Implement N2439 (ref-qualifiers for 'this')

	Implement N2439 (ref-qualifiers for 'this')
	* cp-tree.h (FUNCTION_REF_QUALIFIED): New.
	(FUNCTION_RVALUE_QUALIFIED): New.
	(FUNCTION_OR_METHOD_TYPE_CHECK): New.
	(cpp0x_warn_str): Add CPP0X_REF_QUALIFIER.
	(cp_ref_qualifier): New enum.
	(cp_declarator): Add ref_qualifier.
	* parser.c (cp_parser_ref_qualifier_seq_opt): New.
	(cp_parser_direct_declarator): Use it.
	(make_call_declarator): Adjust.
	(cp_parser_lambda_declarator_opt): Adjust.
	* call.c (add_function_candidate): Handle ref-qualifier overload
	resolution semantics.
	(standard_conversion): Adjust.
	* class.c (add_method, same_signature_p): Compare ref-qualifiers.
	* decl.c (grokdeclarator): Handle ref-qualifiers.
	(grokfndecl): Check for invalid ref-qualifiers.
	(static_fn_type, revert_static_member_fn): Adjust.
	* decl2.c (build_memfn_type): Handle ref-qualifiers.
	(check_classfn): Check them.
	(cp_reconstruct_complex_type): Retain them.
	* error.c (dump_ref_qualifier): New.
	(dump_type_suffix, dump_function_decl): Use it.
	(maybe_warn_cpp0x): Handle CPP0X_REF_QUALIFIER.
	* pt.c (tsubst, tsubst_function_type): Instantiate ref-quals.
	(unify): Retain them.
	* tree.c (cp_check_qualified_type): New.
	(cp_build_qualified_type_real): Keep exception spec and ref-qual.
	(build_ref_qualified_type): New.
	(strip_typedefs, build_exception_variant): Keep ref-qualifier.
	(cp_build_type_attribute_variant): Keep ref-qualifier.
	* typeck.c (merge_types): Keep ref-qualifier.
	(structural_comptypes): Compare ref-qualifier.
	(type_memfn_rqual): New.
	(apply_memfn_quals): Take ref-qual argument.
	* typeck2.c (build_m_component_ref): Check ref-qualifier.

Co-Authored-By: Jason Merrill <jason@redhat.com>

From-SVN: r197315

1 files changed, 78 insertions, 5 deletions

diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 7fb8698..ce9568c 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1081,6 +1081,15 @@ cp_build_qualified_type_real (tree type,
   /* Retrieve (or create) the appropriately qualified variant.  */
   result = build_qualified_type (type, type_quals);
 
+  /* Preserve exception specs and ref-qualifier since build_qualified_type
+     doesn't know about them.  */
+  if (TREE_CODE (result) == FUNCTION_TYPE
+      || TREE_CODE (result) == METHOD_TYPE)
+    {
+      result = build_exception_variant (result, TYPE_RAISES_EXCEPTIONS (type));
+      result = build_ref_qualified_type (result, type_memfn_rqual (type));
+    }
+
   /* If this was a pointer-to-method type, and we just made a copy,
      then we need to unshare the record that holds the cached
      pointer-to-member-function type, because these will be distinct
@@ -1214,7 +1223,9 @@ strip_typedefs (tree t)
 	  {
 	    result = build_function_type (type,
 					  arg_types);
-	    result = apply_memfn_quals (result, type_memfn_quals (t));
+	    result = apply_memfn_quals (result,
+					type_memfn_quals (t),
+					type_memfn_rqual (t));
 	  }
 
 	if (TYPE_RAISES_EXCEPTIONS (t))
@@ -1702,6 +1713,64 @@ build_qualified_name (tree type, tree scope, tree name, bool template_p)
   return t;
 }
 
+/* Like check_qualified_type, but also check ref-qualifier and exception
+   specification.  */
+
+static bool
+cp_check_qualified_type (const_tree cand, const_tree base, int type_quals,
+			 cp_ref_qualifier rqual, tree raises)
+{
+  return (check_qualified_type (cand, base, type_quals)
+	  && comp_except_specs (raises, TYPE_RAISES_EXCEPTIONS (cand),
+				ce_exact)
+	  && type_memfn_rqual (cand) == rqual);
+}
+
+/* Build the FUNCTION_TYPE or METHOD_TYPE with the ref-qualifier RQUAL.  */
+
+tree
+build_ref_qualified_type (tree type, cp_ref_qualifier rqual)
+{
+  tree t;
+
+  if (rqual == type_memfn_rqual (type))
+    return type;
+
+  int type_quals = TYPE_QUALS (type);
+  tree raises = TYPE_RAISES_EXCEPTIONS (type);
+  for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
+    if (cp_check_qualified_type (t, type, type_quals, rqual, raises))
+      return t;
+
+  t = build_variant_type_copy (type);
+  switch (rqual)
+    {
+    case REF_QUAL_RVALUE:
+      FUNCTION_RVALUE_QUALIFIED (t) = 1;
+      /* Intentional fall through */
+    case REF_QUAL_LVALUE:
+      FUNCTION_REF_QUALIFIED (t) = 1;
+      break;
+    default:
+      FUNCTION_REF_QUALIFIED (t) = 0;
+      break;
+    }
+
+  if (TYPE_STRUCTURAL_EQUALITY_P (type))
+    /* Propagate structural equality. */
+    SET_TYPE_STRUCTURAL_EQUALITY (t);
+  else if (TYPE_CANONICAL (type) != type)
+    /* Build the underlying canonical type, since it is different
+       from TYPE. */
+    TYPE_CANONICAL (t) = build_ref_qualified_type (TYPE_CANONICAL (type),
+						   rqual);
+  else
+    /* T is its own canonical type. */
+    TYPE_CANONICAL (t) = t;
+
+  return t;
+}
+
 /* Returns nonzero if X is an expression for a (possibly overloaded)
    function.  If "f" is a function or function template, "f", "c->f",
    "c.f", "C::f", and "f<int>" will all be considered possibly
@@ -1907,9 +1976,9 @@ build_exception_variant (tree type, tree raises)
     return type;
 
   type_quals = TYPE_QUALS (type);
+  cp_ref_qualifier rqual = type_memfn_rqual (type);
   for (v = TYPE_MAIN_VARIANT (type); v; v = TYPE_NEXT_VARIANT (v))
-    if (check_qualified_type (v, type, type_quals)
-	&& comp_except_specs (raises, TYPE_RAISES_EXCEPTIONS (v), ce_exact))
+    if (cp_check_qualified_type (v, type, type_quals, rqual, raises))
       return v;
 
   /* Need to build a new variant.  */
@@ -3308,8 +3377,12 @@ cp_build_type_attribute_variant (tree type, tree attributes)
   new_type = build_type_attribute_variant (type, attributes);
   if (TREE_CODE (new_type) == FUNCTION_TYPE
       || TREE_CODE (new_type) == METHOD_TYPE)
-    new_type = build_exception_variant (new_type,
-					TYPE_RAISES_EXCEPTIONS (type));
+    {
+      new_type = build_exception_variant (new_type,
+					  TYPE_RAISES_EXCEPTIONS (type));
+      new_type = build_ref_qualified_type (new_type,
+					   type_memfn_rqual (type));
+    }
 
   /* Making a new main variant of a class type is broken.  */
   gcc_assert (!CLASS_TYPE_P (type) || new_type == type);