From b6cc099a561d99f9834f17005588f57c70e02608 Mon Sep 17 00:00:00 2001
From: Rafael Fourquet <fourquet.rafael@gmail.com>
Date: Tue, 24 Sep 2019 11:21:59 +0200
Subject: [PATCH] remove vcat(A::Vector{<: MatrixElem})

This is commiting "type-piracy".
This method is already defined in Base and gives a different result,
i.e. vcat on a Vector returns another Vector equal to the input.
Similar for hcat.
---
 src/generic/Matrix.jl       | 28 ++++++++++------------------
 test/generic/Matrix-test.jl | 13 +++++++++++--
 2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/src/generic/Matrix.jl b/src/generic/Matrix.jl
index cd3a966e4a..1f4147b0f8 100644
--- a/src/generic/Matrix.jl
+++ b/src/generic/Matrix.jl
@@ -4765,14 +4765,10 @@ function vcat(a::AbstractAlgebra.MatElem, b::AbstractAlgebra.MatElem)
 end
 
 @doc Markdown.doc"""
-    vcat(A::Vector{<: MatrixElem}) -> MatrixElem
-> Return the horizontal concatenation of the matrices in $A$.
+    vcat(A::MatrixElem...) -> MatrixElem
+> Return the horizontal concatenation of the matrices $A$.
 > All component matrices need to have the same base ring and number of columns.
 """
-function vcat(A::Vector{<: MatrixElem})
-  return _vcat(A)
-end
-
 function Base.vcat(A::MatrixElem...)
   return _vcat(A)
 end
@@ -4785,7 +4781,7 @@ function _vcat(A)
   if any(x -> ncols(x) != ncols(A[1]), A)
     error("Matrices must have the same number of columns")
   end
-  
+
   if any(x -> base_ring(x) != base_ring(A[1]), A)
     error("Matrices must have the same base ring")
   end
@@ -4804,11 +4800,11 @@ function _vcat(A)
 end
 
 @doc Markdown.doc"""
-    hcat(A::Vector{<: MatrixElem}) -> MatrixElem
-> Return the horizontal concatenating of the matrices in $A$.
+    hcat(A::MatrixElem...) -> MatrixElem
+> Return the horizontal concatenating of the matrices $A$.
 > All component matrices need to have the same base ring and number of rows.
 """
-function hcat(A::Vector{<: MatrixElem})
+function Base.hcat(A::MatrixElem...)
   return _hcat(A)
 end
 
@@ -4816,11 +4812,11 @@ function _hcat(A)
   if length(A) == 0
     error("Number of matrices to concatenate must be positive")
   end
-  
+
   if any(x -> nrows(x) != nrows(A[1]), A)
     error("Matrices must have the same number of rows")
   end
-  
+
   if any(x -> base_ring(x) != base_ring(A[1]), A)
     error("Matrices must have the same base ring")
   end
@@ -4838,14 +4834,10 @@ function _hcat(A)
   return M
 end
 
-function Base.hcat(A::MatrixElem...)
-  return _hcat(A)
-end
-
-function Base.cat(A::MatrixElem...;dims) 
+function Base.cat(A::MatrixElem...;dims)
   @assert dims == (1,2) || isa(dims, Int)
 
-  if isa(dims, Int) 
+  if isa(dims, Int)
     if dims == 1
       return hcat(A...)
     elseif dims == 2
diff --git a/test/generic/Matrix-test.jl b/test/generic/Matrix-test.jl
index b9b9a03f1b..6dccd9d2f8 100644
--- a/test/generic/Matrix-test.jl
+++ b/test/generic/Matrix-test.jl
@@ -1651,7 +1651,11 @@ function test_gen_mat_concat()
                                   0 1 0;
                                   0 1 2;])
    @test hcat(B, C) == [B C]
-   @test hcat([B, C]) == [B C]
+   let BC = hcat([B, C])
+      @test size(BC) == (2, 1)
+      @test BC[1] == B
+      @test BC[2] == C
+   end
 
    @test vcat(A, B) == matrix(R, [1 2;
                                   3 4;
@@ -1661,7 +1665,12 @@ function test_gen_mat_concat()
                                   0 1;])
 
    @test vcat(A, B) == [A; B]
-   @test vcat(A, B) == vcat([A, B])
+   let AB = vcat([A, B])
+      @test size(AB) == (2,)
+      @test AB[1] == A
+      @test AB[2] == B
+   end
+
 
    @test [A D; B B C] == matrix(R, [1 2 1 2 3;
                                     3 4 4 5 6;