feat: Support string-alias type's `ToStringE`

cast_test.go

@@ -233,11 +233,15 @@ func TestToStringE(t *testing.T) {
 
 	var jn json.Number
 	_ = json.Unmarshal([]byte("8"), &jn)
+
 	type Key struct {
 		k string
 	}
 	key := &Key{"foo"}
 
+	type StrAlias string
+	sa := StrAlias("bar")
+
 	tests := []struct {
 		input  interface{}
 		expect string
@@ -266,6 +270,8 @@ func TestToStringE(t *testing.T) {
 		{template.JS("(1+2)"), "(1+2)", false},
 		{template.CSS("a"), "a", false},
 		{template.HTMLAttr("a"), "a", false},
+		{sa, "bar", false},
+
 		// errors
 		{testing.T{}, "", true},
 		{key, "", true},

caste.go

@@ -911,7 +911,7 @@ func indirect(a interface{}) interface{} {
 // Copyright 2011 The Go Authors. All rights reserved.
 // indirectToStringerOrError returns the value, after dereferencing as many times
 // as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
-// or error,
+// or error.
 func indirectToStringerOrError(a interface{}) interface{} {
 	if a == nil {
 		return nil
@@ -980,6 +980,12 @@ func ToStringE(i interface{}) (string, error) {
 		return s.String(), nil
 	case error:
 		return s.Error(), nil
+	}
+
+	iReflectVal := reflect.ValueOf(i)
+	switch iReflectVal.Kind() {
+	case reflect.String:
+		return iReflectVal.String(), nil
 	default:
 		return "", fmt.Errorf("unable to cast %#v of type %T to string", i, i)
 	}

go.mod

@@ -1,4 +1,4 @@
-module github.com/spf13/cast
+module github.com/PeterlitsZo/cast
 
 go 1.19