From 19c9526512aba74a506f847f3800f38163320743 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Fri, 29 Dec 2023 20:37:57 +0000
Subject: [PATCH] Fix crash with aliased enumeration literal in case choice

Fixes #819
---
 src/common.c             |  6 ++----
 test/bounds/issue819.vhd | 39 +++++++++++++++++++++++++++++++++++++++
 test/test_bounds.c       | 11 +++++++++++
 3 files changed, 52 insertions(+), 4 deletions(-)
 create mode 100644 test/bounds/issue819.vhd

diff --git a/src/common.c b/src/common.c
index d3638912..74acaf28 100644
--- a/src/common.c
+++ b/src/common.c
@@ -1487,10 +1487,8 @@ unsigned get_case_choice_char(tree_t value, int depth)
 {
    switch (tree_kind(value)) {
    case T_STRING:
-      if (depth < tree_chars(value)) {
-         tree_t ch = tree_char(value, depth);
-         return tree_pos(tree_ref(ch));
-      }
+      if (depth < tree_chars(value))
+         return assume_int(tree_char(value, depth));
       else
          return ~0;   // Out of bounds
 
diff --git a/test/bounds/issue819.vhd b/test/bounds/issue819.vhd
new file mode 100644
index 00000000..9d449ce2
--- /dev/null
+++ b/test/bounds/issue819.vhd
@@ -0,0 +1,39 @@
+package my_logic is
+    type std_ulogic is ('0', '1');
+    type std_ulogic_vector is array (natural range <>) of std_ulogic;
+    type unsigned is array (natural range <>) of std_ulogic;
+    type signed is array (natural range <>) of std_ulogic;
+end package;
+
+-------------------------------------------------------------------------------
+
+use work.my_logic.all;
+
+package uCPUtypes is
+  alias logic is std_ulogic;
+  alias logic_vec is std_ulogic_vector;
+end package uCPUtypes;
+
+-------------------------------------------------------------------------------
+
+use work.uCPUtypes.all;
+
+entity uCPU is
+end entity uCPU;
+
+architecture RTL of uCPU is
+
+    signal rom_data : logic_vec(11 downto 0);
+
+begin
+
+--------------- combination logic ----------------
+
+    process (rom_data) is
+    begin
+        case rom_data(11 downto 10) is
+            when "00" => null;
+            when others => null;
+        end case;
+    end process;
+end architecture RTL;
diff --git a/test/test_bounds.c b/test/test_bounds.c
index 9614d13f..c190670a 100644
--- a/test/test_bounds.c
+++ b/test/test_bounds.c
@@ -693,6 +693,16 @@ START_TEST(test_issue806)
 }
 END_TEST
 
+START_TEST(test_issue819)
+{
+   input_from_file(TESTDIR "/bounds/issue819.vhd");
+
+   parse_check_and_simplify(T_PACKAGE, T_PACKAGE, T_ENTITY, T_ARCH);
+
+   fail_if_errors();
+}
+END_TEST
+
 Suite *get_bounds_tests(void)
 {
    Suite *s = suite_create("bounds");
@@ -729,6 +739,7 @@ Suite *get_bounds_tests(void)
    tcase_add_test(tc_core, test_case5);
    tcase_add_test(tc_core, test_issue800);
    tcase_add_test(tc_core, test_issue806);
+   tcase_add_test(tc_core, test_issue819);
    suite_add_tcase(s, tc_core);
 
    return s;
-- 
2.39.2