diff --git a/src/measure.jl b/src/measure.jl
index 612f9427b..ef4eb122c 100644
--- a/src/measure.jl
+++ b/src/measure.jl
@@ -16,14 +16,14 @@ function _measure(pl::AbstractMatrix, nshots::Int)
     return res
 end
 
-YaoBase.measure(reg::ArrayReg{1}; nshots::Int=1) = _measure(reg |> probs, nshots)
+YaoBase.measure(::ComputationalBasis, reg::ArrayReg{1}, ::AllLocs; nshots::Int=1) = _measure(reg |> probs, nshots)
 
-function YaoBase.measure(reg::ArrayReg{B}; nshots::Int=1) where B
+function YaoBase.measure(::ComputationalBasis, reg::ArrayReg{B}, ::AllLocs; nshots::Int=1) where B
     pl = dropdims(sum(reg |> rank3 .|> abs2, dims=2), dims=2)
     return _measure(pl, nshots)
 end
 
-function YaoBase.measure_remove!(reg::ArrayReg{B}) where B
+function YaoBase.measure_remove!(::ComputationalBasis, reg::ArrayReg{B}, ::AllLocs) where B
     state = reg |> rank3
     nstate = similar(reg.state, 1<<nremain(reg), B)
     pl = dropdims(sum(state .|> abs2, dims=2), dims=2)
@@ -37,7 +37,7 @@ function YaoBase.measure_remove!(reg::ArrayReg{B}) where B
     return res
 end
 
-function YaoBase.measure!(reg::ArrayReg{B}) where B
+function YaoBase.measure!(::ComputationalBasis, reg::ArrayReg{B}, ::AllLocs) where B
     state = reg |> rank3
     nstate = zero(state)
     res = measure_remove!(reg)
@@ -49,7 +49,7 @@ function YaoBase.measure!(reg::ArrayReg{B}) where B
     return res
 end
 
-function YaoBase.measure_collapseto!(reg::ArrayReg{B}; config::Integer=0) where B
+function YaoBase.measure_collapseto!(::ComputationalBasis, reg::ArrayReg{B}, ::AllLocs; config::Integer=0) where B
     state = rank3(reg)
     M, N, B1 = size(state)
     nstate = zero(state)
diff --git a/src/register.jl b/src/register.jl
index b9cd7c7e0..bf80c51f0 100644
--- a/src/register.jl
+++ b/src/register.jl
@@ -11,6 +11,7 @@ export ArrayReg,
     nbatch,
     viewbatch,
     addbits!,
+    insert_qubits!,
     datatype,
     probs,
     reorder!,
@@ -72,9 +73,13 @@ function ArrayReg{B}(raw::MT) where {B, T, MT <: AbstractMatrix{T}}
     return ArrayReg{B, T, MT}(raw)
 end
 
-ArrayReg(raw::AbstractVector{<:Complex}) = ArrayReg(reshape(raw, :, 1))
-ArrayReg(raw::AbstractMatrix{<:Complex}) = ArrayReg{size(raw, 2)}(raw)
-ArrayReg(raw::AbstractArray{<:Complex, 3}) = ArrayReg{size(raw, 3)}(reshape(raw, size(raw, 1), :))
+function _warn_type(raw)
+    eltype(raw) <: Complex || @warn "Input type of `ArrayReg` is not Complex, got $(eltype(raw))"
+end
+
+ArrayReg(raw::AbstractVector) = (_warn_type(raw); ArrayReg(reshape(raw, :, 1)))
+ArrayReg(raw::AbstractMatrix) = (_warn_type(raw); ArrayReg{size(raw, 2)}(raw))
+ArrayReg(raw::AbstractArray{<:Any, 3}) = (_warn_type(raw); ArrayReg{size(raw, 3)}(reshape(raw, size(raw, 1), :)))
 
 # bit literal
 # NOTE: batch size B and element type T are 1 and ComplexF64 by default
@@ -138,6 +143,14 @@ function YaoBase.addbits!(r::ArrayReg, n::Int)
     return r
 end
 
+function YaoBase.insert_qubits!(reg::ArrayReg{B}, loc::Int; nqubits::Int=1) where B
+    na = nactive(reg)
+    focus!(reg, 1:loc-1)
+    reg2 = join(zero_state(nqubits; nbatch=B), reg) |> relax! |> focus!((1:na+nqubits)...)
+    reg.state = reg2.state
+    reg
+end
+
 function YaoBase.probs(r::ArrayReg{1})
     if size(r.state, 2) == 1
         return vec(r.state .|> abs2)
diff --git a/test/focus.jl b/test/focus.jl
index cfa2dc5e7..efd9d28ee 100644
--- a/test/focus.jl
+++ b/test/focus.jl
@@ -35,6 +35,8 @@ end
     @test copy(reg) |> addbits!(2) |> nactive == 5
     reg2 = copy(reg) |> addbits!(2) |> focus!(4,5)
     @test (reg2 |> measure_remove!; reg2) |> relax!(to_nactive=nqubits(reg2)) ≈ reg
+
+    @test insert_qubits!(copy(reg), 2; nqubits=2) |> nactive == 5
 end
 
 @testset "Focus 2" begin
diff --git a/test/measure.jl b/test/measure.jl
index fa4d4751d..e425a5070 100644
--- a/test/measure.jl
+++ b/test/measure.jl
@@ -12,7 +12,7 @@ using Test, YaoArrayRegister, YaoBase
     @test r3 ≈ r2
 end
 
-@testset "measure and reset/remove" begin
+@testset "measure and collapseto/remove" begin
     reg = rand_state(4)
     res = measure_collapseto!(reg, (4,))
     @test isnormalized(reg)
@@ -24,4 +24,8 @@ end
     res = measure_remove!(reg)
     select(reg0, res)
     @test select(reg0, res) |> normalize! ≈ reg
+
+    reg = rand_state(6, nbatch=5) |> focus!((1:5)...)
+    measure_collapseto!(reg, 1)
+    @test nactive(reg) == 5
 end
diff --git a/test/register.jl b/test/register.jl
index 8f87ffa86..d829c14c1 100644
--- a/test/register.jl
+++ b/test/register.jl
@@ -4,7 +4,7 @@ using Test, YaoArrayRegister, BitBasis, LinearAlgebra
     @test ArrayReg{3}(rand(4, 6)) isa ArrayReg{3}
     @test_throws DimensionMismatch ArrayReg{2}(rand(4, 3))
     @test_throws DimensionMismatch ArrayReg{2}(rand(5, 2))
-    @test_throws MethodError ArrayReg(rand(4, 3))
+    @test_logs (:warn, "Input type of `ArrayReg` is not Complex, got Float64") ArrayReg(rand(4, 3))
 
     @test ArrayReg(rand(ComplexF64, 4, 3)) isa ArrayReg{3}
     @test ArrayReg(rand(ComplexF64, 4)) isa ArrayReg{1}