Function name_error 

pub fn name_error(
    e: &EmbedDecl,
    prev_embed: Option<&Ident>,
    prev_asset: Option<&Ident>,
    prev_fn: Option<&Ident>,
    prev_type: Option<&Ident>,
) -> Option<CompileError>

The name rule for embed e, given what its unit already declares under that name: an earlier embed is bynk.embed.duplicate; an asset, a free function or a type is bynk.resolve.name_conflict (an embed is a value, in the function namespace, and a type name in value position is an error). None when the name is free. One rule for the project pipeline (symbols::build_unit_table) and the single-file compile, which has no unit table.