cmd/compile: fix panic when refer to method of imported instantiated type
In case of reference to method call of an imported fully-instantiated
type, nameNode.Func will be nil causes checkFetchBody panic. To fix
this, make sure checkFetchBody is only called when Func is not nil.
Fixes #49246
Change-Id: I32e9208385a86d4600d8ebf6f5efd8fca571ea16
Reviewed-on: https://go-review.googlesource.com/c/go/+/360056
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Dan Scales <danscales@google.com>