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Remove dead ScopeTree code
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@matthewjasper
matthewjasper committed May 22, 2020
1 parent 52d628f commit 3d8a073
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Showing 12 changed files with 57 additions and 374 deletions.
139 changes: 38 additions & 101 deletions src/librustc_infer/infer/error_reporting/mod.rs
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Expand Up @@ -61,7 +61,6 @@ use rustc_errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_hir::Node;
use rustc_middle::middle::region;
use rustc_middle::ty::error::TypeError;
use rustc_middle::ty::{
self,
Expand All @@ -81,7 +80,6 @@ pub mod nice_region_error;

pub(super) fn note_and_explain_region(
tcx: TyCtxt<'tcx>,
region_scope_tree: &region::ScopeTree,
err: &mut DiagnosticBuilder<'_>,
prefix: &str,
region: ty::Region<'tcx>,
Expand Down Expand Up @@ -239,7 +237,6 @@ fn explain_span(tcx: TyCtxt<'tcx>, heading: &str, span: Span) -> (String, Option

pub fn unexpected_hidden_region_diagnostic(
tcx: TyCtxt<'tcx>,
region_scope_tree: Option<&region::ScopeTree>,
span: Span,
hidden_ty: Ty<'tcx>,
hidden_region: ty::Region<'tcx>,
Expand All @@ -264,78 +261,53 @@ pub fn unexpected_hidden_region_diagnostic(
err.span_note(span, &message);
}
ty::ReEarlyBound(_) | ty::ReFree(_) | ty::ReStatic | ty::ReEmpty(_) => {
// Assuming regionck succeeded (*), we ought to always be
// capturing *some* region from the fn header, and hence it
// ought to be free. So under normal circumstances, we will go
// down this path which gives a decent human readable
// explanation.
//
// (*) if not, the `tainted_by_errors` field would be set to
// `Some(ErrorReported)` in any case, so we wouldn't be here at all.
note_and_explain_free_region(
tcx,
&mut err,
&format!("hidden type `{}` captures ", hidden_ty),
hidden_region,
"",
);
// Assuming regionck succeeded (*), we ought to always be
// capturing *some* region from the fn header, and hence it
// ought to be free. So under normal circumstances, we will go
// down this path which gives a decent human readable
// explanation.
//
// (*) if not, the `tainted_by_errors` field would be set to
// `Some(ErrorReported)` in any case, so we wouldn't be here at all.
note_and_explain_free_region(
tcx,
&mut err,
&format!("hidden type `{}` captures ", hidden_ty),
hidden_region,
"",
);
}
_ => {
// Ugh. This is a painful case: the hidden region is not one
// that we can easily summarize or explain. This can happen
// in a case like
// `src/test/ui/multiple-lifetimes/ordinary-bounds-unsuited.rs`:
//
// ```
// fn upper_bounds<'a, 'b>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'a, 'b> {
// if condition() { a } else { b }
// }
// ```
//
// Here the captured lifetime is the intersection of `'a` and
// `'b`, which we can't quite express.

if let Some(region_scope_tree) = region_scope_tree {
// If the `region_scope_tree` is available, this is being
// invoked from the "region inferencer error". We can at
// least report a really cryptic error for now.
// Ugh. This is a painful case: the hidden region is not one
// that we can easily summarize or explain. This can happen
// in a case like
// `src/test/ui/multiple-lifetimes/ordinary-bounds-unsuited.rs`:
//
// ```
// fn upper_bounds<'a, 'b>(a: Ordinary<'a>, b: Ordinary<'b>) -> impl Trait<'a, 'b> {
// if condition() { a } else { b }
// }
// ```
//
// Here the captured lifetime is the intersection of `'a` and
// `'b`, which we can't quite express.

// We can at least report a really cryptic error for now.
note_and_explain_region(
tcx,
region_scope_tree,
&mut err,
&format!("hidden type `{}` captures ", hidden_ty),
hidden_region,
"",
);
} else {
// If the `region_scope_tree` is *unavailable*, this is
// being invoked by the code that comes *after* region
// inferencing. This is a bug, as the region inferencer
// ought to have noticed the failed constraint and invoked
// error reporting, which in turn should have prevented us
// from getting trying to infer the hidden type
// completely.
tcx.sess.delay_span_bug(
span,
&format!(
"hidden type captures unexpected lifetime `{:?}` \
but no region inference failure",
hidden_region,
),
);
}
}
}

err
}

impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
pub fn report_region_errors(
&self,
region_scope_tree: &region::ScopeTree,
errors: &Vec<RegionResolutionError<'tcx>>,
) {
pub fn report_region_errors(&self, errors: &Vec<RegionResolutionError<'tcx>>) {
debug!("report_region_errors(): {} errors to start", errors.len());

// try to pre-process the errors, which will group some of them
Expand All @@ -358,17 +330,14 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
// general bit of code that displays the error information
RegionResolutionError::ConcreteFailure(origin, sub, sup) => {
if sub.is_placeholder() || sup.is_placeholder() {
self.report_placeholder_failure(region_scope_tree, origin, sub, sup)
.emit();
self.report_placeholder_failure(origin, sub, sup).emit();
} else {
self.report_concrete_failure(region_scope_tree, origin, sub, sup)
.emit();
self.report_concrete_failure(origin, sub, sup).emit();
}
}

RegionResolutionError::GenericBoundFailure(origin, param_ty, sub) => {
self.report_generic_bound_failure(
region_scope_tree,
origin.span(),
Some(origin),
param_ty,
Expand All @@ -385,29 +354,12 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
sup_r,
) => {
if sub_r.is_placeholder() {
self.report_placeholder_failure(
region_scope_tree,
sub_origin,
sub_r,
sup_r,
)
.emit();
self.report_placeholder_failure(sub_origin, sub_r, sup_r).emit();
} else if sup_r.is_placeholder() {
self.report_placeholder_failure(
region_scope_tree,
sup_origin,
sub_r,
sup_r,
)
.emit();
self.report_placeholder_failure(sup_origin, sub_r, sup_r).emit();
} else {
self.report_sub_sup_conflict(
region_scope_tree,
var_origin,
sub_origin,
sub_r,
sup_origin,
sup_r,
var_origin, sub_origin, sub_r, sup_origin, sup_r,
);
}
}
Expand All @@ -428,13 +380,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
// value.
let sub_r = self.tcx.mk_region(ty::ReEmpty(var_universe));

self.report_placeholder_failure(
region_scope_tree,
sup_origin,
sub_r,
sup_r,
)
.emit();
self.report_placeholder_failure(sup_origin, sub_r, sup_r).emit();
}

RegionResolutionError::MemberConstraintFailure {
Expand All @@ -445,7 +391,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
let hidden_ty = self.resolve_vars_if_possible(&hidden_ty);
unexpected_hidden_region_diagnostic(
self.tcx,
Some(region_scope_tree),
span,
hidden_ty,
member_region,
Expand Down Expand Up @@ -1722,19 +1667,16 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {

pub fn report_generic_bound_failure(
&self,
region_scope_tree: &region::ScopeTree,
span: Span,
origin: Option<SubregionOrigin<'tcx>>,
bound_kind: GenericKind<'tcx>,
sub: Region<'tcx>,
) {
self.construct_generic_bound_failure(region_scope_tree, span, origin, bound_kind, sub)
.emit();
self.construct_generic_bound_failure(span, origin, bound_kind, sub).emit();
}

pub fn construct_generic_bound_failure(
&self,
region_scope_tree: &region::ScopeTree,
span: Span,
origin: Option<SubregionOrigin<'tcx>>,
bound_kind: GenericKind<'tcx>,
Expand Down Expand Up @@ -1886,7 +1828,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
));
note_and_explain_region(
self.tcx,
region_scope_tree,
&mut err,
&format!("{} must be valid for ", labeled_user_string),
sub,
Expand All @@ -1904,7 +1845,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {

fn report_sub_sup_conflict(
&self,
region_scope_tree: &region::ScopeTree,
var_origin: RegionVariableOrigin,
sub_origin: SubregionOrigin<'tcx>,
sub_region: Region<'tcx>,
Expand All @@ -1915,7 +1855,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {

note_and_explain_region(
self.tcx,
region_scope_tree,
&mut err,
"first, the lifetime cannot outlive ",
sup_region,
Expand All @@ -1941,7 +1880,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
if sub_expected == sup_expected && sub_found == sup_found {
note_and_explain_region(
self.tcx,
region_scope_tree,
&mut err,
"...but the lifetime must also be valid for ",
sub_region,
Expand All @@ -1963,7 +1901,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {

note_and_explain_region(
self.tcx,
region_scope_tree,
&mut err,
"but, the lifetime must be valid for ",
sub_region,
Expand Down

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