call.c (convert_like): Macrofy.

	* call.c (convert_like): Macrofy.
	(convert_like_with_context): New macro.
	(convert_like_real): Renamed from convert_like.  Add calling
	context parameters, for diagnostics. Add recursive flag.  Call
	dubious_conversion_warnings for outer conversion.
	(build_user_type_conversion): Use convert_like_with_context.
	(build_over_call): Likewise. Don't warn about dubious
	conversions here. Adjust convert_default_arg calls.
	(convert_default_arg): Add context parameters for diagnostics.
	Pass throught to convert_like_with_context.
	* cp-tree.h (convert_default_arg): Add context parameters.
	(dubious_conversion_warnings): Prototype new function.
	* typeck.c (convert_arguments): Adjust convert_default_arg call.
	(dubious_conversion_warnings): New function, broken
	out of convert_for_assignment.
	(convert_for_assignment): Adjust.

From-SVN: r32341

gcc/cp/ChangeLog

+2000-03-05  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* call.c (convert_like): Macrofy.
+	(convert_like_with_context): New macro.
+	(convert_like_real): Renamed from convert_like.  Add calling
+	context parameters, for diagnostics. Add recursive flag.  Call 
+	dubious_conversion_warnings for outer conversion.
+	(build_user_type_conversion): Use convert_like_with_context.
+	(build_over_call): Likewise. Don't warn about dubious
+	conversions here. Adjust convert_default_arg calls.
+	(convert_default_arg): Add context parameters for diagnostics.
+	Pass throught to convert_like_with_context.
+	* cp-tree.h (convert_default_arg): Add context parameters.
+	(dubious_conversion_warnings): Prototype new function.
+	* typeck.c (convert_arguments): Adjust convert_default_arg call.
+	(dubious_conversion_warnings): New function, broken
+	out of convert_for_assignment. 
+	(convert_for_assignment): Adjust.
+
 2000-03-03  Jason Merrill  <jason@casey.cygnus.com>
 
 	* decl2.c (key_method): Break out from...

gcc/cp/call.c

@@ -49,7 +49,9 @@ static int equal_functions PARAMS ((tree, tree));
 static int joust PARAMS ((struct z_candidate *, struct z_candidate *, int));
 static int compare_ics PARAMS ((tree, tree));
 static tree build_over_call PARAMS ((struct z_candidate *, tree, int));
-static tree convert_like PARAMS ((tree, tree));
+#define convert_like(CONV, EXPR) convert_like_real (CONV, EXPR, NULL_TREE, 0, 0)
+#define convert_like_with_context(CONV, EXPR, FN, ARGNO) convert_like_real (CONV, EXPR, FN, ARGNO, 0)
+static tree convert_like_real PARAMS ((tree, tree, tree, int, int));
 static void op_error PARAMS ((enum tree_code, enum tree_code, tree, tree,
 			    tree, const char *));
 static tree build_object_call PARAMS ((tree, tree));
@@ -2450,7 +2452,9 @@ build_user_type_conversion (totype, expr, flags)
     {
       if (TREE_CODE (cand->second_conv) == AMBIG_CONV)
 	return error_mark_node;
-      return convert_from_reference (convert_like (cand->second_conv, expr));
+      return convert_from_reference
+              (convert_like_with_context
+                (cand->second_conv, expr, cand->fn, 0));
     }
   return NULL_TREE;
 }
@@ -2654,7 +2658,8 @@ build_object_call (obj, args)
       && DECL_NAME (cand->fn) == ansi_opname [CALL_EXPR])
     return build_over_call (cand, mem_args, LOOKUP_NORMAL);
 
-  obj = convert_like (TREE_VEC_ELT (cand->convs, 0), obj);
+  obj = convert_like_with_context
+          (TREE_VEC_ELT (cand->convs, 0), obj, cand->fn, -1);
 
   /* FIXME */
   return build_function_call (obj, args);
@@ -3593,11 +3598,17 @@ enforce_access (basetype_path, decl)
   return 1;
 }
 
-/* Perform the conversions in CONVS on the expression EXPR.  */
+/* Perform the conversions in CONVS on the expression EXPR. 
+   FN and ARGNUM are used for diagnostics.  ARGNUM is zero based, -1
+   indicates the `this' argument of a method.  INNER is non-zero when
+   being called to continue a conversion chain. */
 
 static tree
-convert_like (convs, expr)
+convert_like_real (convs, expr, fn, argnum, inner)
      tree convs, expr;
+     tree fn;
+     int argnum;
+     int inner;
 {
   if (ICS_BAD_FLAG (convs)
       && TREE_CODE (convs) != USER_CONV
@@ -3609,19 +3620,22 @@ convert_like (convs, expr)
 	{
 	  if (TREE_CODE (t) == USER_CONV)
 	    {
-	      expr = convert_like (t, expr);
+	      expr = convert_like_real (t, expr, fn, argnum, 1);
 	      break;
 	    }
 	  else if (TREE_CODE (t) == AMBIG_CONV)
-	    return convert_like (t, expr);
+	    return convert_like_real (t, expr, fn, argnum, 1);
 	  else if (TREE_CODE (t) == IDENTITY_CONV)
 	    break;
 	}
       return convert_for_initialization
 	(NULL_TREE, TREE_TYPE (convs), expr, LOOKUP_NORMAL,
-	 "conversion", NULL_TREE, 0);
+	 "conversion", fn, argnum);
     }
-
+  
+  if (!inner)
+    expr = dubious_conversion_warnings
+             (TREE_TYPE (convs), expr, "argument", fn, argnum);
   switch (TREE_CODE (convs))
     {
     case USER_CONV:
@@ -3665,7 +3679,7 @@ convert_like (convs, expr)
       break;
     };
 
-  expr = convert_like (TREE_OPERAND (convs, 0), expr);
+  expr = convert_like_real (TREE_OPERAND (convs, 0), expr, fn, argnum, 1);
   if (expr == error_mark_node)
     return error_mark_node;
 
@@ -3840,10 +3854,11 @@ convert_type_from_ellipsis (type)
    conversions.  Return the converted value.  */
 
 tree
-convert_default_arg (type, arg, fn)
+convert_default_arg (type, arg, fn, parmnum)
      tree type;
      tree arg;
      tree fn;
+     int parmnum;
 {
   if (fn && DECL_TEMPLATE_INFO (fn))
     arg = tsubst_default_argument (fn, type, arg);
@@ -3854,7 +3869,7 @@ convert_default_arg (type, arg, fn)
     {
       arg = digest_init (type, arg, 0);
       arg = convert_for_initialization (0, type, arg, LOOKUP_NORMAL,
-					"default argument", 0, 0);
+					"default argument", fn, parmnum);
     }
   else
     {
@@ -3863,7 +3878,7 @@ convert_default_arg (type, arg, fn)
 	arg = copy_node (arg);
 
       arg = convert_for_initialization (0, type, arg, LOOKUP_NORMAL,
-					"default argument", 0, 0);
+					"default argument", fn, parmnum);
       if (PROMOTE_PROTOTYPES
 	  && (TREE_CODE (type) == INTEGER_TYPE
 	      || TREE_CODE (type) == ENUMERAL_TYPE)
@@ -3956,7 +3971,7 @@ build_over_call (cand, args, flags)
 	      if (TREE_CODE (t) == USER_CONV
 		  || TREE_CODE (t) == AMBIG_CONV)
 		{
-		  val = convert_like (t, val);
+		  val = convert_like_with_context (t, val, fn, i - is_method);
 		  break;
 		}
 	      else if (TREE_CODE (t) == IDENTITY_CONV)
@@ -3964,16 +3979,13 @@ build_over_call (cand, args, flags)
 	    }
 	  val = convert_for_initialization
 	    (NULL_TREE, type, val, LOOKUP_NORMAL,
-	     "argument passing", fn, i - is_method);
+	     "argument", fn, i - is_method);
 	}
       else
 	{
-	  /* Issue warnings about peculiar, but legal, uses of NULL.  */
-	  if (ARITHMETIC_TYPE_P (TREE_VALUE (parm))
-	      && TREE_VALUE (arg) == null_node)
-	    cp_warning ("converting NULL to non-pointer type");
-	    
-	  val = convert_like (conv, TREE_VALUE (arg));
+	  val = TREE_VALUE (arg);
+	  val = convert_like_with_context
+	          (conv, TREE_VALUE (arg), fn, i - is_method);
 	}
 
       if (PROMOTE_PROTOTYPES
@@ -3985,12 +3997,12 @@ build_over_call (cand, args, flags)
     }
 
   /* Default arguments */
-  for (; parm && parm != void_list_node; parm = TREE_CHAIN (parm))
+  for (; parm && parm != void_list_node; parm = TREE_CHAIN (parm), i++)
     converted_args 
       = tree_cons (NULL_TREE, 
 		   convert_default_arg (TREE_VALUE (parm), 
 					TREE_PURPOSE (parm),
-					fn),
+					fn, i - is_method),
 		   converted_args);
 
   /* Ellipsis */

gcc/cp/cp-tree.h

@@ -3616,7 +3616,7 @@ extern tree build_op_delete_call		PARAMS ((enum tree_code, tree, tree, int, tree
 extern int can_convert				PARAMS ((tree, tree));
 extern int can_convert_arg			PARAMS ((tree, tree, tree));
 extern int enforce_access                       PARAMS ((tree, tree));
-extern tree convert_default_arg                 PARAMS ((tree, tree, tree));
+extern tree convert_default_arg                 PARAMS ((tree, tree, tree, int));
 extern tree convert_arg_to_ellipsis             PARAMS ((tree));
 extern tree build_x_va_arg                      PARAMS ((tree, tree));
 extern tree convert_type_from_ellipsis          PARAMS ((tree));
@@ -4407,6 +4407,7 @@ extern tree build_const_cast			PARAMS ((tree, tree));
 extern tree build_c_cast			PARAMS ((tree, tree));
 extern tree build_x_modify_expr			PARAMS ((tree, enum tree_code, tree));
 extern tree build_modify_expr			PARAMS ((tree, enum tree_code, tree));
+extern tree dubious_conversion_warnings         PARAMS ((tree, tree, const char *, tree, int));
 extern tree convert_for_initialization		PARAMS ((tree, tree, tree, int, const char *, tree, int));
 extern void c_expand_asm_operands		PARAMS ((tree, tree, tree, tree, int, char *, int));
 extern void c_expand_return			PARAMS ((tree));

gcc/cp/typeck.c

@@ -3215,7 +3215,7 @@ convert_arguments (typelist, values, fndecl, flags)
 	      tree parmval 
 		= convert_default_arg (TREE_VALUE (typetail), 
 				       TREE_PURPOSE (typetail), 
-				       fndecl);
+				       fndecl, i);
 
 	      if (parmval == error_mark_node)
 		return error_mark_node;
@@ -6421,6 +6421,59 @@ pfn_from_ptrmemfunc (t)
 	     pfn_identifier, NULL_TREE, 0)); 
 }
 
+/* Expression EXPR is about to be implicitly converted to TYPE.  Warn
+   if this is a potentially dangerous thing to do.  Returns a possibly
+   marked EXPR.  */
+
+tree
+dubious_conversion_warnings (type, expr, errtype, fndecl, parmnum)
+     tree type;
+     tree expr;
+     const char *errtype;
+     tree fndecl;
+     int parmnum;
+{
+  /* Issue warnings about peculiar, but legal, uses of NULL.  */
+  if (ARITHMETIC_TYPE_P (type) && expr == null_node)
+    {
+      if (fndecl)
+        cp_warning ("passing NULL used for non-pointer %s %P of `%D'",
+                    errtype, parmnum, fndecl);
+      else
+        cp_warning ("%s to non-pointer type `%T' from NULL", errtype, type);
+    }
+  
+  /* Warn about assigning a floating-point type to an integer type.  */
+  if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
+      && TREE_CODE (type) == INTEGER_TYPE)
+    {
+      if (fndecl)
+	cp_warning ("passing `%T' for %s %P of `%D'",
+		    TREE_TYPE (expr), errtype, parmnum, fndecl);
+      else
+	cp_warning ("%s to `%T' from `%T'", errtype, type, TREE_TYPE (expr));
+    }
+  /* And warn about assigning a negative value to an unsigned
+     variable.  */
+  else if (TREE_UNSIGNED (type) && TREE_CODE (type) != BOOLEAN_TYPE)
+    {
+      if (TREE_CODE (expr) == INTEGER_CST
+	  && TREE_NEGATED_INT (expr))
+	{
+	  if (fndecl)
+	    cp_warning ("passing negative value `%E' for %s %P of `%D'",
+			expr, errtype, parmnum, fndecl);
+	  else
+	    cp_warning ("%s of negative value `%E' to `%T'",
+			errtype, expr, type);
+	}
+      overflow_warning (expr);
+      if (TREE_CONSTANT (expr))
+	expr = fold (expr);
+    }
+  return expr;
+}
+
 /* Convert value RHS to type TYPE as preparation for an assignment to
    an lvalue of type TYPE.  ERRTYPE is a string to use in error
    messages: "assignment", "return", etc.  If FNDECL is non-NULL, we
@@ -6456,12 +6509,7 @@ convert_for_assignment (type, rhs, errtype, fndecl, parmnum)
   if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)
     return error_mark_node;
 
-  /* Issue warnings about peculiar, but legal, uses of NULL.  We
-     do this *before* the call to decl_constant_value so as to
-     avoid duplicate warnings on code like `const int I = NULL;
-     f(I);'.  */
-  if (ARITHMETIC_TYPE_P (type) && rhs == null_node)
-    cp_warning ("converting NULL to non-pointer type");
+  rhs = dubious_conversion_warnings (type, rhs, errtype, fndecl, parmnum);
 
   /* The RHS of an assignment cannot have void type.  */
   if (coder == VOID_TYPE)
@@ -6476,34 +6524,6 @@ convert_for_assignment (type, rhs, errtype, fndecl, parmnum)
   else if (TREE_READONLY_DECL_P (rhs))
     rhs = decl_constant_value (rhs);
 
-  /* Warn about assigning a floating-point type to an integer type.  */
-  if (coder == REAL_TYPE && codel == INTEGER_TYPE)
-    {
-      if (fndecl)
-	cp_warning ("`%T' used for argument %P of `%D'",
-		    rhstype, parmnum, fndecl);
-      else
-	cp_warning ("%s to `%T' from `%T'", errtype, type, rhstype);
-    }
-  /* And warn about assigning a negative value to an unsigned
-     variable.  */
-  else if (TREE_UNSIGNED (type) && codel != BOOLEAN_TYPE)
-    {
-      if (TREE_CODE (rhs) == INTEGER_CST
-	  && TREE_NEGATED_INT (rhs))
-	{
-	  if (fndecl)
-	    cp_warning ("negative value `%E' passed as argument %P of `%D'",
-			rhs, parmnum, fndecl);
-	  else
-	    cp_warning ("%s of negative value `%E' to `%T'",
-			errtype, rhs, type);
-	}
-      overflow_warning (rhs);
-      if (TREE_CONSTANT (rhs))
-	rhs = fold (rhs);
-    }
-
   /* [expr.ass]
 
      The expression is implicitly converted (clause _conv_) to the