diff --git a/src/backend/parser/Makefile b/src/backend/parser/Makefile
index f14febdbda..3a2459cb72 100644
--- a/src/backend/parser/Makefile
+++ b/src/backend/parser/Makefile
@@ -40,7 +40,6 @@ gram.c: BISON_CHECK_CMD = $(PERL) $(srcdir)/check_keywords.pl $< $(top_srcdir)/s
 
 
 scan.c: FLEXFLAGS = -CF -p -p
-scan.c: FLEX_NO_BACKUP=yes
 scan.c: FLEX_FIX_WARNING=yes
 
 
diff --git a/src/backend/parser/scan.l b/src/backend/parser/scan.l
index e1cae859e8..24f351229b 100644
--- a/src/backend/parser/scan.l
+++ b/src/backend/parser/scan.l
@@ -56,6 +56,8 @@ fprintf_to_ereport(const char *fmt, const char *msg)
 	ereport(ERROR, (errmsg_internal("%s", msg)));
 }
 
+static int state_before;
+
 /*
  * GUC variables.  This is a DIRECT violation of the warning given at the
  * head of gram.y, ie flex/bison code must not depend on any GUC variables;
@@ -168,6 +170,7 @@ extern void core_yyset_column(int column_no, yyscan_t yyscanner);
  *  <xd> delimited identifiers (double-quoted identifiers)
  *  <xh> hexadecimal numeric string
  *  <xq> standard quoted strings
+ *  <xqs> quote stop (detect continued strings)
  *  <xe> extended quoted strings (support backslash escape sequences)
  *  <xdolq> $foo$ quoted strings
  *  <xui> quoted identifier with Unicode escapes
@@ -185,6 +188,7 @@ extern void core_yyset_column(int column_no, yyscan_t yyscanner);
 %x xd
 %x xh
 %x xq
+%x xqs
 %x xe
 %x xdolq
 %x xui
@@ -231,19 +235,7 @@ special_whitespace		({space}+|{comment}{newline})
 horiz_whitespace		({horiz_space}|{comment})
 whitespace_with_newline	({horiz_whitespace}*{newline}{special_whitespace}*)
 
-/*
- * To ensure that {quotecontinue} can be scanned without having to back up
- * if the full pattern isn't matched, we include trailing whitespace in
- * {quotestop}.  This matches all cases where {quotecontinue} fails to match,
- * except for {quote} followed by whitespace and just one "-" (not two,
- * which would start a {comment}).  To cover that we have {quotefail}.
- * The actions for {quotestop} and {quotefail} must throw back characters
- * beyond the quote proper.
- */
 quote			'
-quotestop		{quote}{whitespace}*
-quotecontinue	{quote}{whitespace_with_newline}{quote}
-quotefail		{quote}{whitespace}*"-"
 
 /* Bit string
  * It is tempting to scan the string for only those characters
@@ -476,21 +468,10 @@ other			.
 					startlit();
 					addlitchar('b', yyscanner);
 				}
-<xb>{quotestop}	|
-<xb>{quotefail} {
-					yyless(1);
-					BEGIN(INITIAL);
-					yylval->str = litbufdup(yyscanner);
-					return BCONST;
-				}
 <xh>{xhinside}	|
 <xb>{xbinside}	{
 					addlit(yytext, yyleng, yyscanner);
 				}
-<xh>{quotecontinue}	|
-<xb>{quotecontinue}	{
-					/* ignore */
-				}
 <xb><<EOF>>		{ yyerror("unterminated bit string literal"); }
 
 {xhstart}		{
@@ -505,13 +486,6 @@ other			.
 					startlit();
 					addlitchar('x', yyscanner);
 				}
-<xh>{quotestop}	|
-<xh>{quotefail} {
-					yyless(1);
-					BEGIN(INITIAL);
-					yylval->str = litbufdup(yyscanner);
-					return XCONST;
-				}
 <xh><<EOF>>		{ yyerror("unterminated hexadecimal string literal"); }
 
 {xnstart}		{
@@ -568,28 +542,65 @@ other			.
 					BEGIN(xus);
 					startlit();
 				}
-<xq,xe>{quotestop}	|
-<xq,xe>{quotefail} {
-					yyless(1);
-					BEGIN(INITIAL);
+
+<xb,xh,xq,xe,xus>{quote} {
+					state_before = YYSTATE;
+					BEGIN(xqs);
+				}
+<xqs>{whitespace_with_newline}{quote} {
+					/* resume scanning string that started on a previous line */
+					BEGIN(state_before);
+				}
+<xqs>{whitespace}*{quote} {
 					/*
-					 * check that the data remains valid if it might have been
-					 * made invalid by unescaping any chars.
+					 * SQL requires at least one newline in the whitespace separating
+					 * string literals that are to be concatenated, so throw an error
+					 * if we see the start of a new string on the same line.
 					 */
-					if (yyextra->saw_non_ascii)
-						pg_verifymbstr(yyextra->literalbuf,
-									   yyextra->literallen,
-									   false);
-					yylval->str = litbufdup(yyscanner);
-					return SCONST;
+					SET_YYLLOC();
+					ADVANCE_YYLLOC(yyleng - 1);
+					yyerror("syntax error");
 				}
-<xus>{quotestop} |
-<xus>{quotefail} {
-					/* throw back all but the quote */
-					yyless(1);
-					/* xusend state looks for possible UESCAPE */
-					BEGIN(xusend);
+<xqs><<EOF>> |
+<xqs>{whitespace}*[^'] {
+					/* throw back everything and handle the string we just scanned */
+					yyless(0);
+
+					switch (state_before)
+					{
+						case xb:
+							BEGIN(INITIAL);
+							yylval->str = litbufdup(yyscanner);
+							return BCONST;
+						case xh:
+							BEGIN(INITIAL);
+							yylval->str = litbufdup(yyscanner);
+							return XCONST;
+						case xe:
+							/* fallthrough */
+						case xq:
+							BEGIN(INITIAL);
+
+							/*
+							 * check that the data remains valid if it might have been
+							 * made invalid by unescaping any chars.
+							 */
+							if (yyextra->saw_non_ascii)
+								pg_verifymbstr(yyextra->literalbuf,
+											   yyextra->literallen,
+											   false);
+							yylval->str = litbufdup(yyscanner);
+							return SCONST;
+						case xus:
+							/* xusend state looks for possible UESCAPE */
+							BEGIN(xusend);
+							break;
+						default:
+							yyerror("unhandled previous state in quote continuation");
+					}
+
 				}
+
 <xusend>{whitespace} {
 					/* stay in xusend state over whitespace */
 				}
@@ -693,9 +704,6 @@ other			.
 					if (c == '\0' || IS_HIGHBIT_SET(c))
 						yyextra->saw_non_ascii = true;
 				}
-<xq,xe,xus>{quotecontinue} {
-					/* ignore */
-				}
 <xe>.			{
 					/* This is only needed for \ just before EOF */
 					addlitchar(yytext[0], yyscanner);