gccrs: Add catch for recusive type queries

When we have a type query where by generic substitution occurs we can hit
the case where we need to Probe the bounds of the substited item to
determine whether the the bounds are compatible this can cause us to
end up querying the same type recursively.

Fixes #1550

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-base.cc (TypeCheckBase::query_type):
	Check for recursive queries.
	* typecheck/rust-hir-type-check.h: New functions: `query_completed`,
	`query_in_progress`, `insert_query`.
	* typecheck/rust-tyty-bounds.cc (TypeBoundsProbe::scan): Use `query_type` API.

diff --git a/gcc/rust/typecheck/rust-hir-type-check-base.cc b/gcc/rust/typecheck/rust-hir-type-check-base.cc
index cf496d3eb19fedacf29f82b407f95993ae955b42..85826aec8fe955336f41984973f1ab2c2ce9ef23 100644 (file)
--- a/gcc/rust/typecheck/rust-hir-type-check-base.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-base.cc
@@ -495,14 +495,20 @@ TypeCheckBase::resolve_generic_params (
 bool
 TypeCheckBase::query_type (HirId reference, TyTy::BaseType **result)
 {
+  if (context->query_in_progress (reference))
+    return false;
+
   if (context->lookup_type (reference, result))
     return true;
 
+  context->insert_query (reference);
+
   HIR::Item *item = mappings->lookup_hir_item (reference);
   if (item != nullptr)
     {
       rust_debug_loc (item->get_locus (), "resolved item {%u} to", reference);
       *result = TypeCheckItem::Resolve (*item);
+      context->query_completed (reference);
       return true;
     }
 
@@ -520,6 +526,7 @@ TypeCheckBase::query_type (HirId reference, TyTy::BaseType **result)
                      reference);
 
       *result = TypeCheckItem::ResolveImplItem (*impl_block, *impl_item);
+      context->query_completed (reference);
       return true;
     }
 
@@ -530,6 +537,7 @@ TypeCheckBase::query_type (HirId reference, TyTy::BaseType **result)
   if (found_impl_block_type)
     {
       *result = TypeCheckItem::ResolveImplBlockSelf (*impl_block_by_type);
+      context->query_completed (reference);
       return true;
     }
 
@@ -544,6 +552,7 @@ TypeCheckBase::query_type (HirId reference, TyTy::BaseType **result)
       rust_assert (block != nullptr);
 
       *result = TypeCheckTopLevelExternItem::Resolve (extern_item, *block);
+      context->query_completed (reference);
       return true;
     }
 
@@ -551,6 +560,7 @@ TypeCheckBase::query_type (HirId reference, TyTy::BaseType **result)
   Location possible_locus = mappings->lookup_location (reference);
   rust_debug_loc (possible_locus, "query system failed to resolve: [%u]",
                  reference);
+  context->query_completed (reference);
 
   return false;
 }

diff --git a/gcc/rust/typecheck/rust-hir-type-check.h b/gcc/rust/typecheck/rust-hir-type-check.h
index 3e9c9c4d21a8e52e55b2dad32364fd45b7fd9e87..a1dd8052246ff3169c9c75d4e82156922e09aa46 100644 (file)
--- a/gcc/rust/typecheck/rust-hir-type-check.h
+++ b/gcc/rust/typecheck/rust-hir-type-check.h
@@ -372,6 +372,15 @@ public:
     return true;
   }
 
+  void insert_query (HirId id) { querys_in_progress.insert (id); }
+
+  void query_completed (HirId id) { querys_in_progress.erase (id); }
+
+  bool query_in_progress (HirId id) const
+  {
+    return querys_in_progress.find (id) != querys_in_progress.end ();
+  }
+
 private:
   TypeCheckContext ();
 
@@ -406,6 +415,9 @@ private:
 
   // predicates
   std::map<HirId, TyTy::TypeBoundPredicate> predicates;
+
+  // query context lookups
+  std::set<HirId> querys_in_progress;
 };
 
 class TypeResolution

diff --git a/gcc/rust/typecheck/rust-tyty-bounds.cc b/gcc/rust/typecheck/rust-tyty-bounds.cc
index 5b5ff751e2b01e1e105a66c3d96d4cde9fa81a17..1a2ed3b7422ad7349ffd323af1320020d1fe03cc 100644 (file)
--- a/gcc/rust/typecheck/rust-tyty-bounds.cc
+++ b/gcc/rust/typecheck/rust-tyty-bounds.cc
@@ -34,8 +34,9 @@ TypeBoundsProbe::scan ()
       if (!impl->has_trait_ref ())
        return true;
 
-      TyTy::BaseType *impl_type = TypeCheckItem::ResolveImplBlockSelf (*impl);
-      if (impl_type->get_kind () == TyTy::TypeKind::ERROR)
+      HirId impl_ty_id = impl->get_type ()->get_mappings ().get_hirid ();
+      TyTy::BaseType *impl_type = nullptr;
+      if (!query_type (impl_ty_id, &impl_type))
        return true;
 
       if (!receiver->can_eq (impl_type, false))