Deprecate +/- methods for array+scalar etc

The elementwise definition is incorrect for linear algebra.

NEWS.md

@@ -265,6 +265,11 @@ Deprecated or removed
  * Calling `union` with no arguments is deprecated; construct an empty set with an appropriate
  element type using `Set{T}()` instead ([#23144]).
 
+ * Automatically broadcasted `+` and `-` for `array + scalar`, `scalar - array`, and so-on have
+ been deprecated due to inconsistency with linear algebra. Use `.+` and `.-` for these operations
+ instead.
+
+
 Julia v0.6.0 Release Notes
 ==========================
 

base/abstractarray.jl

@@ -1256,7 +1256,7 @@ function _cat(A, shape::NTuple{N}, catdims, X...) where N
  for x in X
  for i = 1:N
  if concat[i]
- inds[i] = offsets[i] + cat_indices(x, i)
+ inds[i] = broadcast(+, offsets[i], cat_indices(x, i))
  offsets[i] += cat_size(x, i)
  else
  inds[i] = 1:shape[i]

base/arraymath.jl

@@ -40,7 +40,7 @@ for f in (:+, :-)
  end
 end
 
-for f in (:/, :\, :*, :+, :-)
+for f in (:/, :\, :*)
  if f != :/
  @eval ($f)(A::Number, B::AbstractArray) = broadcast($f, A, B)
  end

base/dates/periods.jl

@@ -358,8 +358,6 @@ GeneralPeriod = Union{Period, CompoundPeriod}
 
 for op in (:+, :-)
  @eval begin
- ($op)(x::GeneralPeriod, Y::StridedArray{<:GeneralPeriod}) = broadcast($op, x, Y)
- ($op)(Y::StridedArray{<:GeneralPeriod}, x::GeneralPeriod) = broadcast($op, Y, x)
  ($op)(X::StridedArray{<:GeneralPeriod}, Y::StridedArray{<:GeneralPeriod}) =
  reshape(CompoundPeriod[($op)(x, y) for (x, y) in zip(X, Y)], promote_shape(size(X), size(Y)))
  end