diff --git a/src/metadata.jl b/src/metadata.jl
index d80e7c1..0409333 100644
--- a/src/metadata.jl
+++ b/src/metadata.jl
@@ -17,7 +17,7 @@ using .MaxLengthStrings: MaxLengthString
 primitive type ASCIIChar <: AbstractChar 8 end
 ASCIIChar(x::UInt8) = reinterpret(ASCIIChar, x)
 ASCIIChar(x::Integer) = ASCIIChar(UInt8(x))
-UInt8(x::ASCIIChar) = reinterpret(UInt8, x)
+Base.UInt8(x::ASCIIChar) = reinterpret(UInt8, x)
 Base.codepoint(x::ASCIIChar) = UInt8(x)
 Base.show(io::IO, x::ASCIIChar) = print(io, Char(x))
 Base.zero(::Union{ASCIIChar,Type{ASCIIChar}}) = ASCIIChar(Base.zero(UInt8))