Note this isn't implementing checking through imports. The parse node
there is harder to access through the context, so would require
examining the entity in order to get the import declaration, to get at
the ImportIR. We also don't have a parse tree attached in that case, and
would need to add one to SemIR::File. But I believe we do want to add
that, so it's explicitly a TODO.
Note GetTokenText re-lexes literal values, so there's a bit of potential
overhead there. Not sure if we want a more efficient manner for
comparing in cases like this.
Previously we did some of this in decl_name_stack and some of it in the
callers of decl_name_stack. Factor out a single place to pop a name and
its optional following parameters.
Part of making this behavior consistent is that we now track whether an
implicit parameter list was present or absent rather than mapping an
absent list to `InstBlockId::Empty`. This improves our redeclaration
checking and the precision of some diagnostics.
Jon Ross-Perkins
Richard Smith