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Friendlier error message for break outside a loop

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The typechecker should really check for this, but at least now
there's an error message rather than an inexhaustive match failure
in trans.
This commit is contained in:
Tim Chevalier 2011-06-10 14:34:01 -07:00
parent e5eacf8ea9
commit 774c6d0198
2 changed files with 19 additions and 7 deletions
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19
src/comp/middle/trans.rs
View file

@ -5691,11 +5691,11 @@ fn trans_expr_out(&@block_ctxt cx, &@ast::expr e, out_method output)
}
case (ast::expr_break(?a)) {
ret trans_break(cx);
ret trans_break(e.span, cx);
}
case (ast::expr_cont(?a)) {
ret trans_cont(cx);
ret trans_cont(e.span, cx);
}
case (ast::expr_ret(?e, _)) {
@ -5972,7 +5972,7 @@ fn trans_put(&@block_ctxt cx, &option::t[@ast::expr] e) -> result {
ret res(bcx, bcx.build.FastCall(llcallee, llargs));
}
fn trans_break_cont(&@block_ctxt cx, bool to_end) -> result {
fn trans_break_cont(&span sp, &@block_ctxt cx, bool to_end) -> result {
auto bcx = cx;
// Locate closest loop block, outputting cleanup as we go.
auto cleanup_cx = cx;
@ -5998,6 +5998,11 @@ fn trans_break_cont(&@block_ctxt cx, bool to_end) -> result {
case (_) {
alt ({cleanup_cx.parent}) {
case (parent_some(?cx)) { cleanup_cx = cx; }
case (parent_none) {
cx.fcx.lcx.ccx.sess.span_err(sp,
(if (to_end) { "Break" } else { "Cont" })
+ " outside a loop");
}
}
}
}
@ -6007,12 +6012,12 @@ fn trans_break_cont(&@block_ctxt cx, bool to_end) -> result {
cx.fcx.lcx.ccx.sess.bug("in trans::trans_break_cont()");
}
fn trans_break(&@block_ctxt cx) -> result {
ret trans_break_cont(cx, true);
fn trans_break(&span sp, &@block_ctxt cx) -> result {
ret trans_break_cont(sp, cx, true);
}
fn trans_cont(&@block_ctxt cx) -> result {
ret trans_break_cont(cx, false);
fn trans_cont(&span sp, &@block_ctxt cx) -> result {
ret trans_break_cont(sp, cx, false);
}

7
src/test/compile-fail/break-outside-loop.rs Normal file
View file

@ -0,0 +1,7 @@
// error-pattern:Break outside a loop
fn main() {
auto pth = break;
let rec(str t) res = rec(t=pth);
}