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.

Author: Patrick Palka

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

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); }