Unable to edit with heredoc

[bryan-kramer]

I have inherited a file with several large heredoc blocks (SQL for use by PDO).
It is proving impossible to edit PHP code - trying to type -> or ( or enter causes php mode to fail without inserting the character. It makes editing impossible.

The messages include

Error running timer ‘show-paren-function’: (error "parse-sexp-propertize-function did not move syntax-propertize--done")
Error during redisplay: (internal--syntax-propertize 10201) signaled (error "Too much matching reentrancy")
Error during redisplay: (internal--syntax-propertize 10201) signaled (error "parse-sexp-propertize-function did not move syntax-propertize--done") [16 times]
Error during redisplay: (internal--syntax-propertize 9560) signaled (error "parse-sexp-propertize-function did not move syntax-propertize--done")

I am using commit a9ee3af but I have been seeing it before I pulled the latest.

Emacs version

GNU Emacs 27.0.50 (build 20, x86_64-pc-linux-gnu, GTK+ Version 3.22.26) of 2018-11-30

[imabug]

Also running into this with one of my PHP scripts with a heredoc block.

PHP Mode 1.20.0 of 2018-12-05
GNU Emacs 27.0.50 (build 3, x86_64-pc-linux-gnu, GTK+ Version 3.24.1) of 2019-01-02

[zonuexe]

@bryan-kramer @imabug
Sorry for not commenting on this issue.
This issue was resolved in #496 and released yesterday as v1.21.2.

If this error recurs, please reopen it. Thank you.