From f11ed24075538b660cd14571b87417d0ce5d2275 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Thu, 17 Nov 2022 21:47:11 +0000
Subject: [PATCH] Incorrect application of implicit condition conversion. Issue
 #571

---
 src/names.c                | 24 +++++++++++----
 test/regress/operator6.vhd | 61 ++++++++++++++++++++++++++++++++++++++
 test/regress/testlist.txt  |  1 +
 3 files changed, 81 insertions(+), 5 deletions(-)
 create mode 100644 test/regress/operator6.vhd

diff --git a/src/names.c b/src/names.c
index f812c588..2e4ff23a 100644
--- a/src/names.c
+++ b/src/names.c
@@ -2432,6 +2432,19 @@ static void overload_push_names(overload_t *o)
    o->state = O_NAMED;
 }
 
+static void overload_add_argument_type(overload_t *o, type_t type, tree_t d)
+{
+   type_set_t *ts = o->nametab->top_type_set;
+   if (ts->down && ts->down->cconv && !ts->cconv) {
+      // Boolean interpretation should be preferred in case of ambiguity
+      type_t boolean = std_type(NULL, STD_BOOLEAN);
+      if (type_eq(type, boolean))
+         ts->cconv = true;
+   }
+
+   type_set_add(o->nametab, type, d);
+}
+
 static void overload_positional_argument(overload_t *o, int pos)
 {
    if (o == NULL)
@@ -2450,7 +2463,7 @@ static void overload_positional_argument(overload_t *o, int pos)
       tree_t d = o->candidates.items[i];
       if (pos < tree_ports(d)) {
          tree_t p = tree_port(d, pos);
-         type_set_add(o->nametab, tree_type(p), d);
+         overload_add_argument_type(o, tree_type(p), d);
          o->candidates.items[wptr++] = d;
       }
       else if (o->initial > 1)
@@ -2511,12 +2524,13 @@ static void overload_named_argument(overload_t *o, tree_t name)
                   if (field == NULL)
                      continue;   // Argument does not have this field name
 
-                  type_set_add(o->nametab, tree_type(field),
-                               o->candidates.items[i]);
+                  overload_add_argument_type(o, tree_type(field),
+                                             o->candidates.items[i]);
                }
                break;
             default:
-               type_set_add(o->nametab, tree_type(p), o->candidates.items[i]);
+               overload_add_argument_type(o, tree_type(p),
+                                          o->candidates.items[i]);
                break;
             }
             port = p;
@@ -2930,7 +2944,7 @@ static void solve_subprogram_params(nametab_t *tab, tree_t call, overload_t *o)
       }
    }
 
-   // Solve all remaining function call parameters
+   // Solve all remaining parameters which are themselves function calls
 
    for (int i = 0; i < nparams; i++) {
       if (pmask & (1 << i))
diff --git a/test/regress/operator6.vhd b/test/regress/operator6.vhd
new file mode 100644
index 00000000..77c9ce36
--- /dev/null
+++ b/test/regress/operator6.vhd
@@ -0,0 +1,61 @@
+entity operator6 is
+end entity;
+
+architecture test of operator6 is
+
+  function "=" (L: bit; R: bit) return bit is
+  begin
+      report "custom bit =" severity failure;
+    return L xnor R;
+  end function "=";
+
+  function "/=" (L: bit; R: bit) return bit is
+  begin
+      report "custom bit /=" severity failure;
+    return L xor R;
+  end function "/=";
+
+  function "=" (L: bit_vector; R: bit_vector) return bit is
+  begin
+      report "custom bit_vector =" severity failure;
+    if L = R then
+      return '1';
+    else
+      return '0';
+    end if;
+  end function "=";
+
+  function "/=" (L: bit_vector; R: bit_vector) return bit is
+  begin
+      report "custom bit_vector /=" severity failure;
+    if L /= R then
+      return '1';
+    else
+      return '0';
+    end if;
+  end function "/=";
+
+  constant ID_FLAG_C_SHF : bit_vector(1 to 3) := "100";
+  constant ID_RMW_SHF : bit := '1';
+
+  -- ** Note: 3972750ns+1: Report Note: bad else: s1_id_flag_c = 4 s1_id_rmw = '0'
+
+  signal s1_id_flag_c : bit_vector(1 to 3) := ID_FLAG_C_SHF;
+  signal s1_id_rmw : bit := '0';
+
+begin
+
+    p1: process is
+    begin
+--        report "bad else: s1_id_flag_c = " & integer'image(to_integer(unsigned(s1_id_flag_c))) & " s1_id_rmw = " & bit'image(to_bit(s1_id_rmw));
+        if s1_id_flag_c = ID_FLAG_C_SHF then
+            report "s1_id_flag_c = ID_FLAG_C_SHF";
+        end if;
+        if s1_id_rmw /= ID_RMW_SHF then
+            report "s1_id_rmw /= ID_RMW_SHF";
+        end if;
+        assert s1_id_flag_c = ID_FLAG_C_SHF and s1_id_rmw /= ID_RMW_SHF;
+        wait;
+    end process;
+
+end architecture;
diff --git a/test/regress/testlist.txt b/test/regress/testlist.txt
index b511d711..f22c3aaa 100644
--- a/test/regress/testlist.txt
+++ b/test/regress/testlist.txt
@@ -690,3 +690,4 @@ record38        fail,gold,2008
 issue560        normal,2008
 issue570        normal,2008
 issue571        normal,2008,relaxed
+operator6       normal,2008
-- 
2.39.2