compilers/mixins: make xc16 type safe

mesonbuild/compilers/mixins/xc16.py

@@ -47,7 +47,12 @@ xc16_debug_args = {
 
 
 class Xc16Compiler:
-    def __init__(self):
+
+    if T.TYPE_CHECKING:
+        can_compile_suffixes = set()  # type: T.Set[str]
+        is_cross = True
+
+    def __init__(self) -> None:
         if not self.is_cross:
             raise EnvironmentException('xc16 supports only cross-compilation.')
         self.id = 'xc16'

run_mypy.py

@@ -28,6 +28,7 @@ modules = [
   'mesonbuild/compilers/mixins/islinker.py',
   'mesonbuild/compilers/mixins/pgi.py',
   'mesonbuild/compilers/mixins/visualstudio.py',
+  'mesonbuild/compilers/mixins/xc16.py',
   # 'mesonbuild/coredata.py',
   'mesonbuild/dependencies/boost.py',
   'mesonbuild/dependencies/hdf5.py',