diff --git a/mesonbuild/compilers/mixins/arm.py b/mesonbuild/compilers/mixins/arm.py
index d0faf949b..ba6e0b139 100644
--- a/mesonbuild/compilers/mixins/arm.py
+++ b/mesonbuild/compilers/mixins/arm.py
@@ -18,39 +18,48 @@ import os
 import typing
 
 from ...mesonlib import EnvironmentException
+from ..compilers import clike_debug_args
+
+if typing.TYPE_CHECKING:
+    from ..compilers import CompilerType
+    from ...environment import Environment
+
+arm_buildtype_args = {
+    'plain': [],
+    'debug': ['-O0', '--debug'],
+    'debugoptimized': ['-O1', '--debug'],
+    'release': ['-O3', '-Otime'],
+    'minsize': ['-O3', '-Ospace'],
+    'custom': [],
+}  # type: typing.Dict[str, typing.List[str]]
+
+arm_buildtype_linker_args = {
+    'plain': [],
+    'debug': [],
+    'debugoptimized': [],
+    'release': [],
+    'minsize': [],
+    'custom': [],
+}  # type: typing.Dict[str, typing.List[str]]
+
+arm_optimization_args = {
+    '0': ['-O0'],
+    'g': ['-g'],
+    '1': ['-O1'],
+    '2': ['-O2'],
+    '3': ['-O3'],
+    's': [],
+}  # type: typing.Dict[str, typing.List[str]]
 
-arm_buildtype_args = {'plain': [],
-                      'debug': ['-O0', '--debug'],
-                      'debugoptimized': ['-O1', '--debug'],
-                      'release': ['-O3', '-Otime'],
-                      'minsize': ['-O3', '-Ospace'],
-                      'custom': [],
-                      }
-
-arm_buildtype_linker_args = {'plain': [],
-                             'debug': [],
-                             'debugoptimized': [],
-                             'release': [],
-                             'minsize': [],
-                             'custom': [],
-                             }
-
-arm_optimization_args = {'0': ['-O0'],
-                         'g': ['-g'],
-                         '1': ['-O1'],
-                         '2': ['-O2'],
-                         '3': ['-O3'],
-                         's': [],
-                         }
 
 class ArmCompiler:
     # Functionality that is common to all ARM family compilers.
-    def __init__(self, compiler_type):
+    def __init__(self, compiler_type: 'CompilerType'):
         if not self.is_cross:
             raise EnvironmentException('armcc supports only cross-compilation.')
         self.id = 'arm'
         self.compiler_type = compiler_type
-        default_warn_args = []
+        default_warn_args = []  # type: typing.List[str]
         self.warn_args = {'0': [],
                           '1': default_warn_args,
                           '2': default_warn_args + [],
@@ -58,32 +67,32 @@ class ArmCompiler:
         # Assembly
         self.can_compile_suffixes.add('s')
 
-    def can_linker_accept_rsp(self):
+    def can_linker_accept_rsp(self) -> bool:
         return False
 
-    def get_pic_args(self):
+    def get_pic_args(self) -> typing.List[str]:
         # FIXME: Add /ropi, /rwpi, /fpic etc. qualifiers to --apcs
         return []
 
-    def get_buildtype_args(self, buildtype):
+    def get_buildtype_args(self, buildtype: str) -> typing.List[str]:
         return arm_buildtype_args[buildtype]
 
-    def get_buildtype_linker_args(self, buildtype):
+    def get_buildtype_linker_args(self, buildtype: str) -> typing.List[str]:
         return arm_buildtype_linker_args[buildtype]
 
     # Override CCompiler.get_always_args
-    def get_always_args(self):
+    def get_always_args(self) -> typing.List[str]:
         return []
 
     # Override CCompiler.get_dependency_gen_args
-    def get_dependency_gen_args(self, outtarget, outfile):
+    def get_dependency_gen_args(self, outtarget: str, outfile: str) -> typing.List[str]:
         return []
 
     # Override CCompiler.get_std_shared_lib_link_args
-    def get_std_shared_lib_link_args(self):
+    def get_std_shared_lib_link_args(self) -> typing.List[str]:
         return []
 
-    def get_pch_use_args(self, pch_dir, header):
+    def get_pch_use_args(self, pch_dir: str, header: str) -> typing.List[str]:
         # FIXME: Add required arguments
         # NOTE from armcc user guide:
         # "Support for Precompiled Header (PCH) files is deprecated from ARM Compiler 5.05
@@ -91,36 +100,36 @@ class ArmCompiler:
         # PCH files."
         return []
 
-    def get_pch_suffix(self):
+    def get_pch_suffix(self) -> str:
         # NOTE from armcc user guide:
         # "Support for Precompiled Header (PCH) files is deprecated from ARM Compiler 5.05
         # onwards on all platforms. Note that ARM Compiler on Windows 8 never supported
         # PCH files."
         return 'pch'
 
-    def thread_flags(self, env):
+    def thread_flags(self, env: 'Environment') -> typing.List[str]:
         return []
 
-    def thread_link_flags(self, env):
+    def thread_link_flags(self, env: 'Environment') -> typing.List[str]:
         return []
 
-    def get_linker_exelist(self):
+    def get_linker_exelist(self) -> typing.List[str]:
         args = ['armlink']
         return args
 
-    def get_coverage_args(self):
+    def get_coverage_args(self) -> typing.List[str]:
         return []
 
-    def get_coverage_link_args(self):
+    def get_coverage_link_args(self) -> typing.List[str]:
         return []
 
-    def get_optimization_args(self, optimization_level):
+    def get_optimization_args(self, optimization_level: str) -> typing.List[str]:
         return arm_optimization_args[optimization_level]
 
-    def get_debug_args(self, is_debug):
+    def get_debug_args(self, is_debug: bool) -> typing.List[str]:
         return clike_debug_args[is_debug]
 
-    def compute_parameters_with_absolute_paths(self, parameter_list, build_dir):
+    def compute_parameters_with_absolute_paths(self, parameter_list: typing.List[str], build_dir: str) -> typing.List[str]:
         for idx, i in enumerate(parameter_list):
             if i[:2] == '-I' or i[:2] == '-L':
                 parameter_list[idx] = i[:2] + os.path.normpath(os.path.join(build_dir, i[2:]))