Thanks for your response. Particularly the first words : "TypeResolver really wasn't designed to be used outside the configuration loading process."
That makes me aware of a design issue and I finally refactor my whole code.
I now load my types directly in the method GetInjectionMember of my InjectionMemberElement (instead of loading it inside the builder strategy - the lazy way). The constructor of my InjectionMember now takes types instead of literals and a
configsection. (actually, it's a more complex problem, but I finally found a solution that looks good to me).
FYI, this config file resumes pretty well my original design issue :
<!-- some elements with attributes containing type aliases -->
I have naturally opted for a lazy loading. But I realized that performance was not really a requirement at this stage of my application.