bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Improve diagnostics when a static lifetime is expected

Browse source
This commit is contained in:
Lucas Kent 2021-11-13 16:43:43 +11:00
parent 3e018ce194
commit 130b9e9e3b
26 changed files with 269 additions and 176 deletions
Download patch file Download diff file Expand all files Collapse all files

65
compiler/rustc_infer/src/infer/error_reporting/nice_region_error/named_anon_conflict.rs
View file

@ -3,8 +3,6 @@
use crate::infer::error_reporting::nice_region_error::find_anon_type::find_anon_type;
use crate::infer::error_reporting::nice_region_error::NiceRegionError;
use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
use rustc_hir::intravisit::Visitor;
use rustc_hir::FnRetTy;
use rustc_middle::ty;
impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
@ -48,19 +46,24 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
return None; // inapplicable
};
// Suggesting to add a `'static` lifetime to a parameter is nearly always incorrect,
// and can steer users down the wrong path.
if *named == ty::ReStatic {
return None;
}
debug!("try_report_named_anon_conflict: named = {:?}", named);
debug!("try_report_named_anon_conflict: anon_param_info = {:?}", anon_param_info);
debug!("try_report_named_anon_conflict: region_info = {:?}", region_info);
let (param, new_ty, new_ty_span, br, is_first, scope_def_id, is_impl_item) = (
anon_param_info.param,
anon_param_info.param_ty,
anon_param_info.param_ty_span,
anon_param_info.bound_region,
anon_param_info.is_first,
region_info.def_id,
region_info.is_impl_item,
);
let param = anon_param_info.param;
let new_ty = anon_param_info.param_ty;
let new_ty_span = anon_param_info.param_ty_span;
let br = anon_param_info.bound_region;
let is_first = anon_param_info.is_first;
let scope_def_id = region_info.def_id;
let is_impl_item = region_info.is_impl_item;
match br {
ty::BrAnon(_) => {}
_ => {
@ -75,26 +78,10 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
return None;
}
if let Some((_, fndecl)) = find_anon_type(self.tcx(), anon, &br) {
if self.is_self_anon(is_first, scope_def_id) {
return None;
}
if let FnRetTy::Return(ty) = &fndecl.output {
let mut v = ty::TraitObjectVisitor(vec![], self.tcx().hir());
v.visit_ty(ty);
debug!("try_report_named_anon_conflict: ret ty {:?}", ty);
if sub == &ty::ReStatic
&& v.0.into_iter().any(|t| t.span.desugaring_kind().is_none())
{
// If the failure is due to a `'static` requirement coming from a `dyn` or
// `impl` Trait that *isn't* caused by `async fn` desugaring, handle this case
// better in `static_impl_trait`.
debug!("try_report_named_anon_conflict: impl Trait + 'static");
return None;
}
}
if find_anon_type(self.tcx(), anon, &br).is_some()
&& self.is_self_anon(is_first, scope_def_id)
{
return None;
}
let (error_var, span_label_var) = match param.pat.simple_ident() {
@ -114,16 +101,12 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
);
diag.span_label(span, format!("lifetime `{}` required", named));
// Suggesting `'static` is nearly always incorrect, and can steer users
// down the wrong path.
if *named != ty::ReStatic {
diag.span_suggestion(
new_ty_span,
&format!("add explicit lifetime `{}` to {}", named, span_label_var),
new_ty.to_string(),
Applicability::Unspecified,
);
}
diag.span_suggestion(
new_ty_span,
&format!("add explicit lifetime `{}` to {}", named, span_label_var),
new_ty.to_string(),
Applicability::Unspecified,
);
Some(diag)
}