1 use fmt_macros::{Parser, Piece, Position};
3 use rustc::ty::{self, GenericParamDefKind, TyCtxt};
4 use rustc::util::common::ErrorReported;
6 use rustc_ast::ast::{MetaItem, NestedMetaItem};
7 use rustc_attr as attr;
8 use rustc_data_structures::fx::FxHashMap;
9 use rustc_errors::struct_span_err;
10 use rustc_hir::def_id::DefId;
11 use rustc_span::symbol::{kw, sym, Symbol};
14 #[derive(Clone, Debug)]
15 pub struct OnUnimplementedFormatString(Symbol);
18 pub struct OnUnimplementedDirective {
19 pub condition: Option<MetaItem>,
20 pub subcommands: Vec<OnUnimplementedDirective>,
21 pub message: Option<OnUnimplementedFormatString>,
22 pub label: Option<OnUnimplementedFormatString>,
23 pub note: Option<OnUnimplementedFormatString>,
24 pub enclosing_scope: Option<OnUnimplementedFormatString>,
28 pub struct OnUnimplementedNote {
29 pub message: Option<String>,
30 pub label: Option<String>,
31 pub note: Option<String>,
32 pub enclosing_scope: Option<String>,
42 let mut diag = struct_span_err!(tcx.sess, span, E0232, "{}", message);
43 diag.span_label(span, label);
44 if let Some(note) = note {
51 impl<'tcx> OnUnimplementedDirective {
55 items: &[NestedMetaItem],
58 ) -> Result<Self, ErrorReported> {
59 let mut errored = false;
60 let mut item_iter = items.iter();
62 let condition = if is_root {
71 "empty `on`-clause in `#[rustc_on_unimplemented]`",
72 "empty on-clause here",
81 "invalid `on`-clause in `#[rustc_on_unimplemented]`",
82 "invalid on-clause here",
86 attr::eval_condition(cond, &tcx.sess.parse_sess, &mut |_| true);
90 let mut message = None;
93 let mut enclosing_scope = None;
94 let mut subcommands = vec![];
96 let parse_value = |value_str| {
97 OnUnimplementedFormatString::try_parse(tcx, trait_def_id, value_str, span).map(Some)
100 for item in item_iter {
101 if item.check_name(sym::message) && message.is_none() {
102 if let Some(message_) = item.value_str() {
103 message = parse_value(message_)?;
106 } else if item.check_name(sym::label) && label.is_none() {
107 if let Some(label_) = item.value_str() {
108 label = parse_value(label_)?;
111 } else if item.check_name(sym::note) && note.is_none() {
112 if let Some(note_) = item.value_str() {
113 note = parse_value(note_)?;
116 } else if item.check_name(sym::enclosing_scope) && enclosing_scope.is_none() {
117 if let Some(enclosing_scope_) = item.value_str() {
118 enclosing_scope = parse_value(enclosing_scope_)?;
121 } else if item.check_name(sym::on)
127 if let Some(items) = item.meta_item_list() {
128 if let Ok(subcommand) =
129 Self::parse(tcx, trait_def_id, &items, item.span(), false)
131 subcommands.push(subcommand);
143 "this attribute must have a valid value",
144 "expected value here",
145 Some(r#"eg `#[rustc_on_unimplemented(message="foo")]`"#),
152 Ok(OnUnimplementedDirective {
167 ) -> Result<Option<Self>, ErrorReported> {
168 let attrs = tcx.get_attrs(impl_def_id);
170 let attr = if let Some(item) = attr::find_by_name(&attrs, sym::rustc_on_unimplemented) {
176 let result = if let Some(items) = attr.meta_item_list() {
177 Self::parse(tcx, trait_def_id, &items, attr.span, true).map(Some)
178 } else if let Some(value) = attr.value_str() {
179 Ok(Some(OnUnimplementedDirective {
183 label: Some(OnUnimplementedFormatString::try_parse(
190 enclosing_scope: None,
193 return Err(ErrorReported);
195 debug!("of_item({:?}/{:?}) = {:?}", trait_def_id, impl_def_id, result);
202 trait_ref: ty::TraitRef<'tcx>,
203 options: &[(Symbol, Option<String>)],
204 ) -> OnUnimplementedNote {
205 let mut message = None;
206 let mut label = None;
208 let mut enclosing_scope = None;
209 info!("evaluate({:?}, trait_ref={:?}, options={:?})", self, trait_ref, options);
211 for command in self.subcommands.iter().chain(Some(self)).rev() {
212 if let Some(ref condition) = command.condition {
213 if !attr::eval_condition(condition, &tcx.sess.parse_sess, &mut |c| {
214 c.ident().map_or(false, |ident| {
215 options.contains(&(ident.name, c.value_str().map(|s| s.to_string())))
218 debug!("evaluate: skipping {:?} due to condition", command);
222 debug!("evaluate: {:?} succeeded", command);
223 if let Some(ref message_) = command.message {
224 message = Some(message_.clone());
227 if let Some(ref label_) = command.label {
228 label = Some(label_.clone());
231 if let Some(ref note_) = command.note {
232 note = Some(note_.clone());
235 if let Some(ref enclosing_scope_) = command.enclosing_scope {
236 enclosing_scope = Some(enclosing_scope_.clone());
240 let options: FxHashMap<Symbol, String> =
241 options.iter().filter_map(|(k, v)| v.as_ref().map(|v| (*k, v.to_owned()))).collect();
242 OnUnimplementedNote {
243 label: label.map(|l| l.format(tcx, trait_ref, &options)),
244 message: message.map(|m| m.format(tcx, trait_ref, &options)),
245 note: note.map(|n| n.format(tcx, trait_ref, &options)),
246 enclosing_scope: enclosing_scope.map(|e_s| e_s.format(tcx, trait_ref, &options)),
251 impl<'tcx> OnUnimplementedFormatString {
257 ) -> Result<Self, ErrorReported> {
258 let result = OnUnimplementedFormatString(from);
259 result.verify(tcx, trait_def_id, err_sp)?;
268 ) -> Result<(), ErrorReported> {
269 let name = tcx.item_name(trait_def_id);
270 let generics = tcx.generics_of(trait_def_id);
271 let s = self.0.as_str();
272 let parser = Parser::new(&s, None, vec![], false);
273 let mut result = Ok(());
274 for token in parser {
276 Piece::String(_) => (), // Normal string, no need to check it
277 Piece::NextArgument(a) => match a.position {
278 // `{Self}` is allowed
279 Position::ArgumentNamed(s) if s == kw::SelfUpper => (),
280 // `{ThisTraitsName}` is allowed
281 Position::ArgumentNamed(s) if s == name => (),
282 // `{from_method}` is allowed
283 Position::ArgumentNamed(s) if s == sym::from_method => (),
284 // `{from_desugaring}` is allowed
285 Position::ArgumentNamed(s) if s == sym::from_desugaring => (),
286 // `{ItemContext}` is allowed
287 Position::ArgumentNamed(s) if s == sym::item_context => (),
288 // So is `{A}` if A is a type parameter
289 Position::ArgumentNamed(s) => {
290 match generics.params.iter().find(|param| param.name == s) {
297 "there is no parameter `{}` on trait `{}`",
302 result = Err(ErrorReported);
306 // `{:1}` and `{}` are not to be used
307 Position::ArgumentIs(_) | Position::ArgumentImplicitlyIs(_) => {
312 "only named substitution parameters are allowed"
315 result = Err(ErrorReported);
327 trait_ref: ty::TraitRef<'tcx>,
328 options: &FxHashMap<Symbol, String>,
330 let name = tcx.item_name(trait_ref.def_id);
331 let trait_str = tcx.def_path_str(trait_ref.def_id);
332 let generics = tcx.generics_of(trait_ref.def_id);
333 let generic_map = generics
336 .filter_map(|param| {
337 let value = match param.kind {
338 GenericParamDefKind::Type { .. } | GenericParamDefKind::Const => {
339 trait_ref.substs[param.index as usize].to_string()
341 GenericParamDefKind::Lifetime => return None,
343 let name = param.name;
346 .collect::<FxHashMap<Symbol, String>>();
347 let empty_string = String::new();
349 let s = self.0.as_str();
350 let parser = Parser::new(&s, None, vec![], false);
351 let item_context = (options.get(&sym::item_context)).unwrap_or(&empty_string);
354 Piece::String(s) => s,
355 Piece::NextArgument(a) => match a.position {
356 Position::ArgumentNamed(s) => match generic_map.get(&s) {
358 None if s == name => &trait_str,
360 if let Some(val) = options.get(&s) {
362 } else if s == sym::from_desugaring || s == sym::from_method {
363 // don't break messages using these two arguments incorrectly
365 } else if s == sym::item_context {
369 "broken on_unimplemented {:?} for {:?}: \
370 no argument matching {:?}",
378 _ => bug!("broken on_unimplemented {:?} - bad format arg", self.0),