Add extra fetch test for funcs

Author: antonmedv

expr_test.go

@@ -808,6 +808,24 @@ func TestExpr(t *testing.T) {
 	}
 }
 
+func TestExpr_eval_with_env(t *testing.T) {
+	_, err := expr.Eval("true", expr.Env(map[string]interface{}{}))
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "misused")
+}
+
+func TestExpr_fetch_from_func(t *testing.T) {
+	_, err := expr.Eval("foo.Value", map[string]interface{}{
+		"foo": func() {},
+	})
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "cannot fetch Value from func()")
+}
+
+//
+// Mock types
+//
+
 type mockEnv struct {
 	Any                  interface{}
 	Int, One, Two, Three int
@@ -903,9 +921,3 @@ type segment struct {
 	Destination string
 	Date        time.Time
 }
-
-func TestExpr_eval_with_env(t *testing.T) {
-	_, err := expr.Eval("true", expr.Env(map[string]interface{}{}))
-	assert.Error(t, err)
-	assert.Contains(t, err.Error(), "misused")
-}

vm/runtime.go

@@ -46,6 +46,9 @@ func fetch(from interface{}, i interface{}) interface{} {
 		if value.IsValid() && value.CanInterface() {
 			return value.Interface()
 		}
+
+	case reflect.Func:
+		panic(fmt.Sprintf("cannot fetch %v from %T", i, from))
 	}
 	return nil
 }