diff --git a/src/FixedPointNumbers.jl b/src/FixedPointNumbers.jl
index 3873dc7..65e6704 100644
--- a/src/FixedPointNumbers.jl
+++ b/src/FixedPointNumbers.jl
@@ -469,7 +469,9 @@ function _length(r::StepRange{<:FixedPoint})
 end
 
 hasalias(::Type) = false
-hasalias(::Type{X}) where {T<:NotBiggerThanInt64, f, X<:FixedPoint{T,f}} = f isa Int
+function hasalias(::Type{X}) where {T<:NotBiggerThanInt64, f, X<:FixedPoint{T,f}}
+    isprimitivetype(T) && (f isa Int)
+end
 
 # `alias_symbol` is used to define type aliases, so we need this before we
 # include "src/fixed.jl" / "src/normed.jl".
@@ -623,15 +625,18 @@ scaledual(::Type{Tdual}, x::AbstractArray{T}) where {Tdual, T <: FixedPoint} =
     convert(Tdual, 1/rawone(T)), reinterpret(rawtype(T), x)
 
 @noinline function throw_converterror(::Type{X}, @nospecialize(x)) where X <: FixedPoint
-    nbits = bitwidth(rawtype(X))
     io = IOBuffer()
     showtype(io, X)
-    print(io, " is ")
-    print(io, nbits == 8 ? "an " : "a ", nbits, "-bit type representing ")
-    print(io, nbits <= 16 ? string(2^nbits) : "2^$nbits", " values from ")
-    print(IOContext(io, :compact=>true), typemin(X), " to ")
-    print(IOContext(io, :compact=>true), typemax(X), "; ")
-    print(io, "cannot represent ", x)
+    T = rawtype(X)
+    if isprimitivetype(T) && !(X <: FixedPoint{Union{}}) # The latter is a hint for JET.
+        nbits = bitwidth(T)
+        print(io, " is ")
+        print(io, nbits == 8 ? "an " : "a ", nbits, "-bit type representing ")
+        print(io, nbits <= 16 ? string(2^nbits) : "2^$nbits", " values from ")
+        print(IOContext(io, :compact=>true), typemin(X), " to ")
+        print(IOContext(io, :compact=>true), typemax(X), ";")
+    end
+    print(io, " cannot represent ", x)
     throw(ArgumentError(String(take!(io))))
 end
 
diff --git a/test/fixed.jl b/test/fixed.jl
index c12f130..4d4ba10 100644
--- a/test/fixed.jl
+++ b/test/fixed.jl
@@ -805,6 +805,9 @@ end
     show(iob, Fixed{Int128,64}(-1.2345e6))
     @test String(take!(iob)) == "Fixed{Int128,$(SP)64}(-1.2345e6)"
 
+    FixedPointNumbers.showtype(iob, Fixed{Union{}, 7})
+    @test String(take!(iob)) == "Fixed{Union{},$(SP)7}"
+
     # TODO: remove this test
     show(iob, reinterpret(Fixed{Int8,8}, signed(0xaa)))
     @test String(take!(iob)) == "Fixed{Int8,$(SP)8}(-0.336)"
diff --git a/test/normed.jl b/test/normed.jl
index c9e5e4b..be01472 100644
--- a/test/normed.jl
+++ b/test/normed.jl
@@ -782,6 +782,9 @@ end
 
     show(iob, Normed{UInt128,64}(1.2345e6))
     @test String(take!(iob)) == "Normed{UInt128,$(SP)64}(1.2345e6)"
+
+    FixedPointNumbers.showtype(iob, Normed{Union{}, 8})
+    @test String(take!(iob)) == "Normed{Union{},$(SP)8}"
 end
 
 @testset "summary" begin