src/librustc_typeck/coherence/inherent_impls_overlap.rs

   1 use crate::namespace::Namespace;
   2 use errors::struct_span_err;
   3 use rustc::traits::{self, IntercrateMode};
   4 use rustc::ty::TyCtxt;
   5 use rustc_hir as hir;
   6 use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
   7 use rustc_hir::itemlikevisit::ItemLikeVisitor;
   8
   9 use rustc_error_codes::*;
  10
  11 pub fn crate_inherent_impls_overlap_check(tcx: TyCtxt<'_>, crate_num: CrateNum) {
  12     assert_eq!(crate_num, LOCAL_CRATE);
  13     let krate = tcx.hir().krate();
  14     krate.visit_all_item_likes(&mut InherentOverlapChecker { tcx });
  15 }
  16
  17 struct InherentOverlapChecker<'tcx> {
  18     tcx: TyCtxt<'tcx>,
  19 }
  20
  21 impl InherentOverlapChecker<'tcx> {
  22     fn check_for_common_items_in_impls(
  23         &self,
  24         impl1: DefId,
  25         impl2: DefId,
  26         overlap: traits::OverlapResult<'_>,
  27     ) {
  28         let name_and_namespace = |def_id| {
  29             let item = self.tcx.associated_item(def_id);
  30             (item.ident.modern(), Namespace::from(item.kind))
  31         };
  32
  33         let impl_items1 = self.tcx.associated_item_def_ids(impl1);
  34         let impl_items2 = self.tcx.associated_item_def_ids(impl2);
  35
  36         for &item1 in &impl_items1[..] {
  37             let (name, namespace) = name_and_namespace(item1);
  38
  39             for &item2 in &impl_items2[..] {
  40                 if (name, namespace) == name_and_namespace(item2) {
  41                     let mut err = struct_span_err!(
  42                         self.tcx.sess,
  43                         self.tcx.span_of_impl(item1).unwrap(),
  44                         E0592,
  45                         "duplicate definitions with name `{}`",
  46                         name
  47                     );
  48                     err.span_label(
  49                         self.tcx.span_of_impl(item1).unwrap(),
  50                         format!("duplicate definitions for `{}`", name),
  51                     );
  52                     err.span_label(
  53                         self.tcx.span_of_impl(item2).unwrap(),
  54                         format!("other definition for `{}`", name),
  55                     );
  56
  57                     for cause in &overlap.intercrate_ambiguity_causes {
  58                         cause.add_intercrate_ambiguity_hint(&mut err);
  59                     }
  60
  61                     if overlap.involves_placeholder {
  62                         traits::add_placeholder_note(&mut err);
  63                     }
  64
  65                     err.emit();
  66                 }
  67             }
  68         }
  69     }
  70
  71     fn check_for_overlapping_inherent_impls(&self, ty_def_id: DefId) {
  72         let impls = self.tcx.inherent_impls(ty_def_id);
  73
  74         for (i, &impl1_def_id) in impls.iter().enumerate() {
  75             for &impl2_def_id in &impls[(i + 1)..] {
  76                 traits::overlapping_impls(
  77                     self.tcx,
  78                     impl1_def_id,
  79                     impl2_def_id,
  80                     IntercrateMode::Issue43355,
  81                     |overlap| {
  82                         self.check_for_common_items_in_impls(impl1_def_id, impl2_def_id, overlap);
  83                         false
  84                     },
  85                     || true,
  86                 );
  87             }
  88         }
  89     }
  90 }
  91
  92 impl ItemLikeVisitor<'v> for InherentOverlapChecker<'tcx> {
  93     fn visit_item(&mut self, item: &'v hir::Item<'v>) {
  94         match item.kind {
  95             hir::ItemKind::Enum(..)
  96             | hir::ItemKind::Struct(..)
  97             | hir::ItemKind::Trait(..)
  98             | hir::ItemKind::Union(..) => {
  99                 let type_def_id = self.tcx.hir().local_def_id(item.hir_id);
 100                 self.check_for_overlapping_inherent_impls(type_def_id);
 101             }
 102             _ => {}
 103         }
 104     }
 105
 106     fn visit_trait_item(&mut self, _trait_item: &hir::TraitItem<'v>) {}
 107
 108     fn visit_impl_item(&mut self, _impl_item: &hir::ImplItem<'v>) {}
 109 }