Cleanup C++ buffer type name mangling.

Cython/Compiler/Buffer.py

@@ -631,10 +631,7 @@ def mangle_dtype_name(dtype):
             prefix = "nn_"
         else:
             prefix = ""
-        type_decl = dtype.empty_declaration_code()
-        type_decl = type_decl.replace(" ", "_")
-        type_decl = type_decl.replace("::", "_pyxns_")
-        return prefix + type_decl.replace("[", "_").replace("]", "_")
+        return prefix + dtype.specialization_name()
 
 def get_type_information_cname(code, dtype, maxdepth=None):
     """

tests/bugs.txt

@@ -5,7 +5,6 @@ class_attribute_init_values_T18
 unsignedbehaviour_T184
 missing_baseclass_in_predecl_T262
 cfunc_call_tuple_args_T408
-# cpp_structs
 genexpr_iterable_lookup_T600
 generator_expressions_in_class
 for_from_pyvar_loop_T601