diff --git a/src/longlonguint.jl b/src/longlonguint.jl
index 00774a9..ce3a7ee 100644
--- a/src/longlonguint.jl
+++ b/src/longlonguint.jl
@@ -23,8 +23,8 @@ Base.zero(::Type{LongLongUInt{C}}) where {C} = LongLongUInt{C}(ntuple(_->UInt(0)
 Base.zero(::LongLongUInt{C}) where {C} = zero(LongLongUInt{C})
 # convert from integers
 LongLongUInt{C}(x::T) where {C, T<:Integer} = LongLongUInt{C}(ntuple(i->i==C ? UInt(x) : zero(UInt), Val{C}()))
-Base.promote_type(::Type{LongLongUInt{C}}, ::Type{Int}) where {C} = LongLongUInt{C}
-Base.promote_type(::Type{LongLongUInt{C}}, ::Type{UInt}) where {C} = LongLongUInt{C}
+Base.promote_rule(::Type{LongLongUInt{C}}, ::Type{Int}) where {C} = LongLongUInt{C}
+Base.promote_rule(::Type{LongLongUInt{C}}, ::Type{UInt}) where {C} = LongLongUInt{C}
 function Base.mod(x::LongLongUInt{C}, D::Int) where {C}
     D == 2 ? mod(x.content[end], 2) : error("mod only supports 2")
 end
@@ -134,4 +134,4 @@ function longinttype(n::Int, D::Int)
 end
 
 Base.hash(x::LongLongUInt{1}) = hash(x.content[1])
-Base.hash(x::LongLongUInt{C}) where{C} = hash(x.content)
\ No newline at end of file
+Base.hash(x::LongLongUInt{C}) where{C} = hash(x.content)
diff --git a/test/longlonguint.jl b/test/longlonguint.jl
index a53b5c3..22e645b 100644
--- a/test/longlonguint.jl
+++ b/test/longlonguint.jl
@@ -14,6 +14,7 @@ using Test, BitBasis
     @test x >> 1 == LongLongUInt((UInt(1), UInt(3) + UInt(1)<<63))
     @test count_ones(x) == 4
     @test ~x == LongLongUInt((~UInt(3), ~UInt(6)))
+    @test promote(UInt(1), LongLongUInt((3, 4))) == (LongLongUInt((0, 1)), LongLongUInt((3, 4)))
 
     y = LongLongUInt((5, 7))
     @test one(y) == LongLongUInt((0, 1))
@@ -120,4 +121,4 @@ end
     xs = [LongLongUInt((3, 6)), LongLongUInt((3, 7)), LongLongUInt((2, 4))]
     sorted_xs = sort(xs)
     @test sorted_xs == [LongLongUInt((2, 4)), LongLongUInt((3, 6)), LongLongUInt((3, 7))]
-end
\ No newline at end of file
+end