compiler/rustc_ty_utils/src/implied_bounds.rs

   1 use crate::rustc_middle::ty::DefIdTree;
   2 use rustc_hir::{self as hir, def::DefKind, def_id::DefId};
   3 use rustc_middle::ty::{self, Ty, TyCtxt};
   4 use rustc_span::{Span, DUMMY_SP};
   5
   6 pub fn provide(providers: &mut ty::query::Providers) {
   7     *providers = ty::query::Providers { assumed_wf_types, ..*providers };
   8 }
   9
  10 fn assumed_wf_types(tcx: TyCtxt<'_>, def_id: DefId) -> &[(Ty<'_>, Span)] {
  11     match tcx.def_kind(def_id) {
  12         DefKind::Fn => {
  13             let sig = tcx.fn_sig(def_id);
  14             let liberated_sig = tcx.liberate_late_bound_regions(def_id, sig);
  15             if let Some(node) = tcx.hir().get_if_local(def_id)
  16                 && let Some(decl) = node.fn_decl()
  17             {
  18                 assert_eq!(decl.inputs.len(), liberated_sig.inputs().len());
  19                 tcx.arena.alloc_from_iter(std::iter::zip(
  20                     liberated_sig.inputs_and_output,
  21                     decl.inputs.iter().map(|ty| ty.span).chain([decl.output.span()]),
  22                 ))
  23             } else {
  24                 tcx.arena.alloc_from_iter(
  25                     liberated_sig.inputs_and_output.iter().map(|ty| (ty, DUMMY_SP)),
  26                 )
  27             }
  28         }
  29         DefKind::AssocFn => {
  30             let sig = tcx.fn_sig(def_id);
  31             let liberated_sig = tcx.liberate_late_bound_regions(def_id, sig);
  32             let assumed_wf_types = tcx.assumed_wf_types(tcx.parent(def_id));
  33             if let Some(node) = tcx.hir().get_if_local(def_id)
  34                 && let Some(decl) = node.fn_decl()
  35             {
  36                 assert_eq!(decl.inputs.len(), liberated_sig.inputs().len());
  37                 tcx.arena.alloc_from_iter(assumed_wf_types.iter().copied().chain(std::iter::zip(
  38                     liberated_sig.inputs_and_output,
  39                     decl.inputs.iter().map(|ty| ty.span).chain([decl.output.span()]),
  40                 )))
  41             } else {
  42                 tcx.arena.alloc_from_iter(assumed_wf_types.iter().copied().chain(
  43                     liberated_sig.inputs_and_output.iter().map(|ty| (ty, DUMMY_SP)),
  44                 ))
  45             }
  46         }
  47         DefKind::Impl => match tcx.impl_trait_ref(def_id) {
  48             Some(trait_ref) => {
  49                 let types: Vec<_> = trait_ref.substs.types().collect();
  50                 let self_span = if let Some(hir::Node::Item(hir::Item {
  51                     kind: hir::ItemKind::Impl(impl_),
  52                     ..
  53                 })) = tcx.hir().get_if_local(def_id)
  54                 {
  55                     impl_.self_ty.span
  56                 } else {
  57                     DUMMY_SP
  58                 };
  59                 tcx.arena.alloc_from_iter(std::iter::zip(
  60                     types,
  61                     // FIXME: reliable way of getting trait ref substs...
  62                     [self_span].into_iter().chain(std::iter::repeat(DUMMY_SP)),
  63                 ))
  64             }
  65             // Only the impl self type
  66             None => {
  67                 let span = if let Some(hir::Node::Item(hir::Item {
  68                     kind: hir::ItemKind::Impl(impl_),
  69                     ..
  70                 })) = tcx.hir().get_if_local(def_id)
  71                 {
  72                     impl_.self_ty.span
  73                 } else {
  74                     DUMMY_SP
  75                 };
  76                 tcx.arena.alloc_from_iter([(tcx.type_of(def_id), span)])
  77             }
  78         },
  79         DefKind::AssocConst | DefKind::AssocTy => tcx.assumed_wf_types(tcx.parent(def_id)),
  80         DefKind::Mod
  81         | DefKind::Struct
  82         | DefKind::Union
  83         | DefKind::Enum
  84         | DefKind::Variant
  85         | DefKind::Trait
  86         | DefKind::TyAlias
  87         | DefKind::ForeignTy
  88         | DefKind::TraitAlias
  89         | DefKind::TyParam
  90         | DefKind::Const
  91         | DefKind::ConstParam
  92         | DefKind::Static(_)
  93         | DefKind::Ctor(_, _)
  94         | DefKind::Macro(_)
  95         | DefKind::ExternCrate
  96         | DefKind::Use
  97         | DefKind::ForeignMod
  98         | DefKind::AnonConst
  99         | DefKind::InlineConst
 100         | DefKind::OpaqueTy
 101         | DefKind::ImplTraitPlaceholder
 102         | DefKind::Field
 103         | DefKind::LifetimeParam
 104         | DefKind::GlobalAsm
 105         | DefKind::Closure
 106         | DefKind::Generator => &[],
 107     }
 108 }