[Bug c++/61362] g++ (Ubuntu 4.8.2-19ubuntu1) 4.8.2 does not compile lambda with template

["daniel.kruegler at googlemail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61362

--- Comment #2 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
Reduced example (removing library dependencies) using compiler flags

 -Wall -Wextra -std=c++11 -pedantic 

for gcc HEAD 4.10.0 20140529 (experimental)

//---------------------
struct function {
  template<class F>
  function(F){}

  void operator()(...) {}
};

struct Node {
  unsigned length;
};

template<typename N>
class C {
public:
  unsigned longest = 0;
  function f = [this](N node) {
    if(node->length > this->longest) this->longest = node->length;
  };
};

int main() {
  Node n;
  n.length = 5;
  C<Node*> c;
  c.f(&n);
}
//---------------------

results in

"prog.cc: In instantiation of 'C<N>::<lambda(N)> [with N = Node*]':
prog.cc:16:17: required from 'struct C<Node*>::<lambda(struct Node*)>'
prog.cc:24:12: required from here prog.cc:16:29: internal compiler error:
Segmentation fault function f = [this](N node) { ^ 0x96976f crash_signal
/home/heads/gcc/gcc-source/gcc/toplev.c:337 0x56ddb5
instantiate_decl(tree_node*, int, bool)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:19932 0x5802b1
instantiate_class_template_1 /home/heads/gcc/gcc-source/gcc/cp/pt.c:9367
0x5802b1 instantiate_class_template(tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:9435 0x5d726d complete_type(tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/typeck.c:134 0x567644
tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool, bool)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:15327 0x5ec715 get_nsdmi(tree_node*,
bool) /home/heads/gcc/gcc-source/gcc/cp/init.c:543 0x5f4bf4 walk_field_subobs
/home/heads/gcc/gcc-source/gcc/cp/method.c:1098 0x5f53bc
synthesized_method_walk /home/heads/gcc/gcc-source/gcc/cp/method.c:1424
0x5f64b5 get_defaulted_eh_spec(tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/method.c:1455 0x581707
maybe_instantiate_noexcept(tree_node*)
/home/heads/gcc/gcc-source/gcc/cp/pt.c:19563 0x599ae7 mark_used(tree_node*,
int) /home/heads/gcc/gcc-source/gcc/cp/decl2.c:4823 0x537459 build_over_call
/home/heads/gcc/gcc-source/gcc/cp/call.c:7325 0x53de3a build_new_method_call_1
/home/heads/gcc/gcc-source/gcc/cp/call.c:8037 0x53de3a
build_new_method_call(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, tree_node*, int, tree_node**, int)
/home/heads/gcc/gcc-source/gcc/cp/call.c:8107 0x53e6e6
build_special_member_call(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, tree_node*, int, int)
/home/heads/gcc/gcc-source/gcc/cp/call.c:7651 0x5ef036 expand_default_init
/home/heads/gcc/gcc-source/gcc/cp/init.c:1713 0x5ef036 expand_aggr_init_1
/home/heads/gcc/gcc-source/gcc/cp/init.c:1814 0x5f096e
build_aggr_init(tree_node*, tree_node*, int, int)
/home/heads/gcc/gcc-source/gcc/cp/init.c:1566 0x549a2d
build_aggr_init_full_exprs /home/heads/gcc/gcc-source/gcc/cp/decl.c:5642 Please
submit a full bug report, with preprocessed source if appropriate. Please
include the complete backtrace with any bug report. See
<http://gcc.gnu.org/bugs.html> for instructions."
>From gcc-bugs-return-452868-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Fri May 30 15:39:58 2014
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Subject: [Bug c++/36183] misleading error message with explicit copy constructor call
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36183

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-05-30
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |manu at gcc dot gnu.org
     Ever confirmed|0                           |1
           Severity|trivial                     |normal

--- Comment #1 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
It seems to me that the problem is the "explicit" keyword, so an error like:

test.cc:14:6: error: no matching function for call to ‘B::B(const B&)’
   f(b); // error: no matching function for call to 'B::B(const B&)'
      ^
test.cc:4:3: note: candidate: 'explicit B::B(const B&)'
   B() {}
   ^
test.cc:4:3: note:   is marked as explicit but implicit conversion required
test.cc:8:6: note:   initializing argument 1 of ‘void f(B)’
 void f(B obj) {}
      ^

Jason?
>From gcc-bugs-return-452869-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Fri May 30 15:46:01 2014
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From: "crrodriguez at opensuse dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug preprocessor/61371] New: cpp: Implement -fno-date-time/-freproducible-dates or similar
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida371

            Bug ID: 61371
           Summary: cpp: Implement -fno-date-time/-freproducible-dates or
                    similar
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: crrodriguez at opensuse dot org

Hi:

Current releases have the option to warn/err on the use of __DATE__ , __TIME__
and __TIMESTAMP__, first thanks for implementing this as it is a good step to
aid reproducible builds. That said, it is unfortunately still quite
inconvenient for large scale projects such as distributions because it requires
going through hundreds or thousands of packages.

I suggest a command line option to be implemented such as

-fno-date-time
-freproducible-dates

Or whatever other appropriate name that behaves in one of this ways:

Either:

- __DATE__, __TIME__ and __TIMESTAMP__ expand as  "If GCC cannot determine the
current date" (that is ???...)

- __DATE__ and __TIME__ expand to the file 's  last modification time

- Whatever other sane alternative that ensures different builds of the same
source code and same preprocessor/compiler/linker options result in identical
builds.