diff options
| -rw-r--r-- | src/librustc_typeck/check/mod.rs | 14 | ||||
| -rw-r--r-- | src/test/ui/break-while-condition.rs | 17 | ||||
| -rw-r--r-- | src/test/ui/break-while-condition.stderr | 15 |
3 files changed, 42 insertions, 4 deletions
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs index 70d299437a6..b0766f05913 100644 --- a/src/librustc_typeck/check/mod.rs +++ b/src/librustc_typeck/check/mod.rs @@ -3841,10 +3841,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { let ctxt = BreakableCtxt { // cannot use break with a value from a while loop coerce: None, - may_break: true, + may_break: false, // Will get updated if/when we find a `break`. }; - self.with_breakable_ctxt(expr.id, ctxt, || { + let (ctxt, ()) = self.with_breakable_ctxt(expr.id, ctxt, || { self.check_expr_has_type_or_error(&cond, tcx.types.bool); let cond_diverging = self.diverges.get(); self.check_block_no_value(&body); @@ -3853,6 +3853,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { self.diverges.set(cond_diverging); }); + if ctxt.may_break { + // No way to know whether it's diverging because + // of a `break` or an outer `break` or `return`. + self.diverges.set(Diverges::Maybe); + } + self.tcx.mk_nil() } hir::ExprLoop(ref body, _, source) => { @@ -3871,7 +3877,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { let ctxt = BreakableCtxt { coerce, - may_break: false, // will get updated if/when we find a `break` + may_break: false, // Will get updated if/when we find a `break`. }; let (ctxt, ()) = self.with_breakable_ctxt(expr.id, ctxt, || { @@ -3880,7 +3886,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> { if ctxt.may_break { // No way to know whether it's diverging because - // of a `break` or an outer `break` or `return. + // of a `break` or an outer `break` or `return`. self.diverges.set(Diverges::Maybe); } diff --git a/src/test/ui/break-while-condition.rs b/src/test/ui/break-while-condition.rs new file mode 100644 index 00000000000..cc5d17e42d5 --- /dev/null +++ b/src/test/ui/break-while-condition.rs @@ -0,0 +1,17 @@ +// Copyright 2018 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +#![feature(never_type)] + +fn main() { + let _: ! = { //~ ERROR mismatched types + 'a: while break 'a {}; + }; +} diff --git a/src/test/ui/break-while-condition.stderr b/src/test/ui/break-while-condition.stderr new file mode 100644 index 00000000000..5abf60c86d3 --- /dev/null +++ b/src/test/ui/break-while-condition.stderr @@ -0,0 +1,15 @@ +error[E0308]: mismatched types + --> $DIR/break-while-condition.rs:14:16 + | +LL | let _: ! = { //~ ERROR mismatched types + | ________________^ +LL | | 'a: while break 'a {}; +LL | | }; + | |_____^ expected !, found () + | + = note: expected type `!` + found type `()` + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0308`. |