Implement P1946R0, Allow defaulting comparisons by value.

	* method.c (early_check_defaulted_comparison): Accept by-value,
	reject mixed by-value and by-reference parms.
	* decl.c (grokdeclarator): Set funcdef_flag for defaulted friend.
	* decl2.c (grokfield): Don't SET_DECL_FRIEND_CONTEXT.

From-SVN: r278078

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 7e5e446a8287ff855715bf9635ed5b16df49d1cf..23339b6fc762a12fc716a305a819d07871ffa9df 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,11 @@
 2019-11-11  Jason Merrill  <jason@redhat.com>
 
+       Implement P1946R0, Allow defaulting comparisons by value.
+       * method.c (early_check_defaulted_comparison): Accept by-value,
+       reject mixed by-value and by-reference parms.
+       * decl.c (grokdeclarator): Set funcdef_flag for defaulted friend.
+       * decl2.c (grokfield): Don't SET_DECL_FRIEND_CONTEXT.
+
        * typeck.c (cp_build_binary_op): Sorry about <=> on VECTOR_TYPE.
 
 2019-11-11  Jakub Jelinek  <jakub@redhat.com>

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index caa04afe805bff3e16a46af5161a9b5cf8bf3868..86e38f4af691a51b98adeb01a408eaad715d7404 100644 (file)
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -13202,6 +13202,11 @@ grokdeclarator (const cp_declarator *declarator,
              ;  /* We already issued a permerror.  */
            else if (decl && DECL_NAME (decl))
              {
+               if (initialized)
+                 /* Kludge: We need funcdef_flag to be true in do_friend for
+                    in-class defaulted functions, but that breaks grokfndecl.
+                    So set it here.  */
+                 funcdef_flag = true;
                if (template_class_depth (current_class_type) == 0)
                  {
                    decl = check_explicit_specialization

diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 4f0b2161db1fdca8bed6571db793e03ecc0c0d98..f164494afdc6c19b523f6e54e45a08bc5d9923fd 100644 (file)
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -927,10 +927,6 @@ grokfield (const cp_declarator *declarator,
            }
          else if (init == ridpointers[(int)RID_DEFAULT])
            {
-             if (friendp)
-               /* ??? do_friend doesn't set this because funcdef_flag is false
-                  for in-class defaulted functions.  So set it here.  */
-               SET_DECL_FRIEND_CONTEXT (value, current_class_type);
              if (defaultable_fn_check (value))
                {
                  DECL_DEFAULTED_FN (value) = 1;

diff --git a/gcc/cp/method.c b/gcc/cp/method.c
index 47441c10c52fb1ea4e5b320402120aa21ef021ec..acba6c6da8ce38f14eb5259ecf9b71b9aae95fd6 100644 (file)
--- a/gcc/cp/method.c
+++ b/gcc/cp/method.c
@@ -1094,38 +1094,54 @@ early_check_defaulted_comparison (tree fn)
   if (!DECL_OVERLOADED_OPERATOR_IS (fn, SPACESHIP_EXPR)
       && !same_type_p (TREE_TYPE (TREE_TYPE (fn)), boolean_type_node))
     {
-      error_at (loc, "defaulted %qD must return %<bool%>", fn);
-      ok = false;
+      diagnostic_t kind = DK_UNSPECIFIED;
+      int opt = 0;
+      if (is_auto (TREE_TYPE (fn)))
+       kind = DK_PEDWARN;
+      else
+       kind = DK_ERROR;
+      emit_diagnostic (kind, loc, opt,
+                      "defaulted %qD must return %<bool%>", fn);
+      if (kind == DK_ERROR)
+       ok = false;
     }
 
-  int i = DECL_NONSTATIC_MEMBER_FUNCTION_P (fn);
-  if (i && type_memfn_quals (TREE_TYPE (fn)) != TYPE_QUAL_CONST)
+  bool mem = DECL_NONSTATIC_MEMBER_FUNCTION_P (fn);
+  if (mem && type_memfn_quals (TREE_TYPE (fn)) != TYPE_QUAL_CONST)
     {
       error_at (loc, "defaulted %qD must be %<const%>", fn);
       ok = false;
     }
   tree parmnode = FUNCTION_FIRST_USER_PARMTYPE (fn);
+  bool saw_byval = false;
+  bool saw_byref = mem;
+  bool saw_bad = false;
   for (; parmnode != void_list_node; parmnode = TREE_CHAIN (parmnode))
     {
-      ++i;
       tree parmtype = TREE_VALUE (parmnode);
-      diagnostic_t kind = DK_UNSPECIFIED;
-      int opt = 0;
       if (same_type_p (parmtype, ctx))
-       /* The draft specifies const reference, but let's also allow by-value
-          unless -Wpedantic, hopefully it will be added soon. */
-       kind = DK_PEDWARN,
-         opt = OPT_Wpedantic;
+       saw_byval = true;
       else if (TREE_CODE (parmtype) != REFERENCE_TYPE
               || TYPE_QUALS (TREE_TYPE (parmtype)) != TYPE_QUAL_CONST
               || !(same_type_ignoring_top_level_qualifiers_p
                    (TREE_TYPE (parmtype), ctx)))
-       kind = DK_ERROR;
-      if (kind)
-       emit_diagnostic (kind, loc, opt, "defaulted %qD must have "
-                        "parameter type %<const %T&%>", fn, ctx);
-      if (kind == DK_ERROR)
-       ok = false;
+       saw_bad = true;
+      else
+       saw_byref = true;
+    }
+
+  if (saw_bad || (saw_byval && saw_byref))
+    {
+      if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn))
+       error_at (loc, "defaulted member %qD must have parameter type "
+                 "%<const %T&%>", fn, ctx);
+      else if (saw_bad)
+       error_at (loc, "defaulted %qD must have parameters of either type "
+                 "%<const %T&%> or %qT", fn, ctx, ctx);
+      else
+       error_at (loc, "defaulted %qD must have parameters of either type "
+                 "%<const %T&%> or %qT, not both", fn, ctx, ctx);
+      ok = false;
     }
 
   /* We still need to deduce deleted/constexpr/noexcept and maybe return. */

diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg1.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg1.C
new file mode 100644 (file)
index 0000000..f9b2dc4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg1.C
@@ -0,0 +1,29 @@
+// { dg-do compile { target c++2a } }
+
+#include <compare>
+
+template <class T>
+struct D
+{
+  T i;
+  auto operator<=>(D) const = default; // { dg-error "defaulted member" }
+  bool operator==(D) const = default; // { dg-error "defaulted member" }
+  bool operator!=(D) const = default; // { dg-error "defaulted member" }
+  bool operator<(D) const = default; // { dg-error "defaulted member" }
+  bool operator<=(D) const = default; // { dg-error "defaulted member" }
+  bool operator>(D) const = default; // { dg-error "defaulted member" }
+  bool operator>=(D) const = default; // { dg-error "defaulted member" }
+};
+
+template <class T>
+struct E
+{
+  T i;
+  friend auto operator<=>(const E&, E) = default; // { dg-error "not both" }
+  friend bool operator==(const E&, E) = default; // { dg-error "not both" }
+  friend bool operator!=(const E&, E) = default; // { dg-error "not both" }
+  friend bool operator<(E, const E&) = default; // { dg-error "not both" }
+  friend bool operator<=(E, const E&) = default; // { dg-error "not both" }
+  friend bool operator>(E, const E&) = default; // { dg-error "not both" }
+  friend bool operator>=(E, const E&) = default; // { dg-error "not both" }
+};

diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth4.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth4.C
new file mode 100644 (file)
index 0000000..0335781
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth4.C
@@ -0,0 +1,43 @@
+// Test with all operators explicitly defaulted.
+// { dg-do run { target c++2a } }
+
+#include <compare>
+
+struct D
+{
+  int i;
+  friend auto operator<=>(const D& x, const D& y) = default;
+  friend bool operator==(const D& x, const D& y) = default;
+  friend bool operator!=(const D& x, const D& y) = default;
+  friend bool operator<(const D& x, const D& y) = default;
+  friend bool operator<=(const D& x, const D& y) = default;
+  friend bool operator>(const D& x, const D& y) = default;
+  friend bool operator>=(const D& x, const D& y) = default;
+};
+
+#define assert(X) do { if (!(X)) __builtin_abort(); } while (0)
+
+int main()
+{
+  D d{42};
+  D d2{24};
+
+  assert (is_eq (d <=> d));
+  assert (is_lteq (d <=> d));
+  assert (is_gteq (d <=> d));
+  assert (is_lt (d2 <=> d));
+  assert (is_lteq (d2 <=> d));
+  assert (is_gt (d <=> d2));
+  assert (is_gteq (d <=> d2));
+
+  assert (d == d);
+  assert (!(d2 == d));
+  assert (!(d == d2));
+  assert (d != d2);
+  assert (!(d2 != d2));
+
+  assert (d2 < d);
+  assert (d2 <= d);
+  assert (d > d2);
+  assert (d >= d2);
+}

diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth5.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth5.C
new file mode 100644 (file)
index 0000000..8e4aa86
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth5.C
@@ -0,0 +1,43 @@
+// Test with all operators explicitly defaulted.
+// { dg-do run { target c++2a } }
+
+#include <compare>
+
+struct D
+{
+  int i;
+  friend auto operator<=>(D x, D y) = default;
+  friend bool operator==(D x, D y) = default;
+  friend bool operator!=(D x, D y) = default;
+  friend bool operator<(D x, D y) = default;
+  friend bool operator<=(D x, D y) = default;
+  friend bool operator>(D x, D y) = default;
+  friend bool operator>=(const D x, const D y) = default;
+};
+
+#define assert(X) do { if (!(X)) __builtin_abort(); } while (0)
+
+int main()
+{
+  D d{42};
+  D d2{24};
+
+  assert (is_eq (d <=> d));
+  assert (is_lteq (d <=> d));
+  assert (is_gteq (d <=> d));
+  assert (is_lt (d2 <=> d));
+  assert (is_lteq (d2 <=> d));
+  assert (is_gt (d <=> d2));
+  assert (is_gteq (d <=> d2));
+
+  assert (d == d);
+  assert (!(d2 == d));
+  assert (!(d == d2));
+  assert (d != d2);
+  assert (!(d2 != d2));
+
+  assert (d2 < d);
+  assert (d2 <= d);
+  assert (d > d2);
+  assert (d >= d2);
+}