trouble with ovl.h

[Ben Abbott]

Carne,

I’m seeing an error that looks to be triggered by your recent change below.

http://hg.savannah.gnu.org/hgweb/octave/rev/55c20a3e3e59

 
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang"
 -cc1 -triple x86_64-apple-macosx10.11.0 -Wdeprecated-objc-isa-usage 
-Werror=deprecated-objc-isa-usage -emit-obj -disable-free 
-disable-llvm-verifier -main-file-name octave.cc -mrelocation-model pic 
-pic-level 2 -mthread-model posix -mdisable-fp-elim -masm-verbose 
-munwind-tables -target-cpu core2 -target-linker-version 264.3.102 -v 
-dwarf-column-info -coverage-file 
/Users/bpabbott/Development/mercurial/default/build/octave.cc -resource-dir 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/7.3.0
 -dependency-file libinterp/.deps/libinterp_liboctinterp_la-octave.Tpo 
-sys-header-deps -MP -MT libinterp/libinterp_liboctinterp_la-octave.lo -D 
HAVE_CONFIG_H -I . -I ../sources -I liboctave -I ../sources/liboctave -I 
../sources/liboctave/cruft/misc -I ../sources/liboctave/array -I 
liboctave/numeric -I ../sources/liboctave/numeric -I liboctave/operators -I 
../sources/liboctave/operators -I ../sources/liboctave/system -I 
../sources/liboctave/util -I ../sources/libinterp/octave-value -I libinterp -I 
../sources/libinterp -I ../sources/libinterp/operators -I libinterp/parse-tree 
-I ../sources/libinterp/parse-tree -I libinterp/corefcn -I 
../sources/libinterp/corefcn -I ../sources/liboctave/wrappers -I 
/sw/include/GraphicsMagick -I /sw/include/mesa -I /sw/include -D _THREAD_SAFE 
-D _THREAD_SAFE -stdlib=libc++ -O3 -Wall -W -Wshadow -Wold-style-cast -Wformat 
-Wpointer-arith -Wwrite-strings -Wcast-align -Wcast-qual -std=gnu++11 
-fdeprecated-macro -fdebug-compilation-dir 
/Users/bpabbott/Development/mercurial/default/build -ferror-limit 19 
-fmessage-length 188 -pthread -stack-protector 1 -fblocks 
-fobjc-runtime=macosx-10.11.0 -fencode-extended-block-signature 
-fcxx-exceptions -fexceptions -fmax-type-align=16 -fdiagnostics-show-option 
-fcolor-diagnostics -vectorize-loops -vectorize-slp -o octave.o -x c++ 
../sources/libinterp/octave.cc
clang -cc1 version 7.3.0 (clang-703.0.31) default target 
x86_64-apple-darwin15.5.0
ignoring nonexistent directory "/sw/include/mesa"
ignoring nonexistent directory "/usr/include/c++/v1"
ignoring nonexistent directory "/usr/local/include"
#include "..." search starts here:
#include <...> search starts here:
 .
 ../sources
 liboctave
 ../sources/liboctave
 ../sources/liboctave/cruft/misc
 ../sources/liboctave/array
 liboctave/numeric
 ../sources/liboctave/numeric
 liboctave/operators
 ../sources/liboctave/operators
 ../sources/liboctave/system
 ../sources/liboctave/util
 ../sources/libinterp/octave-value
 libinterp
 ../sources/libinterp
 ../sources/libinterp/operators
 libinterp/parse-tree
 ../sources/libinterp/parse-tree
 libinterp/corefcn
 ../sources/libinterp/corefcn
 ../sources/liboctave/wrappers
 /sw/include/GraphicsMagick
 /sw/include
 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1
 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/7.3.0/include
 
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include
 /usr/include
 /System/Library/Frameworks (framework directory)
 /Library/Frameworks (framework directory)
End of search list.
In file included from ../sources/libinterp/octave.cc:48:
In file included from ../sources/libinterp/build-env.h:28:
In file included from ../sources/libinterp/corefcn/oct-map.h:33:
../sources/libinterp/octave-value/ovl.h:195:10: error: ambiguous conversion for 
functional-style cast from 'void' to 'octave_value_list'
  return octave_value_list ({args...});
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
../sources/libinterp/octave.cc:1128:10: note: in instantiation of function 
template specialization 'ovl<std::__1::basic_string<char> >' requested here
  return ovl (octave_program_invocation_name);
         ^
../sources/libinterp/octave-value/ovl.h:60:3: note: candidate constructor
  octave_value_list (const std::initializer_list<octave_value>& args)
  ^
../sources/libinterp/octave-value/ovl.h:54:3: note: candidate constructor
  octave_value_list (const octave_value& tc)
  ^
../sources/libinterp/octave-value/ovl.h:68:3: note: candidate constructor
  octave_value_list (const Cell& tc)
  ^
../sources/libinterp/octave-value/ovl.h:71:3: note: candidate constructor
  octave_value_list (const octave_value_list& obj)
  ^
1 error generated.

Ben