demand_base_struct

Author: SparrowLii

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -113,6 +113,260 @@ fn adt_destructor(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::Destructor> {
     tcx.calculate_dtor(def_id, dropck::check_drop_impl)
 }
 
+/// If this `DefId` is a "primary tables entry", returns
+/// `Some((body_id, body_ty, fn_sig))`. Otherwise, returns `None`.
+///
+/// If this function returns `Some`, then `typeck_results(def_id)` will
+/// succeed; if it returns `None`, then `typeck_results(def_id)` may or
+/// may not succeed. In some cases where this function returns `None`
+/// (notably closures), `typeck_results(def_id)` would wind up
+/// redirecting to the owning function.
+fn primary_body_of(
+    tcx: TyCtxt<'_>,
+    id: hir::HirId,
+) -> Option<(hir::BodyId, Option<&hir::Ty<'_>>, Option<&hir::FnSig<'_>>)> {
+    match tcx.hir().get(id) {
+        Node::Item(item) => match item.kind {
+            hir::ItemKind::Const(ty, body) | hir::ItemKind::Static(ty, _, body) => {
+                Some((body, Some(ty), None))
+            }
+            hir::ItemKind::Fn(ref sig, .., body) => Some((body, None, Some(sig))),
+            _ => None,
+        },
+        Node::TraitItem(item) => match item.kind {
+            hir::TraitItemKind::Const(ty, Some(body)) => Some((body, Some(ty), None)),
+            hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
+                Some((body, None, Some(sig)))
+            }
+            _ => None,
+        },
+        Node::ImplItem(item) => match item.kind {
+            hir::ImplItemKind::Const(ty, body) => Some((body, Some(ty), None)),
+            hir::ImplItemKind::Fn(ref sig, body) => Some((body, None, Some(sig))),
+            _ => None,
+        },
+        Node::AnonConst(constant) => Some((constant.body, None, None)),
+        _ => None,
+    }
+}
+
+fn has_typeck_results(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
+    // Closures' typeck results come from their outermost function,
+    // as they are part of the same "inference environment".
+    let typeck_root_def_id = tcx.typeck_root_def_id(def_id);
+    if typeck_root_def_id != def_id {
+        return tcx.has_typeck_results(typeck_root_def_id);
+    }
+
+    if let Some(def_id) = def_id.as_local() {
+        let id = tcx.hir().local_def_id_to_hir_id(def_id);
+        primary_body_of(tcx, id).is_some()
+    } else {
+        false
+    }
+}
+
+fn used_trait_imports(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &FxHashSet<LocalDefId> {
+    &*tcx.typeck(def_id).used_trait_imports
+}
+
+fn typeck_const_arg<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    (did, param_did): (LocalDefId, DefId),
+) -> &ty::TypeckResults<'tcx> {
+    let fallback = move || tcx.type_of(param_did);
+    typeck_with_fallback(tcx, did, fallback)
+}
+
+fn typeck<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::TypeckResults<'tcx> {
+    if let Some(param_did) = tcx.opt_const_param_of(def_id) {
+        tcx.typeck_const_arg((def_id, param_did))
+    } else {
+        let fallback = move || tcx.type_of(def_id.to_def_id());
+        typeck_with_fallback(tcx, def_id, fallback)
+    }
+}
+
+/// Used only to get `TypeckResults` for type inference during error recovery.
+/// Currently only used for type inference of `static`s and `const`s to avoid type cycle errors.
+fn diagnostic_only_typeck<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &ty::TypeckResults<'tcx> {
+    let fallback = move || {
+        let span = tcx.hir().span(tcx.hir().local_def_id_to_hir_id(def_id));
+        tcx.ty_error_with_message(span, "diagnostic only typeck table used")
+    };
+    typeck_with_fallback(tcx, def_id, fallback)
+}
+
+fn typeck_with_fallback<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    def_id: LocalDefId,
+    fallback: impl Fn() -> Ty<'tcx> + 'tcx,
+) -> &'tcx ty::TypeckResults<'tcx> {
+    // Closures' typeck results come from their outermost function,
+    // as they are part of the same "inference environment".
+    let typeck_root_def_id = tcx.typeck_root_def_id(def_id.to_def_id()).expect_local();
+    if typeck_root_def_id != def_id {
+        return tcx.typeck(typeck_root_def_id);
+    }
+
+    let id = tcx.hir().local_def_id_to_hir_id(def_id);
+    let span = tcx.hir().span(id);
+
+    // Figure out what primary body this item has.
+    let (body_id, body_ty, fn_sig) = primary_body_of(tcx, id).unwrap_or_else(|| {
+        span_bug!(span, "can't type-check body of {:?}", def_id);
+    });
+    let body = tcx.hir().body(body_id);
+
+    let typeck_results = Inherited::build(tcx, def_id).enter(|inh| {
+        let param_env = tcx.param_env(def_id);
+        let mut fcx = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
+            let fn_sig = if crate::collect::get_infer_ret_ty(&decl.output).is_some() {
+                let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
+                <dyn AstConv<'_>>::ty_of_fn(&fcx, id, header.unsafety, header.abi, decl, None, None)
+            } else {
+                tcx.fn_sig(def_id)
+            };
+
+            check_abi(tcx, id, span, fn_sig.abi());
+
+            // Compute the function signature from point of view of inside the fn.
+            let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig);
+            let fn_sig = inh.normalize_associated_types_in(
+                body.value.span,
+                body_id.hir_id,
+                param_env,
+                fn_sig,
+            );
+            check_fn(&inh, param_env, fn_sig, decl, id, body, None, true).0
+        } else {
+            let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
+            let expected_type = body_ty
+                .and_then(|ty| match ty.kind {
+                    hir::TyKind::Infer => Some(<dyn AstConv<'_>>::ast_ty_to_ty(&fcx, ty)),
+                    _ => None,
+                })
+                .unwrap_or_else(|| match tcx.hir().get(id) {
+                    Node::AnonConst(_) => match tcx.hir().get(tcx.hir().get_parent_node(id)) {
+                        Node::Expr(&hir::Expr {
+                            kind: hir::ExprKind::ConstBlock(ref anon_const),
+                            ..
+                        }) if anon_const.hir_id == id => fcx.next_ty_var(TypeVariableOrigin {
+                            kind: TypeVariableOriginKind::TypeInference,
+                            span,
+                        }),
+                        Node::Ty(&hir::Ty {
+                            kind: hir::TyKind::Typeof(ref anon_const), ..
+                        }) if anon_const.hir_id == id => fcx.next_ty_var(TypeVariableOrigin {
+                            kind: TypeVariableOriginKind::TypeInference,
+                            span,
+                        }),
+                        Node::Expr(&hir::Expr { kind: hir::ExprKind::InlineAsm(asm), .. })
+                        | Node::Item(&hir::Item { kind: hir::ItemKind::GlobalAsm(asm), .. }) => {
+                            let operand_ty = asm
+                                .operands
+                                .iter()
+                                .filter_map(|(op, _op_sp)| match op {
+                                    hir::InlineAsmOperand::Const { anon_const }
+                                        if anon_const.hir_id == id =>
+                                    {
+                                        // Inline assembly constants must be integers.
+                                        Some(fcx.next_int_var())
+                                    }
+                                    hir::InlineAsmOperand::SymFn { anon_const }
+                                        if anon_const.hir_id == id =>
+                                    {
+                                        Some(fcx.next_ty_var(TypeVariableOrigin {
+                                            kind: TypeVariableOriginKind::MiscVariable,
+                                            span,
+                                        }))
+                                    }
+                                    _ => None,
+                                })
+                                .next();
+                            operand_ty.unwrap_or_else(fallback)
+                        }
+                        _ => fallback(),
+                    },
+                    _ => fallback(),
+                });
+
+            let expected_type = fcx.normalize_associated_types_in(body.value.span, expected_type);
+            fcx.require_type_is_sized(expected_type, body.value.span, traits::ConstSized);
+
+            // Gather locals in statics (because of block expressions).
+            GatherLocalsVisitor::new(&fcx).visit_body(body);
+
+            fcx.check_expr_coercable_to_type(&body.value, expected_type, None);
+
+            fcx.write_ty(id, expected_type);
+
+            fcx
+        };
+
+        let fallback_has_occurred = fcx.type_inference_fallback();
+
+        // Even though coercion casts provide type hints, we check casts after fallback for
+        // backwards compatibility. This makes fallback a stronger type hint than a cast coercion.
+        fcx.check_casts();
+        fcx.select_obligations_where_possible(fallback_has_occurred, |_| {});
+
+        // Closure and generator analysis may run after fallback
+        // because they don't constrain other type variables.
+        // Closure analysis only runs on closures. Therefore they only need to fulfill non-const predicates (as of now)
+        let prev_constness = fcx.param_env.constness();
+        fcx.param_env = fcx.param_env.without_const();
+        fcx.closure_analyze(body);
+        fcx.param_env = fcx.param_env.with_constness(prev_constness);
+        assert!(fcx.deferred_call_resolutions.borrow().is_empty());
+        // Before the generator analysis, temporary scopes shall be marked to provide more
+        // precise information on types to be captured.
+        fcx.resolve_rvalue_scopes(def_id.to_def_id());
+        fcx.resolve_generator_interiors(def_id.to_def_id());
+
+        for (ty, span, code) in fcx.deferred_sized_obligations.borrow_mut().drain(..) {
+            let ty = fcx.normalize_ty(span, ty);
+            fcx.require_type_is_sized(ty, span, code);
+        }
+
+        fcx.resolve_base_expr();
+
+        fcx.select_all_obligations_or_error();
+
+        if !fcx.infcx.is_tainted_by_errors() {
+            fcx.check_transmutes();
+        }
+
+        fcx.check_asms();
+
+        fcx.infcx.skip_region_resolution();
+
+        fcx.resolve_type_vars_in_body(body)
+    });
+
+    // Consistency check our TypeckResults instance can hold all ItemLocalIds
+    // it will need to hold.
+    assert_eq!(typeck_results.hir_owner, id.owner);
+
+    typeck_results
+}
+
+/// When `check_fn` is invoked on a generator (i.e., a body that
+/// includes yield), it returns back some information about the yield
+/// points.
+struct GeneratorTypes<'tcx> {
+    /// Type of generator argument / values returned by `yield`.
+    resume_ty: Ty<'tcx>,
+
+    /// Type of value that is yielded.
+    yield_ty: Ty<'tcx>,
+
+    /// Types that are captured (see `GeneratorInterior` for more).
+    interior: Ty<'tcx>,
+
+    /// Indicates if the generator is movable or static (immovable).
+    movability: hir::Movability,
+}
 /// Given a `DefId` for an opaque type in return position, find its parent item's return
 /// expressions.
 fn get_owner_return_paths<'tcx>(

compiler/rustc_hir_typeck/src/demand.rs

@@ -174,6 +174,22 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         (expected, Some(err))
     }
 
+    #[instrument(skip(self), level = "debug")]
+    pub fn demand_base_struct(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        expected: Ty<'tcx>,
+        actual: Ty<'tcx>,
+    ) -> Option<DiagnosticBuilder<'tcx, ErrorGuaranteed>> {
+        match self.at(cause, self.param_env).base_struct(expected, actual) {
+            Ok(InferOk { obligations, value: () }) => {
+                self.register_predicates(obligations);
+                None
+            }
+            Err(e) => Some(self.report_mismatched_types(&cause, expected, actual, e)),
+        }
+    }
+
     fn annotate_expected_due_to_let_ty(
         &self,
         err: &mut Diagnostic,

compiler/rustc_hir_typeck/src/expr.rs

@@ -39,7 +39,6 @@ use rustc_infer::infer::InferOk;
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::middle::stability;
 use rustc_middle::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase};
-use rustc_middle::ty::error::TypeError::FieldMisMatch;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::{self, AdtKind, Ty, TypeVisitable};
 use rustc_session::errors::ExprParenthesesNeeded;
@@ -1677,8 +1676,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                                 fru_ty,
                                                 FieldMisMatch(variant.name, ident.name),
                                             )
-                                            .emit();
-                                    }
+                                            .emit();                                    }
                                 }
                             }
                             self.resolve_vars_if_possible(fru_ty)
@@ -1705,9 +1703,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let fresh_base_ty = self.tcx.mk_adt(*adt, fresh_substs);
                     self.check_expr_has_type_or_error(
                         base_expr,
-                        self.resolve_vars_if_possible(fresh_base_ty),
+                        fresh_base_ty,
                         |_| {},
                     );
+                    self.typeck_results.borrow_mut().base_expr_backup_mut().insert(base_expr.hir_id, (fresh_base_ty, adt_ty));
                     fru_tys
                 } else {
                     // Check the base_expr, regardless of a bad expected adt_ty, so we can get

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -605,6 +605,19 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub(in super::super) fn resolve_base_expr(&self) {
+        for (_, (base_ty, adt_ty)) in self.typeck_results.borrow().base_expr_backup().iter() {
+            let base_ty = self.resolve_vars_if_possible(*base_ty);
+            if base_ty.has_infer_types() {
+                if let Some(mut err) =
+                    self.demand_base_struct(&self.misc(DUMMY_SP), *adt_ty, base_ty)
+                {
+                    err.emit();
+                }
+            }
+        }
+    }
+
     #[instrument(skip(self), level = "debug")]
     pub(in super::super) fn select_all_obligations_or_error(&self) {
         let mut errors = self.fulfillment_cx.borrow_mut().select_all_or_error(&self);

compiler/rustc_infer/src/infer/at.rs

@@ -218,6 +218,17 @@ impl<'a, 'tcx> At<'a, 'tcx> {
         self.trace(expected, actual).glb(expected, actual)
     }
 
+    pub fn base_struct<T>(
+        self,
+        expected: T,
+        actual: T,
+    ) -> InferResult<'tcx, ()>
+    where
+        T: ToTrace<'tcx>,
+    {
+        self.trace(expected, actual).base_struct(expected, actual)
+    }
+
     /// Sets the "trace" values that will be used for
     /// error-reporting, but doesn't actually perform any operation
     /// yet (this is useful when you want to set the trace using
@@ -259,6 +270,21 @@ impl<'a, 'tcx> Trace<'a, 'tcx> {
         })
     }
 
+    #[instrument(skip(self), level = "debug")]
+    pub fn base_struct<T>(self, a: T, b: T) -> InferResult<'tcx, ()>
+        where
+            T: Relate<'tcx>,
+    {
+        let Trace { at, trace, a_is_expected } = self;
+        at.infcx.commit_if_ok(|_| {
+            let mut fields = at.infcx.combine_fields(trace, at.param_env, at.define_opaque_types);
+            fields
+                .base_struct(a_is_expected)
+                .relate(a, b)
+                .map(move |_| InferOk { value: (), obligations: fields.obligations })
+        })
+    }
+
     /// Makes `a == b`; the expectation is set by the call to
     /// `trace()`.
     #[instrument(skip(self), level = "debug")]