The following code compiles with gcc 4.8 and clang, but not with gcc 4.9:


template <typename>
void foo_impl()
{
    int data;
    auto L = [&](){ return data; };
    [&](){ L(); }();
}

void foo()
{
    foo_impl<int>();
}


The error is:


test.cpp: In instantiation of 'foo_impl() [with <template-parameter-1-1> = int]::__lambda1':
test.cpp:6:12:   required from 'struct foo_impl() [with <template-parameter-1-1> = int]::__lambda1'
test.cpp:6:19:   required from 'void foo_impl() [with <template-parameter-1-1> = int]'
test.cpp:11:19:   required from here
test.cpp:5:14: error: uninitialized const member 'foo_impl() [with <template-parameter-1-1> = int]::__lambda0::__data'
     auto L = [&](){ return data; };
              ^


The error goes away if:
  - foo_impl is made a nontemplate
  - the call to the second lambda is inlined
  - either lambda is made to capture by value instead of reference