1 // Copyright 2018 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
13 use rustc::ty::ToPredicate;
14 use rustc::ty::subst::Subst;
15 use rustc::infer::InferOk;
16 use syntax_pos::DUMMY_SP;
18 use core::DocAccessLevels;
22 use self::def_ctor::{get_def_from_def_id, get_def_from_node_id};
24 pub struct BlanketImplFinder<'a, 'tcx: 'a, 'rcx: 'a, 'cstore: 'rcx> {
25 pub cx: &'a core::DocContext<'a, 'tcx, 'rcx, 'cstore>,
28 impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
29 pub fn new(cx: &'a core::DocContext<'a, 'tcx, 'rcx, 'cstore>) -> Self {
30 BlanketImplFinder { cx }
33 pub fn get_with_def_id(&self, def_id: DefId) -> Vec<Item> {
34 get_def_from_def_id(&self.cx, def_id, &|def_ctor| {
35 self.get_blanket_impls(def_id, &def_ctor, None)
39 pub fn get_with_node_id(&self, id: ast::NodeId, name: String) -> Vec<Item> {
40 get_def_from_node_id(&self.cx, id, name, &|def_ctor, name| {
41 let did = self.cx.tcx.hir.local_def_id(id);
42 self.get_blanket_impls(did, &def_ctor, Some(name))
46 pub fn get_blanket_impls<F>(
52 where F: Fn(DefId) -> Def {
53 debug!("get_blanket_impls(def_id={:?}, ...)", def_id);
54 let mut impls = Vec::new();
62 "get_blanket_impls(def_id={:?}, def_ctor=...): item has doc('hidden'), \
68 let ty = self.cx.tcx.type_of(def_id);
69 let generics = self.cx.tcx.generics_of(def_id);
70 let real_name = name.clone().map(|name| Ident::from_str(&name));
71 let param_env = self.cx.tcx.param_env(def_id);
72 for &trait_def_id in self.cx.all_traits.iter() {
73 if !self.cx.renderinfo.borrow().access_levels.is_doc_reachable(trait_def_id) ||
74 self.cx.generated_synthetics
76 .get(&(def_id, trait_def_id))
80 self.cx.tcx.for_each_relevant_impl(trait_def_id, ty, |impl_def_id| {
81 self.cx.tcx.infer_ctxt().enter(|infcx| {
82 debug!("get_blanet_impls: Considering impl for trait '{:?}' {:?}",
83 trait_def_id, impl_def_id);
84 let t_generics = infcx.tcx.generics_of(impl_def_id);
85 let trait_ref = infcx.tcx.impl_trait_ref(impl_def_id)
86 .expect("Cannot get impl trait");
88 match trait_ref.self_ty().sty {
93 let substs = infcx.fresh_substs_for_item(DUMMY_SP, def_id);
94 let ty = ty.subst(infcx.tcx, substs);
95 let param_env = param_env.subst(infcx.tcx, substs);
97 let impl_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
98 let trait_ref = trait_ref.subst(infcx.tcx, impl_substs);
100 // Require the type the impl is implemented on to match
101 // our type, and ignore the impl if there was a mismatch.
102 let cause = traits::ObligationCause::dummy();
103 let eq_result = infcx.at(&cause, param_env)
104 .eq(trait_ref.self_ty(), ty);
105 if let Ok(InferOk { value: (), obligations }) = eq_result {
106 // FIXME(eddyb) ignoring `obligations` might cause false positives.
110 "invoking predicate_may_hold: param_env={:?}, trait_ref={:?}, ty={:?}",
111 param_env, trait_ref, ty
113 let may_apply = match infcx.evaluate_obligation(
114 &traits::Obligation::new(
117 trait_ref.to_predicate(),
120 Ok(eval_result) => eval_result.may_apply(),
121 Err(traits::OverflowError) => true, // overflow doesn't mean yes *or* no
123 debug!("get_blanket_impls: found applicable impl: {}\
124 for trait_ref={:?}, ty={:?}",
125 may_apply, trait_ref, ty);
130 self.cx.generated_synthetics.borrow_mut()
131 .insert((def_id, trait_def_id));
132 let trait_ = hir::TraitRef {
133 path: get_path_for_type(infcx.tcx,
135 hir::def::Def::Trait),
136 ref_id: ast::DUMMY_NODE_ID,
137 hir_ref_id: hir::DUMMY_HIR_ID,
139 let provided_trait_methods =
140 infcx.tcx.provided_trait_methods(trait_def_id)
142 .map(|meth| meth.ident.to_string())
145 let ty = self.cx.get_real_ty(def_id, def_ctor, &real_name, generics);
146 let predicates = infcx.tcx.predicates_of(impl_def_id);
149 source: infcx.tcx.def_span(impl_def_id).clean(self.cx),
151 attrs: Default::default(),
153 def_id: self.cx.next_def_id(impl_def_id.krate),
156 inner: ImplItem(Impl {
157 unsafety: hir::Unsafety::Normal,
158 generics: (t_generics, &predicates).clean(self.cx),
159 provided_trait_methods,
160 trait_: Some(trait_.clean(self.cx)),
161 for_: ty.clean(self.cx),
162 items: infcx.tcx.associated_items(impl_def_id)
167 blanket_impl: Some(infcx.tcx.type_of(impl_def_id)