76f342f2e83c8db9ac6b43dc5354b55b74a5eebe,h2o-core/src/main/java/water/currents/ASTColSlice.java,ASTRowSliceAssign,apply,#Env#Env.StackHelp#AST#,83
Before Change
Frame dst = stk.track(asts[1].exec(env)).getFrame();
// Sanity check src vs dst
Frame src = stk.track(asts[2].exec(env)).getFrame();
if( dst.numCols() != src.numCols() )
throw new IllegalArgumentException("Source and destination frames must have the same count and type of columns");
Vec[] dvecs = dst.vecs();
After Change
long nrows = nlist.cnt();
// Sanity check src vs dst.
Val vsrc = stk.track(asts[2].exec(env));
if( vsrc.isFrame() ) { // Frame vs Frame
Frame src = vsrc.getFrame();
if( dst.numCols() != src.numCols() )