Make rustc::traits::object_safety::{astconv_object_safety_violations,is_vtable_safe_method,object_safety_violations} free functions.

Author: cjgillot

src/librustc/infer/error_reporting/mod.rs

@@ -54,6 +54,7 @@ use crate::infer::opaque_types;
 use crate::infer::{self, SuppressRegionErrors};
 use crate::middle::region;
 use crate::traits::error_reporting::report_object_safety_error;
+use crate::traits::object_safety_violations;
 use crate::traits::{
     IfExpressionCause, MatchExpressionArmCause, ObligationCause, ObligationCauseCode,
 };
@@ -1487,7 +1488,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let failure_code = trace.cause.as_failure_code(terr);
         let mut diag = match failure_code {
             FailureCode::Error0038(did) => {
-                let violations = self.tcx.object_safety_violations(did);
+                let violations = object_safety_violations(self.tcx, did);
                 report_object_safety_error(self.tcx, span, did, violations)
             }
             FailureCode::Error0317(failure_str) => {

src/librustc/traits/error_reporting.rs

@@ -11,6 +11,7 @@ use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
 use crate::infer::{self, InferCtxt};
 use crate::mir::interpret::ErrorHandled;
 use crate::session::DiagnosticMessageId;
+use crate::traits::object_safety_violations;
 use crate::ty::error::ExpectedFound;
 use crate::ty::fast_reject;
 use crate::ty::fold::TypeFolder;
@@ -915,7 +916,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                     }
 
                     ty::Predicate::ObjectSafe(trait_def_id) => {
-                        let violations = self.tcx.object_safety_violations(trait_def_id);
+                        let violations = object_safety_violations(self.tcx, trait_def_id);
                         report_object_safety_error(self.tcx, span, trait_def_id, violations)
                     }
 
@@ -1079,7 +1080,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             }
 
             TraitNotObjectSafe(did) => {
-                let violations = self.tcx.object_safety_violations(did);
+                let violations = object_safety_violations(self.tcx, did);
                 report_object_safety_error(self.tcx, span, did, violations)
             }
 

src/librustc/traits/mod.rs

@@ -47,6 +47,9 @@ pub use self::coherence::{add_placeholder_note, orphan_check, overlapping_impls}
 pub use self::coherence::{OrphanCheckErr, OverlapResult};
 pub use self::engine::{TraitEngine, TraitEngineExt};
 pub use self::fulfill::{FulfillmentContext, PendingPredicateObligation};
+pub use self::object_safety::astconv_object_safety_violations;
+pub use self::object_safety::is_vtable_safe_method;
+pub use self::object_safety::object_safety_violations;
 pub use self::object_safety::MethodViolationCode;
 pub use self::object_safety::ObjectSafetyViolation;
 pub use self::on_unimplemented::{OnUnimplementedDirective, OnUnimplementedNote};
@@ -1062,7 +1065,7 @@ fn vtable_methods<'tcx>(
             let def_id = trait_method.def_id;
 
             // Some methods cannot be called on an object; skip those.
-            if !tcx.is_vtable_safe_method(trait_ref.def_id(), &trait_method) {
+            if !is_vtable_safe_method(tcx, trait_ref.def_id(), &trait_method) {
                 debug!("vtable_methods: not vtable safe");
                 return None;
             }

src/librustc/traits/object_safety.rs

@@ -108,54 +108,52 @@ pub enum MethodViolationCode {
     UndispatchableReceiver,
 }
 
-impl<'tcx> TyCtxt<'tcx> {
-    /// Returns the object safety violations that affect
-    /// astconv -- currently, `Self` in supertraits. This is needed
-    /// because `object_safety_violations` can't be used during
-    /// type collection.
-    pub fn astconv_object_safety_violations(
-        self,
-        trait_def_id: DefId,
-    ) -> Vec<ObjectSafetyViolation> {
-        debug_assert!(self.generics_of(trait_def_id).has_self);
-        let violations = traits::supertrait_def_ids(self, trait_def_id)
-            .filter(|&def_id| predicates_reference_self(self, def_id, true))
-            .map(|_| ObjectSafetyViolation::SupertraitSelf)
-            .collect();
+/// Returns the object safety violations that affect
+/// astconv -- currently, `Self` in supertraits. This is needed
+/// because `object_safety_violations` can't be used during
+/// type collection.
+pub fn astconv_object_safety_violations(
+    tcx: TyCtxt<'_>,
+    trait_def_id: DefId,
+) -> Vec<ObjectSafetyViolation> {
+    debug_assert!(tcx.generics_of(trait_def_id).has_self);
+    let violations = traits::supertrait_def_ids(tcx, trait_def_id)
+        .filter(|&def_id| predicates_reference_self(tcx, def_id, true))
+        .map(|_| ObjectSafetyViolation::SupertraitSelf)
+        .collect();
 
-        debug!(
-            "astconv_object_safety_violations(trait_def_id={:?}) = {:?}",
-            trait_def_id, violations
-        );
+    debug!("astconv_object_safety_violations(trait_def_id={:?}) = {:?}", trait_def_id, violations);
 
-        violations
-    }
+    violations
+}
+
+pub fn object_safety_violations(
+    tcx: TyCtxt<'_>,
+    trait_def_id: DefId,
+) -> Vec<ObjectSafetyViolation> {
+    debug_assert!(tcx.generics_of(trait_def_id).has_self);
+    debug!("object_safety_violations: {:?}", trait_def_id);
 
-    pub fn object_safety_violations(self, trait_def_id: DefId) -> Vec<ObjectSafetyViolation> {
-        debug_assert!(self.generics_of(trait_def_id).has_self);
-        debug!("object_safety_violations: {:?}", trait_def_id);
+    traits::supertrait_def_ids(tcx, trait_def_id)
+        .flat_map(|def_id| object_safety_violations_for_trait(tcx, def_id))
+        .collect()
+}
 
-        traits::supertrait_def_ids(self, trait_def_id)
-            .flat_map(|def_id| object_safety_violations_for_trait(self, def_id))
-            .collect()
+/// We say a method is *vtable safe* if it can be invoked on a trait
+/// object. Note that object-safe traits can have some
+/// non-vtable-safe methods, so long as they require `Self: Sized` or
+/// otherwise ensure that they cannot be used when `Self = Trait`.
+pub fn is_vtable_safe_method(tcx: TyCtxt<'_>, trait_def_id: DefId, method: &ty::AssocItem) -> bool {
+    debug_assert!(tcx.generics_of(trait_def_id).has_self);
+    debug!("is_vtable_safe_method({:?}, {:?})", trait_def_id, method);
+    // Any method that has a `Self: Sized` bound cannot be called.
+    if generics_require_sized_self(tcx, method.def_id) {
+        return false;
     }
 
-    /// We say a method is *vtable safe* if it can be invoked on a trait
-    /// object. Note that object-safe traits can have some
-    /// non-vtable-safe methods, so long as they require `Self: Sized` or
-    /// otherwise ensure that they cannot be used when `Self = Trait`.
-    pub fn is_vtable_safe_method(self, trait_def_id: DefId, method: &ty::AssocItem) -> bool {
-        debug_assert!(self.generics_of(trait_def_id).has_self);
-        debug!("is_vtable_safe_method({:?}, {:?})", trait_def_id, method);
-        // Any method that has a `Self: Sized` bound cannot be called.
-        if generics_require_sized_self(self, method.def_id) {
-            return false;
-        }
-
-        match virtual_call_violation_for_method(self, trait_def_id, method) {
-            None | Some(MethodViolationCode::WhereClauseReferencesSelf) => true,
-            Some(_) => false,
-        }
+    match virtual_call_violation_for_method(tcx, trait_def_id, method) {
+        None | Some(MethodViolationCode::WhereClauseReferencesSelf) => true,
+        Some(_) => false,
     }
 }
 
@@ -724,5 +722,5 @@ fn contains_illegal_self_type_reference<'tcx>(
 }
 
 pub(super) fn is_object_safe_provider(tcx: TyCtxt<'_>, trait_def_id: DefId) -> bool {
-    tcx.object_safety_violations(trait_def_id).is_empty()
+    object_safety_violations(tcx, trait_def_id).is_empty()
 }

src/librustc_typeck/astconv.rs

@@ -13,6 +13,7 @@ use errors::{Applicability, DiagnosticId};
 use rustc::hir::intravisit::Visitor;
 use rustc::lint::builtin::AMBIGUOUS_ASSOCIATED_ITEMS;
 use rustc::traits;
+use rustc::traits::astconv_object_safety_violations;
 use rustc::traits::error_reporting::report_object_safety_error;
 use rustc::ty::subst::{self, InternalSubsts, Subst, SubstsRef};
 use rustc::ty::wf::object_region_bounds;
@@ -1453,7 +1454,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         // to avoid ICEs.
         for item in &regular_traits {
             let object_safety_violations =
-                tcx.astconv_object_safety_violations(item.trait_ref().def_id());
+                astconv_object_safety_violations(tcx, item.trait_ref().def_id());
             if !object_safety_violations.is_empty() {
                 report_object_safety_error(
                     tcx,

src/librustc_typeck/check/cast.rs

@@ -38,6 +38,7 @@ use rustc::middle::lang_items;
 use rustc::session::Session;
 use rustc::traits;
 use rustc::traits::error_reporting::report_object_safety_error;
+use rustc::traits::object_safety_violations;
 use rustc::ty::adjustment::AllowTwoPhase;
 use rustc::ty::cast::{CastKind, CastTy};
 use rustc::ty::error::TypeError;
@@ -519,7 +520,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
     }
 
     fn report_object_unsafe_cast(&self, fcx: &FnCtxt<'a, 'tcx>, did: DefId) {
-        let violations = fcx.tcx.object_safety_violations(did);
+        let violations = object_safety_violations(fcx.tcx, did);
         let mut err = report_object_safety_error(fcx.tcx, self.cast_span, did, violations);
         err.note(&format!("required by cast to type '{}'", fcx.ty_to_string(self.cast_ty)));
         err.emit();