Auto merge of #41055 - Archytaus:compile-fail/const-match-pattern-arm, r=arielb1

Fixed ICEs with pattern matching in const expression

Fixed 2 ICEs with when pattern matching inside a constant expression.

Both of these ICEs now resolve to an appropriate compiler error.

1. ICE was caused by a compiler bug to implement discriminant const qualify.

    I removed this intentionally thrown bug and changed it to a FIXME as the unimplemented expression type is handled as a compiler error elsewhere.

2. ICE was caused during a drop check when checking if a variable lifetime outlives the current scope if there was no parent scope .

    I've changed it to stop checking if there is no parent scope for the current scope. It is valid syntax for a const variable to be assigned a match expression with no enclosing scope.

    The ICE seemed to mainly be used as a defensive check for bugs elsewhere.

Fixes #38199.
Fixes #31577.
Fixes #29093.
Fixes #40012.
This commit is contained in:
bors 2017-04-08 14:05:06 +00:00
commit a61011761d
3 changed files with 33 additions and 12 deletions

View File

@ -603,7 +603,8 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
Rvalue::Cast(CastKind::ReifyFnPointer, ..) | Rvalue::Cast(CastKind::ReifyFnPointer, ..) |
Rvalue::Cast(CastKind::UnsafeFnPointer, ..) | Rvalue::Cast(CastKind::UnsafeFnPointer, ..) |
Rvalue::Cast(CastKind::ClosureFnPointer, ..) | Rvalue::Cast(CastKind::ClosureFnPointer, ..) |
Rvalue::Cast(CastKind::Unsize, ..) => {} Rvalue::Cast(CastKind::Unsize, ..) |
Rvalue::Discriminant(..) => {}
Rvalue::Len(_) => { Rvalue::Len(_) => {
// Static lvalues in consts would have errored already, // Static lvalues in consts would have errored already,
@ -721,14 +722,6 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
} }
} }
Rvalue::Discriminant(..) => {
// FIXME discriminant
self.add(Qualif::NOT_CONST);
if self.mode != Mode::Fn {
bug!("implement discriminant const qualify");
}
}
Rvalue::Box(_) => { Rvalue::Box(_) => {
self.add(Qualif::NOT_CONST); self.add(Qualif::NOT_CONST);
if self.mode != Mode::Fn { if self.mode != Mode::Fn {

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@ -278,9 +278,12 @@ pub fn check_safety_of_destructor_if_necessary<'a, 'gcx, 'tcx>(
debug!("check_safety_of_destructor_if_necessary typ: {:?} scope: {:?}", debug!("check_safety_of_destructor_if_necessary typ: {:?} scope: {:?}",
typ, scope); typ, scope);
let parent_scope = rcx.tcx.region_maps.opt_encl_scope(scope).unwrap_or_else(|| {
span_bug!(span, "no enclosing scope found for scope: {:?}", scope) let parent_scope = match rcx.tcx.region_maps.opt_encl_scope(scope) {
}); Some(parent_scope) => parent_scope,
// If no enclosing scope, then it must be the root scope which cannot be outlived.
None => return
};
let result = iterate_over_potentially_unsafe_regions_in_type( let result = iterate_over_potentially_unsafe_regions_in_type(
&mut DropckContext { &mut DropckContext {

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@ -0,0 +1,25 @@
// Copyright 2017 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.
const x: bool = match Some(true) {
Some(value) => true,
//~^ ERROR: constant contains unimplemented expression type [E0019]
_ => false
};
const y: bool = {
match Some(true) {
Some(value) => true,
//~^ ERROR: constant contains unimplemented expression type [E0019]
_ => false
}
};
fn main() {}