Merge pull request #25413 from nkcsgexi/allow-single-quote

Syntax: introduce a token kind for single quote to preserve round-trip printing of syntax tree

Author: nkcsgexi

lib/Parse/ParseExpr.cpp

@@ -1963,8 +1963,9 @@ ParserResult<Expr> Parser::parseExprStringLiteral() {
   unsigned QuoteLength;
   tok QuoteKind;
   std::tie(QuoteLength, QuoteKind) =
-      Tok.isMultilineString() ? std::make_tuple(3, tok::multiline_string_quote)
-                              : std::make_tuple(1, tok::string_quote);
+    Tok.isMultilineString() ? std::make_tuple(3, tok::multiline_string_quote)
+                            : std::make_tuple(1, Tok.getText().startswith("\'") ?
+                                          tok::single_quote: tok::string_quote);
   unsigned CloseQuoteBegin = Tok.getLength() - DelimiterLength - QuoteLength;
 
   OpenDelimiterStr = Tok.getRawText().take_front(DelimiterLength);

test/Syntax/round_trip_fix_quote.swift

@@ -0,0 +1,7 @@
+// RUN: rm -rf %t
+// RUN: %swift-syntax-test -input-source-filename %s -parse-gen > %t
+// RUN: diff -u %s %t
+
+"abc"
+
+RoundedRectangle(cornerRadius: 6.0)lengthlength'Integer' field' [binding value: \(int.value)]int'Double' field [binding value: \(double.value)]double

utils/gyb_syntax_support/Token.py

@@ -249,6 +249,8 @@ def macro_name(self):
 
     Punctuator('StringQuote', 'string_quote', text='\\\"',
                classification='StringLiteral', serialization_code=102),
+    Punctuator('SingleQuote', 'single_quote', text='\\\'',
+               classification='StringLiteral', serialization_code=120),
     Punctuator('MultilineStringQuote', 'multiline_string_quote',
                text='\\\"\\\"\\\"', classification='StringLiteral',
                serialization_code=103),