fix(derive): Remove structopt attribute support

CHANGELOG.md

@@ -53,6 +53,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - *(derive)* Changed the default for arguments from `parse` to `value_parser`., removing `parse` support
 - *(derive)* `subcommand_required(true).arg_required_else_help(true)` is set instead of `SubcommandRequiredElseHelp` (#3280)
 - *(derive)* Remove `arg_enum` attribute in favor of `value_enum`
+- *(derive)* Remove `structopt()` attributes in favor of `clap()`
 
 ### Compatibility
 

clap_derive/src/lib.rs

@@ -42,7 +42,7 @@ pub fn value_enum(input: TokenStream) -> TokenStream {
 /// receiving an instance of `clap::ArgMatches` from conducting parsing, and then
 /// implementing a conversion code to instantiate an instance of the user
 /// context struct.
-#[proc_macro_derive(Parser, attributes(clap, structopt))]
+#[proc_macro_derive(Parser, attributes(clap))]
 #[proc_macro_error]
 pub fn parser(input: TokenStream) -> TokenStream {
     let input: DeriveInput = parse_macro_input!(input);

clap_derive/src/parse.rs

@@ -23,7 +23,7 @@ impl ClapAttr {
     pub fn parse_all(all_attrs: &[Attribute]) -> Vec<Self> {
         all_attrs
             .iter()
-            .filter(|attr| attr.path.is_ident("clap") || attr.path.is_ident("structopt"))
+            .filter(|attr| attr.path.is_ident("clap"))
             .flat_map(|attr| {
                 attr.parse_args_with(Punctuated::<ClapAttr, Token![,]>::parse_terminated)
                     .unwrap_or_abort()