Diagnose certain constraint errors as hard errors, but otherwise treat them the…

Diagnose certain constraint errors as hard errors, but otherwise treat them the same as normal SFINAE-type errors.

2019-11-27  Andrew Sutton  <asutton@lock3software.com>

	Diagnose certain constraint errors as hard errors, but otherwise treat
	them the same as normal SFINAE-type errors. Also, generally clean up
	the satisfaction functions.

gcc/cp/
	* constexpr.c (cxx_eval_constant_expression): Use
	evaluate_concept_check.
	* constraint.cc (normalize_concept_definition): Accept a diagnostic
	flag and only cache when not diagnosing errors.
	(decl_satisfied_cache): Map to trees instead of bools.
	(satisfy_atom): Guarantee a location for the errors, propagate complain
	flags to force_rvalue, and emit errors for non-boolean constraints.
	(get_normalized_constraints_and_args): New overloads. Factored out of
	satisfy_constraint_expression and satisfy_declaration_constraints.
	(satisfy_constraint_expression): Propagate diagnostic info to
	normalization.
	(satisfy_declaration_constraints): New. Factored out of
	constraints_satisfied_p.
	(constraint_satisfaction_value): New. Calls
	satisfy_constraint_expression or satisfy_declaration_constraints.
	(constraints_satisfied_p): Call constraint_satisfaction_value.
	(evaluate_concept_check): Don't take tsubst_falgs_t. Replay
	satisfaction if an error is encountered.
	(current_failed_constraint): Moved from pt.c.
	(diagnose_constraints): Call constraint_satisfaction_value.
	* cp-tree.h: Update declarations.
	* pt.c (current_failed_constraint): Moved to constraint.cc.
	* semantics.c (finish_id_expression_1): Remove a duplicate case.

gcc/testsuite/
	* g++.dg/concepts/pr84330.C: Update diagnostics.
	* g++.dg/cpp2a/concepts-requires2.C: Likewise.

From-SVN: r278768

gcc/cp/ChangeLog

+2019-11-27  Andrew Sutton  <asutton@lock3software.com>
+
+	Diagnose certain constraint errors as hard errors, but otherwise treat
+	them the same as normal SFINAE-type errors. Also, generally clean up
+	the satisfaction functions.
+
+	* constexpr.c (cxx_eval_constant_expression): Use
+	evaluate_concept_check.
+	* constraint.cc (normalize_concept_definition): Accept a diagnostic
+	flag and only cache when not diagnosing errors.
+	(decl_satisfied_cache): Map to trees instead of bools.
+	(satisfy_atom): Guarantee a location for the errors, propagate complain
+	flags to force_rvalue, and emit errors for non-boolean constraints.
+	(get_normalized_constraints_and_args): New overloads. Factored out of
+	satisfy_constraint_expression and satisfy_declaration_constraints.
+	(satisfy_constraint_expression): Propagate diagnostic info to
+	normalization.
+	(satisfy_declaration_constraints): New. Factored out of
+	constraints_satisfied_p.
+	(constraint_satisfaction_value): New. Calls
+	satisfy_constraint_expression or satisfy_declaration_constraints.
+	(constraints_satisfied_p): Call constraint_satisfaction_value.
+	(evaluate_concept_check): Don't take tsubst_falgs_t. Replay
+	satisfaction if an error is encountered.
+	(current_failed_constraint): Moved from pt.c.
+	(diagnose_constraints): Call constraint_satisfaction_value.
+	* cp-tree.h: Update declarations.
+	* pt.c (current_failed_constraint): Moved to constraint.cc.
+	* semantics.c (finish_id_expression_1): Remove a duplicate case.
+
 2019-11-27  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/92524

gcc/cp/constexpr.c

@@ -5649,7 +5649,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 	  internal_error ("unexpected template-id %qE", t);
 
 	if (!processing_template_decl)
-	  return satisfy_constraint_expression (t);
+	  return evaluate_concept_check (t, tf_warning_or_error);
 	else
 	  *non_constant_p = true;
 	return t;

gcc/cp/cp-tree.h

@@ -7821,8 +7821,8 @@ extern bool processing_constraint_expression_p	();
 extern tree unpack_concept_check		(tree);
 extern tree evaluate_concept_check              (tree, tsubst_flags_t);
 extern tree satisfy_constraint_expression	(tree);
-extern bool constraints_satisfied_p             (tree);
-extern bool constraints_satisfied_p             (tree, tree);
+extern bool constraints_satisfied_p		(tree);
+extern bool constraints_satisfied_p		(tree, tree);
 extern void clear_satisfaction_cache		();
 extern bool* lookup_subsumption_result          (tree, tree);
 extern bool save_subsumption_result             (tree, tree, bool);

gcc/cp/error.c

@@ -3358,6 +3358,9 @@ cp_print_error_function (diagnostic_context *context,
      to be wrong, so just rely on print_instantiation_full_context.  */
   if (current_instantiation ())
     return;
+  /* The above is true for constraint satisfaction also.  */
+  if (current_failed_constraint)
+    return;
   if (diagnostic_last_function_changed (context, diagnostic))
     {
       char *old_prefix = pp_take_prefix (context->printer);

gcc/cp/pt.c

@@ -28736,8 +28736,6 @@ convert_generic_types_to_packs (tree parm, int start_idx, int end_idx)
   return tsubst (parm, replacement, tf_none, NULL_TREE);
 }
 
-GTY(()) tree current_failed_constraint;
-
 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
    0..N-1.  */
 

gcc/cp/semantics.c

@@ -3970,16 +3970,6 @@ finish_id_expression_1 (tree id_expression,
 
 	  decl = baselink_for_fns (decl);
 	}
-      else if (concept_check_p (decl))
-	{
-	  /* If this is a standard or variable concept check, potentially
-	     evaluate it. Function concepts need to be called as functions,
-	     so don't try evaluating them here.  */
-	  tree tmpl = TREE_OPERAND (decl, 0);
-	  tree args = TREE_OPERAND (decl, 1);
-	  if (!function_concept_p (tmpl) && !uses_template_parms (args))
-	    decl = evaluate_concept_check (decl, tf_warning_or_error);
-	}
       else
 	{
 	  if (DECL_P (decl) && DECL_NONLOCAL (decl)

gcc/testsuite/ChangeLog

+2019-11-27  Andrew Sutton  <asutton@lock3software.com>
+
+	Emit hard errors for certain satisfaction errors.
+	* g++.dg/concepts/pr84330.C: Update diagnostics.
+	* g++.dg/cpp2a/concepts-requires2.C: Likewise.
+
 2019-11-27  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/92690

gcc/testsuite/g++.dg/concepts/pr84330.C

@@ -5,7 +5,7 @@
 struct A
 {
   template<typename T>
-    requires (sizeof(T) >> 0)
+    requires (sizeof(T) >> 0) // { dg-error "constraint does not have type 'bool'" }
   void foo(T);
 
   void bar()

gcc/testsuite/g++.dg/cpp2a/concepts-requires2.C

@@ -12,7 +12,7 @@ template<typename T> constexpr fool p1() { return {}; }
 template<typename T> constexpr fool p2() { return {}; }
 
 template<typename T>
-concept Bad = p1<T>() && p2<T>();
+concept Bad = p1<T>() && p2<T>(); // { dg-error "does not have type 'bool'" }
 
 template<typename T> requires Bad<T> void bad(T x) { }
 
@@ -26,14 +26,14 @@ struct X { };
 int operator==(X, X) { return 0; }
 
 template<typename T>
-concept C1 = (X());
+concept C1 = (X()); // { dg-error "does not have type 'bool'" }
 
 template<typename T>
-concept C2 = (X() == X());
+concept C2 = (X() == X()); // { dg-error "does not have type 'bool'" }
 
 template<typename T>
   requires C1<T>
-void h1(T) { } 
+void h1(T) { }
 
 template<typename T>
   requires C2<T>
@@ -42,12 +42,12 @@ void h2(T);
 void driver_3()
 {
   h1(0); // { dg-error "" }
-  h2(0); // { dg-error "" } 
+  h2(0); // { dg-error "" }
 }
 
 // req7.C
 template<bool B>
-struct boolean_constant 
+struct boolean_constant
 {
   constexpr operator bool() const { return B; }
 };