From: Robert Findley <rfindley@google.com>
Date: Sun, 15 Aug 2021 23:47:08 +0000 (-0400)
Subject: cmd/compile/internal/types2: use the underlying TypeParam in
X-Git-Tag: go1.18beta1~1785
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c88e3ff648;p=gostls13.git

cmd/compile/internal/types2: use the underlying TypeParam in
assignableTo

In CL 338310, assignableTo was altered to walk the constituent types of
TypeParams rather than Unions, but was not also adjusted to use under
rather than optype. This manifested in the port to go/types.

Change-Id: Ie057b96ce93cef204af88b536ea49344c9bc8f12
Reviewed-on: https://go-review.googlesource.com/c/go/+/342409
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
---

diff --git a/src/cmd/compile/internal/types2/operand.go b/src/cmd/compile/internal/types2/operand.go
index 8336451e9c..19326b8342 100644
--- a/src/cmd/compile/internal/types2/operand.go
+++ b/src/cmd/compile/internal/types2/operand.go
@@ -273,7 +273,7 @@ func (x *operand) assignableTo(check *Checker, T Type, reason *string) (bool, er
 
 	// x is an untyped value representable by a value of type T.
 	if isUntyped(Vu) {
-		if t, ok := Tu.(*TypeParam); ok {
+		if t, ok := under(T).(*TypeParam); ok {
 			return t.is(func(t *term) bool {
 				// TODO(gri) this could probably be more efficient
 				if t.tilde {