Before filing a bug, please check whether it has been fixed since
the latest release: run "hg pull -u" and retry what you did to
reproduce the problem.  Thanks.

What steps will reproduce the problem?
1. Compile the following program:
package main
const a [2]int = -1
func main() { println(a) }

What is the expected output? What do you see instead?
The program compiles and prints "-1" when executed rather than failing to
compile with an error such as:
badconst.go:2: cannot use -1 (type int) as type [2]int in constant declaration

What is your $GOOS?  $GOARCH?
GOOS=linux GOARCH=386

Which revision are you using?  (hg identify)
7929874a70ae tip

Please provide any additional information below.
It appears that the assignment compatibility check for constant
declarations is different than the check for assignments.