Fix gorountine arguments not copied.

Fixes #1498

interp/run.go

@@ -1292,14 +1292,24 @@ func call(n *node) {
 				// The receiver is already passed in the function wrapper, skip it.
 				values = values[1:]
 			}
-			in := make([]reflect.Value, len(values))
-			for i, v := range values {
-				in[i] = v(f)
-			}
+
 			if goroutine {
+				// Goroutine's arguments should be copied.
+				in := make([]reflect.Value, len(values))
+				for i, v := range values {
+					value := v(f)
+					in[i] = reflect.New(value.Type()).Elem()
+					in[i].Set(value)
+				}
+
 				go callf(in)
 				return tnext
 			}
+
+			in := make([]reflect.Value, len(values))
+			for i, v := range values {
+				in[i] = v(f)
+			}
 			out := callf(in)
 			for i, v := range rvalues {
 				if v != nil {