Commit 2023-03-02 18:05 c310cfdc
View on Github →chore(algebra/algebra/restrict_scalars): replace restrict_scalars_smul_def
with version that does not commit defeq-abuse. (#18540)
This lemma abuses definitional equality and I think we are better without it. My immediate motivation is the trouble it is causing in the Mathlib4 porting PR: https://github.com/leanprover-community/mathlib4/pull/2563
Note that it was only used in one place and there is a better proof.