R CMD check looks for nonexisting file

R CMD check looks for a nonexisting .R file when preparing package for lazy loading, Rcpp.package.skeleton produces seemingly corrupted RcppExports.cpp file.

I am trying to build an R-package using Rcpp setting it up with a call to Rcpp.package.skeleton. This produces a seemingly corrupted RcppExports.cpp file (duplicate function definitions).

After manually correcting this file I run devtools::check() on this, compilation and linking succeeds and the dll is built. But then the following output from R CMD check

   ** R
   ** data
   ** byte-compile and prepare package for lazy loading
   Reading DataUtils.R
   Reading Env.R
   Reading Paths.R
   Reading RcppExports.R
   Reading StatUtils.R
   Reading SynData.R
   Warnung in file(filename, "r", encoding = encoding)
       cannot open file 'src/Env.R': No such file or directory
   Error in file(filename, "r", encoding = encoding) : 
       cannot open file connection
   Error : unable to load R code in package 'ZA'
   ERROR: lazy loading failed for package 'ZA'
   * removing 'C:/Users/MeyerM/Projects/R/ZA/ZA.Rcheck/ZA'
   In R CMD INSTALL

Why would it look for a file "src/Env.R"?

The package can be obtained from https://github.com/spyqqqdia/ZAp (file ZAp.zip).

Thanks in advance!

Solution

There are many errors in that code:

Duplicate // [[Rcpp::export]] before function declaration and definition. This leads to the redefinition errors from compiling RcppExports.cpp.
Using string instead of std::string or using std::string in some files.
Code that must not be part of a package, e.g. compileCpp.R:
```
source("src/Env.R")
library(Rcpp)
```

As a first approximation, files in R should only contain function definitions.