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