core 1.5.1 breaks icons 1.*

Building breaks for users of @material-ui/icons 1.1.0 with error

Error: Cannot find module '@babel/runtime/helpers/builtin/interopRequireDefault' from '.../node_modules/@material-ui/icons'

@material-ui/icons 1.1.0 declares that it works with any core of v1

  "peerDependencies": {
    "@material-ui/core": "^1.0.0-rc.0",

but that’s not true for 1.5.1. 1.5.1 depends on @babel/runtime 7.0.0-rc.1 as opposed to 7.0.0-beta.42 in 1.5.0. 7.0.0-rc.1 changes the location of interopRequireDefault.

• This is a v1.x issue.
• I have searched the issues of this repository and believe that is a duplicate of https://github.com/mui-org/material-ui/issues/12587, but it’s closed.

Expected Behavior

icons v1 can be used

Current Behavior

Error: Cannot find module '@babel/runtime/helpers/builtin/interopRequireDefault' from '.../node_modules/@material-ui/icons'

Steps to Reproduce

https://codesandbox.io/s/oow4nvrm36

Proposal

Release icons 1.1.1 that would work with core 1.5.1 and babel core 7.0.0-rc.1

[fzaninotto]

I’m concerned about this.

As @material-ui/icons@2.0 is a breaking change over 1.1, the fact that @material-ui/core@1.5.1 requires us to upgrade @material-ui/icons to 2.0 IS a breaking change for the core. So core 1.5.1 should have been a 2.0 in that regard.

Alternatively, please revert the babel upgrade in 1.5.1, or backport the material-ui/icons fix to the 1.x branch.

[oliviertassinari]

@fzaninotto Fair point. I guess we can make a patch release for @material-ui/icons@1.x.