m = TreeMaker.instance(c);
}
CompilationUnitTree removeRedundantImports(CompilationUnitTree t) {
JCCompilationUnit tree = (JCCompilationUnit) t;
tree.accept(this);
ListBuffer<JCTree> defs = new ListBuffer<JCTree>();
for (JCTree def: tree.defs) {
if (def.getTag() == JCTree.Tag.IMPORT) {
JCImport imp = (JCImport) def;
if (imp.qualid.getTag() == JCTree.Tag.SELECT) {