[Bug c++/67561] New: [C++14] ICE in tsubst_copy (nested auto lambdas may be involved)

["bisqwit at iki dot fi" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67561

            Bug ID: 67561
           Summary: [C++14] ICE in tsubst_copy (nested auto lambdas may be
                    involved)
           Product: gcc
           Version: 5.2.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: bisqwit at iki dot fi
  Target Milestone: ---

When compiling this program, 

    struct Polygon {};

    template<typename PixType>
    struct View {};

    template<typename PixType, typename... Params>
    void RenderLight(PixType, Params&&... pack)
    {
        View<PixType> tmp;
        DrawView(pack..., tmp);
    }

    template<typename Plotter>
    static void DrawPolygon(Plotter plot_pixel)
    {
        plot_pixel(1,1,1, [&](unsigned n) { return n; });
    }

    template<typename View, typename PlotFunc>
    static void DrawView(PlotFunc&& GetPlotFunc,
                         View& view)
    {
        DrawPolygon(GetPlotFunc(view, Polygon{}, false));
    }

    static auto LightmapRenderer = [](unsigned round)
    {
        return [round](auto& view, const Polygon& polygon, bool)
        {
            return [=,&view,&polygon](unsigned x,unsigned y, float z, auto&&
prop)
            {
                if(true) { if(round == 1) {} }
                else     { if(round > 1) {} }
            };
        };
    };

    void CalculateLightmap()
    {
        RenderLight( 0, LightmapRenderer(1) );
    }

The following error is produced:

    testv.cc: In instantiation of '<lambda(unsigned int)>::<lambda(auto:1&,
const Polygon&, bool)>::<lambda(unsigned int, unsigned int, float, auto:2&&)>
[with auto:2 = DrawPolygon(Plotter) [with Plotter = <lambda(unsigned
int)>::<lambda(auto:1&, const Polygon&, bool)> [with auto:1 =
View<int>]::<lambda(unsigned int, unsigned int, float,
auto:2&&)>]::<lambda(unsigned int)>; auto:1 = View<int>]':
    testv.cc:16:15:   required from 'void DrawPolygon(Plotter) [with Plotter =
<lambda(unsigned int)>::<lambda(auto:1&, const Polygon&, bool)> [with auto:1 =
View<int>]::<lambda(unsigned int, unsigned int, float, auto:2&&)>]'
    testv.cc:23:16:   required from 'void DrawView(PlotFunc&&, View&) [with
View = View<int>; PlotFunc = <lambda(unsigned int)>::<lambda(auto:1&, const
Polygon&, bool)>&]'
    testv.cc:10:13:   required from 'void RenderLight(PixType, Params&& ...)
[with PixType = int; Params = {<lambda(unsigned int)>::<lambda(auto:1&, const
Polygon&, bool)>}]'
    testv.cc:40:41:   required from here
    testv.cc:29:5: internal compiler error: in tsubst_copy, at cp/pt.c:12997
         {
         ^
    0x632bbe tsubst_copy
        ../../src/gcc/cp/pt.c:12997
    0x623a08 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*,
bool, bool)
        ../../src/gcc/cp/pt.c:15740
    0x6246c8 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*,
bool, bool)
        ../../src/gcc/cp/pt.c:14771
    0x6242d1 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*,
bool, bool)
        ../../src/gcc/cp/pt.c:15522
    0x62c002 tsubst_expr
        ../../src/gcc/cp/pt.c:14552
    0x63492d tsubst_decl
        ../../src/gcc/cp/pt.c:11500
    0x632a7a tsubst_copy
        ../../src/gcc/cp/pt.c:13127
    0x623a08 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*,
bool, bool)
        ../../src/gcc/cp/pt.c:15740
    0x624ae7 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*,
bool, bool)
        ../../src/gcc/cp/pt.c:14930
    0x62c002 tsubst_expr
        ../../src/gcc/cp/pt.c:14552
    0x62b3c5 tsubst_expr
        ../../src/gcc/cp/pt.c:14113
    0x62bf4c tsubst_expr
        ../../src/gcc/cp/pt.c:14135
    0x62b3e5 tsubst_expr
        ../../src/gcc/cp/pt.c:14115
    0x62bf4c tsubst_expr
        ../../src/gcc/cp/pt.c:14135
    0x62b8f4 tsubst_expr
        ../../src/gcc/cp/pt.c:13949
    0x62bf4c tsubst_expr
        ../../src/gcc/cp/pt.c:14135
    0x62acb7 instantiate_decl(tree_node*, int, bool)
        ../../src/gcc/cp/pt.c:20582
    0x659f62 mark_used(tree_node*, int)
        ../../src/gcc/cp/decl2.c:5035
    0x5f9800 build_over_call
        ../../src/gcc/cp/call.c:7501
    0x5fbf31 build_op_call_1
        ../../src/gcc/cp/call.c:4345
    Please submit a full bug report,
    with preprocessed source if appropriate.
    Please include the complete backtrace with any bug report.
    See <file:///usr/share/doc/gcc-5/README.Bugs> for instructions.

Compiler version 5.2.1, on Debian x86_64. More information (g++ -v):

    Using built-in specs.
    COLLECT_GCC=g++
    COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/5/lto-wrapper
    Target: x86_64-linux-gnu
    Configured with: ../src/configure -v --with-pkgversion='Debian 5.2.1-16'
--with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-5 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-amd64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-amd64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-amd64
--with-arch-directory=amd64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --with-arch-32=i586 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
    Thread model: posix
    gcc version 5.2.1 20150903 (Debian 5.2.1-16) 
    COLLECT_GCC_OPTIONS='-v' '-Wall' '-Wextra' '-std=c++14' '-O0'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
     /usr/lib/gcc/x86_64-linux-gnu/5/cc1plus -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE testv.cc -quiet -dumpbase testv.cc
-mtune=generic -march=x86-64 -auxbase testv -O0 -Wall -Wextra -std=c++14
-version -o /tmp/cc99eXwV.s
    GNU C++14 (Debian 5.2.1-16) version 5.2.1 20150903 (x86_64-linux-gnu)
        compiled by GNU C version 5.2.1 20150903, GMP version 6.0.0, MPFR
version 3.1.3, MPC version 1.0.3
    GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
    ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/5"
    ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
    ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/include"
    #include "..." search starts here:
    #include <...> search starts here:
     /usr/include/c++/5
     /usr/include/x86_64-linux-gnu/c++/5
     /usr/include/c++/5/backward
     /usr/lib/gcc/x86_64-linux-gnu/5/include
     /usr/local/include
     /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed
     /usr/include/x86_64-linux-gnu
     /usr/include
    End of search list.
    GNU C++14 (Debian 5.2.1-16) version 5.2.1 20150903 (x86_64-linux-gnu)
        compiled by GNU C version 5.2.1 20150903, GMP version 6.0.0, MPFR
version 3.1.3, MPC version 1.0.3
    GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
    Compiler executable checksum: 8c90e1ad7f61e19a950a98d7345debd3

Occurs on all optimization levels through -O0 and -Ofast.
Does not occur in GCC 4.9. Unfortunately I don't have a copy of GCC 5.1 to test
with. Looks like Debian replaced 5.1 with 5.2 and doesn't give an opportunity
for them to coexist.