NoProtectStorage compile error

[romainfrancois]

NoProtectStorage was meant to be used in cases when you don't want to pay for preserve and release because the object is already protected:

> Rcpp::cppFunction( 'void f(){ Rcpp::Vector<STRSXP, NoProtectStorage> s(1); s[0] = "" ; }' )
In file included from file1c206f8abb9c.cpp:1:
In file included from /Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp.h:40:
In file included from /Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp/Vector.h:54:
/Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp/vector/traits.h:73:41: error: no matching constructor for initialization of 'Rcpp::traits::proxy_cache<16, NoProtectStorage>::proxy' (aka 'string_proxy<16>')
                inline proxy ref(R_xlen_t i) { return proxy(*p,i);}
                                                      ^     ~~~~
/Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp/vector/Vector.h:339:57: note: in instantiation of member function 'Rcpp::traits::proxy_cache<16, NoProtectStorage>::ref' requested here
    inline Proxy operator[]( R_xlen_t i ){ return cache.ref(i) ; }
                                                        ^
file1c206f8abb9c.cpp:6:57: note: in instantiation of member function 'Rcpp::Vector<16, NoProtectStorage>::operator[]' requested here
void f(){ Rcpp::Vector<STRSXP, NoProtectStorage> s(1); s[0] = "" ; }
                                                        ^
/Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp/vector/string_proxy.h:43:3: note: candidate constructor not viable: no known conversion from 'Rcpp::traits::proxy_cache<16, NoProtectStorage>::VECTOR' (aka 'Vector<16, NoProtectStorage>') to 'Rcpp::internal::string_proxy<16>::VECTOR &' (aka 'Vector<16> &') for 1st argument
                string_proxy( VECTOR& v, R_xlen_t index_ ) : parent(&v), index(index_){}
                ^
/Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp/vector/string_proxy.h:45:3: note: candidate constructor not viable: requires single argument 'other', but 2 arguments were provided
                string_proxy( const string_proxy& other ) :
                ^
/Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include/Rcpp/vector/string_proxy.h:35:3: note: candidate constructor not viable: requires 0 arguments, but 2 were provided
                string_proxy() : parent(0), index(-1){};
                ^
1 error generated.
make: *** [file1c206f8abb9c.o] Error 1
clang++  -I"/Library/Frameworks/R.framework/Resources/include" -DNDEBUG   -I"/Library/Frameworks/R.framework/Versions/3.5/Resources/library/Rcpp/include" -I"/private/var/folders/r_/1b2gjtsd7j92jbbpz4t7ps340000gn/T/Rtmp4GFH1U/sourceCpp-x86_64-apple-darwin15.6.0-0.12.16" -I/usr/local/include   -fPIC  -Wno-unused-result -Wno-c++11-inline-namespace -O3 -c file1c206f8abb9c.cpp -o file1c206f8abb9c.o
Error in sourceCpp(code = code, env = env, rebuild = rebuild, cacheDir = cacheDir,  : 
  Error 1 occurred building shared library.

[eddelbuettel]

Hm, still works for, e.g., INTSXP:

R> Rcpp::cppFunction('void f(){ Rcpp::Vector<INTSXP, NoProtectStorage> s(1); s[0] = 1;}')
R> f()
R> 

The string proxies are trickier. Do you consider this fixable? Would you like to work on a fix?

[romainfrancois]

Probably just an oversight. I don't suspect many people know about NoProtectStorage. I'll deal with it.