import syntax::ast::*; import syntax::visit; import driver::session::session; type ctx = {in_loop: bool, can_ret: bool}; fn check_crate(tcx: ty::ctxt, crate: @crate) { visit::visit_crate(*crate, {in_loop: false,can_ret: true}, visit::mk_vt(@{ visit_item: {|i, _cx, v| visit::visit_item(i, {in_loop: false, can_ret: true}, v); }, visit_expr: {|e: @expr, cx: ctx, v: visit::vt| alt e.node { expr_for(_, e, b) | expr_while(e, b) | expr_do_while(b, e) { v.visit_expr(e, cx, v); v.visit_block(b, {in_loop: true with cx}, v); } expr_loop(b) { v.visit_block(b, {in_loop: true with cx}, v); } expr_fn(_, _, _, _) { visit::visit_expr(e, {in_loop: false, can_ret: true}, v); } expr_fn_block(_, b) { v.visit_block(b, {in_loop: false, can_ret: false}, v); } expr_loop_body(@{node: expr_fn_block(_, b), _}) { v.visit_block(b, {in_loop: true, can_ret: false}, v); } expr_break { if !cx.in_loop { tcx.sess.span_err(e.span, "`break` outside of loop"); } } expr_cont { if !cx.in_loop { tcx.sess.span_err(e.span, "`cont` outside of loop"); } } expr_ret(oe) { if !cx.can_ret { tcx.sess.span_err(e.span, "`ret` in block function"); } visit::visit_expr_opt(oe, cx, v); } expr_be(re) { if !cx.can_ret { tcx.sess.span_err(e.span, "`be` in block function"); } v.visit_expr(re, cx, v); } _ { visit::visit_expr(e, cx, v); } } } with *visit::default_visitor() })); }