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 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 crate fn get_upvar_index_for_region(&self, tcx: TyCtxt<'tcx>, fr: RegionVid) -> Option<usize> {
39 self.universal_regions().defining_ty.upvar_tys().position(|upvar_ty| {
40 debug!("get_upvar_index_for_region: upvar_ty={:?}", upvar_ty);
41 tcx.any_free_region_meets(&upvar_ty, |r| {
42 let r = r.to_region_vid();
43 debug!("get_upvar_index_for_region: r={:?} fr={:?}", r, fr);
48 let upvar_ty = self.universal_regions().defining_ty.upvar_tys().nth(upvar_index);
51 "get_upvar_index_for_region: found {:?} in upvar {} which has type {:?}",
52 fr, upvar_index, upvar_ty,
58 /// Given the index of an upvar, finds its name and the span from where it was
60 crate fn get_upvar_name_and_span_for_region(
63 upvars: &[Upvar<'tcx>],
66 let upvar_hir_id = upvars[upvar_index].place.get_root_variable();
67 debug!("get_upvar_name_and_span_for_region: upvar_hir_id={:?}", upvar_hir_id);
69 let upvar_name = tcx.hir().name(upvar_hir_id);
70 let upvar_span = tcx.hir().span(upvar_hir_id);
72 "get_upvar_name_and_span_for_region: upvar_name={:?} upvar_span={:?}",
73 upvar_name, upvar_span
76 (upvar_name, upvar_span)
79 /// Search the argument types for one that references fr (which should be a free region).
80 /// Returns Some(_) with the index of the input if one is found.
82 /// N.B., in the case of a closure, the index is indexing into the signature as seen by the
83 /// user - in particular, index 0 is not the implicit self parameter.
84 crate fn get_argument_index_for_region(
89 let implicit_inputs = self.universal_regions().defining_ty.implicit_inputs();
91 self.universal_regions().unnormalized_input_tys.iter().skip(implicit_inputs).position(
93 debug!("get_argument_index_for_region: arg_ty = {:?}", arg_ty);
94 tcx.any_free_region_meets(arg_ty, |r| r.to_region_vid() == fr)
99 "get_argument_index_for_region: found {:?} in argument {} which has type {:?}",
102 self.universal_regions().unnormalized_input_tys[argument_index],
108 /// Given the index of an argument, finds its name (if any) and the span from where it was
110 crate fn get_argument_name_and_span_for_region(
113 local_names: &IndexVec<Local, Option<Symbol>>,
114 argument_index: usize,
115 ) -> (Option<Symbol>, Span) {
116 let implicit_inputs = self.universal_regions().defining_ty.implicit_inputs();
117 let argument_local = Local::new(implicit_inputs + argument_index + 1);
118 debug!("get_argument_name_and_span_for_region: argument_local={:?}", argument_local);
120 let argument_name = local_names[argument_local];
121 let argument_span = body.local_decls[argument_local].source_info.span;
123 "get_argument_name_and_span_for_region: argument_name={:?} argument_span={:?}",
124 argument_name, argument_span
127 (argument_name, argument_span)