[gcc/devel/c++-modules] c++: satisfaction value of type typedef to bool [PR95386]

[gcc/devel/c++-modules] c++: satisfaction value of type typedef to bool [PR95386]

[Nathan Sidwell]

https://gcc.gnu.org/g:aef6e234a8a78db39b4ba034cc4c100c07c294a7

commit aef6e234a8a78db39b4ba034cc4c100c07c294a7
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri May 29 21:12:21 2020 -0400

    c++: satisfaction value of type typedef to bool [PR95386]
    
    In the testcase below, the satisfaction value of fn1<int>'s constraint
    is INTEGER_CST '1' of type BOOLEAN_TYPE value_type, which is a typedef
    to the standard boolean_type_node.  But satisfaction_value expects to
    see exactly boolean_true_node or integer_one_node, which this value is
    neither, causing us to trip over the assert therein.
    
    This patch changes satisfaction_value to accept INTEGER_CST of any
    boolean type.
    
    gcc/cp/ChangeLog:
    
            PR c++/95386
            * constraint.cc (satisfaction_value): Accept INTEGER_CST of any
            boolean type.
    
    gcc/testsuite/ChangeLog:
    
            PR c++/95386
            * g++.dg/concepts/pr95386.C: New test.

Diff:
---
 gcc/cp/constraint.cc                    | 14 +++++++-------
 gcc/testsuite/g++.dg/concepts/pr95386.C | 11 +++++++++++
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index eb72bfe5936..92ff283013e 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -2490,15 +2490,15 @@ satisfy_disjunction (tree t, tree args, subst_info info)
 tree
 satisfaction_value (tree t)
 {
-  if (t == error_mark_node)
+  if (t == error_mark_node || t == boolean_true_node || t == boolean_false_node)
     return t;
-  if (t == boolean_true_node || t == integer_one_node)
-    return boolean_true_node;
-  if (t == boolean_false_node || t == integer_zero_node)
-    return boolean_false_node;
 
-  /* Anything else should be invalid.  */
-  gcc_assert (false);
+  gcc_assert (TREE_CODE (t) == INTEGER_CST
+	      && same_type_p (TREE_TYPE (t), boolean_type_node));
+  if (integer_zerop (t))
+    return boolean_false_node;
+  else
+    return boolean_true_node;
 }
 
 /* Build a new template argument list with template arguments corresponding
diff --git a/gcc/testsuite/g++.dg/concepts/pr95386.C b/gcc/testsuite/g++.dg/concepts/pr95386.C
new file mode 100644
index 00000000000..3c683e5693c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/concepts/pr95386.C
@@ -0,0 +1,11 @@
+// PR c++/95386
+// { dg-do compile { target concepts } }
+
+template <typename> struct blah {
+ typedef bool value_type;
+ constexpr operator value_type() { return false; }
+};
+
+template <class T> void fn1(T) requires (!blah<T>());
+
+void fn2() { fn1(0); }