cmd/compile: use a non-fragile test for "does f contain closure c?"

The old test relied on naming conventions.  The new test
uses an explicit parent pointer chain initialized when the
closures are created (in the same place that the names
used in the older fragile test were assigned).

Fixes #70035.

Change-Id: Ie834103c7096e4505faaff3bed1fc6e918a21211
Reviewed-on: https://go-review.googlesource.com/c/go/+/622656
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/rangefunc/rangefunc_test.go b/src/cmd/compile/internal/rangefunc/rangefunc_test.go
index 1d0bed05c8..acf0ef6e09 100644
--- a/src/cmd/compile/internal/rangefunc/rangefunc_test.go
+++ b/src/cmd/compile/internal/rangefunc/rangefunc_test.go
@@ -2119,3 +2119,27 @@ func TestTwoLevelReturnCheck(t *testing.T) {
 		t.Errorf("Expected y=3, got y=%d\n", y)
 	}
 }
+
+func Bug70035(s1, s2, s3 []string) string {
+	var c1 string
+	for v1 := range slices.Values(s1) {
+		var c2 string
+		for v2 := range slices.Values(s2) {
+			var c3 string
+			for v3 := range slices.Values(s3) {
+				c3 = c3 + v3
+			}
+			c2 = c2 + v2 + c3
+		}
+		c1 = c1 + v1 + c2
+	}
+	return c1
+}
+
+func Test70035(t *testing.T) {
+	got := Bug70035([]string{"1", "2", "3"}, []string{"a", "b", "c"}, []string{"A", "B", "C"})
+	want := "1aABCbABCcABC2aABCbABCcABC3aABCbABCcABC"
+	if got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}