*** a/src/backend/parser/scan.l
--- b/src/backend/parser/scan.l
***************
*** 162,168 ****
--- 162,170 ----
  %x xq
  %x xdolq
  %x xui
+ %x xuiend
  %x xus
+ %x xusend
  %x xeu

  /*
***************
*** 279,295 ****
  /* Unicode escapes */
  uescape			[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}[^']{quote}
  /* error rule to avoid backup */
! uescapefail		("-"|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*"-"|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}[^']|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*|[uU][eE][sS][cC][aA][pP]|[uU][eE][sS][cC][aA]|[uU][eE][sS][cC]|[uU][eE][sS]|[uU][eE]|[uU])

  /* Quoted identifier with Unicode escapes */
  xuistart		[uU]&{dquote}
- xuistop1		{dquote}{whitespace}*{uescapefail}?
- xuistop2		{dquote}{whitespace}*{uescape}

  /* Quoted string with Unicode escapes */
  xusstart		[uU]&{quote}
! xusstop1		{quote}{whitespace}*{uescapefail}?
! xusstop2		{quote}{whitespace}*{uescape}

  /* error rule to avoid backup */
  xufailed		[uU]&
--- 281,297 ----
  /* Unicode escapes */
  uescape			[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}[^']{quote}
  /* error rule to avoid backup */
! uescapefail		[uU][eE][sS][cC][aA][pP][eE]{whitespace}*"-"|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}[^']|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*{quote}|[uU][eE][sS][cC][aA][pP][eE]{whitespace}*|[uU][eE][sS][cC][aA][pP]|[uU][eE][sS][cC][aA]|[uU][eE][sS][cC]|[uU][eE][sS]|[uU][eE]|[uU]

  /* Quoted identifier with Unicode escapes */
  xuistart		[uU]&{dquote}

  /* Quoted string with Unicode escapes */
  xusstart		[uU]&{quote}
! 
! xustop1		{uescapefail}?
! xustop2		{uescape}
! 

  /* error rule to avoid backup */
  xufailed		[uU]&
***************
*** 536,549 ****
  					yylval->str = litbufdup(yyscanner);
  					return SCONST;
  				}
! <xus>{xusstop1} {
! 					/* throw back all but the quote */
  					yyless(1);
  					BEGIN(INITIAL);
  					yylval->str = litbuf_udeescape('\\', yyscanner);
  					return SCONST;
  				}
! <xus>{xusstop2} {
  					BEGIN(INITIAL);
  					yylval->str = litbuf_udeescape(yytext[yyleng-2], yyscanner);
  					return SCONST;
--- 538,558 ----
  					yylval->str = litbufdup(yyscanner);
  					return SCONST;
  				}
! <xus>{quotestop} |
! <xus>{quotefail} {
  					yyless(1);
+ 					BEGIN(xusend);
+ 				}
+ <xusend>{whitespace}
+ <xusend>{other} |
+ <xusend>{xustop1} {
+ 					/* throw back everything */
+ 					yyless(0);
  					BEGIN(INITIAL);
  					yylval->str = litbuf_udeescape('\\', yyscanner);
  					return SCONST;
  				}
! <xusend>{xustop2} {
  					BEGIN(INITIAL);
  					yylval->str = litbuf_udeescape(yytext[yyleng-2], yyscanner);
  					return SCONST;
***************
*** 702,708 ****
  					yylval->str = ident;
  					return IDENT;
  				}
! <xui>{xuistop1}	{
  					char		   *ident;

  					BEGIN(INITIAL);
--- 711,723 ----
  					yylval->str = ident;
  					return IDENT;
  				}
! <xui>{dquote} {
! 					yyless(1);
! 					BEGIN(xuiend);
! 				}
! <xuiend>{whitespace} { }
! <xuiend>{other} |
! <xuiend>{xustop1}	{
  					char		   *ident;

  					BEGIN(INITIAL);
***************
*** 712,722 ****
  					if (yyextra->literallen >= NAMEDATALEN)
  						truncate_identifier(ident, yyextra->literallen, true);
  					yylval->str = ident;
! 					/* throw back all but the quote */
! 					yyless(1);
  					return IDENT;
  				}
! <xui>{xuistop2}	{
  					char		   *ident;

  					BEGIN(INITIAL);
--- 727,736 ----
  					if (yyextra->literallen >= NAMEDATALEN)
  						truncate_identifier(ident, yyextra->literallen, true);
  					yylval->str = ident;
! 					/* throw back everything that follows the end quote */
  					return IDENT;
  				}
! <xuiend>{xustop2}	{
  					char		   *ident;

  					BEGIN(INITIAL);