gccrs: Fix missing dead code analysis ICE on local enum definition

When resolving local enum's within a Block the name resolution info is
not at the top of the stack so this patch introduces a new mappings class
for miscellaneous name resolutions which can be used during path analaysis.

Fixes #1272

gcc/rust/ChangeLog:

	* resolve/rust-name-resolver.h: Add miscellenaous item mappings.
	* resolve/rust-name-resolver.cc (Resolver::insert_resolved_misc): Use
	new mappings.
	(Resolver::lookup_resolved_misc): Likewise.
	* typecheck/rust-hir-type-check-path.cc (TypeCheckExpr::resolve_segments):
	Adapt function to insert into miscelleanous mappings.
	* checks/lints/rust-lint-marklive.cc (MarkLive::find_ref_node_id):
	Allow lookup in miscelleanous mappings in mark-live phase.

gcc/testsuite/ChangeLog:

	* rust/compile/issue-1272.rs: New test.

gcc/rust/checks/lints/rust-lint-marklive.cc

@@ -273,8 +273,11 @@ MarkLive::find_ref_node_id (NodeId ast_node_id, NodeId &ref_node_id)
 {
   if (!resolver->lookup_resolved_name (ast_node_id, &ref_node_id))
     {
-      bool ok = resolver->lookup_resolved_type (ast_node_id, &ref_node_id);
-      rust_assert (ok);
+      if (!resolver->lookup_resolved_type (ast_node_id, &ref_node_id))
+	{
+	  bool ok = resolver->lookup_resolved_misc (ast_node_id, &ref_node_id);
+	  rust_assert (ok);
+	}
     }
 }
 

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

@@ -499,5 +499,25 @@ Resolver::lookup_resolved_macro (NodeId refId, NodeId *defId)
   return true;
 }
 
+void
+Resolver::insert_resolved_misc (NodeId refId, NodeId defId)
+{
+  auto it = misc_resolved_items.find (refId);
+  rust_assert (it == misc_resolved_items.end ());
+
+  misc_resolved_items[refId] = defId;
+}
+
+bool
+Resolver::lookup_resolved_misc (NodeId refId, NodeId *defId)
+{
+  auto it = misc_resolved_items.find (refId);
+  if (it == misc_resolved_items.end ())
+    return false;
+
+  *defId = it->second;
+  return true;
+}
+
 } // namespace Resolver
 } // namespace Rust

gcc/rust/resolve/rust-name-resolver.h

@@ -126,6 +126,9 @@ public:
   void insert_resolved_macro (NodeId refId, NodeId defId);
   bool lookup_resolved_macro (NodeId refId, NodeId *defId);
 
+  void insert_resolved_misc (NodeId refId, NodeId defId);
+  bool lookup_resolved_misc (NodeId refId, NodeId *defId);
+
   // proxy for scoping
   Scope &get_name_scope () { return name_scope; }
   Scope &get_type_scope () { return type_scope; }
@@ -202,6 +205,9 @@ private:
   std::map<NodeId, NodeId> resolved_labels;
   std::map<NodeId, NodeId> resolved_macros;
 
+  // misc
+  std::map<NodeId, NodeId> misc_resolved_items;
+
   // keep track of the current module scope ids
   std::vector<NodeId> current_module_stack;
 };

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

@@ -462,6 +462,11 @@ TypeCheckExpr::resolve_segments (NodeId root_resolved_node_id,
       resolver->insert_resolved_type (expr_mappings.get_nodeid (),
 				      resolved_node_id);
     }
+  else
+    {
+      resolver->insert_resolved_misc (expr_mappings.get_nodeid (),
+				      resolved_node_id);
+    }
 
   infered = tyseg;
 }

gcc/testsuite/rust/compile/issue-1272.rs

@@ -0,0 +1,8 @@
+fn main() -> i32 {
+    enum E {
+        X(u8),
+    }
+    let _v = E::X(4);
+
+    0
+}