[basic.scope.temp] p2

Each template-declaration D introduces a template parameter scope that extends from the beginning of its template-parameter-list to the end of the template-declaration. Any declaration outside the template-parameter-list that would inhabit that scope instead inhabits the same scope as D.

According to [basic.scope#scope-2]

A declaration inhabits the immediate scope at its locus ([basic.scope.pdecl]).

However, we didn't specify the locus of a template-declaration. The note [basic.scope#scope-2.8] also depends on the scope template-declaration inhabits

The declaration in a template-declaration inhabits the same scope as the template-declaration.