src/librustc_typeck/coherence/inherent_impls_overlap.rs

   1 use crate::namespace::Namespace;
   2 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
   3 use rustc::hir;
   4 use rustc::hir::itemlikevisit::ItemLikeVisitor;
   5 use rustc::traits::{self, IntercrateMode};
   6 use rustc::ty::TyCtxt;
   7
   8 use rustc_error_codes::*;
   9
  10 pub fn crate_inherent_impls_overlap_check(tcx: TyCtxt<'_>, crate_num: CrateNum) {
  11     assert_eq!(crate_num, LOCAL_CRATE);
  12     let krate = tcx.hir().krate();
  13     krate.visit_all_item_likes(&mut InherentOverlapChecker { tcx });
  14 }
  15
  16 struct InherentOverlapChecker<'tcx> {
  17     tcx: TyCtxt<'tcx>,
  18 }
  19
  20 impl InherentOverlapChecker<'tcx> {
  21     fn check_for_common_items_in_impls(&self, impl1: DefId, impl2: DefId,
  22                                        overlap: traits::OverlapResult<'_>) {
  23
  24         let name_and_namespace = |def_id| {
  25             let item = self.tcx.associated_item(def_id);
  26             (item.ident.modern(), Namespace::from(item.kind))
  27         };
  28
  29         let impl_items1 = self.tcx.associated_item_def_ids(impl1);
  30         let impl_items2 = self.tcx.associated_item_def_ids(impl2);
  31
  32         for &item1 in &impl_items1[..] {
  33             let (name, namespace) = name_and_namespace(item1);
  34
  35             for &item2 in &impl_items2[..] {
  36                 if (name, namespace) == name_and_namespace(item2) {
  37                     let mut err =
  38                         struct_span_err!(self.tcx.sess,
  39                                          self.tcx.span_of_impl(item1).unwrap(),
  40                                          E0592,
  41                                          "duplicate definitions with name `{}`",
  42                                          name);
  43                     err.span_label(self.tcx.span_of_impl(item1).unwrap(),
  44                                    format!("duplicate definitions for `{}`", name));
  45                     err.span_label(self.tcx.span_of_impl(item2).unwrap(),
  46                                    format!("other definition for `{}`", name));
  47
  48                     for cause in &overlap.intercrate_ambiguity_causes {
  49                         cause.add_intercrate_ambiguity_hint(&mut err);
  50                     }
  51
  52                     if overlap.involves_placeholder {
  53                         traits::add_placeholder_note(&mut err);
  54                     }
  55
  56                     err.emit();
  57                 }
  58             }
  59         }
  60     }
  61
  62     fn check_for_overlapping_inherent_impls(&self, ty_def_id: DefId) {
  63         let impls = self.tcx.inherent_impls(ty_def_id);
  64
  65         for (i, &impl1_def_id) in impls.iter().enumerate() {
  66             for &impl2_def_id in &impls[(i + 1)..] {
  67                 traits::overlapping_impls(
  68                     self.tcx,
  69                     impl1_def_id,
  70                     impl2_def_id,
  71                     IntercrateMode::Issue43355,
  72                     |overlap| {
  73                         self.check_for_common_items_in_impls(
  74                             impl1_def_id,
  75                             impl2_def_id,
  76                             overlap,
  77                         );
  78                         false
  79                     },
  80                     || true,
  81                 );
  82             }
  83         }
  84     }
  85 }
  86
  87 impl ItemLikeVisitor<'v> for InherentOverlapChecker<'tcx> {
  88     fn visit_item(&mut self, item: &'v hir::Item) {
  89         match item.kind {
  90             hir::ItemKind::Enum(..) |
  91             hir::ItemKind::Struct(..) |
  92             hir::ItemKind::Trait(..) |
  93             hir::ItemKind::Union(..) => {
  94                 let type_def_id = self.tcx.hir().local_def_id(item.hir_id);
  95                 self.check_for_overlapping_inherent_impls(type_def_id);
  96             }
  97             _ => {}
  98         }
  99     }
 100
 101     fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem) {
 102     }
 103
 104     fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem) {
 105     }
 106 }