Bugfix in dispatch: Now properly handles Any (this bug was caused by …

…a previous fix to match mypy behavior)

runtype/dispatch.py

@@ -188,12 +188,15 @@ def define_function(self, f):
 
     def choose_most_specific_function(self, args, *funcs):
         issubclass = self.typesystem.issubclass
+        any_type = self.typesystem.any_type
 
         class IsSubclass:
             def __init__(self, k):
                 self.i, self.t = k
 
             def __lt__(self, other):
+                if self.t is any_type:
+                    return False
                 return issubclass(self.t, other.t)
 
         most_specific_per_param = []
@@ -208,7 +211,7 @@ def __lt__(self, other):
                 if ms_t == t:
                     # Add more indexes with the same type
                     ms_set.add(i)
-                elif issubclass(t, ms_t) or not issubclass(ms_t, t):
+                elif (issubclass(t, ms_t) and t is not any_type) or not issubclass(ms_t, t):
                     # Possibly ambiguous. We might throw an error below
                     # TODO secondary candidates should still obscure less specific candidates
                     #      by only considering the top match, we are ignoring them

runtype/typesystem.py

@@ -1,4 +1,4 @@
-
+from typing import Any
 
 class TypeSystem:
     def isinstance(self, obj, t: type) -> bool:
@@ -14,6 +14,7 @@ def get_type(self, obj) -> type:
         raise NotImplementedError()
 
     default_type: type = NotImplemented
+    any_type: type = NotImplemented
 
 
 
@@ -22,3 +23,4 @@ class PythonBasic(TypeSystem):
     issubclass = issubclass
     get_type = type
     default_type = object
+    any_type = Any

runtype/validation.py

@@ -5,7 +5,8 @@
 
 from .common import CHECK_TYPES
 from .utils import get_func_signatures
-from .pytypes import TypeMismatchError, type_caster, All
+from .pytypes import TypeMismatchError, type_caster
+from . import pytypes
 from .typesystem import TypeSystem
 
 def ensure_isa(obj, t, sampler=None):
@@ -69,7 +70,8 @@ class PythonTyping(TypeSystem):
     issubclass = staticmethod(issubclass)
     to_canonical_type = type_caster.to_canon
     get_type = type
-    default_type = All
+    default_type = pytypes.All
+    any_type = pytypes.Any
 
 
 def validate_func(f):