diff --git a/distutils/command/build_ext.py b/distutils/command/build_ext.py
index c0d61559..5f3b21ff 100644
--- a/distutils/command/build_ext.py
+++ b/distutils/command/build_ext.py
@@ -13,7 +13,7 @@
 from collections.abc import Callable
 from distutils._log import log
 from site import USER_BASE
-from typing import ClassVar
+from typing import ClassVar, cast
 
 from .._modified import newer_group
 from ..ccompiler import CCompiler, new_compiler, show_compilers
@@ -736,7 +736,7 @@ def get_ext_filename(self, ext_name: str) -> str:
         from ..sysconfig import get_config_var
 
         ext_path = ext_name.split('.')
-        ext_suffix = get_config_var('EXT_SUFFIX')
+        ext_suffix = cast('str | None', get_config_var('EXT_SUFFIX')) or ''
         return os.path.join(*ext_path) + ext_suffix
 
     def get_export_symbols(self, ext: Extension) -> list[str]:
@@ -817,7 +817,7 @@ def get_libraries(self, ext: Extension) -> list[str]:
                         link_libpython = True
 
             if link_libpython:
-                ldversion = get_config_var('LDVERSION')
+                ldversion = cast('str | None', get_config_var('LDVERSION')) or ''
                 return ext.libraries + ['python' + ldversion]
 
         return ext.libraries
diff --git a/distutils/compilers/C/base.py b/distutils/compilers/C/base.py
index 902f8bc5..4c1943e2 100644
--- a/distutils/compilers/C/base.py
+++ b/distutils/compilers/C/base.py
@@ -16,6 +16,7 @@
     ClassVar,
     Literal,
     TypeVar,
+    cast,
     overload,
 )
 
@@ -1082,7 +1083,11 @@ def shared_object_filename(
         assert output_dir is not None
         if strip_dir:
             basename = os.path.basename(basename)
-        return os.path.join(output_dir, basename + self.shared_lib_extension)
+        return os.path.join(
+            output_dir,
+            # cast: we only allow basename to PathLike if strip_dir=True, so we always coerce
+            cast("str", basename) + (self.shared_lib_extension or ''),
+        )
 
     @overload
     def executable_filename(
@@ -1107,7 +1112,11 @@ def executable_filename(
         assert output_dir is not None
         if strip_dir:
             basename = os.path.basename(basename)
-        return os.path.join(output_dir, basename + (self.exe_extension or ''))
+        return os.path.join(
+            output_dir,
+            # cast: we only allow basename to PathLike if strip_dir=True, so we always coerce
+            cast("str", basename) + (self.exe_extension or ''),
+        )
 
     def library_filename(
         self,
diff --git a/mypy.ini b/mypy.ini
index 48ddecfd..85f31821 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -24,7 +24,6 @@ disable_error_code =
 	return-value,
 	type-var,
 	# TODO: Resolve and re-enable these gradually
-	operator,
 	arg-type,
 
 allow_redefinition = true