From 2a70a71dc2a2f9bc74c8ebce09462ddb44810353 Mon Sep 17 00:00:00 2001
From: Marc Vertes <mvertes@free.fr>
Date: Mon, 6 Jul 2020 15:30:04 +0200
Subject: [PATCH] fix: avoid infinite loop when parsing recursive types

Mark all visited types as such when walking down struct fields.

Fixes #750.
Updates #652.
---
 _test/struct53.go | 23 +++++++++++++++++++++++
 interp/type.go    |  2 ++
 2 files changed, 25 insertions(+)
 create mode 100644 _test/struct53.go

diff --git a/_test/struct53.go b/_test/struct53.go
new file mode 100644
index 00000000..1d97004a
--- /dev/null
+++ b/_test/struct53.go
@@ -0,0 +1,23 @@
+package main
+
+import "fmt"
+
+type T1 struct {
+	P []*T
+}
+
+type T2 struct {
+	P2 *T
+}
+
+type T struct {
+	*T1
+	S1 *T
+}
+
+func main() {
+	fmt.Println(T2{})
+}
+
+// Output:
+// {<nil>}
diff --git a/interp/type.go b/interp/type.go
index f08ac796..7394d109 100644
--- a/interp/type.go
+++ b/interp/type.go
@@ -1385,6 +1385,8 @@ func hasRecursiveStruct(t *itype, defined map[string]*itype) bool {
 		if defined[typ.path+"/"+typ.name] != nil {
 			return true
 		}
+		defined[typ.path+"/"+typ.name] = typ
+
 		for _, f := range typ.field {
 			if hasRecursiveStruct(f.typ, defined) {
 				return true