Refactor "magic" method constants so that there are no dups (#4838)

This has been hand-checked to verify that MAGIC_METHODS is the same
(the other constants have only been moved within the file)

Author: kamahen

mypy/sharedparse.py

@@ -3,83 +3,39 @@
 """Shared logic between our three mypy parser files."""
 
 
-MAGIC_METHODS = {
+_NON_BINARY_MAGIC_METHODS = {
     "__abs__",
-    "__add__",
-    "__and__",
     "__call__",
-    "__cmp__",
     "__complex__",
     "__contains__",
     "__del__",
     "__delattr__",
     "__delitem__",
-    "__divmod__",
-    "__div__",
     "__enter__",
     "__exit__",
-    "__eq__",
-    "__floordiv__",
     "__float__",
-    "__ge__",
     "__getattr__",
     "__getattribute__",
     "__getitem__",
-    "__gt__",
     "__hex__",
-    "__iadd__",
-    "__iand__",
-    "__idiv__",
-    "__ifloordiv__",
-    "__ilshift__",
-    "__imod__",
-    "__imul__",
     "__init__",
     "__init_subclass__",
     "__int__",
     "__invert__",
-    "__ior__",
-    "__ipow__",
-    "__irshift__",
-    "__isub__",
     "__iter__",
-    "__ixor__",
-    "__le__",
     "__len__",
     "__long__",
-    "__lshift__",
-    "__lt__",
-    "__mod__",
-    "__mul__",
-    "__ne__",
     "__neg__",
     "__new__",
     "__nonzero__",
     "__oct__",
-    "__or__",
     "__pos__",
-    "__pow__",
-    "__radd__",
-    "__rand__",
-    "__rdiv__",
     "__repr__",
     "__reversed__",
-    "__rfloordiv__",
-    "__rlshift__",
-    "__rmod__",
-    "__rmul__",
-    "__ror__",
-    "__rpow__",
-    "__rrshift__",
-    "__rshift__",
-    "__rsub__",
-    "__rxor__",
     "__setattr__",
     "__setitem__",
     "__str__",
-    "__sub__",
     "__unicode__",
-    "__xor__",
 }
 
 MAGIC_METHODS_ALLOWING_KWARGS = {
@@ -89,8 +45,6 @@
     "__call__",
 }
 
-MAGIC_METHODS_POS_ARGS_ONLY = MAGIC_METHODS - MAGIC_METHODS_ALLOWING_KWARGS
-
 BINARY_MAGIC_METHODS = {
     "__add__",
     "__and__",
@@ -138,6 +92,12 @@
     "__xor__",
 }
 
+assert not (_NON_BINARY_MAGIC_METHODS & BINARY_MAGIC_METHODS)
+
+MAGIC_METHODS = _NON_BINARY_MAGIC_METHODS | BINARY_MAGIC_METHODS
+
+MAGIC_METHODS_POS_ARGS_ONLY = MAGIC_METHODS - MAGIC_METHODS_ALLOWING_KWARGS
+
 
 def special_function_elide_names(name: str) -> bool:
     return name in MAGIC_METHODS_POS_ARGS_ONLY