Add some cheap return and parameter annotations

Use: https://github.com/JelleZijlstra/autotyping
to add "safe" return annotations.

Where a parameter has a default value that is an obvious scalar type
(bool, int, str, etc.) add those annotations as well.

Also fixed two small bugs that popped up when sanity-checking with
mypy.  One in FortranCommon, where a return had been previously
annotated to be a tuple of Action, which should be ActionBase -
Action is the factory function, not the base class. The other was
a typo in the error raised in _add_cppdefines - the message was
formatted with the value of "define" which should have been "defines".

Signed-off-by: Mats Wichmann <mats@linux.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/SCons/PathList.py b/SCons/PathList.py
index a7e666d..dab8b2c 100644
--- a/SCons/PathList.py
+++ b/SCons/PathList.py
@@ -67,7 +67,7 @@ class _PathList:
     """
     An actual PathList object.
     """
-    def __init__(self, pathlist):
+    def __init__(self, pathlist) -> None:
         """
         Initializes a PathList object, canonicalizing the input and
         pre-processing it for quicker substitution later.
@@ -113,7 +113,7 @@ class _PathList:
 
         self.pathlist = tuple(pl)
 
-    def __len__(self): return len(self.pathlist)
+    def __len__(self) -> int: return len(self.pathlist)
 
     def __getitem__(self, i): return self.pathlist[i]
 
@@ -168,7 +168,7 @@ class PathListCache:
     cheaply avoid re-parsing both values of CPPPATH by using the
     common value from this cache.
     """
-    def __init__(self):
+    def __init__(self) -> None:
         self._memo = {}
 
     def _PathList_key(self, pathlist):