cmd/compile: fix and improve struct field reflect information

The previous logic was overly complicated, generated suboptimally
encoded struct type descriptors, and mishandled embeddings of
predeclared universal types.

Fixes #21122.
Fixes #21353.
Fixes #21696.
Fixes #21702.
Updates #21357.

Change-Id: If34761fa6dbe4af2af59dee501e7f30845320376
Reviewed-on: https://go-review.googlesource.com/60410
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/runtime/type.go b/src/runtime/type.go
index bf54d54eb4..b3df3353ce 100644
--- a/src/runtime/type.go
+++ b/src/runtime/type.go
@@ -655,15 +655,15 @@ func typesEqual(t, v *_type, seen map[_typePair]struct{}) bool {
 		if len(st.fields) != len(sv.fields) {
 			return false
 		}
+		if st.pkgPath.name() != sv.pkgPath.name() {
+			return false
+		}
 		for i := range st.fields {
 			tf := &st.fields[i]
 			vf := &sv.fields[i]
 			if tf.name.name() != vf.name.name() {
 				return false
 			}
-			if tf.name.pkgPath() != vf.name.pkgPath() {
-				return false
-			}
 			if !typesEqual(tf.typ, vf.typ, seen) {
 				return false
 			}