Add Trait Resolver simple type-path lookup

Post type checking we need to be able to lookup trait references, but do
not need to resolve the trait with error messages. We simple want to look
it up if it exists.

2 files changed, 62 insertions, 0 deletions

diff --git a/gcc/rust/typecheck/rust-hir-trait-resolve.cc b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
index cf3f2fb..aeedf7e 100644
--- a/gcc/rust/typecheck/rust-hir-trait-resolve.cc
+++ b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
@@ -227,5 +227,27 @@ AssociatedImplTrait::get_projected_type (
   return trait_item_tyty;
 }
 
+// rust-hir-path-probe.h
+
+void
+PathProbeImplTrait::process_trait_impl_items_for_candidates ()
+{
+  mappings->iterate_impl_items (
+    [&] (HirId id, HIR::ImplItem *item, HIR::ImplBlock *impl) mutable -> bool {
+      // just need to check if this is an impl block for this trait the next
+      // function checks the receiver
+      if (!impl->has_trait_ref ())
+	return true;
+
+      TraitReference *resolved
+	= TraitResolver::Lookup (*(impl->get_trait_ref ().get ()));
+      if (!trait_reference->is_equal (*resolved))
+	return true;
+
+      process_impl_item_candidate (id, item, impl);
+      return true;
+    });
+}
+
 } // namespace Resolver
 } // namespace Rust
diff --git a/gcc/rust/typecheck/rust-hir-trait-resolve.h b/gcc/rust/typecheck/rust-hir-trait-resolve.h
index 6874a3a..0fe2406 100644
--- a/gcc/rust/typecheck/rust-hir-trait-resolve.h
+++ b/gcc/rust/typecheck/rust-hir-trait-resolve.h
@@ -72,6 +72,12 @@ public:
     return resolver.go (path);
   }
 
+  static TraitReference *Lookup (HIR::TypePath &path)
+  {
+    TraitResolver resolver;
+    return resolver.lookup_path (path);
+  }
+
 private:
   TraitResolver () : TypeCheckBase () {}
 
@@ -162,6 +168,40 @@ private:
     return tref;
   }
 
+  TraitReference *lookup_path (HIR::TypePath &path)
+  {
+    NodeId ref;
+    if (!resolver->lookup_resolved_type (path.get_mappings ().get_nodeid (),
+					 &ref))
+      {
+	rust_error_at (path.get_locus (), "Failed to resolve path to node-id");
+	return &TraitReference::error_node ();
+      }
+
+    HirId hir_node = UNKNOWN_HIRID;
+    if (!mappings->lookup_node_to_hir (mappings->get_current_crate (), ref,
+				       &hir_node))
+      {
+	rust_error_at (path.get_locus (), "Failed to resolve path to hir-id");
+	return &TraitReference::error_node ();
+      }
+
+    HIR::Item *resolved_item
+      = mappings->lookup_hir_item (mappings->get_current_crate (), hir_node);
+
+    rust_assert (resolved_item != nullptr);
+    resolved_item->accept_vis (*this);
+    rust_assert (trait_reference != nullptr);
+
+    TraitReference *tref = &TraitReference::error_node ();
+    if (context->lookup_trait_reference (
+	  trait_reference->get_mappings ().get_defid (), &tref))
+      {
+	return tref;
+      }
+    return &TraitReference::error_node ();
+  }
+
   HIR::Trait *trait_reference;
 
 public: