include review comments

Author: dkarrasch

stdlib/LinearAlgebra/src/uniformscaling.jl

@@ -419,19 +419,18 @@ promote_to_arrays(n,k, ::Type{T}, A, B, Cs...) where {T} =
     (promote_to_arrays_(n[k], T, A), promote_to_arrays_(n[k+1], T, B), promote_to_arrays(n,k+2, T, Cs...)...)
 promote_to_array_type(A::Tuple{Vararg{Union{AbstractVecOrMat,UniformScaling,Number}}}) = Matrix
 
-_us2number(A) = A
-_us2number(J::UniformScaling) = J.λ
+szfun(::UniformScaling, _) = -1
+szfun(A, dim) = (require_one_based_indexing(A); return size(A, dim))
 
 for (f, _f, dim, name) in ((:hcat, :_hcat, 1, "rows"), (:vcat, :_vcat, 2, "cols"))
     @eval begin
         @inline $f(A::Union{AbstractVecOrMat,UniformScaling}...) = $_f(A...)
-        @inline $f(A::Union{AbstractVecOrMat,UniformScaling,Number}...) = $f(map(_us2number, A)...)
+        @inline $f(A::Union{AbstractVecOrMat,UniformScaling,Number}...) = $_f(A...)
         function $_f(A::Union{AbstractVecOrMat,UniformScaling,Number}...; array_type = promote_to_array_type(A))
             n = -1
-            for a in A
-                if !isa(a, UniformScaling)
-                    require_one_based_indexing(a)
-                    na = size(a,$dim)
+            sizes = map(a -> szfun(a, $dim), A)
+            for na in sizes
+                if na != -1
                     n >= 0 && n != na &&
                         throw(DimensionMismatch(string("number of ", $name,
                             " of each array must match (got ", n, " and ", na, ")")))
@@ -455,9 +454,9 @@ function _hvcat(rows::Tuple{Vararg{Int}}, A::Union{AbstractVecOrMat,UniformScali
     j = 0
     for i = 1:nr # infer UniformScaling sizes from row counts, if possible:
         ni = -1 # number of rows in this block-row, -1 indicates unknown
-        for k = 1:rows[i]
-            if !isa(A[j+k], UniformScaling)
-                na = size(A[j+k], 1)
+        sizes = map(a -> szfun(a, 1), A[j+1:j+rows[i]])
+        for na in sizes
+            if na != -1
                 ni >= 0 && ni != na &&
                     throw(DimensionMismatch("mismatch in number of rows"))
                 ni = na