Extend HIR to track the source of a type

Author: shepmaster

compiler/rustc_ast_lowering/src/delegation.rs

@@ -44,6 +44,7 @@ use hir::{BodyId, HirId};
 use rustc_abi::ExternAbi;
 use rustc_ast::*;
 use rustc_errors::ErrorGuaranteed;
+use rustc_hir::TySource;
 use rustc_hir::def_id::DefId;
 use rustc_middle::span_bug;
 use rustc_middle::ty::{Asyncness, ResolverAstLowering};
@@ -165,12 +166,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
             hir_id: self.next_id(),
             kind: hir::TyKind::InferDelegation(sig_id, hir::InferDelegationKind::Input(arg)),
             span,
+            source: TySource::Other,
         }));
 
         let output = self.arena.alloc(hir::Ty {
             hir_id: self.next_id(),
             kind: hir::TyKind::InferDelegation(sig_id, hir::InferDelegationKind::Output),
             span,
+            source: TySource::Other,
         });
 
         self.arena.alloc(hir::FnDecl {

compiler/rustc_ast_lowering/src/expr.rs

@@ -6,9 +6,8 @@ use rustc_ast::ptr::P as AstP;
 use rustc_ast::*;
 use rustc_ast_pretty::pprust::expr_to_string;
 use rustc_data_structures::stack::ensure_sufficient_stack;
-use rustc_hir as hir;
-use rustc_hir::HirId;
 use rustc_hir::def::{DefKind, Res};
+use rustc_hir::{self as hir, HirId, TySource};
 use rustc_middle::span_bug;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::errors::report_lit_error;
@@ -753,6 +752,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir_id: self.next_id(),
                     kind: hir::TyKind::Path(resume_ty),
                     span: unstable_span,
+                    source: TySource::Other,
                 };
                 let inputs = arena_vec![self; input_ty];
 

compiler/rustc_ast_lowering/src/lib.rs

@@ -56,6 +56,7 @@ use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId};
 use rustc_hir::{
     self as hir, ConstArg, GenericArg, HirId, ItemLocalMap, LangItem, ParamName, TraitCandidate,
+    TySource,
 };
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_macros::extension;
@@ -1165,7 +1166,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 bounds,
                 TaggedRef::new(lifetime_bound, TraitObjectSyntax::None),
             );
-            return hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.next_id() };
+            return hir::Ty {
+                kind,
+                span: self.lower_span(t.span),
+                hir_id: self.next_id(),
+                source: TySource::Other,
+            };
         }
 
         let id = self.lower_node_id(t.id);
@@ -1182,7 +1188,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
     }
 
     fn ty(&mut self, span: Span, kind: hir::TyKind<'hir>) -> hir::Ty<'hir> {
-        hir::Ty { hir_id: self.next_id(), kind, span: self.lower_span(span) }
+        hir::Ty {
+            hir_id: self.next_id(),
+            kind,
+            span: self.lower_span(span),
+            source: TySource::Other,
+        }
     }
 
     fn ty_tup(&mut self, span: Span, tys: &'hir [hir::Ty<'hir>]) -> hir::Ty<'hir> {
@@ -1227,7 +1238,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 let lifetime = self.lower_lifetime(&region);
                 let kind = hir::TyKind::Ref(lifetime, self.lower_mt(mt, itctx));
                 let span = self.lower_span(t.span);
-                let arg = hir::Ty { kind, span, hir_id: self.next_id() };
+                let arg = hir::Ty { kind, span, hir_id: self.next_id(), source: TySource::Other };
                 let args = self.arena.alloc(hir::GenericArgs {
                     args: self.arena.alloc([hir::GenericArg::Type(self.arena.alloc(arg))]),
                     constraints: &[],
@@ -1388,7 +1399,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             TyKind::Dummy => panic!("`TyKind::Dummy` should never be lowered"),
         };
 
-        hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.lower_node_id(t.id) }
+        hir::Ty {
+            kind,
+            span: self.lower_span(t.span),
+            hir_id: self.lower_node_id(t.id),
+            source: TySource::Other,
+        }
     }
 
     /// Lowers a `ReturnPositionOpaqueTy` (`-> impl Trait`) or a `TypeAliasesOpaqueTy` (`type F =
@@ -2354,7 +2370,17 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         }
     }
 
-    fn ty_path(&mut self, mut hir_id: HirId, span: Span, qpath: hir::QPath<'hir>) -> hir::Ty<'hir> {
+    fn ty_path(&mut self, hir_id: HirId, span: Span, qpath: hir::QPath<'hir>) -> hir::Ty<'hir> {
+        self.ty_path_with_source(hir_id, span, qpath, TySource::Other)
+    }
+
+    fn ty_path_with_source(
+        &mut self,
+        mut hir_id: HirId,
+        span: Span,
+        qpath: hir::QPath<'hir>,
+        source: TySource,
+    ) -> hir::Ty<'hir> {
         let kind = match qpath {
             hir::QPath::Resolved(None, path) => {
                 // Turn trait object paths into `TyKind::TraitObject` instead.
@@ -2381,7 +2407,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             _ => hir::TyKind::Path(qpath),
         };
 
-        hir::Ty { hir_id, kind, span: self.lower_span(span) }
+        hir::Ty { hir_id, kind, span: self.lower_span(span), source }
     }
 
     /// Invoked to create the lifetime argument(s) for an elided trait object

compiler/rustc_ast_lowering/src/path.rs

@@ -1,10 +1,9 @@
 use std::sync::Arc;
 
 use rustc_ast::{self as ast, *};
-use rustc_hir as hir;
-use rustc_hir::GenericArg;
 use rustc_hir::def::{DefKind, PartialRes, Res};
 use rustc_hir::def_id::DefId;
+use rustc_hir::{self as hir, GenericArg, TySource};
 use rustc_middle::span_bug;
 use rustc_session::parse::add_feature_diagnostics;
 use rustc_span::{BytePos, DUMMY_SP, DesugaringKind, Ident, Span, Symbol, kw, sym};
@@ -170,7 +169,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             // e.g., `Vec` in `Vec::new` or `<I as Iterator>::Item` in
             // `<I as Iterator>::Item::default`.
             let new_id = self.next_id();
-            self.arena.alloc(self.ty_path(new_id, path.span, hir::QPath::Resolved(qself, path)))
+            self.arena.alloc(self.ty_path_with_source(
+                new_id,
+                path.span,
+                hir::QPath::Resolved(qself, path),
+                TySource::ImplicitSelf,
+            ))
         };
 
         // Anything after the base path are associated "extensions",

compiler/rustc_hir/src/hir.rs

@@ -373,7 +373,12 @@ pub struct InferArg {
 
 impl InferArg {
     pub fn to_ty(&self) -> Ty<'static> {
-        Ty { kind: TyKind::Infer(()), span: self.span, hir_id: self.hir_id }
+        Ty {
+            kind: TyKind::Infer(()),
+            span: self.span,
+            hir_id: self.hir_id,
+            source: TySource::Other,
+        }
     }
 }
 
@@ -3120,6 +3125,12 @@ impl<'hir> AssocItemConstraintKind<'hir> {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, HashStable_Generic)]
+pub enum TySource {
+    ImplicitSelf,
+    Other,
+}
+
 /// An uninhabited enum used to make `Infer` variants on [`Ty`] and [`ConstArg`] be
 /// unreachable. Zero-Variant enums are guaranteed to have the same layout as the never
 /// type.
@@ -3139,6 +3150,7 @@ pub struct Ty<'hir, Unambig = ()> {
     pub hir_id: HirId,
     pub span: Span,
     pub kind: TyKind<'hir, Unambig>,
+    pub source: TySource,
 }
 
 impl<'hir> Ty<'hir, AmbigArg> {
@@ -4837,7 +4849,7 @@ mod size_asserts {
     static_assert_size!(StmtKind<'_>, 16);
     static_assert_size!(TraitItem<'_>, 88);
     static_assert_size!(TraitItemKind<'_>, 48);
-    static_assert_size!(Ty<'_>, 48);
+    static_assert_size!(Ty<'_>, 56);
     static_assert_size!(TyKind<'_>, 32);
     // tidy-alphabetical-end
 }

compiler/rustc_hir/src/hir/tests.rs

@@ -20,10 +20,10 @@ macro_rules! define_tests {
 
 define_tests! {
     cast_never TyKind Never {}
-    cast_tup TyKind Tup { 0: &[Ty { span: DUMMY_SP, hir_id: HirId::INVALID, kind: TyKind::Never }] }
-    cast_ptr TyKind Ptr { 0: MutTy { ty: &Ty { span: DUMMY_SP, hir_id: HirId::INVALID, kind: TyKind::Never }, mutbl: Mutability::Not }}
+    cast_tup TyKind Tup { 0: &[Ty { span: DUMMY_SP, hir_id: HirId::INVALID, kind: TyKind::Never, source: TySource::Other }] }
+    cast_ptr TyKind Ptr { 0: MutTy { ty: &Ty { span: DUMMY_SP, hir_id: HirId::INVALID, kind: TyKind::Never, source: TySource::Other }, mutbl: Mutability::Not }}
     cast_array TyKind Array {
-        0: &Ty { span: DUMMY_SP, hir_id: HirId::INVALID, kind: TyKind::Never },
+        0: &Ty { span: DUMMY_SP, hir_id: HirId::INVALID, kind: TyKind::Never, source: TySource::Other },
         1: &ConstArg { hir_id: HirId::INVALID, kind: ConstArgKind::Anon(&AnonConst {
             hir_id: HirId::INVALID,
             def_id: LocalDefId { local_def_index: DefIndex::ZERO },

src/librustdoc/clean/mod.rs

@@ -1677,7 +1677,7 @@ fn first_non_private<'tcx>(
 }
 
 fn clean_qpath<'tcx>(hir_ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> Type {
-    let hir::Ty { hir_id, span, ref kind } = *hir_ty;
+    let hir::Ty { hir_id, span, ref kind, source: _ } = *hir_ty;
     let hir::TyKind::Path(qpath) = kind else { unreachable!() };
 
     match qpath {