From e71908840804bbc8e31d700d659dd25675a9f374 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Tue, 9 Apr 2024 21:41:00 +0100
Subject: [PATCH] Handle force/release in all-sensitised process. Fixes #877

---
 src/common.c              |  5 +++++
 test/regress/issue877.vhd | 47 +++++++++++++++++++++++++++++++++++++++
 test/regress/testlist.txt |  1 +
 3 files changed, 53 insertions(+)
 create mode 100644 test/regress/issue877.vhd

diff --git a/src/common.c b/src/common.c
index b073f970..41fe9697 100644
--- a/src/common.c
+++ b/src/common.c
@@ -2242,10 +2242,15 @@ void build_wait(tree_t expr, build_wait_fn_t fn, void *ctx)
       break;
 
    case T_VAR_ASSIGN:
+   case T_FORCE:
       build_wait_for_target(tree_target(expr), fn, ctx);
       build_wait(tree_value(expr), fn, ctx);
       break;
 
+   case T_RELEASE:
+      build_wait_for_target(tree_target(expr), fn, ctx);
+      break;
+
    case T_CASE:
    case T_MATCH_CASE:
       {
diff --git a/test/regress/issue877.vhd b/test/regress/issue877.vhd
new file mode 100644
index 00000000..6165e698
--- /dev/null
+++ b/test/regress/issue877.vhd
@@ -0,0 +1,47 @@
+entity sub is
+    port ( o : out natural );
+end entity;
+
+architecture test of sub is
+    signal s : natural;
+begin
+    o <= s + 1 after 1 ns;
+end architecture;
+
+-------------------------------------------------------------------------------
+
+entity issue877 is
+end entity;
+
+architecture test of issue877 is
+    signal x : natural;
+begin
+
+    uut: entity work.sub
+        port map ( x );
+
+    update: process (all) is
+        alias s is << signal uut.s : natural >>;
+    begin
+        if x = 10 then
+            s <= release;
+        else
+            s <= force x;
+        end if;
+    end process;
+
+    check: process is
+    begin
+        wait for 1 ns;
+        assert x = 1;
+        wait for 1 ns;
+        assert x = 2;
+        wait for 8 ns;
+        assert x = 10;
+        wait for 1 ns;
+        assert x = 1;
+        std.env.finish;
+        wait;
+    end process;
+
+end architecture;
diff --git a/test/regress/testlist.txt b/test/regress/testlist.txt
index 1e4a95b5..314a46f3 100644
--- a/test/regress/testlist.txt
+++ b/test/regress/testlist.txt
@@ -963,3 +963,4 @@ issue873        normal
 array19         normal
 issue874        normal,2008
 vhpi14          normal,vhpi
+issue877        normal,2008
-- 
2.39.2