Merge branch 'PHP-7.3' into PHP-7.4

* PHP-7.3:
  Avoid duplicate octal warning during heredoc scan ahead

Author: nikic

Zend/tests/warning_during_heredoc_scan_ahead.phpt

@@ -6,6 +6,7 @@ No warnings should be thrown during heredoc scan-ahead
 <<<TEST
 ${x
}
 \400
+${"\400"}
 ${/*}
 TEST;
 
@@ -15,6 +16,8 @@ Warning: Unexpected character in input:  '
' (ASCII=1) state=0 in %s on line %d
 
 Warning: Octal escape sequence overflow \400 is greater than \377 in %s on line %d
 
+Warning: Octal escape sequence overflow \400 is greater than \377 in %s on line %d
+
 Warning: Unterminated comment starting line %d in %s on line %d
 
 Parse error: syntax error, unexpected end of file in %s on line %d

Zend/zend_language_scanner.l

@@ -1072,8 +1072,7 @@ static int zend_scan_escape_string(zval *zendlval, char *str, int len, char quot
 								octal_buf[2] = *(++s);
 							}
 						}
-						if (octal_buf[2] &&
-						    (octal_buf[0] > '3')) {
+						if (octal_buf[2] && (octal_buf[0] > '3') && !SCNG(heredoc_scan_ahead)) {
 							/* 3 octit values must not overflow 0xFF (\377) */
 							zend_error(E_COMPILE_WARNING, "Octal escape sequence overflow \\%s is greater than \\377", octal_buf);
 						}