diff --git a/gcc/rust/resolve/rust-late-name-resolver-2.0.cc b/gcc/rust/resolve/rust-late-name-resolver-2.0.cc
index 352d59b0920..3236886f37d 100644
--- a/gcc/rust/resolve/rust-late-name-resolver-2.0.cc
+++ b/gcc/rust/resolve/rust-late-name-resolver-2.0.cc
@@ -16,18 +16,60 @@
 // along with GCC; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
+#include "optional.h"
 #include "rust-ast-full.h"
 #include "rust-late-name-resolver-2.0.h"
 #include "rust-default-resolver.h"
+#include "rust-tyty.h"
+#include "rust-hir-type-check.h"
 
 namespace Rust {
 namespace Resolver2_0 {
 
 Late::Late (NameResolutionContext &ctx) : DefaultResolver (ctx) {}
 
+void
+Late::setup_builtin_types ()
+{
+  auto next_id = [this] () { return ctx.mappings.get_next_hir_id (); };
+
+  static const std::pair<std::string, TyTy::BaseType *> builtins[] = {
+    {"u8", new TyTy::UintType (next_id (), TyTy::UintType::U8)},
+    {"u16", new TyTy::UintType (next_id (), TyTy::UintType::U16)},
+    {"u32", new TyTy::UintType (next_id (), TyTy::UintType::U32)},
+    {"u64", new TyTy::UintType (next_id (), TyTy::UintType::U64)},
+    {"u128", new TyTy::UintType (next_id (), TyTy::UintType::U128)},
+    {"i8", new TyTy::IntType (next_id (), TyTy::IntType::I8)},
+    {"i16", new TyTy::IntType (next_id (), TyTy::IntType::I16)},
+    {"i32", new TyTy::IntType (next_id (), TyTy::IntType::I32)},
+    {"i64", new TyTy::IntType (next_id (), TyTy::IntType::I64)},
+    {"i128", new TyTy::IntType (next_id (), TyTy::IntType::I128)},
+    {"f32", new TyTy::FloatType (next_id (), TyTy::FloatType::F32)},
+    {"f64", new TyTy::FloatType (next_id (), TyTy::FloatType::F64)},
+    {"usize", new TyTy::USizeType (next_id ())},
+    {"isize", new TyTy::ISizeType (next_id ())},
+    // missing char, str, never, ()
+    // does name resolution play a part for this? or is it all at typechecking?
+    // yeah it seems to be name resolution as well, which makes sense
+  };
+
+  for (const auto &builtin : builtins)
+    {
+      // we should be able to use `insert_at_root` or `insert` here, since we're
+      // at the root :) hopefully!
+      auto ok
+	= ctx.types.insert (builtin.first, builtin.second->get_ref ()
+			    /* FIXME: Invalid! This returns an *HirId* */);
+
+      rust_assert (ok);
+    }
+}
+
 void
 Late::go (AST::Crate &crate)
 {
+  setup_builtin_types ();
+
   for (auto &item : crate.items)
     item->accept_vis (*this);
 }
diff --git a/gcc/rust/resolve/rust-late-name-resolver-2.0.h b/gcc/rust/resolve/rust-late-name-resolver-2.0.h
index 12540c0d220..f54bbf2eea4 100644
--- a/gcc/rust/resolve/rust-late-name-resolver-2.0.h
+++ b/gcc/rust/resolve/rust-late-name-resolver-2.0.h
@@ -47,6 +47,8 @@ public:
   void visit (AST::PathInExpression &) override;
 
 private:
+  /* Setup Rust's builtin types (u8, i32, !...) in the resolver */
+  void setup_builtin_types ();
 };
 
 // TODO: Add missing mappings and data structures
diff --git a/gcc/rust/resolve/rust-name-resolution-context.cc b/gcc/rust/resolve/rust-name-resolution-context.cc
index 8bb7a9a15c1..f71ef91505b 100644
--- a/gcc/rust/resolve/rust-name-resolution-context.cc
+++ b/gcc/rust/resolve/rust-name-resolution-context.cc
@@ -43,6 +43,15 @@ NameResolutionContext::insert (Identifier name, NodeId id, Namespace ns)
     }
 }
 
+void
+NameResolutionContext::map_usage (NodeId usage, NodeId definition)
+{
+  auto inserted = resolved_nodes.emplace (usage, definition).second;
+
+  // is that valid?
+  rust_assert (inserted);
+}
+
 void
 NameResolutionContext::scoped (Rib rib, NodeId id,
 			       std::function<void (void)> lambda,
diff --git a/gcc/rust/resolve/rust-name-resolution-context.h b/gcc/rust/resolve/rust-name-resolution-context.h
index d63ee33378b..7a1924581ab 100644
--- a/gcc/rust/resolve/rust-name-resolution-context.h
+++ b/gcc/rust/resolve/rust-name-resolution-context.h
@@ -19,7 +19,6 @@
 #ifndef RUST_NAME_RESOLVER_2_0_H
 #define RUST_NAME_RESOLVER_2_0_H
 
-#include "optional.h"
 #include "rust-forever-stack.h"
 #include "rust-hir-map.h"
 
@@ -179,6 +178,13 @@ public:
   ForeverStack<Namespace::Labels> labels;
 
   Analysis::Mappings &mappings;
+
+  // TODO: Rename
+  void map_usage (NodeId usage, NodeId definition);
+
+private:
+  /* Map of "usage" nodes which have been resolved to a "definition" node */
+  std::map<NodeId, NodeId> resolved_nodes;
 };
 
 } // namespace Resolver2_0
