tree 91661a98a94614d44edce1db696010dfbe03c916
parent 12d2c3421a761da9f1017f5ada1831d5f08e8fff
author Alan Donovan <adonovan@google.com> 1721953479 -0700
committer Alan Donovan <adonovan@google.com> 1722036448 +0000

go/types/objectpath: support parameterized type aliases

This change caused objectpath to treat Alias nodes more
like Named types: as first-class nodes, with type parameters,
and a destructuring operation (Alias.Rhs(), opRhs, encoded 'a')
access the RHS type.

A number of historical bugs made this trickier than it should
have been:
- go1.22 prints Alias wrongly, requiring a workaround in the test.
- aliases.Enabled is too expensive to call in the decoder,
  so we must trust that when we see an opRhs and we don't
  have an alias, it's because !Enabled(), not a bug.
- legacy aliases still need to be handled, and order matters.
- the test of parameterized aliases can't be added until
  the GOEXPERIMENT has gone away (soon).

Updates golang/go#46477

Change-Id: Ia903f81e29fb7dbb6e17d1e6a962fad73b3e1f7b
Reviewed-on: https://go-review.googlesource.com/c/tools/+/601235
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: Tim King <taking@google.com>
Commit-Queue: Alan Donovan <adonovan@google.com>