From 66a4245befc93cac44e9c84a676691f706cdc3c7 Mon Sep 17 00:00:00 2001
From: Evgeniy Stratonikov <evgeniy@nspcc.ru>
Date: Tue, 30 Nov 2021 12:55:51 +0300
Subject: [PATCH] compiler: allow to slice struct field

It makes no sense to restrict to identifiers.
---
 pkg/compiler/codegen.go    |  6 +++---
 pkg/compiler/slice_test.go | 10 ++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go
index ab66620ed..d6fc6707b 100644
--- a/pkg/compiler/codegen.go
+++ b/pkg/compiler/codegen.go
@@ -641,12 +641,12 @@ func (c *codegen) Visit(node ast.Node) ast.Visitor {
 		return nil
 
 	case *ast.SliceExpr:
-		if isCompoundSlice(c.typeOf(n.X.(*ast.Ident)).Underlying()) {
+		if isCompoundSlice(c.typeOf(n.X).Underlying()) {
 			c.prog.Err = errors.New("subslices are supported only for []byte")
 			return nil
 		}
-		name := n.X.(*ast.Ident).Name
-		c.emitLoadVar("", name)
+
+		ast.Walk(c, n.X)
 
 		if n.Low != nil {
 			ast.Walk(c, n.Low)
diff --git a/pkg/compiler/slice_test.go b/pkg/compiler/slice_test.go
index 82cb9c72c..4ce08291d 100644
--- a/pkg/compiler/slice_test.go
+++ b/pkg/compiler/slice_test.go
@@ -432,6 +432,16 @@ func TestSubsliceCompound(t *testing.T) {
 	require.Error(t, err)
 }
 
+func TestSubsliceFromStructField(t *testing.T) {
+	src := `package foo
+	type pair struct { key, value []byte }
+	func Main() []byte {
+		p := pair{ []byte{1}, []byte{4, 8, 15, 16, 23, 42} }
+		return p.value[2:4]
+	}`
+	eval(t, src, []byte{15, 16})
+}
+
 func TestRemove(t *testing.T) {
 	t.Run("Valid", func(t *testing.T) {
 		src := `package foo