[Syntax] Completely remove 'backtick' trivia kind

Make hash generation to take trivias into account.

Author: rintaro

utils/gyb_syntax_support/Trivia.py

@@ -4,21 +4,21 @@
 
 class Trivia(object):
     def __init__(self, name, comment, serialization_code, characters=[],
-                 swift_characters=[], is_new_line=False, is_comment=False,
-                 deprecated=None):
+                 swift_characters=[], is_new_line=False, is_comment=False):
         self.name = name
         self.comment = comment
         self.serialization_code = serialization_code
-        self.characters = characters
+        self.characters = tuple(characters)
         self.lower_name = lowercase_first_word(name)
         self.is_new_line = is_new_line
         self.is_comment = is_comment
-        self.deprecated = deprecated
 
         # Swift sometimes doesn't support escaped characters like \f or \v;
         # we should allow specifying alternatives explicitly.
-        self.swift_characters = swift_characters if swift_characters else\
-            characters
+        if swift_characters:
+            self.swift_characters = tuple(swift_characters)
+        else:
+            self.swift_characters = characters
         assert len(self.swift_characters) == len(self.characters)
 
     def characters_len(self):
@@ -45,11 +45,6 @@ def is_collection(self):
     Trivia('CarriageReturnLineFeed',
            'A newline consists of contiguous \'\\r\' and \'\\n\' characters.',
            characters=['\\r', '\\n'], is_new_line=True, serialization_code=6),
-    # TODO: Romove 'Backtick' when all known clients are migrated.
-    Trivia('Backtick',
-           'A backtick \'`\' character, used to escape identifiers.',
-           characters=['`'], serialization_code=7,
-           deprecated="backticks are now part of the token text"),
     Trivia('LineComment', 'A developer line comment, starting with \'//\'',
            is_comment=True, serialization_code=8),
     Trivia('BlockComment',

utils/gyb_syntax_support/__init__.py

@@ -13,6 +13,7 @@
 from PatternNodes import PATTERN_NODES  # noqa: I201
 from StmtNodes import STMT_NODES  # noqa: I201
 import Token
+from Trivia import TRIVIAS  # noqa: I201
 from TypeNodes import TYPE_NODES  # noqa: I201
 
 
@@ -161,10 +162,16 @@ def hash_token_syntax(token):
     return hash((token.name, token.serialization_code))
 
 
+def hash_trivia(trivia):
+    return hash((trivia.name, trivia.serialization_code, trivia.characters))
+
+
 def calculate_node_hash():
     result = 0
     for node in SYNTAX_NODES:
         result = hash((result, hash_syntax_node(node)))
     for token in SYNTAX_TOKENS:
         result = hash((result, hash_token_syntax(token)))
+    for trivia in TRIVIAS:
+        result = hash((result, hash_trivia(trivia)))
     return result