For instance = and +. This causes a ton of conflict, and has caused me to write stuff like this:
Require Import MathClasses.interfaces.canonical_names.
(* math-classes uses (=) to denote equivalence, but we will use it for equality *)
Infix "=" := eq : type_scope.
Notation "(=)" := eq (only parsing) : mc_scope.
Notation "( x =)" := (eq x) (only parsing) : mc_scope.
Notation "(= x )" := (λ y, eq y x) (only parsing) : mc_scope.
Could we perhaps separate this into two files, one that exports stuff compatible with standard notation, and one that doesn't?