From d229c2a2c721179e1df6932a520099073ff10dbd Mon Sep 17 00:00:00 2001
From: Nicholas Wiersma <nick@wiersma.co.za>
Date: Fri, 3 Jul 2020 12:25:04 +0200
Subject: [PATCH] fix: handle Func Value in genFunctionWrapper params

* fix: handle Func value in func wrapper params

* fix: lint
---
 interp/interp_eval_test.go | 19 +++++++++++++++++++
 interp/run.go              | 12 ++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/interp/interp_eval_test.go b/interp/interp_eval_test.go
index 45ec5a65..7dd99ed1 100644
--- a/interp/interp_eval_test.go
+++ b/interp/interp_eval_test.go
@@ -385,6 +385,25 @@ func TestEvalChan(t *testing.T) {
 	})
 }
 
+func TestEvalFunctionCallWithFunctionParam(t *testing.T) {
+	i := interp.New(interp.Options{})
+	eval(t, i, `
+		func Bar(s string, fn func(string)string) string { return fn(s) }
+	`)
+
+	v := eval(t, i, "Bar")
+	bar := v.Interface().(func(string, func(string) string) string)
+
+	got := bar("hello ", func(s string) string {
+		return s + "world!"
+	})
+
+	want := "hello world!"
+	if got != want {
+		t.Errorf("unexpected result of function eval: got %q, want %q", got, want)
+	}
+}
+
 func TestEvalMissingSymbol(t *testing.T) {
 	defer func() {
 		r := recover()
diff --git a/interp/run.go b/interp/run.go
index 2ee2b4c0..9bb8da82 100644
--- a/interp/run.go
+++ b/interp/run.go
@@ -679,9 +679,13 @@ func genFunctionWrapper(n *node) func(*frame) reflect.Value {
 
 			// Copy function input arguments in local frame
 			for i, arg := range in {
-				if def.typ.arg[i].cat == interfaceT {
+				typ := def.typ.arg[i]
+				switch {
+				case typ.cat == interfaceT:
 					d[i].Set(reflect.ValueOf(valueInterface{value: arg.Elem()}))
-				} else {
+				case typ.cat == funcT && arg.Kind() == reflect.Func:
+					d[i].Set(reflect.ValueOf(genFunctionNode(arg)))
+				default:
 					d[i].Set(arg)
 				}
 			}
@@ -705,6 +709,10 @@ func genFunctionWrapper(n *node) func(*frame) reflect.Value {
 	}
 }
 
+func genFunctionNode(v reflect.Value) *node {
+	return &node{kind: funcType, action: aNop, rval: v, typ: &itype{cat: valueT, rtype: v.Type()}}
+}
+
 func genInterfaceWrapper(n *node, typ reflect.Type) func(*frame) reflect.Value {
 	value := genValue(n)
 	if typ == nil || typ.Kind() != reflect.Interface || typ.NumMethod() == 0 || n.typ.cat == valueT {