Cannot handle nested calc()?

[assembledadam]

Using reduce-css-calc via cssnano via optimize-cssnano-plugin.

The input CSS I believe is coming from Bootstrap 4, possibly this line, but it's hard to pinpoint based on the error.

height: calc(calc(2.25rem + 2px) - 1px * 2);

Getting:

 ERROR  Error: CSS minification error: Parse error on line 1:
 auto - 1px * 2
              ^
Expecting 'SUB', 'LPAREN', 'NESTED_CALC', 'NUMBER', 'CSS_VAR', 'LENGTH', 'ANGLE', 'TIME', 'FREQ', 'RES', 'EMS', 'EXS', 'CHS', 'REMS', 'VHS', 'VWS', 'VMINS', 'VMAXS', 'PERCENTAGE', got 'PREFIX'. File: css/app.a46e10bb.css
Error: CSS minification error: Parse error on line 1:
auto - 1px * 2
^
Expecting 'SUB', 'LPAREN', 'NESTED_CALC', 'NUMBER', 'CSS_VAR', 'LENGTH', 'ANGLE', 'TIME', 'FREQ', 'RES', 'EMS', 'EXS', 'CHS', 'REMS', 'VHS', 'VWS', 'VMINS', 'VMAXS', 'PERCENTAGE', got 'PREFIX'. File: css/app.a46e10bb.css
    at /develop/node_modules/@intervolga/optimize-cssnano-plugin/index.js:106:21
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] build-prod: `vue-cli-service build && /bin/bash build/prod-server-replace-vars.sh`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the [email protected] build-prod script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2018-10-02T18_06_56_983Z-debug.log

Any ideas?

[andyjansson]

The issue lies with this commit: de1338d The grammar in this change is wrong.

[assembledadam]

Sounds fairly straightforward, but unfortunately my Yacc is more than a little rusty...

[Semigradsky]

@assembledadam I can't reproduce it on last version: https://repl.it/@Semigradsky/reduce-css-calc49