PR c++/6716

	* pt.c (can_complete_type_without_circularity): New function.
	(instantiate_class_template): Use it.
	* typeck2.c (incomplete_type_error): Improve error message
	due to incomplete fields.

	* g++.dg/template/instantiate1.C: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@55182 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 76 insertions, 3 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 27ee0911d79..7382cb3dda0 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2002-07-02  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
+
+	PR c++/6716
+	* pt.c (can_complete_type_without_circularity): New function.
+	(instantiate_class_template): Use it.
+	* typeck2.c (incomplete_type_error): Improve error message
+	due to incomplete fields.
+
 2002-07-01  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/7112
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 46de8dac6f4..68793c78427 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -135,6 +135,7 @@ static int mark_template_parm PARAMS ((tree, void *));
 static int template_parm_this_level_p PARAMS ((tree, void *));
 static tree tsubst_friend_function PARAMS ((tree, tree));
 static tree tsubst_friend_class PARAMS ((tree, tree));
+static int can_complete_type_without_circularity PARAMS ((tree));
 static tree get_bindings_real PARAMS ((tree, tree, tree, int, int, int));
 static int template_decl_level PARAMS ((tree));
 static tree maybe_get_template_decl_from_type_decl PARAMS ((tree));
@@ -4908,6 +4909,25 @@ tsubst_friend_class (friend_tmpl, args)
   return friend_type;
 }
 
+/* Returns zero if TYPE cannot be completed later due to circularity.
+   Otherwise returns one.  */
+
+int
+can_complete_type_without_circularity (type)
+     tree type;
+{
+  if (type == NULL_TREE || type == error_mark_node)
+    return 0;
+  else if (COMPLETE_TYPE_P (type))
+    return 1;
+  else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
+    return can_complete_type_without_circularity (TREE_TYPE (type));
+  else if (CLASS_TYPE_P (type) && TYPE_BEING_DEFINED (TYPE_MAIN_VARIANT (type)))
+    return 0;
+  else
+    return 1;
+}
+
 tree
 instantiate_class_template (type)
      tree type;
@@ -5222,7 +5242,20 @@ instantiate_class_template (type)
 	    if (DECL_INITIALIZED_IN_CLASS_P (r))
 	      check_static_variable_definition (r, TREE_TYPE (r));
 	  }
-	
+	else if (TREE_CODE (r) == FIELD_DECL)
+	  {
+	    /* Determine whether R has a valid type and can be
+	       completed later.  If R is invalid, then it is replaced
+	       by error_mark_node so that it will not be added to
+	       TYPE_FIELDS.  */
+	    tree rtype = TREE_TYPE (r);
+	    if (!can_complete_type_without_circularity (rtype))
+	      {
+		incomplete_type_error (r, rtype);
+		r = error_mark_node;
+	      }
+	  }
+
 	/* R will have a TREE_CHAIN if and only if it has already been
 	   processed by finish_member_declaration.  This can happen
 	   if, for example, it is a TYPE_DECL for a class-scoped
@@ -5303,6 +5336,8 @@ instantiate_class_template (type)
 	--processing_template_decl;
     }
 
+  /* Now that TYPE_FIELDS and TYPE_METHODS are set up.  We can
+     instantiate templates used by this class.  */
   for (t = TYPE_FIELDS (type); t; t = TREE_CHAIN (t))
     if (TREE_CODE (t) == FIELD_DECL)
       {
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index 2cb4cc3b01e..8700a4fe287 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -211,7 +211,8 @@ cxx_incomplete_type_diagnostic (value, type, warn_only)
     return;
 
   if (value != 0 && (TREE_CODE (value) == VAR_DECL
-		     || TREE_CODE (value) == PARM_DECL))
+		     || TREE_CODE (value) == PARM_DECL
+		     || TREE_CODE (value) == FIELD_DECL))
     {
       (*p_msg_at) ("`%D' has incomplete type", value);
       decl = 1;
@@ -226,7 +227,10 @@ retry:
     case ENUMERAL_TYPE:
       if (!decl)
         (*p_msg) ("invalid use of undefined type `%#T'", type);
-      (*p_msg_at)  ("forward declaration of `%#T'", type);
+      if (!TYPE_TEMPLATE_INFO (type))
+	(*p_msg_at) ("forward declaration of `%#T'", type);
+      else
+	(*p_msg_at) ("forward declaration of `%#T'", type);
       break;
 
     case VOID_TYPE:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b7cb0f28e8b..b25b0ef318d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2002-07-02  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>
+
+	PR c++/6716
+	* g++.dg/template/instantiate1.C: New test.
+
 2002-07-01  Mark Mitchell  <mark@codesourcery.com>
 
 	PR c++/7112
diff --git a/gcc/testsuite/g++.dg/template/instantiate1.C b/gcc/testsuite/g++.dg/template/instantiate1.C
new file mode 100644
index 00000000000..e96bcd283fd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/instantiate1.C
@@ -0,0 +1,21 @@
+// { dg-do compile }
+// Origin:
+
+// PR c++/6716
+// ICE in complex class structure when components are incomplete
+
+template <class T> struct X {
+  T t;				// { dg-error "incomplete" }
+};
+
+template <class T> struct Y {	// { dg-error "instantiated" }
+  X<T> x;
+};
+
+template <class T> struct Z {	// { dg-error "instantiated|declaration" }
+  Y<Z<T> > y;
+};
+
+struct ZZ : Z<int>
+{				// { dg-error "instantiated" }
+};