Emit dummy impls on error

CHANGELOG.md

@@ -1,6 +1,8 @@
 # v0.3.1 (2019-08-31)
 * Fix error messages ([#241](https://github.com/TeXitoi/structopt/issues/241))
 * Fix "`skip` plus long doc comment" bug ([#245](https://github.com/TeXitoi/structopt/issues/245))
+* Now `structopt` emits dummy `StructOpt` implementation along with an error. It suppresses
+  meaningless errors like `from_args method is not found for Opt`
 
 # v0.3.0 (2019-08-30)
 

structopt-derive/Cargo.toml

@@ -18,7 +18,7 @@ syn = { version = "1", features = ["full"] }
 quote = "1"
 proc-macro2 = "1"
 heck = "0.3.0"
-proc-macro-error = "0.2"
+proc-macro-error = "0.2.6"
 
 [features]
 paw = []

structopt-derive/src/lib.rs

@@ -22,7 +22,7 @@ use crate::{
 };
 
 use proc_macro2::{Span, TokenStream};
-use proc_macro_error::{call_site_error, filter_macro_errors, span_error};
+use proc_macro_error::{call_site_error, filter_macro_errors, set_dummy, span_error};
 use quote::{quote, quote_spanned};
 use syn::{punctuated::Punctuated, spanned::Spanned, token::Comma, *};
 
@@ -519,6 +519,18 @@ fn impl_structopt(input: &DeriveInput) -> TokenStream {
     use syn::Data::*;
 
     let struct_name = &input.ident;
+
+    set_dummy(Some(quote! {
+        impl ::structopt::StructOpt for #struct_name {
+            fn clap<'a, 'b>() -> ::structopt::clap::App<'a, 'b> {
+                unimplemented!()
+            }
+            fn from_clap(_matches: &::structopt::clap::ArgMatches) -> Self {
+                unimplemented!()
+            }
+        }
+    }));
+
     match input.data {
         Struct(DataStruct {
             fields: syn::Fields::Named(ref fields),

tests/ui-1.39_post/opt_opt_nonpositional.rs

@@ -14,4 +14,7 @@ struct Opt {
     n: Option<Option<u32>>,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-1.39_post/opt_vec_nonpositional.rs

@@ -14,4 +14,7 @@ struct Opt {
     n: Option<Vec<u32>>,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-1.39_post/subcommand_opt_opt.rs

@@ -8,7 +8,7 @@
 
 use structopt::StructOpt;
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 #[structopt(name = "make-cookie")]
 struct MakeCookie {
     #[structopt(short)]
@@ -18,7 +18,7 @@ struct MakeCookie {
     cmd: Option<Option<Command>>,
 }
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 enum Command {
     #[structopt(name = "pound")]
     /// Pound acorns into flour for cookie dough.
@@ -30,4 +30,7 @@ enum Command {
     },
 }
 
-fn main() {}
+fn main() {
+    let opt = MakeCookie::from_args();
+    println!("{:?}", opt);
+}

tests/ui-1.39_post/subcommand_opt_vec.rs

@@ -8,7 +8,7 @@
 
 use structopt::StructOpt;
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 #[structopt(name = "make-cookie")]
 struct MakeCookie {
     #[structopt(short)]
@@ -18,7 +18,7 @@ struct MakeCookie {
     cmd: Option<Vec<Command>>,
 }
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 enum Command {
     #[structopt(name = "pound")]
     /// Pound acorns into flour for cookie dough.
@@ -30,4 +30,7 @@ enum Command {
     },
 }
 
-fn main() {}
+fn main() {
+    let opt = MakeCookie::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/bool_default_value.rs

@@ -15,4 +15,7 @@ struct Opt {
     b: bool,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/bool_required.rs

@@ -15,4 +15,7 @@ struct Opt {
     b: bool,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/flatten_and_doc.rs

@@ -24,4 +24,7 @@ struct Opt {
     opts: DaemonOpts,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/flatten_and_methods.rs

@@ -23,4 +23,7 @@ struct Opt {
     opts: DaemonOpts,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/flatten_and_parse.rs

@@ -23,4 +23,7 @@ struct Opt {
     opts: DaemonOpts,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/non_existent_attr.rs

@@ -15,4 +15,7 @@ struct Opt {
     debug: bool,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/option_default_value.rs

@@ -15,4 +15,7 @@ struct Opt {
     n: Option<u32>,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/option_required.rs

@@ -15,4 +15,7 @@ struct Opt {
     n: Option<u32>,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/parse_empty_try_from_os.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/parse_function_is_not_path.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/parse_literal_spec.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/parse_not_zero_args.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui/raw.rs → tests/ui-common/raw.rs

@@ -14,4 +14,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui/raw.stderr → tests/ui-common/raw.stderr

@@ -1,4 +1,4 @@
-error: `#[structopt(raw(...))` attributes are deprecated in structopt 3.0, only `raw(true)` and `raw(false)` are allowed
+error: `#[structopt(raw(...))` attributes are deprecated in structopt 0.3, only `raw(true)` and `raw(false)` are allowed
   --> $DIR/raw.rs:13:17
    |
 13 |     #[structopt(raw(case_insensitive = "true"))]

tests/ui-common/rename_all_wrong_casing.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/skip_flatten.rs

@@ -8,7 +8,7 @@
 
 use structopt::StructOpt;
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 #[structopt(name = "make-cookie")]
 struct MakeCookie {
     #[structopt(short)]
@@ -18,7 +18,7 @@ struct MakeCookie {
     cmd: Command,
 }
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 enum Command {
     #[structopt(name = "pound")]
     /// Pound acorns into flour for cookie dough.
@@ -36,4 +36,7 @@ impl Default for Command {
     }
 }
 
-fn main() {}
+fn main() {
+    let opt = MakeCookie::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/skip_subcommand.rs

@@ -8,7 +8,7 @@
 
 use structopt::StructOpt;
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 #[structopt(name = "make-cookie")]
 struct MakeCookie {
     #[structopt(short)]
@@ -18,7 +18,7 @@ struct MakeCookie {
     cmd: Command,
 }
 
-#[derive(StructOpt)]
+#[derive(StructOpt, Debug)]
 enum Command {
     #[structopt(name = "pound")]
     /// Pound acorns into flour for cookie dough.
@@ -36,4 +36,7 @@ impl Default for Command {
     }
 }
 
-fn main() {}
+fn main() {
+    let opt = MakeCookie::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/skip_with_other_options.rs

@@ -2,11 +2,14 @@ use structopt::StructOpt;
 
 #[derive(StructOpt, Debug)]
 #[structopt(name = "test")]
-pub struct Opts {
+pub struct Opt {
     #[structopt(long)]
     a: u32,
     #[structopt(skip, long)]
     b: u32,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/skip_without_default.rs

@@ -16,11 +16,14 @@ enum Kind {
 
 #[derive(StructOpt, Debug)]
 #[structopt(name = "test")]
-pub struct Opts {
+pub struct Opt {
     #[structopt(short)]
     number: u32,
     #[structopt(skip)]
     k: Kind,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/struct_flatten.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/struct_parse.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/struct_subcommand.rs

@@ -15,4 +15,7 @@ struct Opt {
     s: String,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}

tests/ui-common/structopt_empty_attr.rs

@@ -15,5 +15,8 @@ struct Opt {
     debug: bool,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}
 

tests/ui-common/structopt_name_value_attr.rs

@@ -15,5 +15,8 @@ struct Opt {
     debug: bool,
 }
 
-fn main() {}
+fn main() {
+    let opt = Opt::from_args();
+    println!("{:?}", opt);
+}