1 //! Error Reporting for Anonymous Region Lifetime Errors
2 //! where both the regions are anonymous.
4 use crate::errors::AddLifetimeParamsSuggestion;
5 use crate::errors::LifetimeMismatch;
6 use crate::errors::LifetimeMismatchLabels;
7 use crate::infer::error_reporting::nice_region_error::find_anon_type::find_anon_type;
8 use crate::infer::error_reporting::nice_region_error::util::AnonymousParamInfo;
9 use crate::infer::error_reporting::nice_region_error::NiceRegionError;
10 use crate::infer::lexical_region_resolve::RegionResolutionError;
11 use crate::infer::SubregionOrigin;
12 use crate::infer::TyCtxt;
14 use rustc_errors::AddSubdiagnostic;
15 use rustc_errors::{Diagnostic, ErrorGuaranteed};
17 use rustc_middle::ty::Region;
19 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
20 /// Print the error message for lifetime errors when both the concerned regions are anonymous.
22 /// Consider a case where we have
24 /// ```compile_fail,E0623
25 /// fn foo(x: &mut Vec<&u8>, y: &u8) {
33 /// fn foo(x: &mut Vec<&u8>, y: &u8) {
34 /// --- --- these references are declared with different lifetimes...
36 /// ^ ...but data from `y` flows into `x` here
39 /// It has been extended for the case of structs too.
41 /// Consider the example
44 /// struct Ref<'a> { x: &'a u32 }
48 /// fn foo(mut x: Vec<Ref>, y: Ref) {
49 /// --- --- these structs are declared with different lifetimes...
51 /// ^ ...but data from `y` flows into `x` here
55 /// It will later be extended to trait objects.
56 pub(super) fn try_report_anon_anon_conflict(&self) -> Option<ErrorGuaranteed> {
57 let (span, sub, sup) = self.regions()?;
59 if let Some(RegionResolutionError::ConcreteFailure(
60 SubregionOrigin::ReferenceOutlivesReferent(..),
64 // This error doesn't make much sense in this case.
68 // Determine whether the sub and sup consist of both anonymous (elided) regions.
69 let anon_reg_sup = self.tcx().is_suitable_region(sup)?;
71 let anon_reg_sub = self.tcx().is_suitable_region(sub)?;
72 let scope_def_id_sup = anon_reg_sup.def_id;
73 let bregion_sup = anon_reg_sup.boundregion;
74 let scope_def_id_sub = anon_reg_sub.def_id;
75 let bregion_sub = anon_reg_sub.boundregion;
77 let ty_sup = find_anon_type(self.tcx(), sup, &bregion_sup)?;
79 let ty_sub = find_anon_type(self.tcx(), sub, &bregion_sub)?;
82 "try_report_anon_anon_conflict: found_param1={:?} sup={:?} br1={:?}",
83 ty_sub, sup, bregion_sup
86 "try_report_anon_anon_conflict: found_param2={:?} sub={:?} br2={:?}",
87 ty_sup, sub, bregion_sub
90 let (ty_sup, ty_fndecl_sup) = ty_sup;
91 let (ty_sub, ty_fndecl_sub) = ty_sub;
93 let AnonymousParamInfo { param: anon_param_sup, .. } =
94 self.find_param_with_region(sup, sup)?;
95 let AnonymousParamInfo { param: anon_param_sub, .. } =
96 self.find_param_with_region(sub, sub)?;
99 self.is_return_type_anon(scope_def_id_sup, bregion_sup, ty_fndecl_sup);
100 let sub_is_ret_type =
101 self.is_return_type_anon(scope_def_id_sub, bregion_sub, ty_fndecl_sub);
104 "try_report_anon_anon_conflict: sub_is_ret_type={:?} sup_is_ret_type={:?}",
105 sub_is_ret_type, sup_is_ret_type
108 let labels = match (sup_is_ret_type, sub_is_ret_type) {
109 (ret_capture @ Some(ret_span), _) | (_, ret_capture @ Some(ret_span)) => {
111 if sup_is_ret_type == ret_capture { ty_sub.span } else { ty_sup.span };
112 LifetimeMismatchLabels::InRet {
116 label_var1: anon_param_sup.pat.simple_ident(),
120 (None, None) => LifetimeMismatchLabels::Normal {
121 hir_equal: ty_sup.hir_id == ty_sub.hir_id,
125 sup: anon_param_sup.pat.simple_ident(),
126 sub: anon_param_sub.pat.simple_ident(),
131 AddLifetimeParamsSuggestion { tcx: self.tcx(), sub, ty_sup, ty_sub, add_note: true };
132 let err = LifetimeMismatch { span, labels, suggestion };
133 let reported = self.tcx().sess.emit_err(err);
138 /// Currently only used in rustc_borrowck, probably should be
139 /// removed in favour of public_errors::AddLifetimeParamsSuggestion
140 pub fn suggest_adding_lifetime_params<'tcx>(
143 ty_sup: &'tcx Ty<'_>,
144 ty_sub: &'tcx Ty<'_>,
145 err: &mut Diagnostic,
147 let suggestion = AddLifetimeParamsSuggestion { tcx, sub, ty_sup, ty_sub, add_note: false };
148 suggestion.add_to_diagnostic(err);