go/types, types2: array size computation may overflow to 0

[griesemer]

package p

import "unsafe"

type E [1 << 32]byte
var a [1<<32]E

func _() {
	trace(unsafe.Sizeof(a))
}

go test -run Manual -- x.go produces

x.go:9:8: unsafe.Sizeof(a) (constant 0 of type uintptr)

[gopherbot]

Change https://go.dev/cl/478921 mentions this issue: go/types, types2: make sure array sizes don't overflow to 0

[gopherbot]

Change https://go.dev/cl/478919 mentions this issue: cmd/compile: don't panic if unsafe.Sizeof/Offsetof is used with oversize types