re PR c++/25185 (deep typedef substitution in error message)

PR c++/25185
	* c-common.h, c-common.c: Add flag_pretty_templates.
	* c-opts.c (c_common_handle_option): Set it.
	* c.opt: Add -fno-pretty-templates.
	* doc/invoke.texi (C++ Dialect Options): Likewise.

	* error.c (dump_function_decl): Don't pretty-print templates
	if -fno-pretty-templates.
	(count_non_default_template_args): Print all args if
	-fno-pretty-templates.

From-SVN: r145697

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2009-04-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/25185
+	* c-common.h, c-common.c: Add flag_pretty_templates.
+	* c-opts.c (c_common_handle_option): Set it.
+	* c.opt: Add -fno-pretty-templates.
+	* doc/invoke.texi (C++ Dialect Options): Likewise.
+
 2009-04-07  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/ia64/ia64.c (ia64_builtins): Add IA64_BUILTIN_HUGE_VALQ.

gcc/c-common.c

@@ -593,6 +593,11 @@ int flag_enforce_eh_specs = 1;
 
 int flag_threadsafe_statics = 1;
 
+/* Nonzero if we want to pretty-print template specializations as the
+   template signature followed by the arguments.  */
+
+int flag_pretty_templates = 1;
+
 /* Nonzero means warn about implicit declarations.  */
 
 int warn_implicit = 1;

gcc/c-common.h

@@ -695,6 +695,11 @@ extern int flag_enforce_eh_specs;
 
 extern int flag_threadsafe_statics;
 
+/* Nonzero if we want to pretty-print template specializations as the
+   template signature followed by the arguments.  */
+
+extern int flag_pretty_templates;
+
 /* Nonzero means warn about implicit declarations.  */
 
 extern int warn_implicit;

gcc/c-opts.c

@@ -808,6 +808,10 @@ c_common_handle_option (size_t scode, const char *arg, int value)
       flag_threadsafe_statics = value;
       break;
 
+    case OPT_fpretty_templates:
+      flag_pretty_templates = value;
+      break;
+
     case OPT_fzero_link:
       flag_zero_link = value;
       break;

gcc/c.opt

@@ -716,6 +716,10 @@ fpreprocessed
 C ObjC C++ ObjC++
 Treat the input file as already preprocessed
 
+fpretty-templates
+C++ ObjC++
+-fno-pretty-templates Do not pretty-print template specializations as the template signature followed by the arguments
+
 freplace-objc-classes
 ObjC ObjC++
 Used in Fix-and-Continue mode to indicate that object files may be swapped in at runtime

gcc/cp/ChangeLog

@@ -1,3 +1,11 @@
+2009-04-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/25185
+	* error.c (dump_function_decl): Don't pretty-print templates
+	if -fno-pretty-templates.
+	(count_non_default_template_args): Print all args if
+	-fno-pretty-templates.
+
 2009-04-06  Jason Merrill  <jason@redhat.com>
 
 	PR c++/35146

gcc/cp/error.c

@@ -163,7 +163,7 @@ count_non_default_template_args (tree args, tree params)
   int n = TREE_VEC_LENGTH (args);
   int last;
 
-  if (params == NULL_TREE)
+  if (params == NULL_TREE || !flag_pretty_templates)
     return n;
 
   for (last = n - 1; last >= 0; --last)
@@ -1206,7 +1206,8 @@ dump_function_decl (tree t, int flags)
   exceptions = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (t));
 
   /* Pretty print template instantiations only.  */
-  if (DECL_USE_TEMPLATE (t) && DECL_TEMPLATE_INFO (t))
+  if (DECL_USE_TEMPLATE (t) && DECL_TEMPLATE_INFO (t)
+      && flag_pretty_templates)
     {
       tree tmpl;
 

gcc/doc/invoke.texi

@@ -188,6 +188,7 @@ in the following sections.
 -fno-implement-inlines  -fms-extensions @gol
 -fno-nonansi-builtins  -fno-operator-names @gol
 -fno-optional-diags  -fpermissive @gol
+-fno-pretty-templates @gol
 -frepo  -fno-rtti  -fstats  -ftemplate-depth-@var{n} @gol
 -fno-threadsafe-statics -fuse-cxa-atexit  -fno-weak  -nostdinc++ @gol
 -fno-default-inline  -fvisibility-inlines-hidden @gol
@@ -1834,6 +1835,19 @@ Downgrade some diagnostics about nonconformant code from errors to
 warnings.  Thus, using @option{-fpermissive} will allow some
 nonconforming code to compile.
 
+@item -fno-pretty-templates
+@opindex fno-pretty-templates
+When an error message refers to a specialization of a function
+template, the compiler will normally print the signature of the
+template followed by the template arguments and any typedefs or
+typenames in the signature (e.g. @code{void f(T) [with T = int]}
+rather than @code{void f(int)}) so that it's clear which template is
+involved.  When an error message refers to a specialization of a class
+template, the compiler will omit any template arguments which match
+the default template arguments for that template.  If either of these
+behaviors make it harder to understand the error message rather than
+easier, using @option{-fno-pretty-templates} will disable them.
+
 @item -frepo
 @opindex frepo
 Enable automatic template instantiation at link time.  This option also

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2009-04-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/25185
+	* g++.dg/template/error40.C: New.
+
 2009-04-07  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/38152

gcc/testsuite/g++.dg/template/error40.C

@@ -0,0 +1,19 @@
+// { dg-options "-fno-pretty-templates" }
+
+template <class T, int N=0, int X=1>
+struct A
+{
+};
+
+void foo(void)
+{
+  A<void> a = 0;		// { dg-error "A<void, 0, 1>" }
+}
+
+template <class T> T f(T);	    // { dg-message "int f<int>.int." }
+template <class T> T f(T, int = 0); // { dg-message "" }
+
+int main()
+{
+  f(1);				// { dg-error "" }
+}