diff --git a/_test/bin4.go b/_test/bin4.go
new file mode 100644
index 00000000..5d9c4fe5
--- /dev/null
+++ b/_test/bin4.go
@@ -0,0 +1,18 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func Bar(s string) bool {
+	a := strings.HasPrefix("fas", "f")
+	b := strings.HasPrefix("aaaaa", "a")
+	a_and_b := strings.HasPrefix("fas", "f") && strings.HasPrefix("aaaaa", "a")
+	fmt.Println(a, b, a && b, a_and_b)
+	return a && b
+}
+
+func main() {
+	println(Bar("kung"))
+}
diff --git a/interp/run.go b/interp/run.go
index 33980228..ef1a0080 100644
--- a/interp/run.go
+++ b/interp/run.go
@@ -933,13 +933,16 @@ func callBin(n *node) {
 		}
 	case fnext != nil:
 		// Handle branching according to boolean result.
+		index := n.findex
 		n.exec = func(f *frame) bltn {
 			in := make([]reflect.Value, l)
 			for i, v := range values {
 				in[i] = v(f)
 			}
 			res := value(f).Call(in)
-			if res[0].Bool() {
+			b := res[0].Bool()
+			f.data[index].SetBool(b)
+			if b {
 				return tnext
 			}
 			return fnext