x/tools: tests fails when run from a module (or with a go.work file) that uses go1.23+

[findleyr]

Various x/tools tests fail when run from a module that has go1.23 in its go directive, or (more likely) when using a go.work file that says go1.23, because the tests themselves assume go1.22 semantics.

In particular, tests of the internal/aliases package that assume a default GODEBUG value for gotypesalias are broken.

> cat go.mod
module mod.test

go 1.24

require golang.org/x/tools v0.26.1-0.20241028184645-73d6794ebbd4
> go test golang.org/x/tools/internal/aliases
--- FAIL: TestNewAlias (0.00s)
    --- FAIL: TestNewAlias/#00 (0.00s)
        aliases_test.go:77: Expected A.Type() to not be a types.Alias(). got "p.A"
FAIL
FAIL    golang.org/x/tools/internal/aliases     0.018s
FAIL

I think we should relax these assertions, since they are not valid in all testing scenarios.

CC @timothy-king @adonovan @pjweinb

[gabyhelp]

Related Issues and Documentation

• x/build: add 1.23 and tip builders with GODEBUG=gotypesalias=1 for at least the x/tools repo #68798 (closed)
• x/tools: get tests passing with GODEBUG=gotypesalias=1 #65294 (closed)
• x/build: add tip builders with GOEXPERIMENT=aliastypeparams=1 for at least go and x/tools repo #69121 (closed)
• x/tools/gopls: handle go1.22's go/types.Alias #64581 (closed)
• all: audit x/ repos for gotypesalias settings #69772

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[gopherbot]

Change https://go.dev/cl/622896 mentions this issue: all: fix x/tools tests that fail with a go1.23.1 go.work file