cmd/compile: internal compiler error: OXDOT in OuterValue

[dsnet]

Git bisect reveals a regression stemming from https://go-review.googlesource.com/c/go/+/371554, where the following reproduction crashes with that change, but works just prior to that change.

Reproduction:

$ git clone https://github.com/go-json-experiment/json.git
$ cd json
$ git checkout arshal-funcs
$ go test -vet off# github.com/go-json-experiment/json_test [github.com/go-json-experiment/json.test]
./arshal_funcs_generic.go:50:15: internal compiler error: OXDOT in OuterValue: "github.com/go-json-experiment/json".a.fncCache

goroutine 1 [running]:
runtime/debug.Stack()
    go/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x4e9ea2?, 0x0?}, {0xd29d8d, 0x17}, {0xc000619988, 0x1, 0x1})
    go/src/cmd/compile/internal/base/print.go:227 +0x1ca
cmd/compile/internal/ir.OuterValue({0xe944a0?, 0xc0006307e0?})
    go/src/cmd/compile/internal/ir/node.go:587 +0x1f3
cmd/compile/internal/typecheck.markAddrOf({0xe944a0?, 0xc0006307e0?})
    go/src/cmd/compile/internal/typecheck/subr.go:88 +0x4d
cmd/compile/internal/typecheck.NodAddrAt({0x74efc0?, 0xc0?}, {0xe944a0?, 0xc0006307e0?})
    go/src/cmd/compile/internal/typecheck/subr.go:75 +0x35
cmd/compile/internal/typecheck.(*importReader).node(0xc00074efc0)
    go/src/cmd/compile/internal/typecheck/iimport.go:1637 +0x1190
cmd/compile/internal/typecheck.(*importReader).expr(0x0?)
    go/src/cmd/compile/internal/typecheck/iimport.go:1285 +0x1d
cmd/compile/internal/typecheck.(*importReader).exprList(0xc00074efc0?)
    go/src/cmd/compile/internal/typecheck/iimport.go:1275 +0x47
cmd/compile/internal/typecheck.(*importReader).node(0xc00074efc0)
    go/src/cmd/compile/internal/typecheck/iimport.go:1585 +0x1cf4
cmd/compile/internal/typecheck.(*importReader).expr(0xce9900?)
    go/src/cmd/compile/internal/typecheck/iimport.go:1285 +0x1d
cmd/compile/internal/typecheck.(*importReader).exprList(0xc00074efc0?)
    go/src/cmd/compile/internal/typecheck/iimport.go:1275 +0x47
cmd/compile/internal/typecheck.(*importReader).node(0xc00074efc0)
    go/src/cmd/compile/internal/typecheck/iimport.go:1722 +0x150a
cmd/compile/internal/typecheck.(*importReader).stmtList(0xc00074efc0?)
    go/src/cmd/compile/internal/typecheck/iimport.go:1207 +0x58
cmd/compile/internal/typecheck.(*importReader).node(0xc00074efc0)
    go/src/cmd/compile/internal/typecheck/iimport.go:1737 +0x212b
cmd/compile/internal/typecheck.(*importReader).stmtList(0x4?)
    go/src/cmd/compile/internal/typecheck/iimport.go:1207 +0x58
cmd/compile/internal/typecheck.(*importReader).funcBody(0xc00074efc0, 0xc00090c2c0)
    go/src/cmd/compile/internal/typecheck/iimport.go:1128 +0xa5
cmd/compile/internal/typecheck.(*importReader).doInline(0xca0360?, 0xc00090c2c0)
    go/src/cmd/compile/internal/typecheck/iimport.go:1092 +0x99
cmd/compile/internal/typecheck.ImportBody(0xc00090c2c0)
    go/src/cmd/compile/internal/typecheck/iimport.go:80 +0x206
cmd/compile/internal/noder.checkFetchBody(0xc0008f7860)
    go/src/cmd/compile/internal/noder/stencil.go:638 +0x96
cmd/compile/internal/noder.(*genInst).getInstantiation(0x1390e00, 0xc0008f7860, {0xc00072c880, 0x2, 0x0?}, 0x0?)
    go/src/cmd/compile/internal/noder/stencil.go:659 +0x5a
cmd/compile/internal/noder.(*genInst).instantiateMethods(0x40d387?)
    go/src/cmd/compile/internal/noder/stencil.go:585 +0x24e
cmd/compile/internal/noder.(*genInst).buildInstantiations(0x1390e00, 0x0)
    go/src/cmd/compile/internal/noder/stencil.go:60 +0x3a
cmd/compile/internal/noder.BuildInstantiations(...)
    go/src/cmd/compile/internal/noder/stencil.go:47
cmd/compile/internal/gc.Main(0xd4bd08)
    go/src/cmd/compile/internal/gc/main.go:251 +0xd7c
main.main()
    go/src/cmd/compile/main.go:55 +0xdd

FAIL    github.com/go-json-experiment/json [build failed]

The code builds and runs fine with GOEXPERIMENT=unified:

$ GOEXPERIMENT=unified go.dev test -vet=off
PASS
ok      github.com/go-json-experiment/json  0.970s

\cc @randall77 @danscales @mdempsky

[gopherbot]

Change https://golang.org/cl/375574 mentions this issue: cmd/compile: fix instantiation of types referenced during inlining