// Attribute all cases and
// check that there are no duplicate case labels or default clauses.
Set<Object> labels = new HashSet<Object>(); // The set of case labels.
boolean hasDefault = false; // Is there a default label?
for (List<JCCase> l = tree.cases; l.nonEmpty(); l = l.tail) {
JCCase c = l.head;
Env<AttrContext> caseEnv =
switchEnv.dup(c, env.info.dup(switchEnv.info.scope.dup()));
if (c.pat != null) {
if (enumSwitch) {
Symbol sym = enumConstant(c.pat, seltype);
if (sym == null) {
log.error(c.pat.pos(), "enum.label.must.be.unqualified.enum");
} else if (!labels.add(sym)) {
log.error(c.pos(), "duplicate.case.label");
}
} else {
Type pattype = attribExpr(c.pat, switchEnv, seltype);
if (pattype.tag != ERROR) {
if (pattype.constValue() == null) {
log.error(c.pat.pos(),
(stringSwitch ? "string.const.req" : "const.expr.req"));
} else if (labels.contains(pattype.constValue())) {
log.error(c.pos(), "duplicate.case.label");
} else {
labels.add(pattype.constValue());
}
}
}
} else if (hasDefault) {
log.error(c.pos(), "duplicate.default.label");
} else {
hasDefault = true;
}
attribStats(c.stats, caseEnv);
caseEnv.info.scope.leave();