.prepareFastSubset fix

Author: MichaelChirico

R/data.table.R

@@ -3240,9 +3240,9 @@ is_constantish = function(q, check_singleton=FALSE) {
       if (length(RHS) != nrow(x)) stopf("RHS of %s is length %d which is not 1 or nrow (%d). For robustness, no recycling is allowed (other than of length 1 RHS). Consider %%in%% instead.", operator, length(RHS), nrow(x))
       return(NULL) # DT[colA == colB] regular element-wise vector scan
     }
-    if ( mode(x[[col]]) != mode(RHS) ||                # mode() so that doubleLHS/integerRHS and integerLHS/doubleRHS&isRealReallyInt32 are optimized (both sides mode 'numeric')
-         is.factor(x[[col]])+is.factor(RHS) == 1L ||   # but factor is also mode 'numeric' so treat that separately
-         is.integer(x[[col]]) && (!is.double(RHS) || !isRealReallyInt32(RHS)) ) { # and if RHS contains fractions then don't optimize that as bmerge truncates the fractions to match to the target integer type
+    if ( (mode(x[[col]]) != mode(RHS)) ||                # mode() so that doubleLHS/integerRHS and integerLHS/doubleRHS&isRealReallyInt32 are optimized (both sides mode 'numeric')
+         (is.factor(x[[col]])+is.factor(RHS) == 1L) ||   # but factor is also mode 'numeric' so treat that separately
+         (is.integer(x[[col]]) && is.double(RHS) && !isRealReallyInt32(RHS)) ) { # and if RHS contains fractions then don't optimize that as bmerge truncates the fractions to match to the target integer type
       # re-direct non-matching type cases to base R, as data.table's binary
       # search based join is strict in types. #957, #961 and #1361
       # the mode() checks also deals with NULL since mode(NULL)=="NULL" and causes this return, as one CRAN package (eplusr 0.9.1) relies on