Add aliases and nested aliases test cases

codegen/config/binder_test.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"go/token"
 	"go/types"
 	"testing"
 
@@ -266,6 +267,11 @@ func TestEnumBinding(t *testing.T) {
 	require.Equal(t, cf.Schema.Types["Baz"].EnumValues[1], baz.EnumValues[1].Definition)
 }
 
+func createTypeAlias(name string, t types.Type) *types.Alias {
+	var nopos token.Pos
+	return types.NewAlias(types.NewTypeName(nopos, nil, name, nil), t)
+}
+
 func TestIsNilable(t *testing.T) {
 	type aTest struct {
 		input    types.Type
@@ -285,6 +291,10 @@ func TestIsNilable(t *testing.T) {
 		{types.NewMap(types.Typ[types.Int], types.Typ[types.Int]), true},
 		{types.NewSlice(types.Typ[types.Int]), true},
 		{types.NewInterfaceType(nil, nil), true},
+		{createTypeAlias("interfaceAlias", types.NewInterfaceType(nil, nil)), true},
+		{createTypeAlias("interfaceNestedAlias", createTypeAlias("interfaceAlias", types.NewInterfaceType(nil, nil))), true},
+		{createTypeAlias("intAlias", types.Typ[types.Int]), false},
+		{createTypeAlias("intNestedAlias", createTypeAlias("intAlias", types.Typ[types.Int])), false},
 	}
 
 	for _, at := range theTests {