diff --git a/base/multidimensional.jl b/base/multidimensional.jl
index f793df068ec5a..314db226b63b7 100644
--- a/base/multidimensional.jl
+++ b/base/multidimensional.jl
@@ -1564,7 +1564,7 @@ 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(i...))
+    isa(i, Tuple{Vararg{Int}}) || return isassigned(A, CartesianIndex(to_indices(A, i)))
     @boundscheck checkbounds(Bool, A, i...) || return false
     S = IndexStyle(A)
     ninds = length(i)
diff --git a/test/abstractarray.jl b/test/abstractarray.jl
index 47a81bbbf5b66..29bc514bb1802 100644
--- a/test/abstractarray.jl
+++ b/test/abstractarray.jl
@@ -1854,3 +1854,9 @@ end
 # type stable [x;;] (https://github.com/JuliaLang/julia/issues/45952)
 f45952(x) = [x;;]
 @inferred f45952(1.0)
+
+@testset "isassigned with a Bool index" begin
+    A = zeros(2,2)
+    @test_throws "invalid index: true of type Bool" isassigned(A, 1, true)
+    @test_throws "invalid index: true of type Bool" isassigned(A, true)
+end