propagate type tests from closure to closure creators
Currently, we only propagate type tests that exclude all regions from the type.
This commit is contained in:
Niko Matsakis
parent
5804637a81
commit
85e1d4749e
7 changed files with 581 additions and 31 deletions
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@ -0,0 +1,66 @@
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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// compile-flags:-Znll -Zborrowck=mir -Zverbose
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#![allow(warnings)]
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#![feature(dyn_trait)]
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#![feature(rustc_attrs)]
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use std::fmt::Debug;
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fn with_signature<'a, T, F>(x: Box<T>, op: F) -> Box<dyn Debug + 'a>
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where F: FnOnce(Box<T>) -> Box<dyn Debug + 'a>
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{
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op(x)
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}
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#[rustc_regions]
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fn no_region<'a, T>(x: Box<T>) -> Box<dyn Debug + 'a>
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where
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T: Debug,
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{
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// Here, the closure winds up being required to prove that `T:
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// 'a`. In principle, it could know that, except that it is
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// type-checked in a fully generic way, and hence it winds up with
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// a propagated requirement that `T: '_#2`, where `'_#2` appears
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// in the return type. The caller makes the mapping from `'_#2` to
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// `'a` (and subsequently reports an error).
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with_signature(x, |y| y)
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//~^ WARNING not reporting region error due to -Znll
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//~| ERROR failed type test
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}
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fn correct_region<'a, T>(x: Box<T>) -> Box<Debug + 'a>
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where
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T: 'a + Debug,
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{
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x
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}
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fn wrong_region<'a, 'b, T>(x: Box<T>) -> Box<Debug + 'a>
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where
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T: 'b + Debug,
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{
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x
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//~^ WARNING not reporting region error due to -Znll
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//~| ERROR failed type test
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}
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fn outlives_region<'a, 'b, T>(x: Box<T>) -> Box<Debug + 'a>
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where
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T: 'b + Debug,
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'b: 'a,
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{
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x
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}
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fn main() {}
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@ -0,0 +1,58 @@
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warning: not reporting region error due to -Znll
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--> $DIR/ty-param-closure-outlives-from-return-type.rs:37:27
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37 | with_signature(x, |y| y)
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| ^
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warning: not reporting region error due to -Znll
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--> $DIR/ty-param-closure-outlives-from-return-type.rs:53:5
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53 | x
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| ^
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note: External requirements
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--> $DIR/ty-param-closure-outlives-from-return-type.rs:37:23
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37 | with_signature(x, |y| y)
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| ^^^^^
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= note: defining type: DefId(0/1:14 ~ ty_param_closure_outlives_from_return_type[317d]::no_region[0]::{{closure}}[0]) with closure substs [
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'_#1r,
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T,
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i32,
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extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<std::fmt::Debug + '_#2r>
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]
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= note: number of external vids: 3
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= note: where T: '_#2r
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error: failed type test: TypeTest { generic_kind: T/#1, lower_bound: '_#4r, point: bb0[5], span: $DIR/ty-param-closure-outlives-from-return-type.rs:37:23: 37:28, test: IsOutlivedByAnyRegionIn(['_#2r]) }
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--> $DIR/ty-param-closure-outlives-from-return-type.rs:37:23
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37 | with_signature(x, |y| y)
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| ^^^^^
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note: No external requirements
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--> $DIR/ty-param-closure-outlives-from-return-type.rs:26:1
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26 | / fn no_region<'a, T>(x: Box<T>) -> Box<dyn Debug + 'a>
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27 | | where
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28 | | T: Debug,
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29 | | {
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... |
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39 | | //~| ERROR failed type test
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40 | | }
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| |_^
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= note: defining type: DefId(0/0:5 ~ ty_param_closure_outlives_from_return_type[317d]::no_region[0]) with substs [
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'_#1r,
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T
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]
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error: failed type test: TypeTest { generic_kind: T/#2, lower_bound: '_#4r, point: bb0[3], span: $DIR/ty-param-closure-outlives-from-return-type.rs:53:5: 53:6, test: IsOutlivedByAnyRegionIn(['_#2r, '_#3r]) }
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--> $DIR/ty-param-closure-outlives-from-return-type.rs:53:5
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53 | x
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| ^
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error: aborting due to 2 previous errors
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@ -0,0 +1,96 @@
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// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// Test that we can propagate `T: 'a` obligations to our caller. See
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// `correct_region` for an explanation of how this test is setup; it's
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// somewhat intricate.
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// compile-flags:-Znll -Zborrowck=mir -Zverbose
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#![allow(warnings)]
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#![feature(dyn_trait)]
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#![feature(rustc_attrs)]
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use std::cell::Cell;
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fn with_signature<'a, T, F>(a: Cell<&'a ()>, b: T, op: F)
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where
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F: FnOnce(Cell<&'a ()>, T),
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{
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op(a, b)
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}
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fn require<'a, T>(_a: &Cell<&'a ()>, _b: &T)
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where
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T: 'a,
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{
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}
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#[rustc_regions]
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fn no_region<'a, T>(a: Cell<&'a ()>, b: T) {
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with_signature(a, b, |x, y| {
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//~^ ERROR failed type test
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//
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// See `correct_region`, which explains the point of this
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// test. The only difference is that, in the case of this
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// function, there is no where clause *anywhere*, and hence we
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// get an error (but reported by the closure creator).
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require(&x, &y)
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//~^ WARNING not reporting region error due to -Znll
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})
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}
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#[rustc_regions]
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fn correct_region<'a, T>(a: Cell<&'a ()>, b: T)
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where
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T: 'a,
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{
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with_signature(a, b, |x, y| {
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// Key point of this test:
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//
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// The *closure* is being type-checked with all of its free
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// regions "universalized". In particular, it does not know
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// that `x` has the type `Cell<&'a ()>`, but rather treats it
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// as if the type of `x` is `Cell<&'A ()>`, where `'A` is some
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// fresh, independent region distinct from the `'a` which
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// appears in the environment. The call to `require` here
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// forces us then to prove that `T: 'A`, but the closure
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// cannot do it on its own. It has to surface this requirement
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// to its creator (which knows that `'a == 'A`).
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require(&x, &y)
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})
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}
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#[rustc_regions]
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fn wrong_region<'a, 'b, T>(a: Cell<&'a ()>, b: T)
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where
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T: 'b,
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{
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with_signature(a, b, |x, y| {
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//~^ ERROR failed type test
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// See `correct_region`
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require(&x, &y)
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//~^ WARNING not reporting region error due to -Znll
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})
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}
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#[rustc_regions]
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fn outlives_region<'a, 'b, T>(a: Cell<&'a ()>, b: T)
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where
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T: 'b,
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'b: 'a,
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{
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with_signature(a, b, |x, y| {
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// See `correct_region`
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require(&x, &y)
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})
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}
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fn main() {}
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@ -0,0 +1,191 @@
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warning: not reporting region error due to -Znll
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:45:9
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45 | require(&x, &y)
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| ^^^^^^^
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warning: not reporting region error due to -Znll
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:79:9
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79 | require(&x, &y)
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| ^^^^^^^
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note: External requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:38:26
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38 | with_signature(a, b, |x, y| {
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| __________________________^
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39 | | //~^ ERROR failed type test
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40 | | //
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41 | | // See `correct_region`, which explains the point of this
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... |
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46 | | //~^ WARNING not reporting region error due to -Znll
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47 | | })
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| |_____^
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= note: defining type: DefId(0/1:16 ~ ty_param_closure_outlives_from_where_clause[317d]::no_region[0]::{{closure}}[0]) with closure substs [
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T,
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i32,
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extern "rust-call" fn((std::cell::Cell<&'_#1r ()>, T))
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]
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= note: number of external vids: 2
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= note: where T: '_#1r
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note: External requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:55:26
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55 | with_signature(a, b, |x, y| {
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| __________________________^
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56 | | // Key point of this test:
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57 | | //
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58 | | // The *closure* is being type-checked with all of its free
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... |
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67 | | require(&x, &y)
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68 | | })
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| |_____^
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= note: defining type: DefId(0/1:19 ~ ty_param_closure_outlives_from_where_clause[317d]::correct_region[0]::{{closure}}[0]) with closure substs [
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'_#1r,
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T,
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i32,
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extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T))
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]
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= note: number of external vids: 3
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= note: where T: '_#2r
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note: External requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:76:26
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76 | with_signature(a, b, |x, y| {
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| __________________________^
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77 | | //~^ ERROR failed type test
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78 | | // See `correct_region`
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79 | | require(&x, &y)
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80 | | //~^ WARNING not reporting region error due to -Znll
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81 | | })
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| |_____^
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|
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= note: defining type: DefId(0/1:23 ~ ty_param_closure_outlives_from_where_clause[317d]::wrong_region[0]::{{closure}}[0]) with closure substs [
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'_#1r,
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T,
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i32,
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extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T))
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]
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= note: number of external vids: 3
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= note: where T: '_#2r
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note: External requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:90:26
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90 | with_signature(a, b, |x, y| {
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| __________________________^
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91 | | // See `correct_region`
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92 | | require(&x, &y)
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93 | | })
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| |_____^
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|
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= note: defining type: DefId(0/1:27 ~ ty_param_closure_outlives_from_where_clause[317d]::outlives_region[0]::{{closure}}[0]) with closure substs [
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'_#1r,
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'_#2r,
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T,
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i32,
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extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T))
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]
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= note: number of external vids: 4
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= note: where T: '_#3r
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error: failed type test: TypeTest { generic_kind: T/#0, lower_bound: '_#3r, point: bb0[5], span: $DIR/ty-param-closure-outlives-from-where-clause.rs:38:26: 47:6, test: IsOutlivedByAnyRegionIn(['_#2r]) }
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:38:26
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38 | with_signature(a, b, |x, y| {
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| __________________________^
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39 | | //~^ ERROR failed type test
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40 | | //
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41 | | // See `correct_region`, which explains the point of this
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... |
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46 | | //~^ WARNING not reporting region error due to -Znll
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47 | | })
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| |_____^
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note: No external requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:37:1
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37 | / fn no_region<'a, T>(a: Cell<&'a ()>, b: T) {
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38 | | with_signature(a, b, |x, y| {
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39 | | //~^ ERROR failed type test
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40 | | //
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... |
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47 | | })
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48 | | }
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| |_^
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|
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= note: defining type: DefId(0/0:6 ~ ty_param_closure_outlives_from_where_clause[317d]::no_region[0]) with substs [
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T
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]
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note: No external requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:51:1
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51 | / fn correct_region<'a, T>(a: Cell<&'a ()>, b: T)
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52 | | where
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53 | | T: 'a,
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54 | | {
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... |
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68 | | })
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69 | | }
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| |_^
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|
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= note: defining type: DefId(0/0:7 ~ ty_param_closure_outlives_from_where_clause[317d]::correct_region[0]) with substs [
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'_#1r,
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T
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]
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error: failed type test: TypeTest { generic_kind: T/#1, lower_bound: '_#5r, point: bb0[5], span: $DIR/ty-param-closure-outlives-from-where-clause.rs:76:26: 81:6, test: IsOutlivedByAnyRegionIn(['_#1r, '_#3r]) }
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:76:26
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|
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76 | with_signature(a, b, |x, y| {
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| __________________________^
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77 | | //~^ ERROR failed type test
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78 | | // See `correct_region`
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79 | | require(&x, &y)
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80 | | //~^ WARNING not reporting region error due to -Znll
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81 | | })
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| |_____^
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note: No external requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:72:1
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|
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72 | / fn wrong_region<'a, 'b, T>(a: Cell<&'a ()>, b: T)
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73 | | where
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74 | | T: 'b,
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75 | | {
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... |
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81 | | })
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82 | | }
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| |_^
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|
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= note: defining type: DefId(0/0:8 ~ ty_param_closure_outlives_from_where_clause[317d]::wrong_region[0]) with substs [
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'_#1r,
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T
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]
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note: No external requirements
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--> $DIR/ty-param-closure-outlives-from-where-clause.rs:85:1
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85 | / fn outlives_region<'a, 'b, T>(a: Cell<&'a ()>, b: T)
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86 | | where
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87 | | T: 'b,
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88 | | 'b: 'a,
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... |
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93 | | })
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94 | | }
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| |_^
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|
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= note: defining type: DefId(0/0:9 ~ ty_param_closure_outlives_from_where_clause[317d]::outlives_region[0]) with substs [
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'_#1r,
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'_#2r,
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T
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]
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error: aborting due to 2 previous errors
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