gccrs: TyTy: Store region constraints

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-implitem.cc (TypeCheckTopLevelExternItem::visit):
	Add region constraints.
	(TypeCheckImplItem::visit): Add region constraints.
	* typecheck/rust-hir-type-check-implitem.h: Add region constraints.
	* typecheck/rust-hir-type-check-item.cc (TypeCheckItem::ResolveImplBlockSelf):
	Add region constraints.
	(TypeCheckItem::visit): Add region constraints.
	(TypeCheckItem::resolve_impl_item): Add region constraints.
	(TypeCheckItem::resolve_impl_block_substitutions): Add region constraints.
	* typecheck/rust-hir-type-check-item.h: Add region constraints.
	* typecheck/rust-hir-type-check-type.cc (ResolveWhereClauseItem::Resolve):
	Add region constraints.
	(ResolveWhereClauseItem::visit): Add region constraints.
	* typecheck/rust-hir-type-check-type.h (class ResolveWhereClauseItem):
	Add region constraints.
	* typecheck/rust-hir-type-check.cc (TraitItemReference::get_type_from_fn):
	Add region constraints.
	* typecheck/rust-tyty-bounds.cc (TypeBoundPredicate::TypeBoundPredicate):
	Add region constraints.
	* typecheck/rust-tyty-subst.cc (SubstitutionRef::get_region_constraints):
	Add region constraints.
	* typecheck/rust-tyty-subst.h (class BaseType): Add region constraints.
	(struct RegionConstraints): Add region constraints.
	* typecheck/rust-tyty.cc (BaseType::monomorphized_clone): Add region constraints.
	(ADTType::clone): Add region constraints.
	(FnType::clone): Add region constraints.
	(ProjectionType::clone): Add region constraints.
	* typecheck/rust-tyty.h: Add region constraints.

Signed-off-by: Jakub Dupak <dev@jakubdupak.com>

12 files changed, 151 insertions, 53 deletions

diff --git a/gcc/rust/typecheck/rust-hir-type-check-implitem.cc b/gcc/rust/typecheck/rust-hir-type-check-implitem.cc
index 0ca59de..6b4141a 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-implitem.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-implitem.cc
@@ -96,6 +96,16 @@ TypeCheckTopLevelExternItem::visit (HIR::ExternalFunctionItem &function)
 	}
     }
 
+  TyTy::RegionConstraints region_constraints;
+  if (function.has_where_clause ())
+    {
+      for (auto &where_clause_item : function.get_where_clause ().get_items ())
+	{
+	  ResolveWhereClauseItem::Resolve (*where_clause_item.get (),
+					   region_constraints);
+	}
+    }
+
   TyTy::BaseType *ret_type = nullptr;
   if (!function.has_return_type ())
     ret_type
@@ -166,7 +176,8 @@ TypeCheckTopLevelExternItem::visit (HIR::ExternalFunctionItem &function)
     function.get_item_name ().as_string (), ident, flags, parent.get_abi (),
     std::move (params), ret_type, std::move (substitutions),
     TyTy::SubstitutionArgumentMappings::empty (
-      context->get_lifetime_resolver ().get_num_bound_regions ()));
+      context->get_lifetime_resolver ().get_num_bound_regions ()),
+    region_constraints);
 
   context->insert_type (function.get_mappings (), fnType);
   resolved = fnType;
@@ -206,9 +217,11 @@ TypeCheckImplItem::visit (HIR::Function &function)
   if (function.has_generics ())
     resolve_generic_params (function.get_generic_params (), substitutions);
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : function.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item.get ());
+      ResolveWhereClauseItem::Resolve (*where_clause_item.get (),
+				       region_constraints);
     }
 
   TyTy::BaseType *ret_type = nullptr;
@@ -334,7 +347,8 @@ TypeCheckImplItem::visit (HIR::Function &function)
 			  : TyTy::FnType::FNTYPE_DEFAULT_FLAGS,
     ABI::RUST, std::move (params), ret_type, std::move (substitutions),
     TyTy::SubstitutionArgumentMappings::empty (
-      context->get_lifetime_resolver ().get_num_bound_regions ()));
+      context->get_lifetime_resolver ().get_num_bound_regions ()),
+    region_constraints);
 
   context->insert_type (function.get_mappings (), fnType);
   result = fnType;
@@ -389,9 +403,11 @@ TypeCheckImplItem::visit (HIR::TypeAlias &alias)
 
   context->insert_type (alias.get_mappings (), actual_type);
   result = actual_type;
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : alias.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item.get ());
+      ResolveWhereClauseItem::Resolve (*where_clause_item.get (),
+				       region_constraints);
     }
 }
 
diff --git a/gcc/rust/typecheck/rust-hir-type-check-implitem.h b/gcc/rust/typecheck/rust-hir-type-check-implitem.h
index 067465e..4d17844 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-implitem.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-implitem.h
@@ -97,6 +97,7 @@ private:
   HIR::ImplBlock *parent;
   TyTy::BaseType *self;
   std::vector<TyTy::SubstitutionParamMapping> substitutions;
+  TyTy::RegionConstraints region_costraints;
 };
 
 } // namespace Resolver
diff --git a/gcc/rust/typecheck/rust-hir-type-check-item.cc b/gcc/rust/typecheck/rust-hir-type-check-item.cc
index eb2698e..16b4906 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-item.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-item.cc
@@ -63,12 +63,15 @@ TypeCheckItem::ResolveImplBlockSelf (HIR::ImplBlock &impl_block)
   TypeCheckItem resolver;
 
   bool failed_flag = false;
-  std::vector<TyTy::SubstitutionParamMapping> substitutions
+  auto result
     = resolver.resolve_impl_block_substitutions (impl_block, failed_flag);
   if (failed_flag)
     {
       return new TyTy::ErrorType (impl_block.get_mappings ().get_hirid ());
     }
+  std::vector<TyTy::SubstitutionParamMapping> substitutions
+    = std::move (result.first);
+  TyTy::RegionConstraints region_constraints = std::move (result.second);
 
   return resolver.resolve_impl_block_self (impl_block);
 }
@@ -81,12 +84,14 @@ TypeCheckItem::ResolveImplBlockSelfWithInference (
   TypeCheckItem resolver;
 
   bool failed_flag = false;
-  std::vector<TyTy::SubstitutionParamMapping> substitutions
-    = resolver.resolve_impl_block_substitutions (impl, failed_flag);
+  auto result = resolver.resolve_impl_block_substitutions (impl, failed_flag);
   if (failed_flag)
     {
       return new TyTy::ErrorType (impl.get_mappings ().get_hirid ());
     }
+  std::vector<TyTy::SubstitutionParamMapping> substitutions
+    = std::move (result.first);
+  TyTy::RegionConstraints region_constraints = std::move (result.second);
 
   // now that we have the param mappings we need to query the self type
   TyTy::BaseType *self = resolver.resolve_impl_block_self (impl);
@@ -140,9 +145,10 @@ TypeCheckItem::visit (HIR::TypeAlias &alias)
 
   context->insert_type (alias.get_mappings (), actual_type);
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : alias.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item);
+      ResolveWhereClauseItem::Resolve (*where_clause_item, region_constraints);
     }
   infered = actual_type;
 }
@@ -156,9 +162,10 @@ TypeCheckItem::visit (HIR::TupleStruct &struct_decl)
   if (struct_decl.has_generics ())
     resolve_generic_params (struct_decl.get_generic_params (), substitutions);
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : struct_decl.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item);
+      ResolveWhereClauseItem::Resolve (*where_clause_item, region_constraints);
     }
 
   std::vector<TyTy::StructFieldType *> fields;
@@ -203,7 +210,8 @@ TypeCheckItem::visit (HIR::TupleStruct &struct_decl)
     TyTy::ADTType::ADTKind::TUPLE_STRUCT, std::move (variants),
     std::move (substitutions), repr,
     TyTy::SubstitutionArgumentMappings::empty (
-      context->get_lifetime_resolver ().get_num_bound_regions ()));
+      context->get_lifetime_resolver ().get_num_bound_regions ()),
+    region_constraints);
 
   context->insert_type (struct_decl.get_mappings (), type);
   infered = type;
@@ -218,9 +226,10 @@ TypeCheckItem::visit (HIR::StructStruct &struct_decl)
   if (struct_decl.has_generics ())
     resolve_generic_params (struct_decl.get_generic_params (), substitutions);
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : struct_decl.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item);
+      ResolveWhereClauseItem::Resolve (*where_clause_item, region_constraints);
     }
 
   std::vector<TyTy::StructFieldType *> fields;
@@ -263,7 +272,8 @@ TypeCheckItem::visit (HIR::StructStruct &struct_decl)
     TyTy::ADTType::ADTKind::STRUCT_STRUCT, std::move (variants),
     std::move (substitutions), repr,
     TyTy::SubstitutionArgumentMappings::empty (
-      context->get_lifetime_resolver ().get_num_bound_regions ()));
+      context->get_lifetime_resolver ().get_num_bound_regions ()),
+    region_constraints);
 
   context->insert_type (struct_decl.get_mappings (), type);
   infered = type;
@@ -316,9 +326,10 @@ TypeCheckItem::visit (HIR::Union &union_decl)
   if (union_decl.has_generics ())
     resolve_generic_params (union_decl.get_generic_params (), substitutions);
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : union_decl.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item);
+      ResolveWhereClauseItem::Resolve (*where_clause_item, region_constraints);
     }
 
   std::vector<TyTy::StructFieldType *> fields;
@@ -401,13 +412,15 @@ TypeCheckItem::visit (HIR::ImplBlock &impl_block)
   auto binder_pin = context->push_clean_lifetime_resolver (true);
 
   bool failed_flag = false;
-  std::vector<TyTy::SubstitutionParamMapping> substitutions
-    = resolve_impl_block_substitutions (impl_block, failed_flag);
+  auto result = resolve_impl_block_substitutions (impl_block, failed_flag);
   if (failed_flag)
     {
       infered = new TyTy::ErrorType (impl_block.get_mappings ().get_hirid ());
       return;
     }
+  std::vector<TyTy::SubstitutionParamMapping> substitutions
+    = std::move (result.first);
+  TyTy::RegionConstraints region_constraints = std::move (result.second);
 
   TyTy::BaseType *self = resolve_impl_block_self (impl_block);
 
@@ -427,13 +440,16 @@ TypeCheckItem::resolve_impl_item (HIR::ImplBlock &impl_block,
 				  HIR::ImplItem &item)
 {
   bool failed_flag = false;
-  std::vector<TyTy::SubstitutionParamMapping> substitutions
-    = resolve_impl_block_substitutions (impl_block, failed_flag);
+  auto result = resolve_impl_block_substitutions (impl_block, failed_flag);
   if (failed_flag)
     {
       return new TyTy::ErrorType (impl_block.get_mappings ().get_hirid ());
     }
 
+  std::vector<TyTy::SubstitutionParamMapping> substitutions
+    = std::move (result.first);
+  TyTy::RegionConstraints region_constraints = std::move (result.second);
+
   TyTy::BaseType *self = resolve_impl_block_self (impl_block);
 
   return TypeCheckImplItem::Resolve (&impl_block, &item, self, substitutions);
@@ -445,11 +461,13 @@ TypeCheckItem::visit (HIR::Function &function)
   auto lifetime_pin = context->push_clean_lifetime_resolver ();
   std::vector<TyTy::SubstitutionParamMapping> substitutions;
   if (function.has_generics ())
-    resolve_generic_params (function.get_generic_params (), substitutions);
+    resolve_generic_params (function.get_generic_params (),
+			    substitutions); // TODO resolve constraints
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : function.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item);
+      ResolveWhereClauseItem::Resolve (*where_clause_item, region_constraints);
     }
 
   TyTy::BaseType *ret_type = nullptr;
@@ -498,7 +516,8 @@ TypeCheckItem::visit (HIR::Function &function)
     TyTy::FnType::FNTYPE_DEFAULT_FLAGS, ABI::RUST, std::move (params), ret_type,
     std::move (substitutions),
     TyTy::SubstitutionArgumentMappings::empty (
-      context->get_lifetime_resolver ().get_num_bound_regions ()));
+      context->get_lifetime_resolver ().get_num_bound_regions ()),
+    region_constraints);
 
   context->insert_type (function.get_mappings (), fn_type);
 
@@ -558,7 +577,7 @@ TypeCheckItem::visit (HIR::ExternBlock &extern_block)
     }
 }
 
-std::vector<TyTy::SubstitutionParamMapping>
+std::pair<std::vector<TyTy::SubstitutionParamMapping>, TyTy::RegionConstraints>
 TypeCheckItem::resolve_impl_block_substitutions (HIR::ImplBlock &impl_block,
 						 bool &failure_flag)
 {
@@ -566,9 +585,10 @@ TypeCheckItem::resolve_impl_block_substitutions (HIR::ImplBlock &impl_block,
   if (impl_block.has_generics ())
     resolve_generic_params (impl_block.get_generic_params (), substitutions);
 
+  TyTy::RegionConstraints region_constraints;
   for (auto &where_clause_item : impl_block.get_where_clause ().get_items ())
     {
-      ResolveWhereClauseItem::Resolve (*where_clause_item);
+      ResolveWhereClauseItem::Resolve (*where_clause_item, region_constraints);
     }
 
   auto specified_bound = TyTy::TypeBoundPredicate::error ();
@@ -600,7 +620,7 @@ TypeCheckItem::resolve_impl_block_substitutions (HIR::ImplBlock &impl_block,
   failure_flag = check_for_unconstrained (substitutions, trait_constraints,
 					  impl_constraints, self);
 
-  return substitutions;
+  return {substitutions, region_constraints};
 }
 
 void
diff --git a/gcc/rust/typecheck/rust-hir-type-check-item.h b/gcc/rust/typecheck/rust-hir-type-check-item.h
index 73cf9de..8a90ba0 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-item.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-item.h
@@ -57,7 +57,8 @@ public:
   void visit (HIR::UseDeclaration &) override {}
 
 protected:
-  std::vector<TyTy::SubstitutionParamMapping>
+  std::pair<std::vector<TyTy::SubstitutionParamMapping>,
+	    TyTy::RegionConstraints>
   resolve_impl_block_substitutions (HIR::ImplBlock &impl_block,
 				    bool &failure_flag);
 
diff --git a/gcc/rust/typecheck/rust-hir-type-check-type.cc b/gcc/rust/typecheck/rust-hir-type-check-type.cc
index e7a86b9..0d108c3 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-type.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-type.cc
@@ -889,9 +889,10 @@ TypeResolveGenericParam::visit (HIR::TypeParam &param)
 }
 
 void
-ResolveWhereClauseItem::Resolve (HIR::WhereClauseItem &item)
+ResolveWhereClauseItem::Resolve (HIR::WhereClauseItem &item,
+				 TyTy::RegionConstraints &region_constraints)
 {
-  ResolveWhereClauseItem resolver;
+  ResolveWhereClauseItem resolver (region_constraints);
 
   auto binder_pin = resolver.context->push_lifetime_binder ();
 
@@ -922,6 +923,8 @@ ResolveWhereClauseItem::visit (HIR::LifetimeWhereClauseItem &item)
 	{
 	  rust_error_at (UNKNOWN_LOCATION, "failed to resolve lifetime");
 	}
+      region_constraints.region_region.emplace_back (lhs.value (),
+						     rhs_i.value ());
     }
 }
 
@@ -958,7 +961,7 @@ ResolveWhereClauseItem::visit (HIR::TypeBoundWhereClauseItem &item)
 	  }
 	  break;
 	  case HIR::TypeParamBound::BoundType::LIFETIME: {
-	    if (binding->is<TyTy::ParamType> ())
+	    if (auto param = binding->try_as<TyTy::ParamType> ())
 	      {
 		auto *b = static_cast<HIR::Lifetime *> (bound.get ());
 		auto region = context->lookup_and_resolve_lifetime (*b);
@@ -967,6 +970,8 @@ ResolveWhereClauseItem::visit (HIR::TypeBoundWhereClauseItem &item)
 		    rust_error_at (UNKNOWN_LOCATION,
 				   "failed to resolve lifetime");
 		  }
+		region_constraints.type_region.emplace_back (param,
+							     region.value ());
 	      }
 	  }
 	  break;
diff --git a/gcc/rust/typecheck/rust-hir-type-check-type.h b/gcc/rust/typecheck/rust-hir-type-check-type.h
index 31b4869..3083a94 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-type.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-type.h
@@ -115,15 +115,21 @@ private:
 
 class ResolveWhereClauseItem : public TypeCheckBase
 {
+  // pair(a, b) => a: b
+  TyTy::RegionConstraints &region_constraints;
+
 public:
-  static void Resolve (HIR::WhereClauseItem &item);
+  static void Resolve (HIR::WhereClauseItem &item,
+		       TyTy::RegionConstraints &region_constraints);
 
 protected:
   void visit (HIR::LifetimeWhereClauseItem &item);
   void visit (HIR::TypeBoundWhereClauseItem &item);
 
 private:
-  ResolveWhereClauseItem () : TypeCheckBase () {}
+  ResolveWhereClauseItem (TyTy::RegionConstraints &region_constraints)
+    : region_constraints (region_constraints)
+  {}
 };
 
 } // namespace Resolver
diff --git a/gcc/rust/typecheck/rust-hir-type-check.cc b/gcc/rust/typecheck/rust-hir-type-check.cc
index 68d9681..2b78686 100644
--- a/gcc/rust/typecheck/rust-hir-type-check.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check.cc
@@ -189,6 +189,7 @@ TraitItemReference::get_type_from_fn (/*const*/ HIR::TraitItemFunc &fn) const
   std::vector<TyTy::SubstitutionParamMapping> substitutions
     = inherited_substitutions;
 
+  TyTy::RegionConstraints region_constraints;
   HIR::TraitFunctionDecl &function = fn.get_decl ();
   if (function.has_generics ())
     {
@@ -224,6 +225,13 @@ TraitItemReference::get_type_from_fn (/*const*/ HIR::TraitItemFunc &fn) const
 	}
     }
 
+  if (function.has_where_clause ())
+    {
+      for (auto &where_clause_item : function.get_where_clause ().get_items ())
+	ResolveWhereClauseItem::Resolve (*where_clause_item,
+					 region_constraints);
+    }
+
   TyTy::BaseType *ret_type = nullptr;
   if (!function.has_return_type ())
     ret_type = TyTy::TupleType::get_unit_type (fn.get_mappings ().get_hirid ());
@@ -336,7 +344,8 @@ TraitItemReference::get_type_from_fn (/*const*/ HIR::TraitItemFunc &fn) const
 			  : TyTy::FnType::FNTYPE_DEFAULT_FLAGS,
     ABI::RUST, std::move (params), ret_type, substitutions,
     TyTy::SubstitutionArgumentMappings::empty (
-      context->get_lifetime_resolver ().get_num_bound_regions ()));
+      context->get_lifetime_resolver ().get_num_bound_regions ()),
+    region_constraints);
   context->insert_type (fn.get_mappings (), resolved);
   return resolved;
 }
diff --git a/gcc/rust/typecheck/rust-tyty-bounds.cc b/gcc/rust/typecheck/rust-tyty-bounds.cc
index 066fe47..f37cf50 100644
--- a/gcc/rust/typecheck/rust-tyty-bounds.cc
+++ b/gcc/rust/typecheck/rust-tyty-bounds.cc
@@ -306,7 +306,7 @@ namespace TyTy {
 TypeBoundPredicate::TypeBoundPredicate (
   const Resolver::TraitReference &trait_reference, BoundPolarity polarity,
   location_t locus)
-  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
+  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty (), {}),
     reference (trait_reference.get_mappings ().get_defid ()), locus (locus),
     error_flag (false), polarity (polarity)
 {
@@ -324,7 +324,7 @@ TypeBoundPredicate::TypeBoundPredicate (
 TypeBoundPredicate::TypeBoundPredicate (
   DefId reference, std::vector<SubstitutionParamMapping> subst,
   BoundPolarity polarity, location_t locus)
-  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
+  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty (), {}),
     reference (reference), locus (locus), error_flag (false),
     polarity (polarity)
 {
@@ -340,13 +340,13 @@ TypeBoundPredicate::TypeBoundPredicate (
 }
 
 TypeBoundPredicate::TypeBoundPredicate (mark_is_error)
-  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
+  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty (), {}),
     reference (UNKNOWN_DEFID), locus (UNDEF_LOCATION), error_flag (true),
     polarity (BoundPolarity::RegularBound)
 {}
 
 TypeBoundPredicate::TypeBoundPredicate (const TypeBoundPredicate &other)
-  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty ()),
+  : SubstitutionRef ({}, SubstitutionArgumentMappings::empty (), {}),
     reference (other.reference), locus (other.locus),
     error_flag (other.error_flag), polarity (other.polarity)
 {
diff --git a/gcc/rust/typecheck/rust-tyty-subst.cc b/gcc/rust/typecheck/rust-tyty-subst.cc
index fcb09d50..0a8340e 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.cc
+++ b/gcc/rust/typecheck/rust-tyty-subst.cc
@@ -440,8 +440,9 @@ SubstitutionArgumentMappings::trait_item_mode () const
 
 SubstitutionRef::SubstitutionRef (
   std::vector<SubstitutionParamMapping> substitutions,
-  SubstitutionArgumentMappings arguments)
-  : substitutions (substitutions), used_arguments (arguments)
+  SubstitutionArgumentMappings arguments, RegionConstraints region_constraints)
+  : substitutions (substitutions), used_arguments (arguments),
+    region_constraints (region_constraints)
 {}
 
 bool
@@ -588,6 +589,12 @@ SubstitutionRef::get_used_arguments () const
   return used_arguments;
 }
 
+const RegionConstraints &
+SubstitutionRef::get_region_constraints () const
+{
+  return region_constraints;
+}
+
 SubstitutionArgumentMappings
 SubstitutionRef::get_mappings_from_generic_args (
   HIR::GenericArgs &args, const std::vector<Region> &regions)
diff --git a/gcc/rust/typecheck/rust-tyty-subst.h b/gcc/rust/typecheck/rust-tyty-subst.h
index dbabff3..562267c 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.h
+++ b/gcc/rust/typecheck/rust-tyty-subst.h
@@ -30,8 +30,17 @@
 namespace Rust {
 namespace TyTy {
 
-class BaseType;
 class ParamType;
+
+struct RegionConstraints
+{
+  /** 'a: 'b */
+  std::vector<std::pair<Region, Region>> region_region;
+  /** T: 'a */
+  std::vector<std::pair<ParamType *, Region>> type_region;
+};
+
+class BaseType;
 class SubstitutionArgumentMappings;
 class SubstitutionParamMapping
 {
@@ -249,7 +258,8 @@ class SubstitutionRef
 {
 public:
   SubstitutionRef (std::vector<SubstitutionParamMapping> substitutions,
-		   SubstitutionArgumentMappings arguments);
+		   SubstitutionArgumentMappings arguments,
+		   RegionConstraints region_constraints);
 
   bool has_substitutions () const;
 
@@ -404,9 +414,12 @@ public:
 
   WARN_UNUSED_RESULT tl::optional<SubstitutionArg> get_arg_at (size_t i) const;
 
+  const RegionConstraints &get_region_constraints () const;
+
 protected:
   std::vector<SubstitutionParamMapping> substitutions;
   SubstitutionArgumentMappings used_arguments;
+  RegionConstraints region_constraints;
 };
 
 } // namespace TyTy
diff --git a/gcc/rust/typecheck/rust-tyty.cc b/gcc/rust/typecheck/rust-tyty.cc
index 890d079..a8d3581 100644
--- a/gcc/rust/typecheck/rust-tyty.cc
+++ b/gcc/rust/typecheck/rust-tyty.cc
@@ -596,6 +596,7 @@ BaseType::monomorphized_clone () const
 			 fn->get_identifier (), fn->ident, fn->get_flags (),
 			 fn->get_abi (), std::move (cloned_params), retty,
 			 fn->clone_substs (), fn->get_substitution_arguments (),
+			 fn->get_region_constraints (),
 			 fn->get_combined_refs ());
     }
   else if (auto fn = x->try_as<const FnPtr> ())
@@ -620,6 +621,7 @@ BaseType::monomorphized_clone () const
 			  adt->get_adt_kind (), cloned_variants,
 			  adt->clone_substs (), adt->get_repr_options (),
 			  adt->get_used_arguments (),
+			  adt->get_region_constraints (),
 			  adt->get_combined_refs ());
     }
   else
@@ -1639,7 +1641,7 @@ ADTType::clone () const
   return new ADTType (get_ref (), get_ty_ref (), identifier, ident,
 		      get_adt_kind (), cloned_variants, clone_substs (),
 		      get_repr_options (), used_arguments,
-		      get_combined_refs ());
+		      get_region_constraints (), get_combined_refs ());
 }
 
 static bool
@@ -1958,7 +1960,8 @@ FnType::clone () const
   return new FnType (get_ref (), get_ty_ref (), get_id (), get_identifier (),
 		     ident, flags, abi, std::move (cloned_params),
 		     get_return_type ()->clone (), clone_substs (),
-		     get_substitution_arguments (), get_combined_refs ());
+		     get_substitution_arguments (), get_region_constraints (),
+		     get_combined_refs ());
 }
 
 FnType *
@@ -3573,11 +3576,13 @@ PlaceholderType::is_equal (const BaseType &other) const
 ProjectionType::ProjectionType (
   HirId ref, BaseType *base, const Resolver::TraitReference *trait, DefId item,
   std::vector<SubstitutionParamMapping> subst_refs,
-  SubstitutionArgumentMappings generic_arguments, std::set<HirId> refs)
+  SubstitutionArgumentMappings generic_arguments,
+  RegionConstraints region_constraints, std::set<HirId> refs)
   : BaseType (ref, ref, KIND,
 	      {Resolver::CanonicalPath::create_empty (), BUILTINS_LOCATION},
-	      refs),
-    SubstitutionRef (std::move (subst_refs), std::move (generic_arguments)),
+	      std::move (refs)),
+    SubstitutionRef (std::move (subst_refs), std::move (generic_arguments),
+		     std::move (region_constraints)),
     base (base), trait (trait), item (item)
 {}
 
@@ -3585,11 +3590,13 @@ ProjectionType::ProjectionType (
   HirId ref, HirId ty_ref, BaseType *base,
   const Resolver::TraitReference *trait, DefId item,
   std::vector<SubstitutionParamMapping> subst_refs,
-  SubstitutionArgumentMappings generic_arguments, std::set<HirId> refs)
+  SubstitutionArgumentMappings generic_arguments,
+  RegionConstraints region_constraints, std::set<HirId> refs)
   : BaseType (ref, ty_ref, KIND,
 	      {Resolver::CanonicalPath::create_empty (), BUILTINS_LOCATION},
 	      refs),
-    SubstitutionRef (std::move (subst_refs), std::move (generic_arguments)),
+    SubstitutionRef (std::move (subst_refs), std::move (generic_arguments),
+		     std::move (region_constraints)),
     base (base), trait (trait), item (item)
 {}
 
@@ -3640,7 +3647,7 @@ ProjectionType::clone () const
 {
   return new ProjectionType (get_ref (), get_ty_ref (), base->clone (), trait,
 			     item, clone_substs (), used_arguments,
-			     get_combined_refs ());
+			     region_constraints, get_combined_refs ());
 }
 
 ProjectionType *
diff --git a/gcc/rust/typecheck/rust-tyty.h b/gcc/rust/typecheck/rust-tyty.h
index 7384c40..570a57b 100644
--- a/gcc/rust/typecheck/rust-tyty.h
+++ b/gcc/rust/typecheck/rust-tyty.h
@@ -650,9 +650,11 @@ public:
 	   std::vector<SubstitutionParamMapping> subst_refs,
 	   SubstitutionArgumentMappings generic_arguments
 	   = SubstitutionArgumentMappings::error (),
+	   RegionConstraints region_constraints = {},
 	   std::set<HirId> refs = std::set<HirId> ())
     : BaseType (ref, ref, TypeKind::ADT, ident, refs),
-      SubstitutionRef (std::move (subst_refs), std::move (generic_arguments)),
+      SubstitutionRef (std::move (subst_refs), std::move (generic_arguments),
+		       region_constraints),
       identifier (identifier), variants (variants), adt_kind (adt_kind)
   {}
 
@@ -661,9 +663,11 @@ public:
 	   std::vector<SubstitutionParamMapping> subst_refs,
 	   SubstitutionArgumentMappings generic_arguments
 	   = SubstitutionArgumentMappings::error (),
+	   RegionConstraints region_constraints = {},
 	   std::set<HirId> refs = std::set<HirId> ())
     : BaseType (ref, ty_ref, TypeKind::ADT, ident, refs),
-      SubstitutionRef (std::move (subst_refs), std::move (generic_arguments)),
+      SubstitutionRef (std::move (subst_refs), std::move (generic_arguments),
+		       region_constraints),
       identifier (identifier), variants (variants), adt_kind (adt_kind)
   {}
 
@@ -672,9 +676,11 @@ public:
 	   std::vector<SubstitutionParamMapping> subst_refs, ReprOptions repr,
 	   SubstitutionArgumentMappings generic_arguments
 	   = SubstitutionArgumentMappings::error (),
+	   RegionConstraints region_constraints = {},
 	   std::set<HirId> refs = std::set<HirId> ())
     : BaseType (ref, ty_ref, TypeKind::ADT, ident, refs),
-      SubstitutionRef (std::move (subst_refs), std::move (generic_arguments)),
+      SubstitutionRef (std::move (subst_refs), std::move (generic_arguments),
+		       region_constraints),
       identifier (identifier), variants (variants), adt_kind (adt_kind),
       repr (repr)
   {}
@@ -774,9 +780,11 @@ public:
 	  std::vector<std::pair<HIR::Pattern *, BaseType *>> params,
 	  BaseType *type, std::vector<SubstitutionParamMapping> subst_refs,
 	  SubstitutionArgumentMappings substitution_argument_mappings,
+	  RegionConstraints region_constraints,
 	  std::set<HirId> refs = std::set<HirId> ())
     : CallableTypeInterface (ref, ref, TypeKind::FNDEF, ident, refs),
-      SubstitutionRef (std::move (subst_refs), substitution_argument_mappings),
+      SubstitutionRef (std::move (subst_refs), substitution_argument_mappings,
+		       region_constraints),
       params (std::move (params)), type (type), flags (flags),
       identifier (identifier), id (id), abi (abi)
   {
@@ -789,9 +797,11 @@ public:
 	  std::vector<std::pair<HIR::Pattern *, BaseType *>> params,
 	  BaseType *type, std::vector<SubstitutionParamMapping> subst_refs,
 	  SubstitutionArgumentMappings substitution_argument_mappings,
+	  RegionConstraints region_constraints,
 	  std::set<HirId> refs = std::set<HirId> ())
     : CallableTypeInterface (ref, ty_ref, TypeKind::FNDEF, ident, refs),
-      SubstitutionRef (std::move (subst_refs), substitution_argument_mappings),
+      SubstitutionRef (std::move (subst_refs), substitution_argument_mappings,
+		       region_constraints),
       params (params), type (type), flags (flags), identifier (identifier),
       id (id), abi (abi)
   {
@@ -962,7 +972,8 @@ public:
 	       = std::vector<TypeBoundPredicate> ())
     : CallableTypeInterface (ref, ref, TypeKind::CLOSURE, ident, refs),
       SubstitutionRef (std::move (subst_refs),
-		       SubstitutionArgumentMappings::error ()),
+		       SubstitutionArgumentMappings::error (),
+		       {}), // TODO: check region constraints
       parameters (parameters), result_type (std::move (result_type)), id (id),
       captures (captures)
   {
@@ -980,7 +991,7 @@ public:
 	       = std::vector<TypeBoundPredicate> ())
     : CallableTypeInterface (ref, ty_ref, TypeKind::CLOSURE, ident, refs),
       SubstitutionRef (std::move (subst_refs),
-		       SubstitutionArgumentMappings::error ()), // TODO
+		       SubstitutionArgumentMappings::error (), {}), // TODO
       parameters (parameters), result_type (std::move (result_type)), id (id),
       captures (captures)
   {
@@ -1534,6 +1545,7 @@ public:
 		  std::vector<SubstitutionParamMapping> subst_refs,
 		  SubstitutionArgumentMappings generic_arguments
 		  = SubstitutionArgumentMappings::error (),
+		  RegionConstraints region_constraints = {},
 		  std::set<HirId> refs = std::set<HirId> ());
 
   ProjectionType (HirId ref, HirId ty_ref, BaseType *base,
@@ -1541,6 +1553,7 @@ public:
 		  std::vector<SubstitutionParamMapping> subst_refs,
 		  SubstitutionArgumentMappings generic_arguments
 		  = SubstitutionArgumentMappings::error (),
+		  RegionConstraints region_constraints = {},
 		  std::set<HirId> refs = std::set<HirId> ());
 
   void accept_vis (TyVisitor &vis) override;