[Bug c++/70182] c++filt fails to demangle _ZNSt17_Function_handlerIFSt4pairImjEjEZN5folly12addBenchmarkI3$_0EENSt9enable_ifIXeqsr5boost14function_types14function_arityIDTadsrT_onclEEE5valueLi2EEvE4typeEPKcSC_OS7_EUljE_E9_M_invokeERKSt9_Any_dataj

[twoh at fb dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70182

--- Comment #2 from Taewook Oh <twoh at fb dot com> ---
Here is a link to the preprocessed text: http://paste.ubuntu.com/15346235/

As I wrote in the description, it seems pretty clear that demangler applies an
incorrect rule to demangle expression. For "srT_oncl", if demangler applies the
correct rule

<expression> ::= sr <type> <base-unresolved-name>,

then "T_" can be processed by rule 

<template-param> ::= T_

and "oncl" can be processed by

<base-unresolved-name> ::= on <operator-name> 
<operator-name> ::= cl  # ().

GCC generates a slightly different name
(_ZNSt17_Function_handlerIFSt4pairImjEjEZN5folly12addBenchmarkIUljE_EENSt9enable_ifIXeqsrN5boost14function_types14function_arityIDTadsrT_clEEE5valueLi2EEvE4typeEPKcSG_OSA_EUljE_E9_M_invokeERKSt9_Any_dataj)
but still cannot be demangled by c++filt.