diff --git a/base/multidimensional.jl b/base/multidimensional.jl
index 4b462c8e2079b..072493f0264fd 100644
--- a/base/multidimensional.jl
+++ b/base/multidimensional.jl
@@ -1565,19 +1565,23 @@ end
     end
 end
 
-isassigned(a::AbstractArray, i::CartesianIndex) = isassigned(a, Tuple(i)...)
-function isassigned(A::AbstractArray, i::Union{Integer, CartesianIndex}...)
-    isa(i, Tuple{Vararg{Int}}) || return isassigned(A, CartesianIndex(to_indices(A, i)))
-    @boundscheck checkbounds(Bool, A, i...) || return false
+@propagate_inbounds isassigned(A::AbstractArray, i::CartesianIndex) = isassigned(A, Tuple(i)...)
+@propagate_inbounds function isassigned(A::AbstractArray, i::Union{Integer, CartesianIndex}...)
+    return isassigned(A, CartesianIndex(to_indices(A, i)))
+end
+@inline function isassigned(A::AbstractArray, i::Integer...)
+    # convert to valid indices, checking for Bool
+    inds = to_indices(A, i)
+    @boundscheck checkbounds(Bool, A, inds...) || return false
     S = IndexStyle(A)
-    ninds = length(i)
+    ninds = length(inds)
     if (isa(S, IndexLinear) && ninds != 1)
-        return @inbounds isassigned(A, _to_linear_index(A, i...))
+        return @inbounds isassigned(A, _to_linear_index(A, inds...))
     elseif (!isa(S, IndexLinear) && ninds != ndims(A))
-        return @inbounds isassigned(A, _to_subscript_indices(A, i...)...)
+        return @inbounds isassigned(A, _to_subscript_indices(A, inds...)...)
     else
        try
-            A[i...]
+            A[inds...]
             true
         catch e
             if isa(e, BoundsError) || isa(e, UndefRefError)
diff --git a/test/abstractarray.jl b/test/abstractarray.jl
index c3409a4a059fb..06fc146ecfc2d 100644
--- a/test/abstractarray.jl
+++ b/test/abstractarray.jl
@@ -548,12 +548,24 @@ function test_primitives(::Type{T}, shape, ::Type{TestAbstractArray}) where T
     @test firstindex(B, 1) == firstindex(A, 1) == first(axes(B, 1))
     @test firstindex(B, 2) == firstindex(A, 2) == first(axes(B, 2))
 
-    # isassigned(a::AbstractArray, i::Int...)
+    @test !isassigned(B)
+    # isassigned(a::AbstractArray, i::Integer...)
     j = rand(1:length(B))
     @test isassigned(B, j)
     if T == T24Linear
         @test !isassigned(B, length(B) + 1)
     end
+    # isassigned(a::AbstractArray, i::CartesianIndex)
+    @test isassigned(B, first(CartesianIndices(B)))
+    ind = last(CartesianIndices(B))
+    @test !isassigned(B, ind + oneunit(ind))
+    # isassigned(a::AbstractArray, i::Union{Integer,CartesianIndex}...)
+    @test isassigned(B, Int16.(first.(axes(B)))..., CartesianIndex(1,1))
+    # Bool isn't a valid index
+    @test_throws ArgumentError isassigned(B, Bool.(first.(axes(B)))..., CartesianIndex(1,1))
+    @test_throws ArgumentError isassigned(B, Bool.(first.(axes(B)))...)
+    @test_throws ArgumentError isassigned(B, true)
+    @test_throws ArgumentError isassigned(B, false)
 
     # reshape(a::AbstractArray, dims::Dims)
     @test_throws DimensionMismatch reshape(B, (0, 1))