mirror of
https://git.proxmox.com/git/rustc
synced 2025-10-15 09:07:20 +00:00
1006 lines
41 KiB
Rust
1006 lines
41 KiB
Rust
use std::fmt::{self, Display};
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use std::iter;
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use rustc_errors::Diagnostic;
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, Res};
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use rustc_middle::ty::print::RegionHighlightMode;
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use rustc_middle::ty::{self, RegionVid, Ty};
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use rustc_middle::ty::{GenericArgKind, GenericArgsRef};
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use rustc_span::symbol::{kw, sym, Ident, Symbol};
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use rustc_span::{Span, DUMMY_SP};
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use crate::{universal_regions::DefiningTy, MirBorrowckCtxt};
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/// A name for a particular region used in emitting diagnostics. This name could be a generated
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/// name like `'1`, a name used by the user like `'a`, or a name like `'static`.
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#[derive(Debug, Clone)]
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pub(crate) struct RegionName {
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/// The name of the region (interned).
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pub(crate) name: Symbol,
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/// Where the region comes from.
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pub(crate) source: RegionNameSource,
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}
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/// Denotes the source of a region that is named by a `RegionName`. For example, a free region that
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/// was named by the user would get `NamedLateParamRegion` and `'static` lifetime would get `Static`.
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/// This helps to print the right kinds of diagnostics.
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#[derive(Debug, Clone)]
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pub(crate) enum RegionNameSource {
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/// A bound (not free) region that was instantiated at the def site (not an HRTB).
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NamedEarlyParamRegion(Span),
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/// A free region that the user has a name (`'a`) for.
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NamedLateParamRegion(Span),
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/// The `'static` region.
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Static,
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/// The free region corresponding to the environment of a closure.
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SynthesizedFreeEnvRegion(Span, &'static str),
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/// The region corresponding to an argument.
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AnonRegionFromArgument(RegionNameHighlight),
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/// The region corresponding to a closure upvar.
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AnonRegionFromUpvar(Span, Symbol),
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/// The region corresponding to the return type of a closure.
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AnonRegionFromOutput(RegionNameHighlight, &'static str),
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/// The region from a type yielded by a coroutine.
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AnonRegionFromYieldTy(Span, String),
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/// An anonymous region from an async fn.
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AnonRegionFromAsyncFn(Span),
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/// An anonymous region from an impl self type or trait
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AnonRegionFromImplSignature(Span, &'static str),
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}
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/// Describes what to highlight to explain to the user that we're giving an anonymous region a
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/// synthesized name, and how to highlight it.
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#[derive(Debug, Clone)]
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pub(crate) enum RegionNameHighlight {
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/// The anonymous region corresponds to a reference that was found by traversing the type in the HIR.
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MatchedHirTy(Span),
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/// The anonymous region corresponds to a `'_` in the generics list of a struct/enum/union.
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MatchedAdtAndSegment(Span),
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/// The anonymous region corresponds to a region where the type annotation is completely missing
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/// from the code, e.g. in a closure arguments `|x| { ... }`, where `x` is a reference.
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CannotMatchHirTy(Span, String),
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/// The anonymous region corresponds to a region where the type annotation is completely missing
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/// from the code, and *even if* we print out the full name of the type, the region name won't
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/// be included. This currently occurs for opaque types like `impl Future`.
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Occluded(Span, String),
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}
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impl RegionName {
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pub(crate) fn was_named(&self) -> bool {
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match self.source {
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RegionNameSource::NamedEarlyParamRegion(..)
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| RegionNameSource::NamedLateParamRegion(..)
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| RegionNameSource::Static => true,
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RegionNameSource::SynthesizedFreeEnvRegion(..)
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| RegionNameSource::AnonRegionFromArgument(..)
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| RegionNameSource::AnonRegionFromUpvar(..)
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| RegionNameSource::AnonRegionFromOutput(..)
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| RegionNameSource::AnonRegionFromYieldTy(..)
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| RegionNameSource::AnonRegionFromAsyncFn(..)
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| RegionNameSource::AnonRegionFromImplSignature(..) => false,
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}
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}
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pub(crate) fn span(&self) -> Option<Span> {
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match self.source {
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RegionNameSource::Static => None,
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RegionNameSource::NamedEarlyParamRegion(span)
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| RegionNameSource::NamedLateParamRegion(span)
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| RegionNameSource::SynthesizedFreeEnvRegion(span, _)
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| RegionNameSource::AnonRegionFromUpvar(span, _)
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| RegionNameSource::AnonRegionFromYieldTy(span, _)
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| RegionNameSource::AnonRegionFromAsyncFn(span)
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| RegionNameSource::AnonRegionFromImplSignature(span, _) => Some(span),
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RegionNameSource::AnonRegionFromArgument(ref highlight)
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| RegionNameSource::AnonRegionFromOutput(ref highlight, _) => match *highlight {
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RegionNameHighlight::MatchedHirTy(span)
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| RegionNameHighlight::MatchedAdtAndSegment(span)
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| RegionNameHighlight::CannotMatchHirTy(span, _)
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| RegionNameHighlight::Occluded(span, _) => Some(span),
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},
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}
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}
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pub(crate) fn highlight_region_name(&self, diag: &mut Diagnostic) {
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match &self.source {
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RegionNameSource::NamedLateParamRegion(span)
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| RegionNameSource::NamedEarlyParamRegion(span) => {
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diag.span_label(*span, format!("lifetime `{self}` defined here"));
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}
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RegionNameSource::SynthesizedFreeEnvRegion(span, note) => {
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diag.span_label(*span, format!("lifetime `{self}` represents this closure's body"));
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diag.note(*note);
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}
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RegionNameSource::AnonRegionFromArgument(RegionNameHighlight::CannotMatchHirTy(
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span,
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type_name,
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)) => {
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diag.span_label(*span, format!("has type `{type_name}`"));
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}
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RegionNameSource::AnonRegionFromArgument(RegionNameHighlight::MatchedHirTy(span))
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| RegionNameSource::AnonRegionFromOutput(RegionNameHighlight::MatchedHirTy(span), _)
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| RegionNameSource::AnonRegionFromAsyncFn(span) => {
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diag.span_label(
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*span,
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format!("let's call the lifetime of this reference `{self}`"),
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);
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}
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RegionNameSource::AnonRegionFromArgument(
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RegionNameHighlight::MatchedAdtAndSegment(span),
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)
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| RegionNameSource::AnonRegionFromOutput(
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RegionNameHighlight::MatchedAdtAndSegment(span),
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_,
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) => {
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diag.span_label(*span, format!("let's call this `{self}`"));
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}
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RegionNameSource::AnonRegionFromArgument(RegionNameHighlight::Occluded(
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span,
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type_name,
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)) => {
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diag.span_label(
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*span,
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format!("lifetime `{self}` appears in the type {type_name}"),
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);
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}
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RegionNameSource::AnonRegionFromOutput(
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RegionNameHighlight::Occluded(span, type_name),
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mir_description,
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) => {
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diag.span_label(
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*span,
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format!(
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"return type{mir_description} `{type_name}` contains a lifetime `{self}`"
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),
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);
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}
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RegionNameSource::AnonRegionFromUpvar(span, upvar_name) => {
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diag.span_label(
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*span,
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format!("lifetime `{self}` appears in the type of `{upvar_name}`"),
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);
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}
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RegionNameSource::AnonRegionFromOutput(
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RegionNameHighlight::CannotMatchHirTy(span, type_name),
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mir_description,
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) => {
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diag.span_label(*span, format!("return type{mir_description} is {type_name}"));
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}
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RegionNameSource::AnonRegionFromYieldTy(span, type_name) => {
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diag.span_label(*span, format!("yield type is {type_name}"));
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}
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RegionNameSource::AnonRegionFromImplSignature(span, location) => {
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diag.span_label(
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*span,
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format!("lifetime `{self}` appears in the `impl`'s {location}"),
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);
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}
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RegionNameSource::Static => {}
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}
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}
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}
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impl Display for RegionName {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(f, "{}", self.name)
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}
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}
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impl rustc_errors::IntoDiagnosticArg for RegionName {
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fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue {
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self.to_string().into_diagnostic_arg()
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}
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}
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impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
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pub(crate) fn mir_def_id(&self) -> hir::def_id::LocalDefId {
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self.body.source.def_id().expect_local()
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}
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pub(crate) fn mir_hir_id(&self) -> hir::HirId {
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self.infcx.tcx.local_def_id_to_hir_id(self.mir_def_id())
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}
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/// Generate a synthetic region named `'N`, where `N` is the next value of the counter. Then,
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/// increment the counter.
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///
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/// This is _not_ idempotent. Call `give_region_a_name` when possible.
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pub(crate) fn synthesize_region_name(&self) -> Symbol {
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let c = self.next_region_name.replace_with(|counter| *counter + 1);
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Symbol::intern(&format!("'{c:?}"))
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}
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/// Maps from an internal MIR region vid to something that we can
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/// report to the user. In some cases, the region vids will map
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/// directly to lifetimes that the user has a name for (e.g.,
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/// `'static`). But frequently they will not, in which case we
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/// have to find some way to identify the lifetime to the user. To
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/// that end, this function takes a "diagnostic" so that it can
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/// create auxiliary notes as needed.
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///
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/// The names are memoized, so this is both cheap to recompute and idempotent.
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///
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/// Example (function arguments):
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///
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/// Suppose we are trying to give a name to the lifetime of the
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/// reference `x`:
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///
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/// ```ignore (pseudo-rust)
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/// fn foo(x: &u32) { .. }
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/// ```
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///
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/// This function would create a label like this:
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///
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/// ```text
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/// | fn foo(x: &u32) { .. }
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/// ------- fully elaborated type of `x` is `&'1 u32`
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/// ```
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///
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/// and then return the name `'1` for us to use.
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pub(crate) fn give_region_a_name(&self, fr: RegionVid) -> Option<RegionName> {
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debug!(
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"give_region_a_name(fr={:?}, counter={:?})",
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fr,
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self.next_region_name.try_borrow().unwrap()
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);
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assert!(self.regioncx.universal_regions().is_universal_region(fr));
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if let Some(value) = self.region_names.try_borrow_mut().unwrap().get(&fr) {
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return Some(value.clone());
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}
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let value = self
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.give_name_from_error_region(fr)
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.or_else(|| self.give_name_if_anonymous_region_appears_in_arguments(fr))
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.or_else(|| self.give_name_if_anonymous_region_appears_in_upvars(fr))
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.or_else(|| self.give_name_if_anonymous_region_appears_in_output(fr))
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.or_else(|| self.give_name_if_anonymous_region_appears_in_yield_ty(fr))
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.or_else(|| self.give_name_if_anonymous_region_appears_in_impl_signature(fr))
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.or_else(|| self.give_name_if_anonymous_region_appears_in_arg_position_impl_trait(fr));
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if let Some(value) = &value {
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self.region_names.try_borrow_mut().unwrap().insert(fr, value.clone());
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}
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debug!("give_region_a_name: gave name {:?}", value);
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value
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}
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/// Checks for the case where `fr` maps to something that the
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/// *user* has a name for. In that case, we'll be able to map
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/// `fr` to a `Region<'tcx>`, and that region will be one of
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/// named variants.
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#[instrument(level = "trace", skip(self))]
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fn give_name_from_error_region(&self, fr: RegionVid) -> Option<RegionName> {
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let error_region = self.to_error_region(fr)?;
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let tcx = self.infcx.tcx;
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debug!("give_region_a_name: error_region = {:?}", error_region);
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match *error_region {
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ty::ReEarlyParam(ebr) => ebr.has_name().then(|| {
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let span = tcx.hir().span_if_local(ebr.def_id).unwrap_or(DUMMY_SP);
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RegionName { name: ebr.name, source: RegionNameSource::NamedEarlyParamRegion(span) }
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}),
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ty::ReStatic => {
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Some(RegionName { name: kw::StaticLifetime, source: RegionNameSource::Static })
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}
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ty::ReLateParam(late_param) => match late_param.bound_region {
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ty::BoundRegionKind::BrNamed(region_def_id, name) => {
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// Get the span to point to, even if we don't use the name.
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let span = tcx.hir().span_if_local(region_def_id).unwrap_or(DUMMY_SP);
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debug!(
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"bound region named: {:?}, is_named: {:?}",
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name,
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late_param.bound_region.is_named()
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);
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if late_param.bound_region.is_named() {
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// A named region that is actually named.
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Some(RegionName {
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name,
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source: RegionNameSource::NamedLateParamRegion(span),
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})
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} else if tcx.asyncness(self.mir_hir_id().owner).is_async() {
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// If we spuriously thought that the region is named, we should let the
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// system generate a true name for error messages. Currently this can
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// happen if we have an elided name in an async fn for example: the
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// compiler will generate a region named `'_`, but reporting such a name is
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// not actually useful, so we synthesize a name for it instead.
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let name = self.synthesize_region_name();
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Some(RegionName {
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name,
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source: RegionNameSource::AnonRegionFromAsyncFn(span),
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})
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} else {
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None
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}
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}
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ty::BoundRegionKind::BrEnv => {
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let def_ty = self.regioncx.universal_regions().defining_ty;
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let DefiningTy::Closure(_, args) = def_ty else {
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// Can't have BrEnv in functions, constants or coroutines.
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bug!("BrEnv outside of closure.");
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};
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let hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. }) =
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tcx.hir().expect_expr(self.mir_hir_id()).kind
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else {
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bug!("Closure is not defined by a closure expr");
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};
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let region_name = self.synthesize_region_name();
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let closure_kind_ty = args.as_closure().kind_ty();
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let note = match closure_kind_ty.to_opt_closure_kind() {
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Some(ty::ClosureKind::Fn) => {
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"closure implements `Fn`, so references to captured variables \
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can't escape the closure"
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}
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Some(ty::ClosureKind::FnMut) => {
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"closure implements `FnMut`, so references to captured variables \
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can't escape the closure"
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}
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Some(ty::ClosureKind::FnOnce) => {
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bug!("BrEnv in a `FnOnce` closure");
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}
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None => bug!("Closure kind not inferred in borrow check"),
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};
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Some(RegionName {
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name: region_name,
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source: RegionNameSource::SynthesizedFreeEnvRegion(fn_decl_span, note),
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})
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}
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ty::BoundRegionKind::BrAnon => None,
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},
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ty::ReBound(..)
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| ty::ReVar(..)
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| ty::RePlaceholder(..)
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| ty::ReErased
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| ty::ReError(_) => None,
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}
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}
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/// Finds an argument that contains `fr` and label it with a fully
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/// elaborated type, returning something like `'1`. Result looks
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/// like:
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///
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/// ```text
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/// | fn foo(x: &u32) { .. }
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/// ------- fully elaborated type of `x` is `&'1 u32`
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/// ```
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#[instrument(level = "trace", skip(self))]
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fn give_name_if_anonymous_region_appears_in_arguments(
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&self,
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fr: RegionVid,
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) -> Option<RegionName> {
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let implicit_inputs = self.regioncx.universal_regions().defining_ty.implicit_inputs();
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let argument_index = self.regioncx.get_argument_index_for_region(self.infcx.tcx, fr)?;
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let arg_ty = self.regioncx.universal_regions().unnormalized_input_tys
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[implicit_inputs + argument_index];
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let (_, span) = self.regioncx.get_argument_name_and_span_for_region(
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self.body,
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&self.local_names,
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argument_index,
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);
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let highlight = self
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.get_argument_hir_ty_for_highlighting(argument_index)
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.and_then(|arg_hir_ty| self.highlight_if_we_can_match_hir_ty(fr, arg_ty, arg_hir_ty))
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.unwrap_or_else(|| {
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// `highlight_if_we_cannot_match_hir_ty` needs to know the number we will give to
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// the anonymous region. If it succeeds, the `synthesize_region_name` call below
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// will increment the counter, "reserving" the number we just used.
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let counter = *self.next_region_name.try_borrow().unwrap();
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self.highlight_if_we_cannot_match_hir_ty(fr, arg_ty, span, counter)
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});
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Some(RegionName {
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name: self.synthesize_region_name(),
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source: RegionNameSource::AnonRegionFromArgument(highlight),
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})
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}
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fn get_argument_hir_ty_for_highlighting(
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&self,
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argument_index: usize,
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) -> Option<&hir::Ty<'tcx>> {
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let fn_decl = self.infcx.tcx.hir().fn_decl_by_hir_id(self.mir_hir_id())?;
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let argument_hir_ty: &hir::Ty<'_> = fn_decl.inputs.get(argument_index)?;
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match argument_hir_ty.kind {
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// This indicates a variable with no type annotation, like
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// `|x|`... in that case, we can't highlight the type but
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// must highlight the variable.
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// NOTE(eddyb) this is handled in/by the sole caller
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// (`give_name_if_anonymous_region_appears_in_arguments`).
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hir::TyKind::Infer => None,
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_ => Some(argument_hir_ty),
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}
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}
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/// Attempts to highlight the specific part of a type in an argument
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/// that has no type annotation.
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/// For example, we might produce an annotation like this:
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///
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/// ```text
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/// | foo(|a, b| b)
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/// | - -
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/// | | |
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/// | | has type `&'1 u32`
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/// | has type `&'2 u32`
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/// ```
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fn highlight_if_we_cannot_match_hir_ty(
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&self,
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needle_fr: RegionVid,
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ty: Ty<'tcx>,
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span: Span,
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counter: usize,
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) -> RegionNameHighlight {
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let mut highlight = RegionHighlightMode::default();
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highlight.highlighting_region_vid(self.infcx.tcx, needle_fr, counter);
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let type_name =
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self.infcx.extract_inference_diagnostics_data(ty.into(), Some(highlight)).name;
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debug!(
|
|
"highlight_if_we_cannot_match_hir_ty: type_name={:?} needle_fr={:?}",
|
|
type_name, needle_fr
|
|
);
|
|
if type_name.contains(&format!("'{counter}")) {
|
|
// Only add a label if we can confirm that a region was labelled.
|
|
RegionNameHighlight::CannotMatchHirTy(span, type_name)
|
|
} else {
|
|
RegionNameHighlight::Occluded(span, type_name)
|
|
}
|
|
}
|
|
|
|
/// Attempts to highlight the specific part of a type annotation
|
|
/// that contains the anonymous reference we want to give a name
|
|
/// to. For example, we might produce an annotation like this:
|
|
///
|
|
/// ```text
|
|
/// | fn a<T>(items: &[T]) -> Box<dyn Iterator<Item = &T>> {
|
|
/// | - let's call the lifetime of this reference `'1`
|
|
/// ```
|
|
///
|
|
/// the way this works is that we match up `ty`, which is
|
|
/// a `Ty<'tcx>` (the internal form of the type) with
|
|
/// `hir_ty`, a `hir::Ty` (the syntax of the type
|
|
/// annotation). We are descending through the types stepwise,
|
|
/// looking in to find the region `needle_fr` in the internal
|
|
/// type. Once we find that, we can use the span of the `hir::Ty`
|
|
/// to add the highlight.
|
|
///
|
|
/// This is a somewhat imperfect process, so along the way we also
|
|
/// keep track of the **closest** type we've found. If we fail to
|
|
/// find the exact `&` or `'_` to highlight, then we may fall back
|
|
/// to highlighting that closest type instead.
|
|
fn highlight_if_we_can_match_hir_ty(
|
|
&self,
|
|
needle_fr: RegionVid,
|
|
ty: Ty<'tcx>,
|
|
hir_ty: &hir::Ty<'_>,
|
|
) -> Option<RegionNameHighlight> {
|
|
let search_stack: &mut Vec<(Ty<'tcx>, &hir::Ty<'_>)> = &mut vec![(ty, hir_ty)];
|
|
|
|
while let Some((ty, hir_ty)) = search_stack.pop() {
|
|
match (ty.kind(), &hir_ty.kind) {
|
|
// Check if the `ty` is `&'X ..` where `'X`
|
|
// is the region we are looking for -- if so, and we have a `&T`
|
|
// on the RHS, then we want to highlight the `&` like so:
|
|
//
|
|
// &
|
|
// - let's call the lifetime of this reference `'1`
|
|
(ty::Ref(region, referent_ty, _), hir::TyKind::Ref(_lifetime, referent_hir_ty)) => {
|
|
if region.as_var() == needle_fr {
|
|
// Just grab the first character, the `&`.
|
|
let source_map = self.infcx.tcx.sess.source_map();
|
|
let ampersand_span = source_map.start_point(hir_ty.span);
|
|
|
|
return Some(RegionNameHighlight::MatchedHirTy(ampersand_span));
|
|
}
|
|
|
|
// Otherwise, let's descend into the referent types.
|
|
search_stack.push((*referent_ty, &referent_hir_ty.ty));
|
|
}
|
|
|
|
// Match up something like `Foo<'1>`
|
|
(ty::Adt(_adt_def, args), hir::TyKind::Path(hir::QPath::Resolved(None, path))) => {
|
|
match path.res {
|
|
// Type parameters of the type alias have no reason to
|
|
// be the same as those of the ADT.
|
|
// FIXME: We should be able to do something similar to
|
|
// match_adt_and_segment in this case.
|
|
Res::Def(DefKind::TyAlias, _) => (),
|
|
_ => {
|
|
if let Some(last_segment) = path.segments.last() {
|
|
if let Some(highlight) = self.match_adt_and_segment(
|
|
args,
|
|
needle_fr,
|
|
last_segment,
|
|
search_stack,
|
|
) {
|
|
return Some(highlight);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// The following cases don't have lifetimes, so we
|
|
// just worry about trying to match up the rustc type
|
|
// with the HIR types:
|
|
(&ty::Tuple(elem_tys), hir::TyKind::Tup(elem_hir_tys)) => {
|
|
search_stack.extend(iter::zip(elem_tys, *elem_hir_tys));
|
|
}
|
|
|
|
(ty::Slice(elem_ty), hir::TyKind::Slice(elem_hir_ty))
|
|
| (ty::Array(elem_ty, _), hir::TyKind::Array(elem_hir_ty, _)) => {
|
|
search_stack.push((*elem_ty, elem_hir_ty));
|
|
}
|
|
|
|
(ty::RawPtr(mut_ty), hir::TyKind::Ptr(mut_hir_ty)) => {
|
|
search_stack.push((mut_ty.ty, &mut_hir_ty.ty));
|
|
}
|
|
|
|
_ => {
|
|
// FIXME there are other cases that we could trace
|
|
}
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
|
|
/// We've found an enum/struct/union type with the generic args
|
|
/// `args` and -- in the HIR -- a path type with the final
|
|
/// segment `last_segment`. Try to find a `'_` to highlight in
|
|
/// the generic args (or, if not, to produce new zipped pairs of
|
|
/// types+hir to search through).
|
|
fn match_adt_and_segment<'hir>(
|
|
&self,
|
|
args: GenericArgsRef<'tcx>,
|
|
needle_fr: RegionVid,
|
|
last_segment: &'hir hir::PathSegment<'hir>,
|
|
search_stack: &mut Vec<(Ty<'tcx>, &'hir hir::Ty<'hir>)>,
|
|
) -> Option<RegionNameHighlight> {
|
|
// Did the user give explicit arguments? (e.g., `Foo<..>`)
|
|
let explicit_args = last_segment.args.as_ref()?;
|
|
let lifetime =
|
|
self.try_match_adt_and_generic_args(args, needle_fr, explicit_args, search_stack)?;
|
|
if lifetime.is_anonymous() {
|
|
None
|
|
} else {
|
|
Some(RegionNameHighlight::MatchedAdtAndSegment(lifetime.ident.span))
|
|
}
|
|
}
|
|
|
|
/// We've found an enum/struct/union type with the generic args
|
|
/// `args` and -- in the HIR -- a path with the generic
|
|
/// arguments `hir_args`. If `needle_fr` appears in the args, return
|
|
/// the `hir::Lifetime` that corresponds to it. If not, push onto
|
|
/// `search_stack` the types+hir to search through.
|
|
fn try_match_adt_and_generic_args<'hir>(
|
|
&self,
|
|
args: GenericArgsRef<'tcx>,
|
|
needle_fr: RegionVid,
|
|
hir_args: &'hir hir::GenericArgs<'hir>,
|
|
search_stack: &mut Vec<(Ty<'tcx>, &'hir hir::Ty<'hir>)>,
|
|
) -> Option<&'hir hir::Lifetime> {
|
|
for (kind, hir_arg) in iter::zip(args, hir_args.args) {
|
|
match (kind.unpack(), hir_arg) {
|
|
(GenericArgKind::Lifetime(r), hir::GenericArg::Lifetime(lt)) => {
|
|
if r.as_var() == needle_fr {
|
|
return Some(lt);
|
|
}
|
|
}
|
|
|
|
(GenericArgKind::Type(ty), hir::GenericArg::Type(hir_ty)) => {
|
|
search_stack.push((ty, hir_ty));
|
|
}
|
|
|
|
(GenericArgKind::Const(_ct), hir::GenericArg::Const(_hir_ct)) => {
|
|
// Lifetimes cannot be found in consts, so we don't need
|
|
// to search anything here.
|
|
}
|
|
|
|
(
|
|
GenericArgKind::Lifetime(_)
|
|
| GenericArgKind::Type(_)
|
|
| GenericArgKind::Const(_),
|
|
_,
|
|
) => {
|
|
// HIR lowering sometimes doesn't catch this in erroneous
|
|
// programs, so we need to use span_delayed_bug here. See #82126.
|
|
self.dcx().span_delayed_bug(
|
|
hir_arg.span(),
|
|
format!("unmatched arg and hir arg: found {kind:?} vs {hir_arg:?}"),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
|
|
/// Finds a closure upvar that contains `fr` and label it with a
|
|
/// fully elaborated type, returning something like `'1`. Result
|
|
/// looks like:
|
|
///
|
|
/// ```text
|
|
/// | let x = Some(&22);
|
|
/// - fully elaborated type of `x` is `Option<&'1 u32>`
|
|
/// ```
|
|
#[instrument(level = "trace", skip(self))]
|
|
fn give_name_if_anonymous_region_appears_in_upvars(&self, fr: RegionVid) -> Option<RegionName> {
|
|
let upvar_index = self.regioncx.get_upvar_index_for_region(self.infcx.tcx, fr)?;
|
|
let (upvar_name, upvar_span) = self.regioncx.get_upvar_name_and_span_for_region(
|
|
self.infcx.tcx,
|
|
&self.upvars,
|
|
upvar_index,
|
|
);
|
|
let region_name = self.synthesize_region_name();
|
|
|
|
Some(RegionName {
|
|
name: region_name,
|
|
source: RegionNameSource::AnonRegionFromUpvar(upvar_span, upvar_name),
|
|
})
|
|
}
|
|
|
|
/// Checks for arguments appearing in the (closure) return type. It
|
|
/// must be a closure since, in a free fn, such an argument would
|
|
/// have to either also appear in an argument (if using elision)
|
|
/// or be early bound (named, not in argument).
|
|
#[instrument(level = "trace", skip(self))]
|
|
fn give_name_if_anonymous_region_appears_in_output(&self, fr: RegionVid) -> Option<RegionName> {
|
|
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);
|
|
if !tcx.any_free_region_meets(&return_ty, |r| r.as_var() == fr) {
|
|
return None;
|
|
}
|
|
|
|
let mir_hir_id = self.mir_hir_id();
|
|
|
|
let (return_span, mir_description, hir_ty) = match tcx.hir_node(mir_hir_id) {
|
|
hir::Node::Expr(hir::Expr {
|
|
kind: hir::ExprKind::Closure(&hir::Closure { fn_decl, kind, fn_decl_span, .. }),
|
|
..
|
|
}) => {
|
|
let (mut span, mut hir_ty) = match fn_decl.output {
|
|
hir::FnRetTy::DefaultReturn(_) => {
|
|
(tcx.sess.source_map().end_point(fn_decl_span), None)
|
|
}
|
|
hir::FnRetTy::Return(hir_ty) => (fn_decl.output.span(), Some(hir_ty)),
|
|
};
|
|
let mir_description = match kind {
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::Async,
|
|
hir::CoroutineSource::Block,
|
|
)) => " of async block",
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::Async,
|
|
hir::CoroutineSource::Closure,
|
|
)) => " of async closure",
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::Async,
|
|
hir::CoroutineSource::Fn,
|
|
)) => {
|
|
let parent_item =
|
|
tcx.hir_node_by_def_id(hir.get_parent_item(mir_hir_id).def_id);
|
|
let output = &parent_item
|
|
.fn_decl()
|
|
.expect("coroutine 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"
|
|
}
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::Gen,
|
|
hir::CoroutineSource::Block,
|
|
)) => " of gen block",
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::Gen,
|
|
hir::CoroutineSource::Closure,
|
|
)) => " of gen closure",
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::Gen,
|
|
hir::CoroutineSource::Fn,
|
|
)) => {
|
|
let parent_item =
|
|
tcx.hir_node_by_def_id(hir.get_parent_item(mir_hir_id).def_id);
|
|
let output = &parent_item
|
|
.fn_decl()
|
|
.expect("coroutine lowered from gen fn should be in fn")
|
|
.output;
|
|
span = output.span();
|
|
" of gen function"
|
|
}
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::AsyncGen,
|
|
hir::CoroutineSource::Block,
|
|
)) => " of async gen block",
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::AsyncGen,
|
|
hir::CoroutineSource::Closure,
|
|
)) => " of async gen closure",
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Desugared(
|
|
hir::CoroutineDesugaring::AsyncGen,
|
|
hir::CoroutineSource::Fn,
|
|
)) => {
|
|
let parent_item =
|
|
tcx.hir_node_by_def_id(hir.get_parent_item(mir_hir_id).def_id);
|
|
let output = &parent_item
|
|
.fn_decl()
|
|
.expect("coroutine lowered from async gen fn should be in fn")
|
|
.output;
|
|
span = output.span();
|
|
" of async gen function"
|
|
}
|
|
|
|
hir::ClosureKind::Coroutine(hir::CoroutineKind::Coroutine(_)) => {
|
|
" of coroutine"
|
|
}
|
|
hir::ClosureKind::Closure => " 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 {
|
|
name: self.synthesize_region_name(),
|
|
source: RegionNameSource::AnonRegionFromOutput(highlight, mir_description),
|
|
})
|
|
}
|
|
|
|
/// 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 { 2 }
|
|
/// ```
|
|
///
|
|
/// this function, given the lowered return type of `foo`, an [`OpaqueDef`] that implements `Future<Output=i32>`,
|
|
/// 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();
|
|
|
|
let hir::TyKind::OpaqueDef(id, _, _) = hir_ty.kind else {
|
|
span_bug!(
|
|
hir_ty.span,
|
|
"lowered return type of async fn is not OpaqueDef: {:?}",
|
|
hir_ty
|
|
);
|
|
};
|
|
let opaque_ty = hir.item(id);
|
|
if let hir::ItemKind::OpaqueTy(hir::OpaqueTy {
|
|
bounds: [hir::GenericBound::Trait(trait_ref, _)],
|
|
..
|
|
}) = opaque_ty.kind
|
|
&& let Some(segment) = trait_ref.trait_ref.path.segments.last()
|
|
&& let Some(args) = segment.args
|
|
&& let [
|
|
hir::TypeBinding {
|
|
ident: Ident { name: sym::Output, .. },
|
|
kind: hir::TypeBindingKind::Equality { term: hir::Term::Ty(ty) },
|
|
..
|
|
},
|
|
] = args.bindings
|
|
{
|
|
ty
|
|
} else {
|
|
span_bug!(
|
|
hir_ty.span,
|
|
"bounds from lowered return type of async fn did not match expected format: {opaque_ty:?}",
|
|
);
|
|
}
|
|
}
|
|
|
|
#[instrument(level = "trace", skip(self))]
|
|
fn give_name_if_anonymous_region_appears_in_yield_ty(
|
|
&self,
|
|
fr: RegionVid,
|
|
) -> Option<RegionName> {
|
|
// Note: coroutines from `async fn` yield `()`, so we don't have to
|
|
// worry about them here.
|
|
let yield_ty = self.regioncx.universal_regions().yield_ty?;
|
|
debug!("give_name_if_anonymous_region_appears_in_yield_ty: yield_ty = {:?}", yield_ty);
|
|
|
|
let tcx = self.infcx.tcx;
|
|
|
|
if !tcx.any_free_region_meets(&yield_ty, |r| r.as_var() == fr) {
|
|
return None;
|
|
}
|
|
|
|
let mut highlight = RegionHighlightMode::default();
|
|
highlight.highlighting_region_vid(tcx, fr, *self.next_region_name.try_borrow().unwrap());
|
|
let type_name =
|
|
self.infcx.extract_inference_diagnostics_data(yield_ty.into(), Some(highlight)).name;
|
|
|
|
let yield_span = match tcx.hir_node(self.mir_hir_id()) {
|
|
hir::Node::Expr(hir::Expr {
|
|
kind: hir::ExprKind::Closure(&hir::Closure { fn_decl_span, .. }),
|
|
..
|
|
}) => tcx.sess.source_map().end_point(fn_decl_span),
|
|
_ => self.body.span,
|
|
};
|
|
|
|
debug!(
|
|
"give_name_if_anonymous_region_appears_in_yield_ty: \
|
|
type_name = {:?}, yield_span = {:?}",
|
|
yield_span, type_name,
|
|
);
|
|
|
|
Some(RegionName {
|
|
name: self.synthesize_region_name(),
|
|
source: RegionNameSource::AnonRegionFromYieldTy(yield_span, type_name),
|
|
})
|
|
}
|
|
|
|
fn give_name_if_anonymous_region_appears_in_impl_signature(
|
|
&self,
|
|
fr: RegionVid,
|
|
) -> Option<RegionName> {
|
|
let ty::ReEarlyParam(region) = *self.to_error_region(fr)? else {
|
|
return None;
|
|
};
|
|
if region.has_name() {
|
|
return None;
|
|
};
|
|
|
|
let tcx = self.infcx.tcx;
|
|
let region_parent = tcx.parent(region.def_id);
|
|
let DefKind::Impl { .. } = tcx.def_kind(region_parent) else {
|
|
return None;
|
|
};
|
|
|
|
let found = tcx
|
|
.any_free_region_meets(&tcx.type_of(region_parent).instantiate_identity(), |r| {
|
|
*r == ty::ReEarlyParam(region)
|
|
});
|
|
|
|
Some(RegionName {
|
|
name: self.synthesize_region_name(),
|
|
source: RegionNameSource::AnonRegionFromImplSignature(
|
|
tcx.def_span(region.def_id),
|
|
// FIXME(compiler-errors): Does this ever actually show up
|
|
// anywhere other than the self type? I couldn't create an
|
|
// example of a `'_` in the impl's trait being referenceable.
|
|
if found { "self type" } else { "header" },
|
|
),
|
|
})
|
|
}
|
|
|
|
fn give_name_if_anonymous_region_appears_in_arg_position_impl_trait(
|
|
&self,
|
|
fr: RegionVid,
|
|
) -> Option<RegionName> {
|
|
let ty::ReEarlyParam(region) = *self.to_error_region(fr)? else {
|
|
return None;
|
|
};
|
|
if region.has_name() {
|
|
return None;
|
|
};
|
|
|
|
let predicates = self
|
|
.infcx
|
|
.tcx
|
|
.predicates_of(self.body.source.def_id())
|
|
.instantiate_identity(self.infcx.tcx)
|
|
.predicates;
|
|
|
|
if let Some(upvar_index) = self
|
|
.regioncx
|
|
.universal_regions()
|
|
.defining_ty
|
|
.upvar_tys()
|
|
.iter()
|
|
.position(|ty| self.any_param_predicate_mentions(&predicates, ty, region))
|
|
{
|
|
let (upvar_name, upvar_span) = self.regioncx.get_upvar_name_and_span_for_region(
|
|
self.infcx.tcx,
|
|
&self.upvars,
|
|
upvar_index,
|
|
);
|
|
let region_name = self.synthesize_region_name();
|
|
|
|
Some(RegionName {
|
|
name: region_name,
|
|
source: RegionNameSource::AnonRegionFromUpvar(upvar_span, upvar_name),
|
|
})
|
|
} else if let Some(arg_index) = self
|
|
.regioncx
|
|
.universal_regions()
|
|
.unnormalized_input_tys
|
|
.iter()
|
|
.position(|ty| self.any_param_predicate_mentions(&predicates, *ty, region))
|
|
{
|
|
let (arg_name, arg_span) = self.regioncx.get_argument_name_and_span_for_region(
|
|
self.body,
|
|
&self.local_names,
|
|
arg_index,
|
|
);
|
|
let region_name = self.synthesize_region_name();
|
|
|
|
Some(RegionName {
|
|
name: region_name,
|
|
source: RegionNameSource::AnonRegionFromArgument(
|
|
RegionNameHighlight::CannotMatchHirTy(arg_span, arg_name?.to_string()),
|
|
),
|
|
})
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
|
|
fn any_param_predicate_mentions(
|
|
&self,
|
|
clauses: &[ty::Clause<'tcx>],
|
|
ty: Ty<'tcx>,
|
|
region: ty::EarlyParamRegion,
|
|
) -> bool {
|
|
let tcx = self.infcx.tcx;
|
|
ty.walk().any(|arg| {
|
|
if let ty::GenericArgKind::Type(ty) = arg.unpack()
|
|
&& let ty::Param(_) = ty.kind()
|
|
{
|
|
clauses.iter().any(|pred| {
|
|
match pred.kind().skip_binder() {
|
|
ty::ClauseKind::Trait(data) if data.self_ty() == ty => {}
|
|
ty::ClauseKind::Projection(data) if data.projection_ty.self_ty() == ty => {}
|
|
_ => return false,
|
|
}
|
|
tcx.any_free_region_meets(pred, |r| *r == ty::ReEarlyParam(region))
|
|
})
|
|
} else {
|
|
false
|
|
}
|
|
})
|
|
}
|
|
}
|