gccrs: Track polarity in type bound predicate

Addresses #2443

gcc/rust/ChangeLog:

	* typecheck/rust-hir-path-probe.cc: track regular polarity
	* typecheck/rust-hir-trait-resolve.cc (TraitResolver::resolve_trait): likewise
	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit): likewise
	* typecheck/rust-hir-type-check-item.cc (TypeCheckItem::visit): likewise
	* typecheck/rust-tyty-bounds.cc (TypeCheckBase::get_predicate_from_bound): likewise
	(TypeBoundPredicate::TypeBoundPredicate): update ctor
	(TypeBoundPredicate::operator=): update copy assignment ctor
	(TypeBoundPredicate::error): update error node
	* typecheck/rust-tyty.h: add polarity field to predicate

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

gcc/rust/typecheck/rust-hir-path-probe.cc

@@ -344,7 +344,8 @@ PathProbeType::process_associated_trait_for_candidates (
       break;
     }
 
-  const TyTy::TypeBoundPredicate p (*trait_ref, UNDEF_LOCATION);
+  const TyTy::TypeBoundPredicate p (*trait_ref, BoundPolarity::RegularBound,
+				    UNDEF_LOCATION);
   TyTy::TypeBoundPredicateItem item (&p, trait_item_ref);
 
   TyTy::BaseType *trait_item_tyty = item.get_raw_item ()->get_tyty ();

gcc/rust/typecheck/rust-hir-trait-resolve.cc

@@ -214,6 +214,7 @@ TraitResolver::resolve_trait (HIR::Trait *trait_reference)
   auto self_hrtb
     = TyTy::TypeBoundPredicate (trait_reference->get_mappings ().get_defid (),
 				std::move (self_subst_copy),
+				BoundPolarity::RegularBound,
 				trait_reference->get_locus ());
   specified_bounds.push_back (self_hrtb);
 

gcc/rust/typecheck/rust-hir-type-check-expr.cc

@@ -1558,7 +1558,8 @@ TypeCheckExpr::visit (HIR::ClosureExpr &expr)
   TraitReference *trait = TraitResolver::Resolve (*trait_item);
   rust_assert (!trait->is_error ());
 
-  TyTy::TypeBoundPredicate predicate (*trait, expr.get_locus ());
+  TyTy::TypeBoundPredicate predicate (*trait, BoundPolarity::RegularBound,
+				      expr.get_locus ());
 
   // resolve the trait bound where the <(Args)> are the parameter tuple type
   HIR::GenericArgs args = HIR::GenericArgs::create_empty (expr.get_locus ());

gcc/rust/typecheck/rust-hir-type-check-item.cc

@@ -528,7 +528,8 @@ TypeCheckItem::visit (HIR::Trait &trait)
   RustIdent ident{CanonicalPath::create_empty (), trait.get_locus ()};
   infered = new TyTy::DynamicObjectType (
     trait.get_mappings ().get_hirid (), ident,
-    {TyTy::TypeBoundPredicate (*trait_ref, trait.get_locus ())});
+    {TyTy::TypeBoundPredicate (*trait_ref, BoundPolarity::RegularBound,
+			       trait.get_locus ())});
 }
 
 void

gcc/rust/typecheck/rust-tyty-bounds.cc

@@ -184,7 +184,8 @@ TypeCheckBase::get_predicate_from_bound (HIR::TypePath &type_path,
   if (trait->is_error ())
     return TyTy::TypeBoundPredicate::error ();
 
-  TyTy::TypeBoundPredicate predicate (*trait, type_path.get_locus ());
+  TyTy::TypeBoundPredicate predicate (*trait, BoundPolarity::RegularBound,
+				      type_path.get_locus ());
   HIR::GenericArgs args
     = HIR::GenericArgs::create_empty (type_path.get_locus ());
 
@@ -290,10 +291,11 @@ TypeCheckBase::get_predicate_from_bound (HIR::TypePath &type_path,
 namespace TyTy {
 
 TypeBoundPredicate::TypeBoundPredicate (
-  const Resolver::TraitReference &trait_reference, location_t locus)
+  const Resolver::TraitReference &trait_reference, BoundPolarity polarity,
+  location_t locus)
   : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
     reference (trait_reference.get_mappings ().get_defid ()), locus (locus),
-    error_flag (false)
+    error_flag (false), polarity (polarity)
 {
   substitutions.clear ();
   for (const auto &p : trait_reference.get_trait_substs ())
@@ -306,9 +308,10 @@ TypeBoundPredicate::TypeBoundPredicate (
 
 TypeBoundPredicate::TypeBoundPredicate (
   DefId reference, std::vector<SubstitutionParamMapping> subst,
-  location_t locus)
+  BoundPolarity polarity, location_t locus)
   : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
-    reference (reference), locus (locus), error_flag (false)
+    reference (reference), locus (locus), error_flag (false),
+    polarity (polarity)
 {
   substitutions.clear ();
   for (const auto &p : subst)
@@ -322,7 +325,7 @@ TypeBoundPredicate::TypeBoundPredicate (
 TypeBoundPredicate::TypeBoundPredicate (const TypeBoundPredicate &other)
   : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
     reference (other.reference), locus (other.locus),
-    error_flag (other.error_flag)
+    error_flag (other.error_flag), polarity (other.polarity)
 {
   substitutions.clear ();
   for (const auto &p : other.get_substs ())
@@ -358,6 +361,7 @@ TypeBoundPredicate::operator= (const TypeBoundPredicate &other)
   reference = other.reference;
   locus = other.locus;
   error_flag = other.error_flag;
+  polarity = other.polarity;
   used_arguments = SubstitutionArgumentMappings::empty ();
 
   substitutions.clear ();
@@ -396,7 +400,8 @@ TypeBoundPredicate::operator= (const TypeBoundPredicate &other)
 TypeBoundPredicate
 TypeBoundPredicate::error ()
 {
-  auto p = TypeBoundPredicate (UNKNOWN_DEFID, {}, UNDEF_LOCATION);
+  auto p = TypeBoundPredicate (UNKNOWN_DEFID, {}, BoundPolarity::RegularBound,
+			       UNDEF_LOCATION);
   p.error_flag = true;
   return p;
 }

gcc/rust/typecheck/rust-tyty.h

@@ -381,11 +381,11 @@ class TypeBoundPredicate : public SubstitutionRef
 {
 public:
   TypeBoundPredicate (const Resolver::TraitReference &trait_reference,
-		      location_t locus);
+		      BoundPolarity polarity, location_t locus);
 
   TypeBoundPredicate (DefId reference,
 		      std::vector<SubstitutionParamMapping> substitutions,
-		      location_t locus);
+		      BoundPolarity polarity, location_t locus);
 
   TypeBoundPredicate (const TypeBoundPredicate &other);
 
@@ -432,6 +432,8 @@ public:
 
   DefId get_id () const { return reference; }
 
+  BoundPolarity get_polarity () const { return polarity; }
+
   std::vector<TypeBoundPredicateItem> get_associated_type_items ();
 
   size_t get_num_associated_bindings () const override final;
@@ -445,6 +447,7 @@ private:
   DefId reference;
   location_t locus;
   bool error_flag;
+  BoundPolarity polarity;
 };
 
 // https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.VariantDef.html