Fix builtin type checks for any

Author: antonmedv

Diff for: builtin/builtin.go

@@ -289,6 +289,8 @@ var Builtins = []*Function{
 			}
 			for _, arg := range args {
 				switch kind(arg) {
+				case reflect.Interface:
+					return anyType, nil
 				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64:
 				default:
 					return anyType, fmt.Errorf("invalid argument for max (type %s)", arg)
@@ -306,6 +308,8 @@ var Builtins = []*Function{
 			}
 			for _, arg := range args {
 				switch kind(arg) {
+				case reflect.Interface:
+					return anyType, nil
 				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Float32, reflect.Float64:
 				default:
 					return anyType, fmt.Errorf("invalid argument for min (type %s)", arg)
@@ -493,6 +497,8 @@ var Builtins = []*Function{
 				return anyType, fmt.Errorf("invalid number of arguments (expected 1, got %d)", len(args))
 			}
 			switch kind(args[0]) {
+			case reflect.Interface:
+				return arrayType, nil
 			case reflect.Map:
 				return arrayType, nil
 			}
@@ -521,6 +527,8 @@ var Builtins = []*Function{
 				return anyType, fmt.Errorf("invalid number of arguments (expected 1, got %d)", len(args))
 			}
 			switch kind(args[0]) {
+			case reflect.Interface:
+				return arrayType, nil
 			case reflect.Map:
 				return arrayType, nil
 			}

Diff for: builtin/builtin_test.go

@@ -3,6 +3,7 @@ package builtin_test
 import (
 	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 	"time"
 
@@ -104,6 +105,32 @@ func TestBuiltin(t *testing.T) {
 	}
 }
 
+func TestBuiltin_works_with_any(t *testing.T) {
+	config := map[string]struct {
+		arity int
+	}{
+		"get": {2},
+	}
+
+	for _, b := range builtin.Builtins {
+		t.Run(b.Name, func(t *testing.T) {
+			arity := 1
+			if c, ok := config[b.Name]; ok {
+				arity = c.arity
+			}
+			if len(b.Types) > 0 {
+				arity = b.Types[0].NumIn()
+			}
+			args := make([]string, arity)
+			for i := 1; i <= arity; i++ {
+				args[i-1] = fmt.Sprintf("arg%d", i)
+			}
+			_, err := expr.Compile(fmt.Sprintf(`%s(%s)`, b.Name, strings.Join(args, ", "))) // expr.Env(env) is not needed
+			assert.NoError(t, err)
+		})
+	}
+}
+
 func TestBuiltin_errors(t *testing.T) {
 	var errorTests = []struct {
 		input string