Add resolution for additional trait bounds

gcc/rust/resolve/rust-ast-resolve-type.cc

@@ -18,6 +18,8 @@
 
 #include "rust-ast-resolve-type.h"
 #include "rust-ast-resolve-expr.h"
+#include "rust-canonical-path.h"
+#include "rust-type.h"
 
 namespace Rust {
 namespace Resolver {
@@ -495,10 +497,59 @@ ResolveTypeToCanonicalPath::visit (AST::TraitObjectTypeOneBound &type)
 }
 
 void
-ResolveTypeToCanonicalPath::visit (AST::TraitObjectType &)
+ResolveTypeToCanonicalPath::visit (AST::TraitObjectType &type)
 {
-  // FIXME is this actually allowed? dyn A+B
-  rust_unreachable ();
+  rust_assert (!type.get_type_param_bounds ().empty ());
+
+  auto &first_bound = type.get_type_param_bounds ().front ();
+
+  // Is it allowed or even possible to have a lifetime bound as a first bound?
+  if (first_bound->get_bound_type () == AST::TraitBound::LIFETIME)
+    rust_unreachable ();
+
+  auto &trait = static_cast<AST::TraitBound &> (*first_bound);
+
+  CanonicalPath path = CanonicalPath::create_empty ();
+  bool ok = ResolveTypeToCanonicalPath::go (trait.get_type_path (), path);
+
+  // right?
+  rust_assert (ok);
+
+  auto slice_path = "<dyn " + path.get ();
+
+  for (size_t idx = 1; idx < type.get_type_param_bounds ().size (); idx++)
+    {
+      auto &additional_bound = type.get_type_param_bounds ()[idx];
+
+      std::string str;
+
+      switch (additional_bound->get_bound_type ())
+	{
+	  case AST::TypeParamBound::TRAIT: {
+	    auto bound_path = CanonicalPath::create_empty ();
+
+	    auto &bound_type_path
+	      = static_cast<AST::TraitBound &> (*additional_bound)
+		  .get_type_path ();
+	    bool ok
+	      = ResolveTypeToCanonicalPath::go (bound_type_path, bound_path);
+
+	    if (!ok)
+	      continue;
+
+	    str = bound_path.get ();
+	    break;
+	  }
+	case AST::TypeParamBound::LIFETIME:
+	  rust_unreachable ();
+	  break;
+	}
+      slice_path += " + " + str;
+    }
+
+  slice_path += ">";
+
+  result = CanonicalPath::new_seg (type.get_node_id (), slice_path);
 }
 
 void

gcc/rust/resolve/rust-late-name-resolver-2.0.cc

@@ -282,7 +282,8 @@ Late::visit (AST::TypePath &type)
     ctx.map_usage (Usage (type.get_node_id ()),
 		   Definition (resolved->get_node_id ()));
   else
-    rust_unreachable ();
+    rust_error_at (type.get_locus (), "could not resolve type path %qs",
+		   str.c_str ());
 
   DefaultResolver::visit (type);
 }

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

@@ -757,6 +757,11 @@ TypeCheckType::visit (HIR::TraitObjectType &type)
   std::vector<TyTy::TypeBoundPredicate> specified_bounds;
   for (auto &bound : type.get_type_param_bounds ())
     {
+      // TODO: here we need to check if there are additional bounds that aren't
+      // auto traits. this is an error. for example, `dyn A + Sized + Sync` is
+      // okay, because Sized and Sync are both auto traits but `dyn A + Copy +
+      // Clone` is not okay and should error out.
+
       if (bound->get_bound_type ()
 	  != HIR::TypeParamBound::BoundType::TRAITBOUND)
 	continue;

gcc/rust/util/rust-lang-item.cc

@@ -62,6 +62,7 @@ const BiMap<std::string, LangItem::Kind> Rust::LangItem::lang_items = {{
   {"copy", Kind::COPY},
   {"clone", Kind::CLONE},
   {"sized", Kind::SIZED},
+  {"sync", Kind::SYNC},
   {"slice_alloc", Kind::SLICE_ALLOC},
   {"slice_u8_alloc", Kind::SLICE_U8_ALLOC},
   {"str_alloc", Kind::STR_ALLOC},

gcc/rust/util/rust-lang-item.h

@@ -82,6 +82,7 @@ class LangItem
     COPY,
     CLONE,
     SIZED,
+    SYNC,
 
     // https://github.com/Rust-GCC/gccrs/issues/1896
     // https://github.com/rust-lang/rust/commit/afbecc0f68c4dcfc4878ba5bcb1ac942544a1bdc

gcc/testsuite/rust/compile/additional-trait-bounds1.rs

@@ -0,0 +1,10 @@
+#![feature(optin_builtin_traits)]
+
+pub unsafe auto trait Send {}
+#[lang = "sync"]
+pub unsafe auto trait Sync {}
+
+trait A {}
+
+impl dyn A + Send {}
+impl dyn A + Send + Sync {}

gcc/testsuite/rust/compile/additional-trait-bounds2.rs

@@ -0,0 +1,9 @@
+#![feature(optin_builtin_traits)]
+
+pub unsafe auto trait Send {}
+#[lang = "sync"]
+pub unsafe auto trait Sync {}
+
+trait A {}
+
+impl dyn A + Send + Sync + NonExist {} // { dg-error "failed to resolve TypePath: NonExist in this scope" }

gcc/testsuite/rust/compile/additional-trait-bounds2nr2.rs

@@ -0,0 +1,11 @@
+// { dg-additional-options "-frust-name-resolution-2.0" }
+
+#![feature(optin_builtin_traits)]
+
+pub unsafe auto trait Send {}
+#[lang = "sync"]
+pub unsafe auto trait Sync {}
+
+trait A {}
+
+impl dyn A + Send + Sync + NonExist {} // { dg-error "could not resolve type path .NonExist." }

gcc/testsuite/rust/compile/nr2/exclude

@@ -208,4 +208,5 @@ issue-2905-2.rs
 issue-2907.rs
 issue-2423.rs
 issue-266.rs
+additional-trait-bounds2.rs
 # please don't delete the trailing newline