rustc_trait_selection/
regions.rs

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1use rustc_hir::def_id::LocalDefId;
2use rustc_infer::infer::outlives::env::OutlivesEnvironment;
3use rustc_infer::infer::{InferCtxt, RegionResolutionError};
4use rustc_macros::extension;
5use rustc_middle::traits::ObligationCause;
6use rustc_middle::traits::query::NoSolution;
7use rustc_middle::ty::{self, Ty};
8
9use crate::traits::ScrubbedTraitError;
10use crate::traits::outlives_bounds::InferCtxtExt;
11
12#[extension(pub trait OutlivesEnvironmentBuildExt<'tcx>)]
13impl<'tcx> OutlivesEnvironment<'tcx> {
14    fn new(
15        infcx: &InferCtxt<'tcx>,
16        body_id: LocalDefId,
17        param_env: ty::ParamEnv<'tcx>,
18        assumed_wf_tys: impl IntoIterator<Item = Ty<'tcx>>,
19    ) -> Self {
20        Self::new_with_implied_bounds_compat(
21            infcx,
22            body_id,
23            param_env,
24            assumed_wf_tys,
25            !infcx.tcx.sess.opts.unstable_opts.no_implied_bounds_compat,
26        )
27    }
28
29    fn new_with_implied_bounds_compat(
30        infcx: &InferCtxt<'tcx>,
31        body_id: LocalDefId,
32        param_env: ty::ParamEnv<'tcx>,
33        assumed_wf_tys: impl IntoIterator<Item = Ty<'tcx>>,
34        implied_bounds_compat: bool,
35    ) -> Self {
36        let mut bounds = vec![];
37
38        for bound in param_env.caller_bounds() {
39            if let Some(mut type_outlives) = bound.as_type_outlives_clause() {
40                if infcx.next_trait_solver() {
41                    match crate::solve::deeply_normalize::<_, ScrubbedTraitError<'tcx>>(
42                        infcx.at(&ObligationCause::dummy(), param_env),
43                        type_outlives,
44                    ) {
45                        Ok(new) => type_outlives = new,
46                        Err(_) => {
47                            infcx.dcx().delayed_bug(format!("could not normalize `{bound}`"));
48                        }
49                    }
50                }
51                bounds.push(type_outlives);
52            }
53        }
54
55        // FIXME: This needs to be modified so that we normalize the known type
56        // outlives obligations then elaborate them into their region/type components.
57        // Otherwise, `<W<'a> as Mirror>::Assoc: 'b` will not imply `'a: 'b` even
58        // if we can normalize `'a`.
59        OutlivesEnvironment::from_normalized_bounds(
60            param_env,
61            bounds,
62            infcx.implied_bounds_tys_with_compat(
63                body_id,
64                param_env,
65                assumed_wf_tys,
66                implied_bounds_compat,
67            ),
68        )
69    }
70}
71
72#[extension(pub trait InferCtxtRegionExt<'tcx>)]
73impl<'tcx> InferCtxt<'tcx> {
74    /// Resolve regions, using the deep normalizer to normalize any type-outlives
75    /// obligations in the process. This is in `rustc_trait_selection` because
76    /// we need to normalize.
77    ///
78    /// Prefer this method over `resolve_regions_with_normalize`, unless you are
79    /// doing something specific for normalization.
80    fn resolve_regions(
81        &self,
82        body_id: LocalDefId,
83        param_env: ty::ParamEnv<'tcx>,
84        assumed_wf_tys: impl IntoIterator<Item = Ty<'tcx>>,
85    ) -> Vec<RegionResolutionError<'tcx>> {
86        self.resolve_regions_with_outlives_env(&OutlivesEnvironment::new(
87            self,
88            body_id,
89            param_env,
90            assumed_wf_tys,
91        ))
92    }
93
94    /// Don't call this directly unless you know what you're doing.
95    fn resolve_regions_with_outlives_env(
96        &self,
97        outlives_env: &OutlivesEnvironment<'tcx>,
98    ) -> Vec<RegionResolutionError<'tcx>> {
99        self.resolve_regions_with_normalize(&outlives_env, |ty, origin| {
100            let ty = self.resolve_vars_if_possible(ty);
101
102            if self.next_trait_solver() {
103                crate::solve::deeply_normalize(
104                    self.at(
105                        &ObligationCause::dummy_with_span(origin.span()),
106                        outlives_env.param_env,
107                    ),
108                    ty,
109                )
110                .map_err(|_: Vec<ScrubbedTraitError<'tcx>>| NoSolution)
111            } else {
112                Ok(ty)
113            }
114        })
115    }
116}
rustc_trait_selection/regions.rs

rustc_trait_selection/
regions.rs
