Fixed given imports and removed reference to toExpr extension (#7608)

[machisuji]

Related to issue #7608 and PR #7609 - two wrong given imports are fixed and one obsolete reference to the toExpr has been updated.

[dottybot]

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Have an awesome day! ☀️

[nicolasstucki]

Thanks @machisuji

[machisuji]

P.S. I did sign the Scala CLA.