD',
             'darwin': 'Darwin',
-        }  # type: T.Dict[str, str]
+        }
 
         # Only set these in a cross build. Otherwise CMake will trip up in native
         # builds and thing they are cross (which causes TRY_RUN() to break)
diff --git a/mesonbuild/cmake/traceparser.py b/mesonbuild/cmake/traceparser.py
index 92ff780..dd0dfb5 100644
--- a/mesonbuild/cmake/traceparser.py
+++ b/mesonbuild/cmake/traceparser.py
@@ -67,9 +67,9 @@ class CMakeTarget:
         self.properties = properties
         self.imported = imported
         self.tline = tline
-        self.depends = []      # type: T.List[str]
-        self.current_bin_dir = None    # type: T.Optional[Path]
-        self.current_src_dir = None    # type: T.Optional[Path]
+        self.depends: T.List[str] = []
+        self.current_bin_dir: T.Optional[Path] = None
+        self.current_src_dir: T.Optional[Path] = None
 
     def __repr__(self) -> str:
         s = 'CMake TARGET:\n  -- name:      {}\n  -- type:      {}\n  -- imported:  {}\n  -- properties: {{\n{}     }}\n  -- tline: {}'
@@ -89,10 +89,10 @@ class CMakeTarget:
 class CMakeGeneratorTarget(CMakeTarget):
     def __init__(self, name: str) -> None:
         super().__init__(name, 'CUSTOM', {})
-        self.outputs = []        # type: T.List[Path]
-        self._outputs_str = []   # type: T.List[str]
-        self.command = []        # type: T.List[T.List[str]]
-        self.working_dir = None  # type: T.Optional[Path]
+        self.outputs: T.List[Path] = []
+        self._outputs_str: T.List[str] = []
+        self.command: T.List[T.List[str]] = []
+        self.working_dir: T.Optional[Path] = None
 
 class CMakeTraceParser:
     def __init__(self, cmake_version: str, build_dir: Path, env: 'Environment', permissive: bool = True) -> None:
@@ -101,10 +101,10 @@ class CMakeTraceParser:
         self.targets:                   T.Dict[str, CMakeTarget] = {}
         self.cache:                     T.Dict[str, CMakeCacheEntry] = {}
 
-        self.explicit_headers = set()  # type: T.Set[Path]
+        self.explicit_headers: T.Set[Path] = set()
 
         # T.List of targes that were added with add_custom_command to generate files
-        self.custom_targets = []  # type: T.List[CMakeGeneratorTarget]
+        self.custom_targets: T.List[CMakeGeneratorTarget] = []
 
         self.env = env
         self.permissive = permissive
@@ -118,11 +118,11 @@ class CMakeTraceParser:
         # State for delayed command execution. Delayed command execution is realised
         # with a custom CMake file that overrides some functions and adds some
         # introspection information to the trace.
-        self.delayed_commands = []  # type: T.List[str]
-        self.stored_commands = []   # type: T.List[CMakeTraceLine]
+        self.delayed_commands: T.List[str] = []
+        self.stored_commands: T.List[CMakeTraceLine] = []
 
         # All supported functions
-        self.functions = {
+        self.functions: T.Dict[str, T.Callable[[CMakeTraceLine], None]] = {
             'set': self._cmake_set,
             'unset': self._cmake_unset,
             'add_executable': self._cmake_add_executable,
@@ -145,7 +145,7 @@ class CMakeTraceParser:
             'meson_ps_execute_delayed_calls': self._meson_ps_execute_delayed_calls,
             'meson_ps_reload_vars': self._meson_ps_reload_vars,
             'meson_ps_disabled_function': self._meson_ps_disabled_function,
-        }  # type: T.Dict[str, T.Callable[[CMakeTraceLine], None]]
+        }
 
         if version_compare(self.cmake_version, '<3.17.0'):
             mlog.deprecation(textwrap.dedent(f'''\
@@ -591,10 +591,10 @@ class CMakeTraceParser:
         # With the JSON output format, introduced in CMake 3.17, spaces are
         # handled properly and we don't have to do either options
 
-        arglist = []  # type: T.List[T.Tuple[str, T.List[str]]]
+        arglist: T.List[T.Tuple[str, T.List[str]]] = []
         if self.trace_format == 'human':
             name = args.pop(0)
-            values = []  # type: T.List[str]
+            values: T.List[str] = []
             prop_regex = re.compile(r'^[A-Z_]+$')
             for a in args:
                 if prop_regex.match(a):
@@ -768,7 +768,7 @@ class CMakeTraceParser:
 
     def _flatten_args(self, args: T.List[str]) -> T.List[str]:
         # Split lists in arguments
-        res = []  # type: T.List[str]
+        res: T.List[str] = []
         for i in args:
             res += i.split(';')
         return res
@@ -783,8 +783,8 @@ class CMakeTraceParser:
         reg_start = re.compile(r'^([A-Za-z]:)?/(.*/)*[^./]+$')
         reg_end = re.compile(r'^.*\.[a-zA-Z]+$')
 
-        fixed_list = []  # type: T.List[str]
-        curr_str = None  # type: T.Optional[str]
+        fixed_list: T.List[str] = []
+        curr_str: T.Optional[str] = None
         path_found = False
 
         for i in broken_list:
diff --git a/mesonbuild/compilers/cs.py b/mesonbuild/compilers/cs.py
index f0bed5f..cd99c81 100644
--- a/mesonbuild/compilers/cs.py
+++ b/mesonbuild/compilers/cs.py
@@ -28,7 +28,7 @@ if T.TYPE_CHECKING:
     from ..environment import Environment
     from ..mesonlib import MachineChoice
 
-cs_optimization_args = {
+cs_optimization_args: T.Dict[str, T.List[str]] = {
                         'plain': [],
                         '0': [],
                         'g': [],
@@ -36,7 +36,7 @@ cs_optimization_args = {
                         '2': ['-optimize+'],
                         '3': ['-optimize+'],
                         's': ['-optimize+'],
-                        }  # type: T.Dict[str, T.List[str]]
+                        }
 
 
 class CsCompiler(BasicLinkerIsCompilerMixin, Compiler):
diff --git a/mesonbuild/compilers/detect.py b/mesonbuild/compilers/detect.py
index 210ec4d..f997247 100644
--- a/mesonbuild/compilers/detect.py
+++ b/mesonbuild/compilers/detect.py
@@ -969,7 +969,7 @@ def detect_vala_compiler(env: 'Environment', for_machine: MachineChoice) -> Comp
 def detect_rust_compiler(env: 'Environment', for_machine: MachineChoice) -> RustCompiler:
     from . import rust
     from ..linkers import linkers
-    popen_exceptions = {}  # type: T.Dict[str, Exception]
+    popen_exceptions: T.Dict[str, Exception] = {}
     compilers, _, exe_wrap = _get_compilers(env, 'rust', for_machine)
     is_cross = env.is_cross_build(for_machine)
     info = env.machines[for_machine]
diff --git a/mesonbuild/compilers/mixins/arm.py b/mesonbuild/compilers/mixins/arm.py
index 22595a8..3abc0c8 100644
--- a/mesonbuild/compilers/mixins/arm.py
+++ b/mesonbuild/compilers/mixins/arm.py
@@ -34,16 +34,16 @@ else:
     # do). This gives up DRYer type checking, with no runtime impact
     Compiler = object
 
-arm_buildtype_args = {
+arm_buildtype_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     'debug': [],
     'debugoptimized': [],
     'release': [],
     'minsize': [],
     'custom': [],
-}  # type: T.Dict[str, T.List[str]]
+}
 
-arm_optimization_args = {
+arm_optimization_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     '0': ['-O0'],
     'g': ['-g'],
@@ -51,18 +51,18 @@ arm_optimization_args = {
     '2': [], # Compiler defaults to -O2
     '3': ['-O3', '-Otime'],
     's': ['-O3'], # Compiler defaults to -Ospace
-}  # type: T.Dict[str, T.List[str]]
+}
 
-armclang_buildtype_args = {
+armclang_buildtype_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     'debug': [],
     'debugoptimized': [],
     'release': [],
     'minsize': [],
     'custom': [],
-}  # type: T.Dict[str, T.List[str]]
+}
 
-armclang_optimization_args = {
+armclang_optimization_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     '0': [], # Compiler defaults to -O0
     'g': ['-g'],
@@ -70,7 +70,7 @@ armclang_optimization_args = {
     '2': ['-O2'],
     '3': ['-O3'],
     's': ['-Oz']
-}  # type: T.Dict[str, T.List[str]]
+}
 
 
 class ArmCompiler(Compiler):
@@ -82,7 +82,7 @@ class ArmCompiler(Compiler):
     def __init__(self) -> None:
         if not self.is_cross:
             raise mesonlib.EnvironmentException('armcc supports only cross-compilation.')
-        default_warn_args = []  # type: T.List[str]
+        default_warn_args: T.List[str] = []
         self.warn_args = {'0': [],
                           '1': default_warn_args,
                           '2': default_warn_args + [],
diff --git a/mesonbuild/compilers/mixins/pgi.py b/mesonbuild/compilers/mixins/pgi.py
index 2fa736c..6362b46 100644
--- a/mesonbuild/compilers/mixins/pgi.py
+++ b/mesonbuild/compilers/mixins/pgi.py
@@ -32,14 +32,14 @@ else:
     # do). This gives up DRYer type checking, with no runtime impact
     Compiler = object
 
-pgi_buildtype_args = {
+pgi_buildtype_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     'debug': [],
     'debugoptimized': [],
     'release': [],
     'minsize': [],
     'custom': [],
-}  # type: T.Dict[str, T.List[str]]
+}
 
 
 class PGICompiler(Compiler):
diff --git a/mesonbuild/compilers/mixins/xc16.py b/mesonbuild/compilers/mixins/xc16.py
index 8957dd9..2b39046 100644
--- a/mesonbuild/compilers/mixins/xc16.py
+++ b/mesonbuild/compilers/mixins/xc16.py
@@ -31,16 +31,16 @@ else:
     # do). This gives up DRYer type checking, with no runtime impact
     Compiler = object
 
-xc16_buildtype_args = {
+xc16_buildtype_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     'debug': [],
     'debugoptimized': [],
     'release': [],
     'minsize': [],
     'custom': [],
-}  # type: T.Dict[str, T.List[str]]
+}
 
-xc16_optimization_args = {
+xc16_optimization_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     '0': ['-O0'],
     'g': ['-O0'],
@@ -48,12 +48,12 @@ xc16_optimization_args = {
     '2': ['-O2'],
     '3': ['-O3'],
     's': ['-Os']
-}  # type: T.Dict[str, T.List[str]]
+}
 
-xc16_debug_args = {
+xc16_debug_args: T.Dict[bool, T.List[str]] = {
     False: [],
     True: []
-}  # type: T.Dict[bool, T.List[str]]
+}
 
 
 class Xc16Compiler(Compiler):
@@ -66,7 +66,7 @@ class Xc16Compiler(Compiler):
         # Assembly
         self.can_compile_suffixes.add('s')
         self.can_compile_suffixes.add('sx')
-        default_warn_args = []  # type: T.List[str]
+        default_warn_args: T.List[str] = []
         self.warn_args = {'0': [],
                           '1': default_warn_args,
                           '2': default_warn_args + [],
diff --git a/mesonbuild/compilers/rust.py b/mesonbuild/compilers/rust.py
index ef0390e..d722039 100644
--- a/mesonbuild/compilers/rust.py
+++ b/mesonbuild/compilers/rust.py
@@ -32,7 +32,7 @@ if T.TYPE_CHECKING:
     from ..dependencies import Dependency
 
 
-rust_optimization_args = {
+rust_optimization_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     '0': [],
     'g': ['-C', 'opt-level=0'],
@@ -40,7 +40,7 @@ rust_optimization_args = {
     '2': ['-C', 'opt-level=2'],
     '3': ['-C', 'opt-level=3'],
     's': ['-C', 'opt-level=s'],
-}  # type: T.Dict[str, T.List[str]]
+}
 
 class RustCompiler(Compiler):
 
diff --git a/mesonbuild/compilers/swift.py b/mesonbuild/compilers/swift.py
index 19866e2..68ef992 100644
--- a/mesonbuild/compilers/swift.py
+++ b/mesonbuild/compilers/swift.py
@@ -26,7 +26,7 @@ if T.TYPE_CHECKING:
     from ..linkers.linkers import DynamicLinker
     from ..mesonlib import MachineChoice
 
-swift_optimization_args = {
+swift_optimization_args: T.Dict[str, T.List[str]] = {
     'plain': [],
     '0': [],
     'g': [],
@@ -34,7 +34,7 @@ swift_optimization_args = {
     '2': ['-O'],
     '3': ['-O'],
     's': ['-O'],
-}  # type: T.Dict[str, T.List[str]]
+}
 
 class SwiftCompiler(Compiler):
 
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
diff --git a/mesonbuild/envconfig.py b/mesonbuild/envconfig.py
index 56dee65..5340521 100644
--- a/mesonbuild/envconfig.py
+++ b/mesonbuild/envconfig.py
@@ -460,7 +460,7 @@ class BinaryTable:
 class CMakeVariables:
     def __init__(self, variables: T.Optional[T.Dict[str, T.Any]] = None) -> None:
         variables = variables or {}
-        self.variables = {}  # type: T.Dict[str, T.List[str]]
+        self.variables: T.Dict[str, T.List[str]] = {}
 
         for key, value in variables.items():
             value = mesonlib.listify(value)
diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index e54f2a6..7bba4fa 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -295,7 +295,7 @@ class Interpreter(InterpreterBase, HoldableObject):
             self.sanity_check_ast()
         self.builtin.update({'meson': MesonMain(self.build, self)})
         self.generators: T.List[build.Generator] = []
-        self.processed_buildfiles = set() # type: T.Set[str]
+        self.processed_buildfiles: T.Set[str] = set()
         self.project_args_frozen = False
         self.global_args_frozen = False  # implies self.project_args_frozen
         self.subprojects: T.Dict[str, SubprojectHolder] = {}
diff --git a/mesonbuild/interpreterbase/interpreterbase.py b/mesonbuild/interpreterbase/interpreterbase.py
index d23a23d..902f84a 100644
--- a/mesonbuild/interpreterbase/interpreterbase.py
+++ b/mesonbuild/interpreterbase/interpreterbase.py
@@ -93,12 +93,12 @@ class InterpreterBase:
         self.current_lineno = -1
         # Current node set during a function call. This can be used as location
         # when printing a warning message during a method call.
-        self.current_node = None  # type: mparser.BaseNode
+        self.current_node: mparser.BaseNode = None
         # This is set to `version_string` when this statement is evaluated:
         # meson.version().compare_version(version_string)
         # If it was part of a if-clause, it is used to temporally override the
         # current meson version target within that if-block.
-        self.tmp_meson_version = None # type: T.Optional[str]
+        self.tmp_meson_version: T.Optional[str] = None
 
     def handle_meson_version_from_ast(self, strict: bool = True) -> None:
         # do nothing in an AST interpreter
diff --git a/mesonbuild/linkers/detect.py b/mesonbuild/linkers/detect.py
index e09a28e..4261144 100644
--- a/mesonbuild/linkers/detect.py
+++ b/mesonbuild/linkers/detect.py
@@ -61,7 +61,7 @@ def guess_win_linker(env: 'Environment', compiler: T.List[str], comp_class: T.Ty
 
     check_args += env.coredata.get_external_link_args(for_machine, comp_class.language)
 
-    override = []  # type: T.List[str]
+    override: T.List[str] = []
     value = env.lookup_binary_entry(for_machine, comp_class.language + '_ld')
     if value is not None:
         override = comp_class.use_linker_args(value[0], comp_version)
@@ -138,7 +138,7 @@ def guess_nix_linker(env: 'Environment', compiler: T.List[str], comp_class: T.Ty
     else:
         check_args = comp_class.LINKER_PREFIX + ['--version'] + extra_args
 
-    override = []  # type: T.List[str]
+    override: T.List[str] = []
     value = env.lookup_binary_entry(for_machine, comp_class.language + '_ld')
     if value is not None:
         override = comp_class.use_linker_args(value[0], comp_version)
diff --git a/mesonbuild/mcompile.py b/mesonbuild/mcompile.py
index 7ae7175..c36c65b 100644
--- a/mesonbuild/mcompile.py
+++ b/mesonbuild/mcompile.py
@@ -54,7 +54,7 @@ def parse_introspect_data(builddir: Path) -> T.Dict[str, T.List[dict]]:
     with path_to_intro.open(encoding='utf-8') as f:
         schema = json.load(f)
 
-    parsed_data = defaultdict(list) # type: T.Dict[str, T.List[dict]]
+    parsed_data: T.Dict[str, T.List[dict]] = defaultdict(list)
     for target in schema:
         parsed_data[target['name']] += [target]
     return parsed_data
@@ -100,7 +100,7 @@ def get_target_from_intro_data(target: ParsedTargetName, builddir: Path, introsp
         raise MesonException(f'Can\'t invoke target `{target.full_name}`: target not found')
 
     intro_targets = introspect_data[target.name]
-    found_targets = []  # type: T.List[T.Dict[str, T.Any]]
+    found_targets: T.List[T.Dict[str, T.Any]] = []
 
     resolved_bdir = builddir.resolve()
 
@@ -337,8 +337,8 @@ def run(options: 'argparse.Namespace') -> int:
     if setup_vsenv(need_vsenv):
         mlog.log(mlog.green('INFO:'), 'automatically activated MSVC compiler environment')
 
-    cmd = []    # type: T.List[str]
-    env = None  # type: T.Optional[T.Dict[str, str]]
+    cmd: T.List[str] = []
+    env: T.Optional[T.Dict[str, str]] = None
 
     backend = cdata.get_option(mesonlib.OptionKey('backend'))
     assert isinstance(backend, str)
diff --git a/mesonbuild/mintro.py b/mesonbuild/mintro.py
index 14f8d86..ab31ec9 100644
--- a/mesonbuild/mintro.py
+++ b/mesonbuild/mintro.py
@@ -132,7 +132,7 @@ def list_installed(installdata: backends.InstallData) -> T.Dict[str, str]:
     return res
 
 def list_install_plan(installdata: backends.InstallData) -> T.Dict[str, T.Dict[str, T.Dict[str, T.Optional[str]]]]:
-    plan = {
+    plan: T.Dict[str, T.Dict[str, T.Dict[str, T.Optional[str]]]] = {
         'targets': {
             os.path.join(installdata.build_dir, target.fname): {
                 'destination': target.out_name,
@@ -141,7 +141,7 @@ def list_install_plan(installdata: backends.InstallData) -> T.Dict[str, T.Dict[s
             }
             for target in installdata.targets
         },
-    }  # type: T.Dict[str, T.Dict[str, T.Dict[str, T.Optional[str]]]]
+    }
     for key, data_list in {
         'data': installdata.data,
         'man': installdata.man,
@@ -178,13 +178,13 @@ def get_target_dir(coredata: cdata.CoreData, subdir: str) -> str:
         return subdir
 
 def list_targets_from_source(intr: IntrospectionInterpreter) -> T.List[T.Dict[str, T.Union[bool, str, T.List[T.Union[str, T.Dict[str, T.Union[str, T.List[str], bool]]]]]]]:
-    tlist = []  # type: T.List[T.Dict[str, T.Union[bool, str, T.List[T.Union[str, T.Dict[str, T.Union[str, T.List[str], bool]]]]]]]
+    tlist: T.List[T.Dict[str, T.Union[bool, str, T.List[T.Union[str, T.Dict[str, T.Union[str, T.List[str], bool]]]]]]] = []
     root_dir = Path(intr.source_root)
 
     def nodes_to_paths(node_list: T.List[BaseNode]) -> T.List[Path]:
-        res = []  # type: T.List[Path]
+        res: T.List[Path] = []
         for n in node_list:
-            args = []  # type: T.List[BaseNode]
+            args: T.List[BaseNode] = []
             if isinstance(n, FunctionNode):
                 args = list(n.args.arguments)
                 if n.func_name in BUILD_TARGET_FUNCTIONS:
@@ -231,7 +231,7 @@ def list_targets_from_source(intr: IntrospectionInterpreter) -> T.List[T.Dict[st
     return tlist
 
 def list_targets(builddata: build.Build, installdata: backends.InstallData, backend: backends.Backend) -> T.List[T.Any]:
-    tlist = []  # type: T.List[T.Any]
+    tlist: T.List[T.Any] = []
     build_dir = builddata.environment.get_build_dir()
     src_dir = builddata.environment.get_source_dir()
 
@@ -290,7 +290,7 @@ def list_buildoptions_from_source(intr: IntrospectionInterpreter) -> T.List[T.Di
     return list_buildoptions(intr.coredata, subprojects)
 
 def list_buildoptions(coredata: cdata.CoreData, subprojects: T.Optional[T.List[str]] = None) -> T.List[T.Dict[str, T.Union[str, bool, int, T.List[str]]]]:
-    optlist = []  # type: T.List[T.Dict[str, T.Union[str, bool, int, T.List[str]]]]
+    optlist: T.List[T.Dict[str, T.Union[str, bool, int, T.List[str]]]] = []
     subprojects = subprojects or []
 
     dir_option_names = set(cdata.BUILTIN_DIR_OPTIONS)
@@ -379,7 +379,7 @@ def list_compilers(coredata: cdata.CoreData) -> T.Dict[str, T.Dict[str, T.Dict[s
     return compilers
 
 def list_deps_from_source(intr: IntrospectionInterpreter) -> T.List[T.Dict[str, T.Union[str, bool]]]:
-    result = []  # type: T.List[T.Dict[str, T.Union[str, bool]]]
+    result: T.List[T.Dict[str, T.Union[str, bool]]] = []
     for i in intr.dependencies:
         keys = [
             'name',
@@ -436,9 +436,9 @@ def list_deps(coredata: cdata.CoreData, backend: backends.Backend) -> T.List[T.D
     return list(result.values())
 
 def get_test_list(testdata: T.List[backends.TestSerialisation]) -> T.List[T.Dict[str, T.Union[str, int, T.List[str], T.Dict[str, str]]]]:
-    result = []  # type: T.List[T.Dict[str, T.Union[str, int, T.List[str], T.Dict[str, str]]]]
+    result: T.List[T.Dict[str, T.Union[str, int, T.List[str], T.Dict[str, str]]]] = []
     for t in testdata:
-        to = {}  # type: T.Dict[str, T.Union[str, int, T.List[str], T.Dict[str, str]]]
+        to: T.Dict[str, T.Union[str, int, T.List[str], T.Dict[str, str]]] = {}
         if isinstance(t.fname, str):
             fname = [t.fname]
         else:
@@ -541,7 +541,7 @@ def run(options: argparse.Namespace) -> int:
     if options.builddir is not None:
         datadir = os.path.join(options.builddir, datadir)
     indent = 4 if options.indent else None
-    results = []  # type: T.List[T.Tuple[str, T.Union[dict, T.List[T.Any]]]]
+    results: T.List[T.Tuple[str, T.Union[dict, T.List[T.Any]]]] = []
     sourcedir = '.' if options.builddir == 'meson.build' else options.builddir[:-11]
     intro_types = get_meson_introspection_types(sourcedir=sourcedir)
 
@@ -594,7 +594,7 @@ def run(options: argparse.Namespace) -> int:
 
     return print_results(options, results, indent)
 
-updated_introspection_files = []  # type: T.List[str]
+updated_introspection_files: T.List[str] = []
 
 def write_intro_info(intro_info: T.Sequence[T.Tuple[str, T.Union[dict, T.List[T.Any]]]], info_dir: str) -> None:
     for kind, data in intro_info:
@@ -609,7 +609,7 @@ def write_intro_info(intro_info: T.Sequence[T.Tuple[str, T.Union[dict, T.List[T.
 def generate_introspection_file(builddata: build.Build, backend: backends.Backend) -> None:
     coredata = builddata.environment.get_coredata()
     intro_types = get_meson_introspection_types(coredata=coredata, builddata=builddata, backend=backend)
-    intro_info = []  # type: T.List[T.Tuple[str, T.Union[dict, T.List[T.Any]]]]
+    intro_info: T.List[T.Tuple[str, T.Union[dict, T.List[T.Any]]]] = []
 
     for key, val in intro_types.items():
         if not val.func:
diff --git a/mesonbuild/mlog.py b/mesonbuild/mlog.py
index e51399b..0e62a57 100644
--- a/mesonbuild/mlog.py
+++ b/mesonbuild/mlog.py
@@ -60,7 +60,7 @@ def _windows_ansi() -> bool:
     return bool(kernel.SetConsoleMode(stdout, mode.value | 0x4) or os.environ.get('ANSICON'))
 
 def colorize_console() -> bool:
-    _colorize_console = getattr(sys.stdout, 'colorize_console', None)  # type: bool
+    _colorize_console: bool = getattr(sys.stdout, 'colorize_console', None)
     if _colorize_console is not None:
         return _colorize_console
 
@@ -201,7 +201,7 @@ class _Logger:
         self.log_fatal_warnings = fatal_warnings
 
     def process_markup(self, args: T.Sequence[TV_Loggable], keep: bool, display_timestamp: bool = True) -> T.List[str]:
-        arr = []  # type: T.List[str]
+        arr: T.List[str] = []
         if self.log_timestamp_start is not None and display_timestamp:
             arr = ['[{:.3f}]'.format(time.monotonic() - self.log_timestamp_start)]
         for arg in args:
@@ -312,7 +312,7 @@ class _Logger:
         # The typing requirements here are non-obvious. Lists are invariant,
         # therefore T.List[A] and T.List[T.Union[A, B]] are not able to be joined
         if severity is _Severity.NOTICE:
-            label = [bold('NOTICE:')]  # type: TV_LoggableList
+            label: TV_LoggableList = [bold('NOTICE:')]
         elif severity is _Severity.WARNING:
             label = [yellow('WARNING:')]
         elif severity is _Severity.ERROR:
@@ -373,7 +373,7 @@ class _Logger:
         if prefix is None:
             prefix = red('ERROR:')
         self.log()
-        args = []  # type: T.List[T.Union[AnsiDecorator, str]]
+        args: T.List[T.Union[AnsiDecorator, str]] = []
         if all(getattr(e, a, None) is not None for a in ['file', 'lineno', 'colno']):
             # Mypy doesn't follow hasattr, and it's pretty easy to visually inspect
             # that this is correct, so we'll just ignore it.
diff --git a/mesonbuild/modules/cmake.py b/mesonbuild/modules/cmake.py
index c6048f9..bec1b2a 100644
--- a/mesonbuild/modules/cmake.py
+++ b/mesonbuild/modules/cmake.py
@@ -188,7 +188,7 @@ class CMakeSubproject(ModuleObject):
 class CMakeSubprojectOptions(ModuleObject):
     def __init__(self) -> None:
         super().__init__()
-        self.cmake_options = []  # type: T.List[str]
+        self.cmake_options: T.List[str] = []
         self.target_options = TargetOptions()
 
         self.methods.update(
diff --git a/mesonbuild/mparser.py b/mesonbuild/mparser.py
index d4ddff9..fb4e433 100644
--- a/mesonbuild/mparser.py
+++ b/mesonbuild/mparser.py
@@ -163,7 +163,7 @@ class Lexer:
         col = 0
         while loc < len(self.code):
             matched = False
-            value = None  # type: T.Union[str, bool, int]
+            value: T.Union[str, bool, int] = None
             for (tid, reg) in self.token_specification:
                 mo = reg.match(self.code, loc)
                 if mo:
@@ -610,7 +610,7 @@ class Parser:
     def __init__(self, code: str, filename: str):
         self.lexer = Lexer(code)
         self.stream = self.lexer.lex(filename)
-        self.current = Token('eof', '', 0, 0, 0, (0, 0), None)  # type: Token
+        self.current: Token = Token('eof', '', 0, 0, 0, (0, 0), None)
         self.getsym()
         self.in_ternary = False
 
diff --git a/mesonbuild/mtest.py b/mesonbuild/mtest.py
index 36afd61..1ac2782 100644
--- a/mesonbuild/mtest.py
+++ b/mesonbuild/mtest.py
@@ -521,9 +521,9 @@ class ConsoleLogger(TestLogger):
     RTRI = "\u25B6 "
 
     def __init__(self) -> None:
-        self.running_tests = OrderedSet()  # type: OrderedSet['TestRun']
-        self.progress_test = None          # type: T.Optional['TestRun']
-        self.progress_task = None          # type: T.Optional[asyncio.Future]
+        self.running_tests: OrderedSet['TestRun'] = OrderedSet()
+        self.progress_test: T.Optional['TestRun'] = None
+        self.progress_task: T.Optional[asyncio.Future] = None
         self.max_left_width = 0
         self.stop = False
         # TODO: before 3.10 this cannot be created immediately, because
@@ -806,7 +806,7 @@ class JunitBuilder(TestLogger):
         self.filename = filename
         self.root = et.Element(
             'testsuites', tests='0', errors='0', failures='0')
-        self.suites = {}  # type: T.Dict[str, et.Element]
+        self.suites: T.Dict[str, et.Element] = {}
 
     def log(self, harness: 'TestHarness', test: 'TestRun') -> None:
         """Log a single test case."""
@@ -924,24 +924,24 @@ class TestRun:
                  name: str, timeout: T.Optional[int], is_parallel: bool, verbose: bool):
         self.res = TestResult.PENDING
         self.test = test
-        self._num = None       # type: T.Optional[int]
+        self._num: T.Optional[int] = None
         self.name = name
         self.timeout = timeout
-        self.results = []      # type: T.List[TAPParser.Test]
-        self.returncode = None  # type: T.Optional[int]
-        self.starttime = None  # type: T.Optional[float]
-        self.duration = None   # type: T.Optional[float]
+        self.results: T.List[TAPParser.Test] = []
+        self.returncode: T.Optional[int] = None
+        self.starttime: T.Optional[float] = None
+        self.duration: T.Optional[float] = None
         self.stdo = ''
         self.stde = ''
         self.additional_error = ''
-        self.cmd = None        # type: T.Optional[T.List[str]]
+        self.cmd: T.Optional[T.List[str]] = None
         self.env = test_env
         self.should_fail = test.should_fail
         self.project = test.project_name
-        self.junit = None      # type: T.Optional[et.ElementTree]
+        self.junit: T.Optional[et.ElementTree] = None
         self.is_parallel = is_parallel
         self.verbose = verbose
-        self.warnings = []     # type: T.List[str]
+        self.warnings: T.List[str] = []
 
     def start(self, cmd: T.List[str]) -> None:
         self.res = TestResult.RUNNING
@@ -1088,7 +1088,7 @@ class TestRunTAP(TestRun):
 
     async def parse(self, harness: 'TestHarness', lines: T.AsyncIterator[str]) -> None:
         res = None
-        warnings = [] # type: T.List[TAPParser.UnknownLine]
+        warnings: T.List[TAPParser.UnknownLine] = []
         version = 12
 
         async for i in TAPParser().parse_async(lines):
@@ -1288,8 +1288,8 @@ class TestSubprocess:
         self.stdo_task: T.Optional[asyncio.Task[None]] = None
         self.stde_task: T.Optional[asyncio.Task[None]] = None
         self.postwait_fn = postwait_fn
-        self.all_futures = []            # type: T.List[asyncio.Future]
-        self.queue = None                # type: T.Optional[asyncio.Queue[T.Optional[str]]]
+        self.all_futures: T.List[asyncio.Future] = []
+        self.queue: T.Optional[asyncio.Queue[T.Optional[str]]] = None
 
     def stdout_lines(self) -> T.AsyncIterator[str]:
         self.queue = asyncio.Queue()
@@ -1535,7 +1535,7 @@ class SingleTestRunner:
                 if not self.options.split and not self.runobj.needs_parsing \
                 else asyncio.subprocess.PIPE
 
-        extra_cmd = []  # type: T.List[str]
+        extra_cmd: T.List[str] = []
         if self.test.protocol is TestProtocol.GTEST:
             gtestname = self.test.name
             if self.test.workdir:
@@ -1570,7 +1570,7 @@ class SingleTestRunner:
 class TestHarness:
     def __init__(self, options: argparse.Namespace):
         self.options = options
-        self.collected_failures = []  # type: T.List[TestRun]
+        self.collected_failures: T.List[TestRun] = []
         self.fail_count = 0
         self.expectedfail_count = 0
         self.unexpectedpass_count = 0
@@ -1580,13 +1580,13 @@ class TestHarness:
         self.test_count = 0
         self.name_max_len = 0
         self.is_run = False
-        self.loggers = []         # type: T.List[TestLogger]
+        self.loggers: T.List[TestLogger] = []
         self.console_logger = ConsoleLogger()
         self.loggers.append(self.console_logger)
         self.need_console = False
-        self.ninja = None # type: T.List[str]
+        self.ninja: T.List[str] = None
 
-        self.logfile_base = None  # type: T.Optional[str]
+        self.logfile_base: T.Optional[str] = None
         if self.options.logbase and not self.options.gdb:
             namebase = None
             self.logfile_base = os.path.join(self.options.wd, 'meson-logs', self.options.logbase)
@@ -1809,7 +1809,7 @@ class TestHarness:
         startdir = os.getcwd()
         try:
             os.chdir(self.options.wd)
-            runners = []             # type: T.List[SingleTestRunner]
+            runners: T.List[SingleTestRunner] = []
             for i in range(self.options.repeat):
                 runners.extend(self.get_test_runner(test) for test in tests)
                 if i == 0:
@@ -1964,7 +1964,7 @@ class TestHarness:
 
     @staticmethod
     def get_wrapper(options: argparse.Namespace) -> T.List[str]:
-        wrap = []  # type: T.List[str]
+        wrap: T.List[str] = []
         if options.gdb:
             wrap = [options.gdb_path, '--quiet']
             if options.repeat > 1:
@@ -2007,10 +2007,10 @@ class TestHarness:
 
     async def _run_tests(self, runners: T.List[SingleTestRunner]) -> None:
         semaphore = asyncio.Semaphore(self.options.num_processes)
-        futures = deque()  # type: T.Deque[asyncio.Future]
-        running_tests = {}  # type: T.Dict[asyncio.Future, str]
+        futures: T.Deque[asyncio.Future] = deque()
+        running_tests: T.Dict[asyncio.Future, str] = {}
         interrupted = False
-        ctrlc_times = deque(maxlen=MAX_CTRLC)  # type: T.Deque[float]
+        ctrlc_times: T.Deque[float] = deque(maxlen=MAX_CTRLC)
         loop = asyncio.get_running_loop()
 
         async def run_test(test: SingleTestRunner) -> None:
@@ -2117,9 +2117,9 @@ def rebuild_deps(ninja: T.List[str], wd: str, tests: T.List[TestSerialisation])
 
     assert len(ninja) > 0
 
-    depends = set()        # type: T.Set[str]
-    targets = set()        # type: T.Set[str]
-    intro_targets = {}     # type: T.Dict[str, T.List[str]]
+    depends: T.Set[str] = set()
+    targets: T.Set[str] = set()
+    intro_targets: T.Dict[str, T.List[str]] = {}
     for target in load_info_file(get_infodir(wd), kind='targets'):
         intro_targets[target['id']] = [
             convert_path_to_target(f)
diff --git a/mesonbuild/scripts/cmake_run_ctgt.py b/mesonbuild/scripts/cmake_run_ctgt.py
index 755530a..df3f361 100755
--- a/mesonbuild/scripts/cmake_run_ctgt.py
+++ b/mesonbuild/scripts/cmake_run_ctgt.py
@@ -9,7 +9,7 @@ from pathlib import Path
 import typing as T
 
 def run(argsv: T.List[str]) -> int:
-    commands = [[]]  # type: T.List[T.List[str]]
+    commands: T.List[T.List[str]] = [[]]
     SEPARATOR = ';;;'
 
     # Generate CMD parameters
diff --git a/mesonbuild/scripts/depfixer.py b/mesonbuild/scripts/depfixer.py
index b9c58fe..593efd9 100644
--- a/mesonbuild/scripts/depfixer.py
+++ b/mesonbuild/scripts/depfixer.py
@@ -123,8 +123,8 @@ class Elf(DataSizes):
     def __init__(self, bfile: str, verbose: bool = True) -> None:
         self.bfile = bfile
         self.verbose = verbose
-        self.sections = []  # type: T.List[SectionHeader]
-        self.dynamic = []   # type: T.List[DynamicEntry]
+        self.sections: T.List[SectionHeader] = []
+        self.dynamic: T.List[DynamicEntry] = []
         self.open_bf(bfile)
         try:
             (self.ptrsize, self.is_le) = self.detect_elf_type()
@@ -329,7 +329,7 @@ class Elf(DataSizes):
         old_rpath = self.read_str()
         # Some rpath entries may come from multiple sources.
         # Only add each one once.
-        new_rpaths = OrderedSet()  # type: OrderedSet[bytes]
+        new_rpaths: OrderedSet[bytes] = OrderedSet()
         if new_rpath:
             new_rpaths.update(new_rpath.split(b':'))
         if old_rpath:
diff --git a/mesonbuild/utils/universal.py b/mesonbuild/utils/universal.py
index c1125fb..73d4523 100644
--- a/mesonbuild/utils/universal.py
+++ b/mesonbuild/utils/universal.py
@@ -1526,7 +1526,7 @@ def Popen_safe_legacy(args: T.List[str], write: T.Optional[str] = None,
                       **kwargs: T.Any) -> T.Tuple['subprocess.Popen[str]', str, str]:
     p = subprocess.Popen(args, universal_newlines=False, close_fds=False,
                          stdin=stdin, stdout=stdout, stderr=stderr, **kwargs)
-    input_ = None  # type: T.Optional[bytes]
+    input_: T.Optional[bytes] = None
     if write is not None:
         input_ = write.encode('utf-8')
     o, e = p.communicate(input_)
diff --git a/mesonbuild/wrap/wrap.py b/mesonbuild/wrap/wrap.py
index 2b0a0ba..c0dd01c 100644
--- a/mesonbuild/wrap/wrap.py
+++ b/mesonbuild/wrap/wrap.py
@@ -145,11 +145,11 @@ class PackageDefinition:
     def __init__(self, fname: str, subproject: str = ''):
         self.filename = fname
         self.subproject = SubProject(subproject)
-        self.type = None  # type: T.Optional[str]
-        self.values = {} # type: T.Dict[str, str]
-        self.provided_deps = {} # type: T.Dict[str, T.Optional[str]]
-        self.provided_programs = [] # type: T.List[str]
-        self.diff_files = [] # type: T.List[Path]
+        self.type: T.Optional[str] = None
+        self.values: T.Dict[str, str] = {}
+        self.provided_deps: T.Dict[str, T.Optional[str]] = {}
+        self.provided_programs: T.List[str] = []
+        self.diff_files: T.List[Path] = []
         self.basename = os.path.basename(fname)
         self.has_wrap = self.basename.endswith('.wrap')
         self.name = self.basename[:-5] if self.has_wrap else self.basename
@@ -290,10 +290,10 @@ class Resolver:
     def __post_init__(self) -> None:
         self.subdir_root = os.path.join(self.source_dir, self.subdir)
         self.cachedir = os.path.join(self.subdir_root, 'packagecache')
-        self.wraps = {} # type: T.Dict[str, PackageDefinition]
+        self.wraps: T.Dict[str, PackageDefinition] = {}
         self.netrc: T.Optional[netrc] = None
-        self.provided_deps = {} # type: T.Dict[str, PackageDefinition]
-        self.provided_programs = {} # type: T.Dict[str, PackageDefinition]
+        self.provided_deps: T.Dict[str, PackageDefinition] = {}
+        self.provided_programs: T.Dict[str, PackageDefinition] = {}
         self.wrapdb: T.Dict[str, T.Any] = {}
         self.wrapdb_provided_deps: T.Dict[str, str] = {}
         self.wrapdb_provided_programs: T.Dict[str, str] = {}
@@ -555,7 +555,7 @@ class Resolver:
         revno = self.wrap.get('revision')
         checkout_cmd = ['-c', 'advice.detachedHead=false', 'checkout', revno, '--']
         is_shallow = False
-        depth_option = []    # type: T.List[str]
+        depth_option: T.List[str] = []
         if self.wrap.values.get('depth', '') != '':
             is_shallow = True
             depth_option = ['--depth', self.wrap.values.get('depth')]