diff --git a/gdb/gdbarch.py b/gdb/gdbarch.py
index d1ac414d0eb3..93b1e8bf84e2 100755
--- a/gdb/gdbarch.py
+++ b/gdb/gdbarch.py
@@ -25,10 +25,10 @@ import textwrap
 # `gdbarch_types.components`.
 import gdbarch_components  # noqa: F401 # type: ignore
 import gdbcopyright
-from gdbarch_types import Function, Info, Value, components
+from gdbarch_types import Component, Function, Info, Value, components
 
 
-def indentation(n_columns):
+def indentation(n_columns: int):
     """Return string with tabs and spaces to indent line to N_COLUMNS."""
     return "\t" * (n_columns // 8) + " " * (n_columns % 8)
 
@@ -38,12 +38,12 @@ copyright = gdbcopyright.copyright(
 )
 
 
-def info(c):
+def info(c: Component):
     "Filter function to only allow Info components."
     return type(c) is Info
 
 
-def not_info(c):
+def not_info(c: Component):
     "Filter function to omit Info components."
     return type(c) is not Info
 
diff --git a/gdb/gdbarch_components.py b/gdb/gdbarch_components.py
index fe5c3b3b4bcd..caa65c334eca 100644
--- a/gdb/gdbarch_components.py
+++ b/gdb/gdbarch_components.py
@@ -166,13 +166,14 @@ Number of bits in an int or unsigned int for the target machine.
     invalid=False,
 )
 
+long_bit_predefault = "4*TARGET_CHAR_BIT"
 long_bit = Value(
     comment="""
 Number of bits in a long or unsigned long for the target machine.
 """,
     type="int",
     name="long_bit",
-    predefault="4*TARGET_CHAR_BIT",
+    predefault=long_bit_predefault,
     invalid=False,
 )
 
@@ -183,7 +184,7 @@ machine.
 """,
     type="int",
     name="long_long_bit",
-    predefault="2*" + long_bit.predefault,
+    predefault="2*" + long_bit_predefault,
     invalid=False,
 )
 
diff --git a/gdb/gdbarch_types.py b/gdb/gdbarch_types.py
index aca23850b911..9eb38c987a2c 100755
--- a/gdb/gdbarch_types.py
+++ b/gdb/gdbarch_types.py
@@ -17,8 +17,10 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+from typing import Optional, Union
 
-def join_type_and_name(t, n):
+
+def join_type_and_name(t: str, n: str):
     "Combine the type T and the name N into a C declaration."
     if t.endswith("*") or t.endswith("&"):
         return t + n
@@ -26,30 +28,29 @@ def join_type_and_name(t, n):
         return t + " " + n
 
 
-def join_params(params):
+def join_params(params: list[tuple[str, str]]):
     """Given a sequence of (TYPE, NAME) pairs, generate a comma-separated
     list of declarations."""
-    params = [join_type_and_name(p[0], p[1]) for p in params]
-    return ", ".join(params)
+    return ", ".join([join_type_and_name(p[0], p[1]) for p in params])
 
 
-class _Component:
+class Component:
     "Base class for all components."
 
     def __init__(
         self,
-        name,
-        type,
-        printer=None,
-        comment=None,
-        predicate=False,
-        predefault=None,
-        postdefault=None,
-        invalid=None,
-        params=None,
-        param_checks=None,
-        result_checks=None,
-        implement=True,
+        name: str,
+        type: str,
+        printer: Optional[str] = None,
+        comment: Optional[str] = None,
+        predicate: bool = False,
+        predefault: Optional[str] = None,
+        postdefault: Optional[str] = None,
+        invalid: Optional[Union[bool, str]] = None,
+        params: Optional[list[tuple[str, str]]] = None,
+        param_checks: Optional[list[str]] = None,
+        result_checks: Optional[list[str]] = None,
+        implement: bool = True,
     ):
         self.name = name
         self.type = type
@@ -59,7 +60,7 @@ class _Component:
         self.predefault = predefault
         self.postdefault = postdefault
         self.invalid = invalid
-        self.params = params
+        self.params = params or []
         self.param_checks = param_checks
         self.result_checks = result_checks
         self.implement = implement
@@ -81,24 +82,24 @@ class _Component:
         return predicate
 
 
-class Info(_Component):
+class Info(Component):
     "An Info component is copied from the gdbarch_info."
 
 
-class Value(_Component):
+class Value(Component):
     "A Value component is just a data member."
 
     def __init__(
         self,
         *,
-        name,
-        type,
-        comment=None,
-        predicate=False,
-        predefault=None,
-        postdefault=None,
-        invalid=None,
-        printer=None,
+        name: str,
+        type: str,
+        comment: Optional[str] = None,
+        predicate: bool = False,
+        predefault: Optional[str] = None,
+        postdefault: Optional[str] = None,
+        invalid: Optional[Union[bool, str]] = None,
+        printer: Optional[str] = None,
     ):
         super().__init__(
             comment=comment,
@@ -112,24 +113,24 @@ class Value(_Component):
         )
 
 
-class Function(_Component):
+class Function(Component):
     "A Function component is a function pointer member."
 
     def __init__(
         self,
         *,
-        name,
-        type,
-        params,
-        comment=None,
-        predicate=False,
-        predefault=None,
-        postdefault=None,
-        invalid=None,
-        printer=None,
-        param_checks=None,
-        result_checks=None,
-        implement=True,
+        name: str,
+        type: str,
+        params: list[tuple[str, str]],
+        comment: Optional[str] = None,
+        predicate: bool = False,
+        predefault: Optional[str] = None,
+        postdefault: Optional[str] = None,
+        invalid: Optional[Union[bool, str]] = None,
+        printer: Optional[str] = None,
+        param_checks: Optional[list[str]] = None,
+        result_checks: Optional[list[str]] = None,
+        implement: bool = True,
     ):
         super().__init__(
             comment=comment,
@@ -180,4 +181,4 @@ class Method(Function):
 
 
 # All the components created in gdbarch-components.py.
-components: list[_Component] = []
+components: list[Component] = []
diff --git a/gdb/gdbcopyright.py b/gdb/gdbcopyright.py
index 9a52bc1d847b..44c88e07cae7 100644
--- a/gdb/gdbcopyright.py
+++ b/gdb/gdbcopyright.py
@@ -18,7 +18,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
-def copyright(tool, description):
+def copyright(tool: str, description: str):
     # Search the tool source itself for the correct copyright years.
     with open(tool, "r") as f:
         for line in f:
