2 use crate::{nll::ToRegionVid, region_infer::RegionInferenceContext};
3 use rustc_index::vec::{Idx, IndexVec};
4 use rustc_middle::mir::{Body, Local};
5 use rustc_middle::ty::{RegionVid, TyCtxt};
6 use rustc_span::source_map::Span;
7 use rustc_span::symbol::Symbol;
9 impl<'tcx> RegionInferenceContext<'tcx> {
10 pub(crate) fn get_var_name_and_span_for_region(
14 local_names: &IndexVec<Local, Option<Symbol>>,
15 upvars: &[Upvar<'tcx>],
17 ) -> Option<(Option<Symbol>, Span)> {
18 debug!("get_var_name_and_span_for_region(fr={:?})", fr);
19 assert!(self.universal_regions().is_universal_region(fr));
21 debug!("get_var_name_and_span_for_region: attempting upvar");
22 self.get_upvar_index_for_region(tcx, fr)
24 // FIXME(project-rfc-2229#8): Use place span for diagnostics
25 let (name, span) = self.get_upvar_name_and_span_for_region(tcx, upvars, index);
29 debug!("get_var_name_and_span_for_region: attempting argument");
30 self.get_argument_index_for_region(tcx, fr).map(|index| {
31 self.get_argument_name_and_span_for_region(body, local_names, index)
36 /// Search the upvars (if any) to find one that references fr. Return its index.
37 pub(crate) fn get_upvar_index_for_region(
43 self.universal_regions().defining_ty.upvar_tys().position(|upvar_ty| {
44 debug!("get_upvar_index_for_region: upvar_ty={:?}", upvar_ty);
45 tcx.any_free_region_meets(&upvar_ty, |r| {
46 let r = r.to_region_vid();
47 debug!("get_upvar_index_for_region: r={:?} fr={:?}", r, fr);
52 let upvar_ty = self.universal_regions().defining_ty.upvar_tys().nth(upvar_index);
55 "get_upvar_index_for_region: found {:?} in upvar {} which has type {:?}",
56 fr, upvar_index, upvar_ty,
62 /// Given the index of an upvar, finds its name and the span from where it was
64 pub(crate) fn get_upvar_name_and_span_for_region(
67 upvars: &[Upvar<'tcx>],
70 let upvar_hir_id = upvars[upvar_index].place.get_root_variable();
71 debug!("get_upvar_name_and_span_for_region: upvar_hir_id={:?}", upvar_hir_id);
73 let upvar_name = tcx.hir().name(upvar_hir_id);
74 let upvar_span = tcx.hir().span(upvar_hir_id);
76 "get_upvar_name_and_span_for_region: upvar_name={:?} upvar_span={:?}",
77 upvar_name, upvar_span
80 (upvar_name, upvar_span)
83 /// Search the argument types for one that references fr (which should be a free region).
84 /// Returns Some(_) with the index of the input if one is found.
86 /// N.B., in the case of a closure, the index is indexing into the signature as seen by the
87 /// user - in particular, index 0 is not the implicit self parameter.
88 pub(crate) fn get_argument_index_for_region(
93 let implicit_inputs = self.universal_regions().defining_ty.implicit_inputs();
95 self.universal_regions().unnormalized_input_tys.iter().skip(implicit_inputs).position(
97 debug!("get_argument_index_for_region: arg_ty = {:?}", arg_ty);
98 tcx.any_free_region_meets(arg_ty, |r| r.to_region_vid() == fr)
103 "get_argument_index_for_region: found {:?} in argument {} which has type {:?}",
106 self.universal_regions().unnormalized_input_tys[argument_index],
112 /// Given the index of an argument, finds its name (if any) and the span from where it was
114 pub(crate) fn get_argument_name_and_span_for_region(
117 local_names: &IndexVec<Local, Option<Symbol>>,
118 argument_index: usize,
119 ) -> (Option<Symbol>, Span) {
120 let implicit_inputs = self.universal_regions().defining_ty.implicit_inputs();
121 let argument_local = Local::new(implicit_inputs + argument_index + 1);
122 debug!("get_argument_name_and_span_for_region: argument_local={:?}", argument_local);
124 let argument_name = local_names[argument_local];
125 let argument_span = body.local_decls[argument_local].source_info.span;
127 "get_argument_name_and_span_for_region: argument_name={:?} argument_span={:?}",
128 argument_name, argument_span
131 (argument_name, argument_span)