libiberty: Add support for in' and in ref' storage classes.

The storage class `in' is now a first-class citizen with its own mangle
symbol, of which also permits `in ref'.  Previously, `in' was an alias
to `const [scope]', which is a type constructor.

The mangle symbol repurposed for this is `I', which was originally used
by identifier types.  However, while TypeIdentifier is part of the
grammar, it must be resolved to some other entity during the semantic
passes, and so shouldn't appear anywhere in the mangled name.

Old tests that are now no longer valid have been removed.

libiberty/ChangeLog:

	* d-demangle.c (dlang_function_args): Handle 'in' and 'in ref'
	parameter storage classes.
	(dlang_type): Remove identifier type.
	* testsuite/d-demangle-expected: Update tests.

libiberty/d-demangle.c

@@ -699,6 +699,15 @@ dlang_function_args (string *decl, const char *mangled, struct dlang_info *info)
 
       switch (*mangled)
 	{
+	case 'I': /* in(T) */
+	  mangled++;
+	  string_append (decl, "in ");
+	  if (*mangled == 'K') /* in ref(T) */
+	    {
+	      mangled++;
+	      string_append (decl, "ref ");
+	    }
+	  break;
 	case 'J': /* out(T) */
 	  mangled++;
 	  string_append (decl, "out ");
@@ -826,7 +835,6 @@ dlang_type (string *decl, const char *mangled, struct dlang_info *info)
       mangled = dlang_function_type (decl, mangled, info);
       string_append (decl, "function");
       return mangled;
-    case 'I': /* ident T */
     case 'C': /* class T */
     case 'S': /* struct T */
     case 'E': /* enum T */

libiberty/testsuite/d-demangle-expected

@@ -274,14 +274,6 @@ _D8demangle4testFNhG4dZv
 demangle.test(__vector(double[4]))
 #
 --format=dlang
-_D8demangle4testFI5identZv
-demangle.test(ident)
-#
---format=dlang
-_D8demangle4testFI5ident4testZv
-demangle.test(ident.test)
-#
---format=dlang
 _D8demangle4testFC5classZv
 demangle.test(class)
 #
@@ -314,6 +306,14 @@ _D8demangle4testFT7typedef4testZv
 demangle.test(typedef.test)
 #
 --format=dlang
+_D8demangle4testFIaZv
+demangle.test(in char)
+#
+--format=dlang
+_D8demangle4testFIKaZv
+demangle.test(in ref char)
+#
+--format=dlang
 _D8demangle4testFJaZv
 demangle.test(out char)
 #