[gcc r15-8389] gccrs: toplevel: Add note for resolving use declarations

[Arthur Cohen]

https://gcc.gnu.org/g:ca285a61c35df7da6ff652a2b2fbba8eef7d246b

commit r15-8389-gca285a61c35df7da6ff652a2b2fbba8eef7d246b
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Wed Apr 3 17:41:47 2024 +0200

    gccrs: toplevel: Add note for resolving use declarations
    
    gcc/rust/ChangeLog:
    
            * resolve/rust-toplevel-name-resolver-2.0.cc (TopLevel::handle_use_dec):
            Add notes on the problem.
            * resolve/rust-toplevel-name-resolver-2.0.h: Likewise.

Diff:
---
 gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc | 11 +++++++++++
 gcc/rust/resolve/rust-toplevel-name-resolver-2.0.h  |  2 +-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc b/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc
index 746b2240d4b7..b18b86ca8218 100644
--- a/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc
+++ b/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.cc
@@ -452,6 +452,13 @@ TopLevel::handle_use_dec (AST::SimplePath &path)
   auto locus = path.get_final_segment ().get_locus ();
   auto declared_name = path.get_final_segment ().as_string ();
 
+  // In that function, we only need to declare a new definition - the use path.
+  // the resolution needs to happpen in the EarlyNameResolver. So the
+  // definitions we'll add will be the path's NodeId - that makes sense, as we
+  // need one definition per path declared in a Use tree. so all good.
+  // alright, now in what namespace do we declare them? all of them? do we only
+  // declare them in the EarlyNameResolver? this is dodgy
+
   // in what namespace do we perform path resolution? All of them? see which one
   // matches? Error out on ambiguities?
   // so, apparently, for each one that matches, add it to the proper namespace
@@ -464,6 +471,10 @@ TopLevel::handle_use_dec (AST::SimplePath &path)
 					     const AST::SimplePath &path) {
 	tl::optional<Rib::Definition> resolved = tl::nullopt;
 
+	insert_or_error_out (declared_name, locus, path.get_node_id (), ns);
+	// what do we do here with the full simplepath? do we add it to an extra
+	// map?
+
 	// FIXME: resolve_path needs to return an `expected<NodeId, Error>` so
 	// that we can improve it with hints or location or w/ever. and maybe
 	// only emit it the first time.
diff --git a/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.h b/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.h
index 095037042658..affddb97d50c 100644
--- a/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.h
+++ b/gcc/rust/resolve/rust-toplevel-name-resolver-2.0.h
@@ -84,7 +84,7 @@ private:
   std::unordered_map<NodeId, location_t> node_locations;
 
   // Store node forwarding for use declaration, the link between a
-  // "new" local name and its definition.
+  // definition and its new local name.
   std::unordered_map<NodeId, NodeId> node_forwarding;
 
   void visit (AST::Module &module) override;