cmd/compile: allow conversion from slice to array ptr

Panic if the slice is too short.

Updates #395

Change-Id: I90f4bff2da5d8f3148ba06d2482084f32b25c29a
Reviewed-on: https://go-review.googlesource.com/c/go/+/301650
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/test/convert2.go b/test/convert2.go
index e7044b2453..8e43967aaa 100644
--- a/test/convert2.go
+++ b/test/convert2.go
@@ -313,3 +313,17 @@ func _() {
 	t = u       // ERROR "cannot use .* in assignment|incompatible type"
 	t = (*T)(u) // ERROR "cannot convert"
 }
+
+func _() {
+	var s []byte
+	_ = ([4]byte)(s) // ERROR "cannot convert"
+	_ = (*[4]byte)(s)
+
+	type A [4]byte
+	_ = (A)(s) // ERROR "cannot convert"
+	_ = (*A)(s)
+
+	type P *[4]byte
+	_ = (P)(s)
+	_ = (*P)(s) // ERROR "cannot convert"
+}