typeck: use NoExpectation to check return type of diverging fn

This fixes #35849, a regression introduced by the typeck refactoring
around TyNever/!.
This commit is contained in:
Alex Burka 2016-08-21 22:45:25 +00:00
parent 490189634b
commit 702ea7169c
5 changed files with 49 additions and 2 deletions

View File

@ -1479,7 +1479,13 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
self.ir.tcx.region_maps.call_site_extent(id, body.id),
&self.fn_ret(id));
if self.live_on_entry(entry_ln, self.s.no_ret_var).is_some() {
if fn_ret.is_never() {
// FIXME(durka) this rejects code like `fn foo(x: !) -> ! { x }`
if self.live_on_entry(entry_ln, self.s.clean_exit_var).is_some() {
span_err!(self.ir.tcx.sess, sp, E0270,
"computation may converge in a function marked as diverging");
}
} else if self.live_on_entry(entry_ln, self.s.no_ret_var).is_some() {
let param_env = ParameterEnvironment::for_item(self.ir.tcx, id);
let t_ret_subst = fn_ret.subst(self.ir.tcx, &param_env.free_substs);
let is_nil = self.ir.tcx.infer_ctxt(None, Some(param_env),

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@ -708,7 +708,13 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
inherited.tables.borrow_mut().liberated_fn_sigs.insert(fn_id, fn_sig);
fcx.check_block_with_expected(body, ExpectHasType(fcx.ret_ty));
// FIXME(aburka) do we need this special case? and should it be is_uninhabited?
let expected = if fcx.ret_ty.is_never() {
NoExpectation
} else {
ExpectHasType(fcx.ret_ty)
};
fcx.check_block_with_expected(body, expected);
fcx
}

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@ -0,0 +1,16 @@
// Copyright 2016 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.
fn _converge() -> ! { //~ ERROR computation may converge
42
}
fn main() { }

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@ -10,6 +10,7 @@
// Test that we can use a ! for an argument of type !
// ignore-test FIXME(durka) can't be done with the current liveness code
// error-pattern:wowzers!
#![feature(never_type)]

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@ -0,0 +1,18 @@
// Copyright 2016 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.
fn assert_sizeof() -> ! {
unsafe {
::std::mem::transmute::<f64, [u8; 8]>(panic!())
}
}
fn main() { }