From fca87fda9f011b69891cbf1663c1553b34546c8a Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Thu, 10 Nov 2022 21:46:01 +0000
Subject: [PATCH] Fix error with condition conversion ambiguity. Issue #568

---
 src/names.c             | 74 ++++++++++++++++++++++++++++++-----------
 test/parse/issue568.vhd | 15 +++++++++
 test/test_parse.c       | 27 +++++++++++++++
 3 files changed, 97 insertions(+), 19 deletions(-)
 create mode 100644 test/parse/issue568.vhd

diff --git a/src/names.c b/src/names.c
index 8bb318ee..c593eab6 100644
--- a/src/names.c
+++ b/src/names.c
@@ -2768,6 +2768,21 @@ static bool is_unambiguous(tree_t t)
       || (kind == T_REF && tree_has_ref(t));
 }
 
+static bool is_unambiguous_fcall(tree_t t)
+{
+   if (tree_kind(t) == T_FCALL) {
+      const int nparams = tree_params(t);
+      for (int i = 0; i < nparams; i++) {
+         if (!is_unambiguous(tree_value(tree_param(t, i))))
+            return false;
+      }
+
+      return true;
+   }
+
+   return false;
+}
+
 static type_list_t possible_types(nametab_t *tab, tree_t value)
 {
    tree_kind_t kind = tree_kind(value);
@@ -2849,31 +2864,52 @@ static void solve_subprogram_params(nametab_t *tab, tree_t call, overload_t *o)
       }
    }
 
-   // Make two additional passes: one to do function calls and a final
-   // catch-all
+   // Solve all parameters which are function calls with unambiguous
+   // arguments
 
-   for (int pass = 0; pass < 2; pass++) {
-      for (int i = 0; i < nparams; i++) {
-         if (pmask & (1 << i))
-            continue;
+   for (int i = 0; i < nparams; i++) {
+      if (pmask & (1 << i))
+         continue;
 
-         tree_t p = tree_param(call, i);
-         tree_t value = tree_value(p);
-         tree_kind_t kind = tree_kind(value);
+      tree_t p = tree_param(call, i);
+      tree_t value = tree_value(p);
 
-         if (o->error && o->initial == 0) {
-            // Avoid cascading errors from an undefined subprogram
-            tree_set_type(value, type_new(T_NONE));
-            pmask |= 1 << i;
-            continue;
-         }
+      if (o->error && o->initial == 0) {
+         // Avoid cascading errors from an undefined subprogram
+         tree_set_type(value, type_new(T_NONE));
+         pmask |= 1 << i;
+      }
+      else if (is_unambiguous_fcall(value)) {
+         solve_one_param(tab, p, o);
+         pmask |= (1 << i);
+      }
+   }
 
-         if (kind == T_FCALL || pass == 1) {
-            solve_one_param(tab, p, o);
-            pmask |= (1 << i);
-         }
+   // Solve all remaining function call parameters
+
+   for (int i = 0; i < nparams; i++) {
+      if (pmask & (1 << i))
+         continue;
+
+      tree_t p = tree_param(call, i);
+      tree_t value = tree_value(p);
+
+      if (tree_kind(value) == T_FCALL) {
+         solve_one_param(tab, p, o);
+         pmask |= (1 << i);
       }
    }
+
+   // Catch-all pass for remaining parameters
+
+   for (int i = 0; i < nparams; i++) {
+      if (pmask & (1 << i))
+         continue;
+
+      tree_t p = tree_param(call, i);
+      solve_one_param(tab, p, o);
+      pmask |= (1 << i);
+   }
 }
 
 static bool can_call_no_args(nametab_t *tab, tree_t decl)
diff --git a/test/parse/issue568.vhd b/test/parse/issue568.vhd
new file mode 100644
index 00000000..399d35c4
--- /dev/null
+++ b/test/parse/issue568.vhd
@@ -0,0 +1,15 @@
+package pack is
+    function "=" (L: bit; R: bit) return bit;
+end package;
+
+use work.pack.all;
+
+entity issue568 is
+    generic (x : boolean);
+end entity;
+
+architecture test of issue568 is
+    signal y : bit;
+begin
+    p1: assert (y = '1') or (not x);
+end architecture;
diff --git a/test/test_parse.c b/test/test_parse.c
index 8f0ad32b..20a923a4 100644
--- a/test/test_parse.c
+++ b/test/test_parse.c
@@ -4968,6 +4968,32 @@ START_TEST(test_issue539)
 }
 END_TEST
 
+START_TEST(test_issue568)
+{
+   set_standard(STD_08);
+
+   input_from_file(TESTDIR "/parse/issue568.vhd");
+
+   tree_t p = parse();
+   fail_if(p == NULL);
+   fail_unless(tree_kind(p) == T_PACKAGE);
+   lib_put(lib_work(), p);
+
+   tree_t e = parse();
+   fail_if(e == NULL);
+   fail_unless(tree_kind(e) == T_ENTITY);
+   lib_put(lib_work(), e);
+
+   tree_t a = parse();
+   fail_if(a == NULL);
+   fail_unless(tree_kind(a) == T_ARCH);
+
+   fail_unless(parse() == NULL);
+
+   fail_if_errors();
+}
+END_TEST
+
 Suite *get_parse_tests(void)
 {
    Suite *s = suite_create("parse");
@@ -5064,6 +5090,7 @@ Suite *get_parse_tests(void)
    tcase_add_test(tc_core, test_typo);
    tcase_add_test(tc_core, test_issue532);
    tcase_add_test(tc_core, test_issue539);
+   tcase_add_test(tc_core, test_issue568);
    suite_add_tcase(s, tc_core);
 
    return s;
-- 
2.39.2