cmd/compile: tip crashes on too-large package-level array declarations

[zigo101]

What version of Go are you using (go version)?

$ go version
go version devel go1.18-fad67f8a53 Sat Nov 27 01:14:21 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

Tip only.

What did you do?

package main

var X [1<<50]byte

func main() {}

What did you expect to see?

Not crash, just fails to compile.

What did you see instead?

Crash

[ianlancetaylor]

To clarify, it is the compiler that crashes, not the program.

CC @griesemer @findleyr

> go build foo.go
# command-line-arguments
<unknown line number>: internal compiler error: bad type: [1125899906842624]byte

goroutine 1 [running]:
runtime/debug.Stack()
	/home/iant/go/src/runtime/debug/stack.go:24 +0x65
cmd/compile/internal/base.FatalfAt({0x10?, 0x0?}, {0xd1d117, 0xc}, {0xc00057b380, 0x1, 0x1})
	/home/iant/go/src/cmd/compile/internal/base/print.go:227 +0x1ca
cmd/compile/internal/base.Fatalf(...)
	/home/iant/go/src/cmd/compile/internal/base/print.go:196
cmd/compile/internal/types.typePos(0xc0004278f0?)
	/home/iant/go/src/cmd/compile/internal/types/size.go:53 +0xad
cmd/compile/internal/types.CalcSize(0xc0000ac310)
	/home/iant/go/src/cmd/compile/internal/types/size.go:495 +0x59e
cmd/compile/internal/types.ResumeCheckSize()
	/home/iant/go/src/cmd/compile/internal/types/size.go:628 +0x4e
cmd/compile/internal/noder.(*irgen).typ(0xc0000b6000, {0xe8bba8?, 0xc000414090?})
	/home/iant/go/src/cmd/compile/internal/noder/types.go:38 +0x3d
cmd/compile/internal/noder.(*irgen).obj(0xc0000b6000, {0xe8ee30, 0xc000424240?})
	/home/iant/go/src/cmd/compile/internal/noder/object.go:147 +0x965
cmd/compile/internal/noder.(*irgen).def(0xc0000b6000, 0xc0000a6020)
	/home/iant/go/src/cmd/compile/internal/noder/object.go:22 +0xbd
cmd/compile/internal/noder.(*irgen).varDecl(0xc0000b6000, 0xc0001640f0, 0xc000424120)
	/home/iant/go/src/cmd/compile/internal/noder/decl.go:243 +0xe5
cmd/compile/internal/noder.(*irgen).decls(0xc0000b6000?, 0xc000596070?, {0xc0000a60a0?, 0x2, 0x203000?})
	/home/iant/go/src/cmd/compile/internal/noder/decl.go:34 +0xfd
cmd/compile/internal/noder.(*irgen).generate(0xc0000b6000, {0xc00006aa90, 0x2, 0x203000?})
	/home/iant/go/src/cmd/compile/internal/noder/irgen.go:270 +0x1ed
cmd/compile/internal/noder.check2({0xc00006aa90, 0x2, 0x2})
	/home/iant/go/src/cmd/compile/internal/noder/irgen.go:92 +0x16d
cmd/compile/internal/noder.LoadPackage({0xc00001e210, 0x2, 0x0?})
	/home/iant/go/src/cmd/compile/internal/noder/noder.go:90 +0x335
cmd/compile/internal/gc.Main(0xd496c0)
	/home/iant/go/src/cmd/compile/internal/gc/main.go:191 +0xb13
main.main()
	/home/iant/go/src/cmd/compile/main.go:55 +0xdd

[griesemer]

The crash happens while trying to report error "type %L larger than address space"; it appears that the type position is unknown.

[gopherbot]

Change https://golang.org/cl/367955 mentions this issue: cmd/compile: report channel size errors correctly for -G=3