1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
use crate::outlives::outlives_bounds::InferCtxtExt as _;
use rustc_data_structures::fx::FxHashSet;
use rustc_hir as hir;
use rustc_infer::infer::outlives::env::OutlivesEnvironment;
use rustc_infer::infer::InferCtxt;
use rustc_middle::ty::Ty;
pub(crate) trait OutlivesEnvironmentExt<'tcx> {
fn add_implied_bounds(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
fn_sig_tys: FxHashSet<Ty<'tcx>>,
body_id: hir::HirId,
);
}
impl<'tcx> OutlivesEnvironmentExt<'tcx> for OutlivesEnvironment<'tcx> {
/// This method adds "implied bounds" into the outlives environment.
/// Implied bounds are outlives relationships that we can deduce
/// on the basis that certain types must be well-formed -- these are
/// either the types that appear in the function signature or else
/// the input types to an impl. For example, if you have a function
/// like
///
/// ```
/// fn foo<'a, 'b, T>(x: &'a &'b [T]) { }
/// ```
///
/// we can assume in the caller's body that `'b: 'a` and that `T:
/// 'b` (and hence, transitively, that `T: 'a`). This method would
/// add those assumptions into the outlives-environment.
///
/// Tests: `src/test/ui/regions/regions-free-region-ordering-*.rs`
#[instrument(level = "debug", skip(self, infcx))]
fn add_implied_bounds<'a>(
&mut self,
infcx: &InferCtxt<'a, 'tcx>,
fn_sig_tys: FxHashSet<Ty<'tcx>>,
body_id: hir::HirId,
) {
for ty in fn_sig_tys {
let ty = infcx.resolve_vars_if_possible(ty);
let implied_bounds = infcx.implied_outlives_bounds(self.param_env, body_id, ty);
self.add_outlives_bounds(Some(infcx), implied_bounds)
}
}
}
|
