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import syntax::visit;
import syntax::ast::*;
type ctx = {tcx: ty::ctxt, mutable allow_block: bool};
fn check_crate(tcx: ty::ctxt, crate: @crate) {
let cx = {tcx: tcx, mutable allow_block: false};
let v = visit::mk_vt(@{visit_expr: visit_expr
with *visit::default_visitor()});
visit::visit_crate(*crate, cx, v);
}
fn visit_expr(ex: @expr, cx: ctx, v: visit::vt<ctx>) {
if !cx.allow_block {
alt ty::struct(cx.tcx, ty::expr_ty(cx.tcx, ex)) {
ty::ty_fn(proto_block., _, _, _, _) {
cx.tcx.sess.span_err(ex.span, "expressions with block type \
can only appear in callee or (by-ref) argument position");
}
_ {}
}
}
let outer = cx.allow_block;
alt ex.node {
expr_call(f, args, _) {
cx.allow_block = true;
v.visit_expr(f, cx, v);
let i = 0u;
for arg_t in ty::ty_fn_args(cx.tcx, ty::expr_ty(cx.tcx, f)) {
cx.allow_block = arg_t.mode == by_ref;
v.visit_expr(args[i], cx, v);
i += 1u;
}
}
_ {
cx.allow_block = false;
visit::visit_expr(ex, cx, v);
}
}
cx.allow_block = outer;
}
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