diff options
| -rw-r--r-- | src/librustc/util/ppaux.rs | 124 | ||||
| -rw-r--r-- | src/librustc_mir/borrow_check/error_reporting.rs | 10 | ||||
| -rw-r--r-- | src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs | 9 |
3 files changed, 91 insertions, 52 deletions
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs index cbba4181271..ea0495c5c73 100644 --- a/src/librustc/util/ppaux.rs +++ b/src/librustc/util/ppaux.rs @@ -21,17 +21,87 @@ use syntax::ast::CRATE_NODE_ID; use syntax::symbol::{Symbol, InternedString}; use hir; +/// The "region highlights" are used to control region printing during +/// specific error messages. When a "region highlight" is enabled, it +/// gives an alternate way to print specific regions. For now, we +/// always print those regions using a number, so something like `'0`. +/// +/// Regions not selected by the region highlight mode are presently +/// unaffected. +#[derive(Copy, Clone, Default)] +pub struct RegionHighlightMode { + /// If enabled, when we see the selected region inference + /// variable, use `"'N"`; otherwise, use an empty string `""` + /// (which is our ordinary behavior). + highlight_region_vid: Option<(RegionVid, usize)>, + + /// If enabled, when printing a "free region" that originated from + /// the given `ty::BoundRegion`, print it as `'1`. Free regions that would ordinarily + /// have names print as normal. + /// + /// This is used when you have a signature like `fn foo(x: &u32, + /// y: &'a u32)` and we want to give a name to the region of the + /// reference `x`. + highlight_bound_region: Option<(ty::BoundRegion, usize)>, +} + thread_local! { /// Mechanism for highlighting of specific regions for display in NLL region inference errors. /// Contains region to highlight and counter for number to use when highlighting. - static HIGHLIGHT_REGION_FOR_REGIONVID: Cell<Option<(RegionVid, usize)>> = Cell::new(None) + static REGION_HIGHLIGHT_MODE: Cell<RegionHighlightMode> = + Cell::new(RegionHighlightMode::default()) } -thread_local! { - /// Mechanism for highlighting of specific regions for display in NLL's 'borrow does not live - /// long enough' errors. Contains a region to highlight and a counter to use. - static HIGHLIGHT_REGION_FOR_BOUND_REGION: Cell<Option<(ty::BoundRegion, usize)>> = - Cell::new(None) +impl RegionHighlightMode { + pub fn get() -> Self { + REGION_HIGHLIGHT_MODE.with(|c| c.get()) + } + + fn set<R>( + old_mode: Self, + new_mode: Self, + op: impl FnOnce() -> R, + ) -> R { + REGION_HIGHLIGHT_MODE.with(|c| { + c.set(new_mode); + let result = op(); + c.set(old_mode); + result + }) + } + + pub fn highlighting_region_vid<R>(vid: RegionVid, number: usize, op: impl FnOnce() -> R) -> R { + let old_mode = Self::get(); + assert!(old_mode.highlight_region_vid.is_none()); + Self::set( + old_mode, + Self { + highlight_region_vid: Some((vid, number)), + ..old_mode + }, + op, + ) + } + + /// During the execution of `op`, highlight the given bound + /// region. We can only highlight one bound region at a time. See + /// the field `highlight_bound_region` for more detailed notes. + pub fn highlighting_bound_region<R>( + br: ty::BoundRegion, + number: usize, + op: impl FnOnce() -> R, + ) -> R { + let old_mode = Self::get(); + assert!(old_mode.highlight_bound_region.is_none()); + Self::set( + old_mode, + Self { + highlight_bound_region: Some((br, number)), + ..old_mode + }, + op, + ) + } } macro_rules! gen_display_debug_body { @@ -553,42 +623,6 @@ pub fn parameterized<F: fmt::Write>(f: &mut F, PrintContext::new().parameterized(f, substs, did, projections) } -fn get_highlight_region_for_regionvid() -> Option<(RegionVid, usize)> { - HIGHLIGHT_REGION_FOR_REGIONVID.with(|hr| hr.get()) -} - -pub fn with_highlight_region_for_regionvid<R>( - r: RegionVid, - counter: usize, - op: impl FnOnce() -> R -) -> R { - HIGHLIGHT_REGION_FOR_REGIONVID.with(|hr| { - assert_eq!(hr.get(), None); - hr.set(Some((r, counter))); - let r = op(); - hr.set(None); - r - }) -} - -fn get_highlight_region_for_bound_region() -> Option<(ty::BoundRegion, usize)> { - HIGHLIGHT_REGION_FOR_BOUND_REGION.with(|hr| hr.get()) -} - -pub fn with_highlight_region_for_bound_region<R>( - r: ty::BoundRegion, - counter: usize, - op: impl Fn() -> R -) -> R { - HIGHLIGHT_REGION_FOR_BOUND_REGION.with(|hr| { - assert_eq!(hr.get(), None); - hr.set(Some((r, counter))); - let r = op(); - hr.set(None); - r - }) -} - impl<'a, T: Print> Print for &'a T { fn print<F: fmt::Write>(&self, f: &mut F, cx: &mut PrintContext) -> fmt::Result { (*self).print(f, cx) @@ -740,7 +774,7 @@ define_print! { return self.print_debug(f, cx); } - if let Some((region, counter)) = get_highlight_region_for_bound_region() { + if let Some((region, counter)) = RegionHighlightMode::get().highlight_bound_region { if *self == region { return match *self { BrNamed(_, name) => write!(f, "{}", name), @@ -807,7 +841,7 @@ define_print! { } } ty::ReVar(region_vid) => { - if get_highlight_region_for_regionvid().is_some() { + if RegionHighlightMode::get().highlight_region_vid.is_some() { write!(f, "{:?}", region_vid) } else if cx.identify_regions { write!(f, "'{}rv", region_vid.index()) @@ -944,7 +978,7 @@ impl fmt::Debug for ty::FloatVid { impl fmt::Debug for ty::RegionVid { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - if let Some((region, counter)) = get_highlight_region_for_regionvid() { + if let Some((region, counter)) = RegionHighlightMode::get().highlight_region_vid { debug!("RegionVid.fmt: region={:?} self={:?} counter={:?}", region, self, counter); return if *self == region { write!(f, "'{:?}", counter) diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs index 6a5b5d172bb..83cd28bbdc5 100644 --- a/src/librustc_mir/borrow_check/error_reporting.rs +++ b/src/librustc_mir/borrow_check/error_reporting.rs @@ -12,7 +12,7 @@ use rustc::mir::{ TerminatorKind, VarBindingForm, }; use rustc::ty::{self, DefIdTree}; -use rustc::util::ppaux::with_highlight_region_for_bound_region; +use rustc::util::ppaux::RegionHighlightMode; use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::indexed_vec::Idx; use rustc_data_structures::sync::Lrc; @@ -2177,7 +2177,7 @@ impl<'tcx> AnnotatedBorrowFnSignature<'tcx> { ty::RegionKind::RePlaceholder(ty::PlaceholderRegion { name: br, .. }), _, _, - ) => with_highlight_region_for_bound_region(*br, counter, || ty.to_string()), + ) => RegionHighlightMode::highlighting_bound_region(*br, counter, || ty.to_string()), _ => ty.to_string(), } } @@ -2189,7 +2189,11 @@ impl<'tcx> AnnotatedBorrowFnSignature<'tcx> { ty::TyKind::Ref(region, _, _) => match region { ty::RegionKind::ReLateBound(_, br) | ty::RegionKind::RePlaceholder(ty::PlaceholderRegion { name: br, .. }) => { - with_highlight_region_for_bound_region(*br, counter, || region.to_string()) + RegionHighlightMode::highlighting_bound_region( + *br, + counter, + || region.to_string(), + ) } _ => region.to_string(), }, diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs index 963d4ab3a54..bff80155112 100644 --- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs +++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs @@ -8,7 +8,7 @@ use rustc::infer::InferCtxt; use rustc::mir::Mir; use rustc::ty::subst::{Substs, UnpackedKind}; use rustc::ty::{self, RegionKind, RegionVid, Ty, TyCtxt}; -use rustc::util::ppaux::with_highlight_region_for_regionvid; +use rustc::util::ppaux::RegionHighlightMode; use rustc_errors::DiagnosticBuilder; use syntax::ast::{Name, DUMMY_NODE_ID}; use syntax::symbol::keywords; @@ -396,7 +396,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { argument_ty: Ty<'tcx>, counter: &mut usize, ) -> Option<RegionName> { - let type_name = with_highlight_region_for_regionvid(needle_fr, *counter, || { + let type_name = RegionHighlightMode::highlighting_region_vid(needle_fr, *counter, || { infcx.extract_type_name(&argument_ty) }); @@ -673,8 +673,9 @@ impl<'tcx> RegionInferenceContext<'tcx> { return None; } - let type_name = with_highlight_region_for_regionvid( - fr, *counter, || infcx.extract_type_name(&return_ty)); + let type_name = RegionHighlightMode::highlighting_region_vid( + fr, *counter, || infcx.extract_type_name(&return_ty), + ); let mir_node_id = tcx.hir().as_local_node_id(mir_def_id).expect("non-local mir"); |