Merge pull request #15527 from JuliaLang/yyc/show-vcat

Fix printing of Expr(:vcat)

base/show.jl

@@ -572,7 +572,7 @@ function show_unquoted(io::IO, ex::Expr, indent::Int, prec::Int)
     # list (i.e. "(1,2,3)" or "[1,2,3]")
     elseif haskey(expr_parens, head)               # :tuple/:vcat/:cell1d
         op, cl = expr_parens[head]
-        if head === :vcat && !isempty(args) && is_expr(args[1], :row)
+        if head === :vcat
             sep = ";"
         elseif head === :hcat || head === :row
             sep = " "
@@ -581,7 +581,9 @@ function show_unquoted(io::IO, ex::Expr, indent::Int, prec::Int)
         end
         head !== :row && print(io, op)
         show_list(io, args, sep, indent)
-        if is(head, :tuple) && nargs == 1; print(io, ','); end
+        if (head === :tuple || head === :vcat) && nargs == 1
+            print(io, sep)
+        end
         head !== :row && print(io, cl)
 
     # function call

test/show.jl

@@ -379,3 +379,9 @@ A = reshape(1:16,4,4)
 @test replstr(Tridiagonal(diag(A,-1),diag(A),diag(A,+1))) == "4x4 Tridiagonal{$Int}:\n 1  5   ⋅   ⋅\n 2  6  10   ⋅\n ⋅  7  11  15\n ⋅  ⋅  12  16"
 @test replstr(UpperTriangular(A)) == "4x4 UpperTriangular{$Int,Array{$Int,2}}:\n 1  5   9  13\n ⋅  6  10  14\n ⋅  ⋅  11  15\n ⋅  ⋅   ⋅  16"
 @test replstr(LowerTriangular(A)) == "4x4 LowerTriangular{$Int,Array{$Int,2}}:\n 1  ⋅   ⋅   ⋅\n 2  6   ⋅   ⋅\n 3  7  11   ⋅\n 4  8  12  16"
+
+# Issue #15525, printing of vcat
+@test sprint(show, :([a;])) == ":([a;])"
+@test sprint(show, :([a;b])) == ":([a;b])"
+@test_repr "[a;]"
+@test_repr "[a;b]"