implement new array assignment shape matching rule. fixes #4048, fixes …

…#4383

this rule ignores singleton dimensions, and allows the last dimension of
one side to match all trailing dimensions of the other.

base/array.jl

@@ -593,20 +593,7 @@ function setindex!(A::Array, x, I::Union(Real,AbstractArray)...)
  assign_cache = Dict()
  end
  X = x
- nel = 1
- for idx in I
- nel *= length(idx)
- end
- if length(X) != nel
- throw(DimensionMismatch(""))
- end
- if ndims(X) > 1
- for i = 1:length(I)
- if size(X,i) != length(I[i])
- throw(DimensionMismatch(""))
- end
- end
- end
+ setindex_shape_check(X, I...)
  gen_array_index_map(assign_cache, storeind -> quote
  A[$storeind] = X[refind]
  refind += 1

base/operators.jl

@@ -206,21 +206,83 @@ index_shape(I::Real...) = ()
 index_shape(i, I...) = tuple(length(i), index_shape(I...)...)
 
 # check for valid sizes in A[I...] = X where X <: AbstractArray
+# we want to allow dimensions that are equal up to permutation, but only
+# for permutations that leave array elements in the same linear order.
+# those are the permutations that preserve the order of the non-singleton
+# dimensions.
 function setindex_shape_check(X::AbstractArray, I...)
+ li = length(I)
+ ii = 1
  nel = 1
- for idx in I
- nel *= length(idx)
- end
- if length(X) != nel
- error("dimensions must match")
- end
- if ndims(X) > 1
- for i = 1:length(I)
- if size(X,i) != length(I[i])
- error("dimensions must match")
+ xi = 1
+ ndx = ndims(X)
+ match = true
+ while ii < li
+ lii = length(I[ii])::Int
+ ii += 1
+ if lii != 1
+ nel *= lii
+ local lxi
+ while true
+ lxi = size(X,xi)
+ xi += 1
+ if lxi != 1 || xi > ndx
+ break
+ end
+ end
+ if xi > ndx
+ trailing = lii
+ while ii <= li
+ lii = length(I[ii])::Int
+ trailing *= lii
+ ii += 1
+ end
+ # X's last dimension can match all the trailing indexes
+ if lxi == trailing && match
+ return
+ else
+ throw(DimensionMismatch(""))
+ end
+ else
+ if lxi != lii
+ match = false
+ end
  end
  end
  end
+
+ # last index can match X's trailing dimensions
+ lii = length(I[ii])::Int
+ nel *= lii
+ if lii != trailingsize(X,xi)
+ match = false
+ end
+
+ if !(match && length(X)==nel)
+ throw(DimensionMismatch(""))
+ end
+end
+
+setindex_shape_check(X::AbstractArray) = (length(X)==1 || throw(DimensionMismatch("")))
+
+setindex_shape_check(X::AbstractArray, i) =
+ (length(X)==length(i) || throw(DimensionMismatch("")))
+
+setindex_shape_check{T}(X::AbstractArray{T,1}, i) =
+ (length(X)==length(i) || throw(DimensionMismatch("")))
+
+setindex_shape_check{T}(X::AbstractArray{T,1}, i, j) =
+ (length(X)==length(i)*length(j) || throw(DimensionMismatch("")))
+
+function setindex_shape_check{T}(X::AbstractArray{T,2}, i, j)
+ li, lj = length(i), length(j)
+ if length(X) != li*lj
+ throw(DimensionMismatch(""))
+ end
+ sx1 = size(X,1)
+ if !(li == 1 || li == sx1 || sx1 == 1)
+ throw(DimensionMismatch(""))
+ end
 end
 
 # convert to integer index