Remove residual Python 2 specific code

Cython/Compiler/ExprNodes.py

@@ -13,8 +13,7 @@
                Builtin=object, Symtab=object, Utils=object, find_coercion_error=object,
                debug_disposal_code=object, debug_temp_alloc=object, debug_coercion=object,
                bytearray_type=object, slice_type=object, memoryview_type=object,
-               builtin_sequence_types=object, _py_int_types=object,
-               IS_PYTHON3=cython.bint)
+               builtin_sequence_types=object)
 
 import re
 import sys

Cython/Compiler/Interpreter.py

@@ -45,7 +45,7 @@ def interpret(node, ix):
             else:
                 raise CompileError(node.pos, "Type not allowed here.")
         else:
-            if (isinstance(node, StringNode) and node.unicode_value is not None):
+            if isinstance(node, StringNode) and node.unicode_value is not None:
                 return (node.unicode_value, node.pos)
             return (node.compile_time_value(empty_scope), node.pos)
 

Cython/Compiler/StringEncoding.py

@@ -16,10 +16,7 @@ def __init__(self):
         self.chars = []
 
     def append(self, characters):
-        if isinstance(characters, bytes):
-            # this came from a Py2 string literal in the parser code
-            characters = characters.decode("ASCII")
-        assert isinstance(characters, str), str(type(characters))
+        assert isinstance(characters, str), f"Expected str, got {type(characters)}"
         self.chars.append(characters)
 
     if sys.maxunicode == 65535:

Cython/Compiler/TreePath.py

@@ -11,11 +11,6 @@
 import operator
 import sys
 
-if sys.version_info[0] >= 3:
-    _unicode = str
-else:
-    _unicode = unicode
-
 path_tokenizer = re.compile(
     r"("
     r"'[^']*'|\"[^\"]*\"|"
@@ -168,7 +163,7 @@ def select(result):
                     continue
                 if attr_value == value:
                     yield attr_value
-                elif (isinstance(attr_value, bytes) and isinstance(value, _unicode) and
+                elif (isinstance(attr_value, bytes) and isinstance(value, str) and
                         attr_value == value.encode()):
                     # allow a bytes-to-string comparison too
                     yield attr_value