test: add a couple of pointer method test cases

Change-Id: If91c8a61fcda93eeb5affe51ef8f537736a28bce
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go2-dev/+/768839
Reviewed-by: Ian Lance Taylor <iant@google.com>

test/gen/err003.go2

@@ -0,0 +1,29 @@
+// errorcheck
+
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+type Setter interface {
+	Set(string)
+}
+
+func FromStrings(type T Setter)(s []string) []T {
+	result := make([]T, len(s))
+	for i, v := range s {
+		result[i].Set(v)
+	}
+	return result
+}
+
+type Settable int
+
+func (p *Settable) Set(s string) {
+	*p = 0
+}
+
+func F() {
+	FromStrings(Settable)([]string{"1"}) // ERROR "Settable does not satisfy Setter.*method Set"
+}

test/gen/g011.go2

@@ -0,0 +1,43 @@
+// run
+
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"log"
+	"strconv"
+)
+
+type Setter interface {
+	Set(string)
+}
+
+func FromStrings(type *T Setter)(s []string) []T {
+	result := make([]T, len(s))
+	for i, v := range s {
+		// result[i] is an addressable value of type T,
+		// so it's OK to call Set.
+		result[i].Set(v)
+	}
+	return result
+}
+
+type Settable int
+
+func (p *Settable) Set(s string) {
+	i, err := strconv.Atoi(s)
+	if err != nil {
+		log.Fatal(err)
+	}
+	*p = Settable(i)
+}
+
+func main() {
+	s := FromStrings(Settable)([]string{"1"})
+	if len(s) != 1 || s[0] != 1 {
+		log.Fatalf("got %v, want %v", s, []int{1})
+	}
+}