@v0.3.3/go/ir: []byte to [4]byte conversion in net/netip package causes builder panic

[adonovan]

The IR builder appears to lack support for the new slice-to-array (not pointer-to-array) conversions supported in the upcoming go1.20 and already used in the standard library, such as in the net/netip package. This causes it to panic.

(@taking has spent a lot of effort thinking about this logic in x/tools/go/ssa so you may want to confer with him.)

Typical panic:
https://storage.googleapis.com/go-build-log/8bcc4906/linux-amd64-boringcrypto_ad40fb56.log

panic: in net/netip.AddrFromSlice: cannot convert Load <[]byte> t0 ([]byte) to [4]byte

goroutine 18344 [running]:
honnef.co/go/tools/go/ir.emitConv(0xc0203aaf00, {0x1350358, 0xc0210a07e0}, {0x13469a0?, 0xc01f2c3a10}, {0x13460b8, 0xc013b3b740})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/emit.go:293 +0xd29
honnef.co/go/tools/go/ir.(*builder).expr0(0xc01cfaf930, 0xc0203aaf00, {0x1348f90?, 0xc013b3b740?}, {0x7, {0x13469a0, 0xc01f2c3a10}, {0x0, 0x0}})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:610 +0x5d7
honnef.co/go/tools/go/ir.(*builder).expr(0x1346ae0?, 0xc0203aaf00, {0x1348f90, 0xc013b3b740})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:566 +0x1fa
honnef.co/go/tools/go/ir.(*builder).emitCallArgs(0x1346ae0?, 0xc0203aaf00, 0xc0153041c0, 0xc013b3b7c0, {0x0?, 0x0, 0x58a2e7?})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:975 +0x135
honnef.co/go/tools/go/ir.(*builder).setCall(0xf99960?, 0xc0203aaf00, 0xc013b3b7c0, 0xc020b3f088)
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:1037 +0x8e
honnef.co/go/tools/go/ir.(*builder).expr0(0xc01cfaf930, 0xc0203aaf00, {0x1348f90?, 0xc013b3b7c0?}, {0x7, {0x1346a68, 0xc01d7fad20}, {0x0, 0x0}})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:623 +0x218e
honnef.co/go/tools/go/ir.(*builder).expr(0xc01cfaed80?, 0xc0203aaf00, {0x1348f90, 0xc013b3b7c0})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:566 +0x1fa
honnef.co/go/tools/go/ir.(*builder).stmt(0xc0203aaf00?, 0xc0203aaf00, {0x13494d0?, 0xc01df1d2e0?})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:2291 +0x194c
honnef.co/go/tools/go/ir.(*builder).stmtList(...)
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:855
honnef.co/go/tools/go/ir.(*builder).switchStmt(0xc01cfaf210?, 0xc0203aaf00, 0xc01df1b0e0, 0x0)
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:1366 +0x19a5
honnef.co/go/tools/go/ir.(*builder).stmt(0x20?, 0xc0203aaf00, {0x1349620?, 0xc01df1b0e0?})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:2365 +0x121c
honnef.co/go/tools/go/ir.(*builder).stmtList(0x5909c5?, 0xc01cfaf400?, {0xc01df1d4a0?, 0x2, 0x5922f0?})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:855 +0x45
honnef.co/go/tools/go/ir.(*builder).stmt(0xc0203aaf00?, 0xc0203aaf00, {0x1348f30?, 0xc01df1b110?})
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:2338 +0x9b9
honnef.co/go/tools/go/ir.(*builder).buildFunction(0xc01cfaf930, 0xc0203aaf00)
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:2450 +0x3d7
honnef.co/go/tools/go/ir.(*builder).buildFuncDecl(0x0?, 0xc020388480, 0xc01df1b140)
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:2488 +0x19b
honnef.co/go/tools/go/ir.(*Package).build(0xc020388480)
	/workdir/gopath/pkg/mod/honnef.co/go/tools@v0.3.3/go/ir/builder.go:2594 +0xc16

[dominikh]

This is already fixed on the master branch (as of 39b8ce7). It'll be part of the next release, which is planned to release shortly after Go 1.20 does.

Generally speaking. the latest release of Staticcheck supports the latest release of Go (and the one before that), and the upcoming release of Go is supported by the master branch.

[adonovan]

Aha, I used @latest and of course didn't get the fix but I should have suspected you'd already fixed it on the master branch. Thanks!