class.c (instantiate_type): Don't treat template-ids that don't specify any template arguments as...

	* class.c (instantiate_type): Don't treat template-ids that don't
	specify any template arguments as equivalent to ordinary
	identifiers.  Use OFFSET_REF instead of SCOPE_REF to refer to
	pointer-to-members for member templates.  Tidy slightly.
	* cp-tree.def (TEMPLATE_ID_EXPR): Revise documentation.
	* init.c (build_offset_ref): Handle template-ids like ordinary
	identifiers, for the most part, but store a TEMPLATE_ID_EXPR in the
	offset part of the OFFSET_REF.
	* typeck.c (build_unary_op): Change check for unknown types to
	look for OFFSET_REFs, not SCOPE_REFs.

From-SVN: r20442

6 files changed, 94 insertions, 52 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5539b4c..aced365 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,16 @@
+1998-06-12  Mark Mitchell  <mark@markmitchell.com>
+
+	* class.c (instantiate_type): Don't treat template-ids that don't
+	specify any template arguments as equivalent to ordinary
+	identifiers.  Use OFFSET_REF instead of SCOPE_REF to refer to
+	pointer-to-members for member templates.  Tidy slightly.
+	* cp-tree.def (TEMPLATE_ID_EXPR): Revise documentation.
+	* init.c (build_offset_ref): Handle template-ids like ordinary
+	identifiers, for the most part, but store a TEMPLATE_ID_EXPR in the
+	offset part of the OFFSET_REF.
+	* typeck.c (build_unary_op): Change check for unknown types to
+	look for OFFSET_REFs, not SCOPE_REFs.
+
 1998-06-11  Mark Mitchell  <mark@markmitchell.com>
 
 	* pt.c (is_member_template_class): New function.
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 0e1aa26..6e3942f 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -4961,6 +4961,7 @@ instantiate_type (lhstype, rhs, complain)
      int complain;
 {
   tree explicit_targs = NULL_TREE;
+  int template_only = 0;
 
   if (TREE_CODE (lhstype) == UNKNOWN_TYPE)
     {
@@ -5090,38 +5091,28 @@ instantiate_type (lhstype, rhs, complain)
 	return rhs;
       }
 
-    case SCOPE_REF:
-      {
-	/* This can happen if we are forming a pointer-to-member for a
-	   member template.  */
-	tree template_id_expr = TREE_OPERAND (rhs, 1);
-	tree name;
-	my_friendly_assert (TREE_CODE (template_id_expr) == TEMPLATE_ID_EXPR,
-			    0);
-	explicit_targs = TREE_OPERAND (template_id_expr, 1);
-	name = TREE_OPERAND (template_id_expr, 0);
-	my_friendly_assert (TREE_CODE (name) == IDENTIFIER_NODE, 0);
-	rhs = lookup_fnfields (TYPE_BINFO (TREE_OPERAND (rhs, 0)), name, 1);
-	goto overload;
-      }
+    case OFFSET_REF:
+      /* This can happen if we are forming a pointer-to-member for a
+	 member template.  */
+      rhs = TREE_OPERAND (rhs, 1);
+      my_friendly_assert (TREE_CODE (rhs) == TEMPLATE_ID_EXPR, 0);
+	
+      /* Fall through.  */
 
     case TEMPLATE_ID_EXPR:
       {
 	explicit_targs = TREE_OPERAND (rhs, 1);
+	template_only = 1;
 	rhs = TREE_OPERAND (rhs, 0);
       }
       /* fall through */
       my_friendly_assert (TREE_CODE (rhs) == OVERLOAD, 980401);
 
     case OVERLOAD:
-    overload:
       {
 	tree elem, elems;
 
-	/* First look for an exact match.  Search overloaded
-	   functions.  May have to undo what `default_conversion'
-	   might do to lhstype.  */
-
+	/* Check that the LHSTYPE and the RHS are reasonable.  */
 	lhstype = validate_lhs (lhstype, complain);
 	if (lhstype == error_mark_node)
 	  return lhstype;
@@ -5129,30 +5120,32 @@ instantiate_type (lhstype, rhs, complain)
 	if (TREE_CODE (lhstype) != FUNCTION_TYPE
 	    && TREE_CODE (lhstype) != METHOD_TYPE)
 	  {
-	    rhs = DECL_NAME (OVL_FUNCTION (rhs));
 	    if (complain)
 	      cp_error("cannot resolve overloaded function `%D' " 
-		       "based on non-function type", rhs);
+		       "based on non-function type", 
+		       DECL_NAME (OVL_FUNCTION (rhs)));
 	    return error_mark_node;
 	  }
 	
-	elems = rhs;
-	/* If there are explicit_targs, only a template function
-	   can match.  */
-	if (explicit_targs == NULL_TREE)
-	  while (elems)
-	    {
-	      elem = OVL_FUNCTION (elems);
-	      if (! comptypes (lhstype, TREE_TYPE (elem), 1))
-		elems = OVL_CHAIN (elems);
-	      else
-		{
-		  mark_used (elem);
-		  return elem;
-		}
-	    }
+	/* Look for an exact match, by searching through the
+	   overloaded functions.  */
+	if (template_only)
+	  /* If we're processing a template-id, only a template
+	     function can match, so we don't look through the
+	     overloaded functions.  */
+	  ;
+	else for (elems = rhs; elems; elems = OVL_CHAIN (elems))
+	  {
+	    elem = OVL_FUNCTION (elems);
+	    if (comptypes (lhstype, TREE_TYPE (elem), 1))
+	      {
+		mark_used (elem);
+		return elem;
+	      }
+	  }
 
-	/* No exact match found, look for a compatible template.  */
+	/* No overloaded function was an exact match.  See if we can
+	   instantiate some template to match.  */
 	{
 	  tree save_elem = 0;
 	  elems = rhs;
@@ -5189,14 +5182,14 @@ instantiate_type (lhstype, rhs, complain)
 	    }
 	}
 
-	/* If there are explicit_targs, only a template function
-	   can match.  */
-	if (explicit_targs == NULL_TREE) 
+	/* There's no exact match, and no templates can be
+	   instantiated to match.  The last thing we try is to see if
+	   some ordinary overloaded function is close enough.  If
+	   we're only looking for template functions, we don't do
+	   this.  */
+	if (!template_only)
 	  {
-	    /* No match found, look for a compatible function.  */
-	    tree elems = rhs;
-	    elems = rhs;
-	    for (; elems; elems = OVL_NEXT (elems))
+	    for (elems = rhs; elems; elems = OVL_NEXT (elems))
 	      {
 		elem = OVL_CURRENT (elems);
 		if (comp_target_types (lhstype, TREE_TYPE (elem), 1) > 0)
@@ -5228,6 +5221,8 @@ instantiate_type (lhstype, rhs, complain)
 		return save_elem;
 	      }
 	  }
+
+	/* We failed to find a match.  */
 	if (complain)
 	  {
 	    cp_error ("cannot resolve overload to target type `%#T'", lhstype);
diff --git a/gcc/cp/cp-tree.def b/gcc/cp/cp-tree.def
index cad0a59..dbbdb66 100644
--- a/gcc/cp/cp-tree.def
+++ b/gcc/cp/cp-tree.def
@@ -163,7 +163,7 @@ DEFTREECODE (DEFAULT_ARG, "default_arg", 'c', 2)
    template will be a FUNCTION_DECL, TEMPLATE_DECL, or a list of
    overloaded functions and templates if the template-id refers to
    a global template.  If the template-id refers to a member template,
-   the template will be an IDENTIFIER_NODE.  */
+   the template may be an IDENTIFIER_NODE.  */
 DEFTREECODE (TEMPLATE_ID_EXPR, "template_id_expr", 'e', 2)
 
 /* An association between namespace and entity. Parameters are the
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 59491a7..cf6378b 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1522,6 +1522,7 @@ build_offset_ref (type, name)
   tree decl, fnfields, fields, t = error_mark_node;
   tree basebinfo = NULL_TREE;
   int dtor = 0;
+  tree orig_name = name;
 
   /* class templates can come in as TEMPLATE_DECLs here.  */
   if (TREE_CODE (name) == TEMPLATE_DECL)
@@ -1532,8 +1533,6 @@ build_offset_ref (type, name)
 
   if (processing_template_decl || uses_template_parms (type))
     return build_min_nt (SCOPE_REF, type, name);
-  else if (TREE_CODE (name) == TEMPLATE_ID_EXPR)
-    return build (SCOPE_REF, unknown_type_node, type, name);
 
   /* Handle namespace names fully here.  */
   if (TREE_CODE (type) == NAMESPACE_DECL)
@@ -1542,6 +1541,16 @@ build_offset_ref (type, name)
   if (type == NULL_TREE || ! is_aggr_type (type, 1))
     return error_mark_node;
 
+  if (TREE_CODE (name) == TEMPLATE_ID_EXPR)
+    {
+      /* If the NAME is a TEMPLATE_ID_EXPR, we are looking at
+	 something like `a.template f<int>' or the like.  For the most
+	 part, we treat this just like a.f.  We do remember, however,
+	 the template-id that was used.  */
+      name = TREE_OPERAND (orig_name, 0);
+      my_friendly_assert (TREE_CODE (name) == IDENTIFIER_NODE, 0);
+    }
+
   if (TREE_CODE (name) == BIT_NOT_EXPR)
     {
       dtor = 1;
@@ -1612,11 +1621,33 @@ build_offset_ref (type, name)
   if (fnfields)
     {
       extern int flag_save_memoized_contexts;
-      basebinfo = TREE_PURPOSE (fnfields);
 
       /* Go from the TREE_BASELINK to the member function info.  */
       t = TREE_VALUE (fnfields);
 
+      if (TREE_CODE (orig_name) == TEMPLATE_ID_EXPR)
+	{
+	  /* The FNFIELDS are going to contain functions that aren't
+	     necessarily templates, and templates that don't
+	     necessarily match the explicit template parameters.  We
+	     save all the functions, and the explicit parameters, and
+	     then figure out exactly what to instantiate with what
+	     arguments in instantiate_type.  */
+
+	  if (TREE_CODE (t) != OVERLOAD)
+	    /* The code in instantiate_type which will process this
+	       expects to encounter OVERLOADs, not raw functions.  */
+	    t = ovl_cons (t, NULL_TREE);
+	  
+	  return build (OFFSET_REF, 
+			build_offset_type (type, unknown_type_node),
+			decl,
+			build (TEMPLATE_ID_EXPR, 
+			       TREE_TYPE (t),
+			       t,
+			       TREE_OPERAND (orig_name, 1)));
+	}
+
       if (!really_overloaded_fn (t))
 	{
 	  tree access;
@@ -1625,6 +1656,7 @@ build_offset_ref (type, name)
 	  t = OVL_CURRENT (t);
 
 	  /* unique functions are handled easily.  */
+	  basebinfo = TREE_PURPOSE (fnfields);
 	  access = compute_access (basebinfo, t);
 	  if (access == access_protected_node)
 	    {
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index d417afb..4b2e587 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -4527,7 +4527,7 @@ build_unary_op (code, xarg, noconvert)
 	}
 
       if (TREE_CODE (arg) == OVERLOAD 
-	  || (TREE_CODE (arg) == SCOPE_REF 
+	  || (TREE_CODE (arg) == OFFSET_REF
 	      && TREE_CODE (TREE_OPERAND (arg, 1)) == TEMPLATE_ID_EXPR))
 	return build1 (ADDR_EXPR, unknown_type_node, arg);
       else if (TREE_CODE (arg) == TREE_LIST)
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/ptrmem1.C b/gcc/testsuite/g++.old-deja/g++.pt/ptrmem1.C
index 3cd9c2b..e14c726 100644
--- a/gcc/testsuite/g++.old-deja/g++.pt/ptrmem1.C
+++ b/gcc/testsuite/g++.old-deja/g++.pt/ptrmem1.C
@@ -1,10 +1,8 @@
-// Build don't run:
-
 class foo
 {
 public:
   template<class T>
-  T bar() {}
+  T bar() { return 7; }
 };
 
 int
@@ -13,4 +11,8 @@ main()
   foo f;
   
   int (foo::*s)() = &foo::template bar<int>;
+  if ((f.*s)() == 7)
+    return 0;
+  else 
+    return 1;
 }