From 0fffc0e772d612d5c6ad72a632ac80b43eca1950 Mon Sep 17 00:00:00 2001
From: Philip Herron <philip.herron@embecosm.com>
Date: Wed, 31 Aug 2022 17:16:13 +0100
Subject: [PATCH] gccrs: Unit structs are not concrete when they need
 substitutions

Fixes #1518

gcc/rust/ChangeLog:

	* typecheck/rust-tyty.h: Fix `is_concrete` for unit types with
	substitutions.
---
 gcc/rust/typecheck/rust-tyty.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gcc/rust/typecheck/rust-tyty.h b/gcc/rust/typecheck/rust-tyty.h
index 24efc7aa54c3..43460d2dd2f3 100644
--- a/gcc/rust/typecheck/rust-tyty.h
+++ b/gcc/rust/typecheck/rust-tyty.h
@@ -1362,6 +1362,11 @@ public:
 
   bool is_concrete () const override final
   {
+    if (is_unit ())
+      {
+	return !needs_substitution ();
+      }
+
     for (auto &variant : variants)
       {
 	for (auto &field : variant->get_fields ())
-- 
2.47.2