If the TypeParam has all the methods of an interface, allow conversions from TypeParam to interface
Fixes#47708
Change-Id: I40a82a31f6ea9354130dbe3bcfc83537094bf12c
Reviewed-on: https://go-review.googlesource.com/c/go/+/342509
Reviewed-by: Dan Scales <danscales@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Trust: Dan Scales <danscales@google.com>
Trust: Keith Randall <khr@golang.org>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
