[Utilities] simplify various operate_ methods (#2212)

Author: odow

src/Utilities/functions.jl

@@ -1283,15 +1283,17 @@ function map_terms!(
     op,
     func::Union{MOI.ScalarAffineFunction,MOI.VectorAffineFunction},
 )
-    return map!(op, func.terms, func.terms)
+    map!(op, func.terms, func.terms)
+    return
 end
 
 function map_terms!(
     op,
     func::Union{MOI.ScalarQuadraticFunction,MOI.VectorQuadraticFunction},
 )
     map!(op, func.affine_terms, func.affine_terms)
-    return map!(op, func.quadratic_terms, func.quadratic_terms)
+    map!(op, func.quadratic_terms, func.quadratic_terms)
+    return
 end
 
 ###################################### +/- #####################################

src/Utilities/mutable_arithmetics.jl

@@ -149,15 +149,11 @@ function MA.operate!(
     return f
 end
 
-function MA.operate!(::typeof(-), f::MOI.ScalarQuadraticFunction)
-    operate_terms!(-, f.quadratic_terms)
-    operate_terms!(-, f.affine_terms)
-    f.constant = -f.constant
-    return f
-end
-
-function MA.operate!(::typeof(-), f::MOI.ScalarAffineFunction)
-    operate_terms!(-, f.terms)
+function MA.operate!(
+    ::typeof(-),
+    f::Union{MOI.ScalarAffineFunction,MOI.ScalarQuadraticFunction},
+)
+    map_terms!(Base.Fix1(operate_term, -), f)
     f.constant = -f.constant
     return f
 end