X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=compiler%2Frustc_mir%2Fsrc%2Fborrow_check%2Fdiagnostics%2Fregion_name.rs;h=2a90fb042dd7183408b0d5d72b73c14c9dff1e89;hb=61b52a33b3a5a170f7760ba3e3efaac25e5085ef;hp=5f64eb3dba8ac4b4b442db830657404bb5af144a;hpb=593b38be6a1cb3a800c3241786df5abe2df2cfa4;p=rust.git diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs index 5f64eb3dba8..2a90fb042dd 100644 --- a/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs +++ b/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs @@ -6,8 +6,8 @@ use rustc_middle::ty::print::RegionHighlightMode; use rustc_middle::ty::subst::{GenericArgKind, SubstsRef}; use rustc_middle::ty::{self, RegionVid, Ty}; -use rustc_span::symbol::kw; -use rustc_span::{symbol::Symbol, Span, DUMMY_SP}; +use rustc_span::symbol::{kw, sym, Ident, Symbol}; +use rustc_span::{Span, DUMMY_SP}; use crate::borrow_check::{nll::ToRegionVid, universal_regions::DefiningTy, MirBorrowckCtxt}; @@ -39,7 +39,7 @@ /// The region corresponding to a closure upvar. AnonRegionFromUpvar(Span, String), /// The region corresponding to the return type of a closure. - AnonRegionFromOutput(Span, String, String), + AnonRegionFromOutput(RegionNameHighlight, String), /// The region from a type yielded by a generator. AnonRegionFromYieldTy(Span, String), /// An anonymous region from an async fn. @@ -57,6 +57,10 @@ /// The anonymous region corresponds to a region where the type annotation is completely missing /// from the code, e.g. in a closure arguments `|x| { ... }`, where `x` is a reference. CannotMatchHirTy(Span, String), + /// The anonymous region corresponds to a region where the type annotation is completely missing + /// from the code, and *even if* we print out the full name of the type, the region name won't + /// be included. This currently occurs for opaque types like `impl Future`. + Occluded(Span, String), } impl RegionName { @@ -81,13 +85,14 @@ impl RegionName { | RegionNameSource::NamedFreeRegion(span) | RegionNameSource::SynthesizedFreeEnvRegion(span, _) | RegionNameSource::AnonRegionFromUpvar(span, _) - | RegionNameSource::AnonRegionFromOutput(span, _, _) | RegionNameSource::AnonRegionFromYieldTy(span, _) | RegionNameSource::AnonRegionFromAsyncFn(span) => Some(span), - RegionNameSource::AnonRegionFromArgument(ref highlight) => match *highlight { + RegionNameSource::AnonRegionFromArgument(ref highlight) + | RegionNameSource::AnonRegionFromOutput(ref highlight, _) => match *highlight { RegionNameHighlight::MatchedHirTy(span) | RegionNameHighlight::MatchedAdtAndSegment(span) - | RegionNameHighlight::CannotMatchHirTy(span, _) => Some(span), + | RegionNameHighlight::CannotMatchHirTy(span, _) + | RegionNameHighlight::Occluded(span, _) => Some(span), }, } } @@ -112,6 +117,7 @@ impl RegionName { diag.span_label(*span, format!("has type `{}`", type_name)); } RegionNameSource::AnonRegionFromArgument(RegionNameHighlight::MatchedHirTy(span)) + | RegionNameSource::AnonRegionFromOutput(RegionNameHighlight::MatchedHirTy(span), _) | RegionNameSource::AnonRegionFromAsyncFn(span) => { diag.span_label( *span, @@ -120,16 +126,44 @@ impl RegionName { } RegionNameSource::AnonRegionFromArgument( RegionNameHighlight::MatchedAdtAndSegment(span), + ) + | RegionNameSource::AnonRegionFromOutput( + RegionNameHighlight::MatchedAdtAndSegment(span), + _, ) => { diag.span_label(*span, format!("let's call this `{}`", self)); } + RegionNameSource::AnonRegionFromArgument(RegionNameHighlight::Occluded( + span, + type_name, + )) => { + diag.span_label( + *span, + format!("lifetime `{}` appears in the type {}", self, type_name), + ); + } + RegionNameSource::AnonRegionFromOutput( + RegionNameHighlight::Occluded(span, type_name), + mir_description, + ) => { + diag.span_label( + *span, + format!( + "return type{} `{}` contains a lifetime `{}`", + mir_description, type_name, self + ), + ); + } RegionNameSource::AnonRegionFromUpvar(span, upvar_name) => { diag.span_label( *span, format!("lifetime `{}` appears in the type of `{}`", self, upvar_name), ); } - RegionNameSource::AnonRegionFromOutput(span, mir_description, type_name) => { + RegionNameSource::AnonRegionFromOutput( + RegionNameHighlight::CannotMatchHirTy(span, type_name), + mir_description, + ) => { diag.span_label(*span, format!("return type{} is {}", mir_description, type_name)); } RegionNameSource::AnonRegionFromYieldTy(span, type_name) => { @@ -147,6 +181,14 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { } impl<'tcx> MirBorrowckCtxt<'_, 'tcx> { + crate fn mir_def_id(&self) -> hir::def_id::LocalDefId { + self.body.source.def_id().as_local().unwrap() + } + + crate fn mir_hir_id(&self) -> hir::HirId { + self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id()) + } + /// Generate a synthetic region named `'N`, where `N` is the next value of the counter. Then, /// increment the counter. /// @@ -266,12 +308,11 @@ fn give_name_from_error_region(&self, fr: RegionVid) -> Option { } ty::BoundRegion::BrEnv => { - let mir_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id); let def_ty = self.regioncx.universal_regions().defining_ty; if let DefiningTy::Closure(_, substs) = def_ty { let args_span = if let hir::ExprKind::Closure(_, _, _, span, _) = - tcx.hir().expect_expr(mir_hir_id).kind + tcx.hir().expect_expr(self.mir_hir_id()).kind { span } else { @@ -342,27 +383,28 @@ fn give_name_if_anonymous_region_appears_in_arguments( argument_index, ); - self.get_argument_hir_ty_for_highlighting(argument_index) + let highlight = self + .get_argument_hir_ty_for_highlighting(argument_index) .and_then(|arg_hir_ty| self.highlight_if_we_can_match_hir_ty(fr, arg_ty, arg_hir_ty)) - .or_else(|| { + .unwrap_or_else(|| { // `highlight_if_we_cannot_match_hir_ty` needs to know the number we will give to // the anonymous region. If it succeeds, the `synthesize_region_name` call below // will increment the counter, "reserving" the number we just used. let counter = *self.next_region_name.try_borrow().unwrap(); self.highlight_if_we_cannot_match_hir_ty(fr, arg_ty, span, counter) - }) - .map(|highlight| RegionName { - name: self.synthesize_region_name(), - source: RegionNameSource::AnonRegionFromArgument(highlight), - }) + }); + + Some(RegionName { + name: self.synthesize_region_name(), + source: RegionNameSource::AnonRegionFromArgument(highlight), + }) } fn get_argument_hir_ty_for_highlighting( &self, argument_index: usize, ) -> Option<&hir::Ty<'tcx>> { - let mir_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id); - let fn_decl = self.infcx.tcx.hir().fn_decl_by_hir_id(mir_hir_id)?; + let fn_decl = self.infcx.tcx.hir().fn_decl_by_hir_id(self.mir_hir_id())?; let argument_hir_ty: &hir::Ty<'_> = fn_decl.inputs.get(argument_index)?; match argument_hir_ty.kind { // This indicates a variable with no type annotation, like @@ -393,7 +435,7 @@ fn highlight_if_we_cannot_match_hir_ty( ty: Ty<'tcx>, span: Span, counter: usize, - ) -> Option { + ) -> RegionNameHighlight { let mut highlight = RegionHighlightMode::default(); highlight.highlighting_region_vid(needle_fr, counter); let type_name = @@ -405,9 +447,9 @@ fn highlight_if_we_cannot_match_hir_ty( ); if type_name.find(&format!("'{}", counter)).is_some() { // Only add a label if we can confirm that a region was labelled. - Some(RegionNameHighlight::CannotMatchHirTy(span, type_name)) + RegionNameHighlight::CannotMatchHirTy(span, type_name) } else { - None + RegionNameHighlight::Occluded(span, type_name) } } @@ -637,6 +679,7 @@ fn give_name_if_anonymous_region_appears_in_upvars(&self, fr: RegionVid) -> Opti /// or be early bound (named, not in argument). fn give_name_if_anonymous_region_appears_in_output(&self, fr: RegionVid) -> Option { let tcx = self.infcx.tcx; + let hir = tcx.hir(); let return_ty = self.regioncx.universal_regions().unnormalized_output_ty; debug!("give_name_if_anonymous_region_appears_in_output: return_ty = {:?}", return_ty); @@ -644,44 +687,123 @@ fn give_name_if_anonymous_region_appears_in_output(&self, fr: RegionVid) -> Opti return None; } - let mut highlight = RegionHighlightMode::default(); - highlight.highlighting_region_vid(fr, *self.next_region_name.try_borrow().unwrap()); - let type_name = - self.infcx.extract_inference_diagnostics_data(return_ty.into(), Some(highlight)).name; - - let mir_hir_id = tcx.hir().local_def_id_to_hir_id(self.mir_def_id); + let mir_hir_id = self.mir_hir_id(); - let (return_span, mir_description) = match tcx.hir().get(mir_hir_id) { + let (return_span, mir_description, hir_ty) = match hir.get(mir_hir_id) { hir::Node::Expr(hir::Expr { - kind: hir::ExprKind::Closure(_, return_ty, _, span, gen_move), + kind: hir::ExprKind::Closure(_, return_ty, body_id, span, _), .. - }) => ( - match return_ty.output { - hir::FnRetTy::DefaultReturn(_) => tcx.sess.source_map().end_point(*span), - hir::FnRetTy::Return(_) => return_ty.output.span(), - }, - if gen_move.is_some() { " of generator" } else { " of closure" }, - ), - hir::Node::ImplItem(hir::ImplItem { - kind: hir::ImplItemKind::Fn(method_sig, _), - .. - }) => (method_sig.decl.output.span(), ""), - _ => (self.body.span, ""), + }) => { + let (mut span, mut hir_ty) = match return_ty.output { + hir::FnRetTy::DefaultReturn(_) => { + (tcx.sess.source_map().end_point(*span), None) + } + hir::FnRetTy::Return(hir_ty) => (return_ty.output.span(), Some(hir_ty)), + }; + let mir_description = match hir.body(*body_id).generator_kind { + Some(hir::GeneratorKind::Async(gen)) => match gen { + hir::AsyncGeneratorKind::Block => " of async block", + hir::AsyncGeneratorKind::Closure => " of async closure", + hir::AsyncGeneratorKind::Fn => { + let parent_item = hir.get(hir.get_parent_item(mir_hir_id)); + let output = &parent_item + .fn_decl() + .expect("generator lowered from async fn should be in fn") + .output; + span = output.span(); + if let hir::FnRetTy::Return(ret) = output { + hir_ty = Some(self.get_future_inner_return_ty(*ret)); + } + " of async function" + } + }, + Some(hir::GeneratorKind::Gen) => " of generator", + None => " of closure", + }; + (span, mir_description, hir_ty) + } + node => match node.fn_decl() { + Some(fn_decl) => { + let hir_ty = match fn_decl.output { + hir::FnRetTy::DefaultReturn(_) => None, + hir::FnRetTy::Return(ty) => Some(ty), + }; + (fn_decl.output.span(), "", hir_ty) + } + None => (self.body.span, "", None), + }, }; + let highlight = hir_ty + .and_then(|hir_ty| self.highlight_if_we_can_match_hir_ty(fr, return_ty, hir_ty)) + .unwrap_or_else(|| { + // `highlight_if_we_cannot_match_hir_ty` needs to know the number we will give to + // the anonymous region. If it succeeds, the `synthesize_region_name` call below + // will increment the counter, "reserving" the number we just used. + let counter = *self.next_region_name.try_borrow().unwrap(); + self.highlight_if_we_cannot_match_hir_ty(fr, return_ty, return_span, counter) + }); + Some(RegionName { - // This counter value will already have been used, so this function will increment it - // so the next value will be used next and return the region name that would have been - // used. name: self.synthesize_region_name(), - source: RegionNameSource::AnonRegionFromOutput( - return_span, - mir_description.to_string(), - type_name, - ), + source: RegionNameSource::AnonRegionFromOutput(highlight, mir_description.to_string()), }) } + /// From the [`hir::Ty`] of an async function's lowered return type, + /// retrieve the `hir::Ty` representing the type the user originally wrote. + /// + /// e.g. given the function: + /// + /// ``` + /// async fn foo() -> i32 {} + /// ``` + /// + /// this function, given the lowered return type of `foo`, an [`OpaqueDef`] that implements `Future`, + /// returns the `i32`. + /// + /// [`OpaqueDef`]: hir::TyKind::OpaqueDef + fn get_future_inner_return_ty(&self, hir_ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> { + let hir = self.infcx.tcx.hir(); + + if let hir::TyKind::OpaqueDef(id, _) = hir_ty.kind { + let opaque_ty = hir.item(id.id); + if let hir::ItemKind::OpaqueTy(hir::OpaqueTy { + bounds: + [hir::GenericBound::LangItemTrait( + hir::LangItem::Future, + _, + _, + hir::GenericArgs { + bindings: + [hir::TypeBinding { + ident: Ident { name: sym::Output, .. }, + kind: hir::TypeBindingKind::Equality { ty }, + .. + }], + .. + }, + )], + .. + }) = opaque_ty.kind + { + ty + } else { + span_bug!( + hir_ty.span, + "bounds from lowered return type of async fn did not match expected format: {:?}", + opaque_ty + ); + } + } else { + span_bug!( + hir_ty.span, + "lowered return type of async fn is not OpaqueDef: {:?}", + hir_ty + ); + } + } + fn give_name_if_anonymous_region_appears_in_yield_ty( &self, fr: RegionVid, @@ -702,9 +824,7 @@ fn give_name_if_anonymous_region_appears_in_yield_ty( let type_name = self.infcx.extract_inference_diagnostics_data(yield_ty.into(), Some(highlight)).name; - let mir_hir_id = tcx.hir().local_def_id_to_hir_id(self.mir_def_id); - - let yield_span = match tcx.hir().get(mir_hir_id) { + let yield_span = match tcx.hir().get(self.mir_hir_id()) { hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, _, _, span, _), .. }) => (tcx.sess.source_map().end_point(*span)),