From ab11395ad163dfa34178edce1021ecf7a6123ffe Mon Sep 17 00:00:00 2001
From: Rafael Fourquet <fourquet.rafael@gmail.com>
Date: Thu, 11 Jun 2020 14:13:54 +0200
Subject: [PATCH 1/2] deleteat! : check bounds for the first passed index

All other indices are bound-checked.
Currently, the behavior looks like:
```julia
julia> deleteat!([1:1000;], [-100])

signal (11): Segmentation fault
[...]

julia>  deleteat!(BigInt[0], [0])
free(): invalid next size (normal)

signal (6): Aborted
[...]

julia> deleteat!(BigInt[0], [-100])
ERROR: UndefRefError: access to undefined reference
[...]

julia> deleteat!([0], [0])
Int64[]

julia> deleteat!([0], [2])
1-element Array{Int64,1}:
 0

julia> deleteat!([0], [3])
ERROR: InexactError: check_top_bit(UInt64, -1)
[...]
```
With this commit, all these expressions throw a `BoundsError`.
---
 base/array.jl    | 4 ++--
 test/arrayops.jl | 6 +++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/base/array.jl b/base/array.jl
index 8954f3e5b9d23..c0a1ec96fb12f 100644
--- a/base/array.jl
+++ b/base/array.jl
@@ -1352,9 +1352,9 @@ function _deleteat!(a::Vector, inds, dltd=Nowhere())
     n = length(a)
     y = iterate(inds)
     y === nothing && return a
-    n == 0 && throw(BoundsError(a, inds))
     (p, s) = y
-    p <= n && push!(dltd, @inbounds a[p])
+    1 <= p <= n || throw(BoundsError(a, p))
+    push!(dltd, @inbounds a[p])
     q = p+1
     while true
         y = iterate(inds, s)
diff --git a/test/arrayops.jl b/test/arrayops.jl
index 9ecd9f4a0bab2..e8acde4c8826e 100644
--- a/test/arrayops.jl
+++ b/test/arrayops.jl
@@ -1446,11 +1446,15 @@ end
     @test deleteat!(a, [1,3,5,7:10...]) == [2,4,6]
     @test_throws BoundsError deleteat!(a, 13)
     @test_throws BoundsError deleteat!(a, [1,13])
-    @test_throws ArgumentError deleteat!(a, [5,3])
+    @test_throws ArgumentError deleteat!(a, [3,2]) # not sorted
     @test_throws BoundsError deleteat!(a, 5:20)
     @test_throws BoundsError deleteat!(a, Bool[])
     @test_throws BoundsError deleteat!(a, [true])
     @test_throws BoundsError deleteat!(a, falses(11))
+    @test_throws BoundsError deleteat!(a, [0])
+    @test_throws BoundsError deleteat!(a, [4])
+    @test_throws BoundsError deleteat!(a, [5])
+    @test_throws BoundsError deleteat!(a, [5, 3])
 
     @test_throws BoundsError deleteat!([], 1)
     @test_throws BoundsError deleteat!([], [1])

From 9a0c498eefa0f31cf021f48d0b3afddb282dc6cd Mon Sep 17 00:00:00 2001
From: Rafael Fourquet <fourquet.rafael@gmail.com>
Date: Tue, 16 Jun 2020 09:47:38 +0200
Subject: [PATCH 2/2] Update base/array.jl

Co-authored-by: Simeon Schaub <simeondavidschaub99@gmail.com>
---
 base/array.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/base/array.jl b/base/array.jl
index c0a1ec96fb12f..bd6807853c93e 100644
--- a/base/array.jl
+++ b/base/array.jl
@@ -1353,7 +1353,7 @@ function _deleteat!(a::Vector, inds, dltd=Nowhere())
     y = iterate(inds)
     y === nothing && return a
     (p, s) = y
-    1 <= p <= n || throw(BoundsError(a, p))
+    checkbounds(a, p)
     push!(dltd, @inbounds a[p])
     q = p+1
     while true