Placate rchk

Author: aitap

src/subset.c

@@ -343,7 +343,8 @@ SEXP subsetDT(SEXP x, SEXP rows, SEXP cols) { // API change needs update NEWS.md
   // but maintain key if ordered subset
   SEXP key = getAttrib(x, sym_sorted);
   if (length(key)) {
-    SEXP in = PROTECT(chin(key, getAttrib(ans,R_NamesSymbol))); nprotect++;
+    SEXP innames = PROTECT(getAttrib(ans,R_NamesSymbol)); nprotect++;
+    SEXP in = PROTECT(chin(key, innames)); nprotect++;
     int i = 0;  while(i<LENGTH(key) && LOGICAL(in)[i]) i++;
     // i is now the keylen that can be kept. 2 lines above much easier in C than R
     if (i==0 || !orderedSubset) {