gc: better error message for bad type in channel send
gc: better error message for bad type in channel send

# test program
1 package main
2
3 type C chan int
4
5 func F(c C) {
6 	c <- true
7 }

# old error
test.go:6: cannot use true (type bool) as type int in function argument

# new error
test.go:6: cannot use true (type bool) as type int in channel send

R=rsc, ejsherry
CC=golang-dev
http://codereview.appspot.com/3231042

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go