src/librustc_typeck/coherence/inherent_impls_overlap.rs

   1 use crate::namespace::Namespace;
   2 use rustc::traits::{self, IntercrateMode};
   3 use rustc::ty::TyCtxt;
   4 use rustc_errors::struct_span_err;
   5 use rustc_hir as hir;
   6 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
   7 use rustc_hir::itemlikevisit::ItemLikeVisitor;
   8
   9 pub fn crate_inherent_impls_overlap_check(tcx: TyCtxt<'_>, crate_num: CrateNum) {
  10     assert_eq!(crate_num, LOCAL_CRATE);
  11     let krate = tcx.hir().krate();
  12     krate.visit_all_item_likes(&mut InherentOverlapChecker { tcx });
  13 }
  14
  15 struct InherentOverlapChecker<'tcx> {
  16     tcx: TyCtxt<'tcx>,
  17 }
  18
  19 impl InherentOverlapChecker<'tcx> {
  20     fn check_for_common_items_in_impls(
  21         &self,
  22         impl1: DefId,
  23         impl2: DefId,
  24         overlap: traits::OverlapResult<'_>,
  25     ) {
  26         let name_and_namespace = |def_id| {
  27             let item = self.tcx.associated_item(def_id);
  28             (item.ident.modern(), Namespace::from(item.kind))
  29         };
  30
  31         let impl_items1 = self.tcx.associated_item_def_ids(impl1);
  32         let impl_items2 = self.tcx.associated_item_def_ids(impl2);
  33
  34         for &item1 in &impl_items1[..] {
  35             let (name, namespace) = name_and_namespace(item1);
  36
  37             for &item2 in &impl_items2[..] {
  38                 if (name, namespace) == name_and_namespace(item2) {
  39                     let mut err = struct_span_err!(
  40                         self.tcx.sess,
  41                         self.tcx.span_of_impl(item1).unwrap(),
  42                         E0592,
  43                         "duplicate definitions with name `{}`",
  44                         name
  45                     );
  46                     err.span_label(
  47                         self.tcx.span_of_impl(item1).unwrap(),
  48                         format!("duplicate definitions for `{}`", name),
  49                     );
  50                     err.span_label(
  51                         self.tcx.span_of_impl(item2).unwrap(),
  52                         format!("other definition for `{}`", name),
  53                     );
  54
  55                     for cause in &overlap.intercrate_ambiguity_causes {
  56                         cause.add_intercrate_ambiguity_hint(&mut err);
  57                     }
  58
  59                     if overlap.involves_placeholder {
  60                         traits::add_placeholder_note(&mut err);
  61                     }
  62
  63                     err.emit();
  64                 }
  65             }
  66         }
  67     }
  68
  69     fn check_for_overlapping_inherent_impls(&self, ty_def_id: DefId) {
  70         let impls = self.tcx.inherent_impls(ty_def_id);
  71
  72         for (i, &impl1_def_id) in impls.iter().enumerate() {
  73             for &impl2_def_id in &impls[(i + 1)..] {
  74                 traits::overlapping_impls(
  75                     self.tcx,
  76                     impl1_def_id,
  77                     impl2_def_id,
  78                     IntercrateMode::Issue43355,
  79                     |overlap| {
  80                         self.check_for_common_items_in_impls(impl1_def_id, impl2_def_id, overlap);
  81                         false
  82                     },
  83                     || true,
  84                 );
  85             }
  86         }
  87     }
  88 }
  89
  90 impl ItemLikeVisitor<'v> for InherentOverlapChecker<'tcx> {
  91     fn visit_item(&mut self, item: &'v hir::Item<'v>) {
  92         match item.kind {
  93             hir::ItemKind::Enum(..)
  94             | hir::ItemKind::Struct(..)
  95             | hir::ItemKind::Trait(..)
  96             | hir::ItemKind::Union(..) => {
  97                 let type_def_id = self.tcx.hir().local_def_id(item.hir_id);
  98                 self.check_for_overlapping_inherent_impls(type_def_id);
  99             }
 100             _ => {}
 101         }
 102     }
 103
 104     fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'v>) {}
 105
 106     fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'v>) {}
 107 }