ca5525d564
This commit makes `AdtDef` use `Interned`. Much the commit is tedious changes to introduce getter functions. The interesting changes are in `compiler/rustc_middle/src/ty/adt.rs`.
536 lines
21 KiB
Rust
536 lines
21 KiB
Rust
use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed};
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use rustc_middle::mir::*;
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use rustc_middle::ty;
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use rustc_mir_dataflow::move_paths::{
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IllegalMoveOrigin, IllegalMoveOriginKind, LookupResult, MoveError, MovePathIndex,
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};
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use rustc_span::{sym, Span};
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use crate::diagnostics::UseSpans;
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use crate::prefixes::PrefixSet;
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use crate::MirBorrowckCtxt;
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// Often when desugaring a pattern match we may have many individual moves in
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// MIR that are all part of one operation from the user's point-of-view. For
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// example:
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//
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// let (x, y) = foo()
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//
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// would move x from the 0 field of some temporary, and y from the 1 field. We
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// group such errors together for cleaner error reporting.
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//
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// Errors are kept separate if they are from places with different parent move
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// paths. For example, this generates two errors:
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//
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// let (&x, &y) = (&String::new(), &String::new());
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#[derive(Debug)]
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enum GroupedMoveError<'tcx> {
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// Place expression can't be moved from,
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// e.g., match x[0] { s => (), } where x: &[String]
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MovesFromPlace {
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original_path: Place<'tcx>,
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span: Span,
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move_from: Place<'tcx>,
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kind: IllegalMoveOriginKind<'tcx>,
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binds_to: Vec<Local>,
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},
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// Part of a value expression can't be moved from,
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// e.g., match &String::new() { &x => (), }
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MovesFromValue {
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original_path: Place<'tcx>,
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span: Span,
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move_from: MovePathIndex,
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kind: IllegalMoveOriginKind<'tcx>,
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binds_to: Vec<Local>,
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},
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// Everything that isn't from pattern matching.
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OtherIllegalMove {
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original_path: Place<'tcx>,
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use_spans: UseSpans<'tcx>,
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kind: IllegalMoveOriginKind<'tcx>,
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},
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}
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impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
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pub(crate) fn report_move_errors(&mut self, move_errors: Vec<(Place<'tcx>, MoveError<'tcx>)>) {
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let grouped_errors = self.group_move_errors(move_errors);
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for error in grouped_errors {
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self.report(error);
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}
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}
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fn group_move_errors(
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&self,
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errors: Vec<(Place<'tcx>, MoveError<'tcx>)>,
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) -> Vec<GroupedMoveError<'tcx>> {
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let mut grouped_errors = Vec::new();
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for (original_path, error) in errors {
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self.append_to_grouped_errors(&mut grouped_errors, original_path, error);
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}
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grouped_errors
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}
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fn append_to_grouped_errors(
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&self,
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grouped_errors: &mut Vec<GroupedMoveError<'tcx>>,
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original_path: Place<'tcx>,
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error: MoveError<'tcx>,
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) {
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match error {
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MoveError::UnionMove { .. } => {
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unimplemented!("don't know how to report union move errors yet.")
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}
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MoveError::IllegalMove { cannot_move_out_of: IllegalMoveOrigin { location, kind } } => {
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// Note: that the only time we assign a place isn't a temporary
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// to a user variable is when initializing it.
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// If that ever stops being the case, then the ever initialized
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// flow could be used.
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if let Some(StatementKind::Assign(box (
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place,
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Rvalue::Use(Operand::Move(move_from)),
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))) = self.body.basic_blocks()[location.block]
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.statements
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.get(location.statement_index)
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.map(|stmt| &stmt.kind)
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{
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if let Some(local) = place.as_local() {
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let local_decl = &self.body.local_decls[local];
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// opt_match_place is the
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// match_span is the span of the expression being matched on
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// match *x.y { ... } match_place is Some(*x.y)
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// ^^^^ match_span is the span of *x.y
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//
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// opt_match_place is None for let [mut] x = ... statements,
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// whether or not the right-hand side is a place expression
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if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
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VarBindingForm {
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opt_match_place: Some((opt_match_place, match_span)),
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binding_mode: _,
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opt_ty_info: _,
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pat_span: _,
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},
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)))) = local_decl.local_info
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{
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let stmt_source_info = self.body.source_info(location);
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self.append_binding_error(
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grouped_errors,
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kind,
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original_path,
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*move_from,
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local,
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opt_match_place,
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match_span,
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stmt_source_info.span,
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);
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return;
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}
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}
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}
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let move_spans = self.move_spans(original_path.as_ref(), location);
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grouped_errors.push(GroupedMoveError::OtherIllegalMove {
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use_spans: move_spans,
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original_path,
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kind,
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});
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}
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}
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}
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fn append_binding_error(
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&self,
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grouped_errors: &mut Vec<GroupedMoveError<'tcx>>,
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kind: IllegalMoveOriginKind<'tcx>,
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original_path: Place<'tcx>,
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move_from: Place<'tcx>,
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bind_to: Local,
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match_place: Option<Place<'tcx>>,
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match_span: Span,
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statement_span: Span,
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) {
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debug!("append_binding_error(match_place={:?}, match_span={:?})", match_place, match_span);
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let from_simple_let = match_place.is_none();
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let match_place = match_place.unwrap_or(move_from);
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match self.move_data.rev_lookup.find(match_place.as_ref()) {
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// Error with the match place
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LookupResult::Parent(_) => {
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for ge in &mut *grouped_errors {
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if let GroupedMoveError::MovesFromPlace { span, binds_to, .. } = ge {
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if match_span == *span {
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debug!("appending local({:?}) to list", bind_to);
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if !binds_to.is_empty() {
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binds_to.push(bind_to);
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}
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return;
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}
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}
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}
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debug!("found a new move error location");
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// Don't need to point to x in let x = ... .
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let (binds_to, span) = if from_simple_let {
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(vec![], statement_span)
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} else {
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(vec![bind_to], match_span)
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};
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grouped_errors.push(GroupedMoveError::MovesFromPlace {
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span,
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move_from,
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original_path,
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kind,
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binds_to,
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});
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}
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// Error with the pattern
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LookupResult::Exact(_) => {
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let LookupResult::Parent(Some(mpi)) = self.move_data.rev_lookup.find(move_from.as_ref()) else {
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// move_from should be a projection from match_place.
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unreachable!("Probably not unreachable...");
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};
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for ge in &mut *grouped_errors {
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if let GroupedMoveError::MovesFromValue {
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span,
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move_from: other_mpi,
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binds_to,
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..
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} = ge
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{
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if match_span == *span && mpi == *other_mpi {
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debug!("appending local({:?}) to list", bind_to);
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binds_to.push(bind_to);
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return;
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}
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}
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}
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debug!("found a new move error location");
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grouped_errors.push(GroupedMoveError::MovesFromValue {
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span: match_span,
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move_from: mpi,
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original_path,
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kind,
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binds_to: vec![bind_to],
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});
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}
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};
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}
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fn report(&mut self, error: GroupedMoveError<'tcx>) {
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let (mut err, err_span) = {
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let (span, use_spans, original_path, kind): (
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Span,
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Option<UseSpans<'tcx>>,
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Place<'tcx>,
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&IllegalMoveOriginKind<'_>,
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) = match error {
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GroupedMoveError::MovesFromPlace { span, original_path, ref kind, .. }
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| GroupedMoveError::MovesFromValue { span, original_path, ref kind, .. } => {
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(span, None, original_path, kind)
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}
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GroupedMoveError::OtherIllegalMove { use_spans, original_path, ref kind } => {
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(use_spans.args_or_use(), Some(use_spans), original_path, kind)
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}
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};
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debug!(
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"report: original_path={:?} span={:?}, kind={:?} \
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original_path.is_upvar_field_projection={:?}",
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original_path,
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span,
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kind,
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self.is_upvar_field_projection(original_path.as_ref())
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);
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(
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match kind {
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&IllegalMoveOriginKind::BorrowedContent { target_place } => self
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.report_cannot_move_from_borrowed_content(
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original_path,
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target_place,
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span,
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use_spans,
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),
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&IllegalMoveOriginKind::InteriorOfTypeWithDestructor { container_ty: ty } => {
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self.cannot_move_out_of_interior_of_drop(span, ty)
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}
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&IllegalMoveOriginKind::InteriorOfSliceOrArray { ty, is_index } => {
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self.cannot_move_out_of_interior_noncopy(span, ty, Some(is_index))
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}
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},
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span,
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)
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};
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self.add_move_hints(error, &mut err, err_span);
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self.buffer_error(err);
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}
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fn report_cannot_move_from_static(
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&mut self,
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place: Place<'tcx>,
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span: Span,
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) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
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let description = if place.projection.len() == 1 {
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format!("static item {}", self.describe_any_place(place.as_ref()))
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} else {
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let base_static = PlaceRef { local: place.local, projection: &[ProjectionElem::Deref] };
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format!(
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"{} as {} is a static item",
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self.describe_any_place(place.as_ref()),
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self.describe_any_place(base_static),
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)
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};
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self.cannot_move_out_of(span, &description)
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}
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fn report_cannot_move_from_borrowed_content(
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&mut self,
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move_place: Place<'tcx>,
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deref_target_place: Place<'tcx>,
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span: Span,
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use_spans: Option<UseSpans<'tcx>>,
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) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
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// Inspect the type of the content behind the
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// borrow to provide feedback about why this
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// was a move rather than a copy.
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let ty = deref_target_place.ty(self.body, self.infcx.tcx).ty;
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let upvar_field = self
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.prefixes(move_place.as_ref(), PrefixSet::All)
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.find_map(|p| self.is_upvar_field_projection(p));
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let deref_base = match deref_target_place.projection.as_ref() {
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[proj_base @ .., ProjectionElem::Deref] => {
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PlaceRef { local: deref_target_place.local, projection: &proj_base }
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}
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_ => bug!("deref_target_place is not a deref projection"),
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};
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if let PlaceRef { local, projection: [] } = deref_base {
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let decl = &self.body.local_decls[local];
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if decl.is_ref_for_guard() {
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let mut err = self.cannot_move_out_of(
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span,
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&format!("`{}` in pattern guard", self.local_names[local].unwrap()),
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);
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err.note(
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"variables bound in patterns cannot be moved from \
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until after the end of the pattern guard",
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);
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return err;
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} else if decl.is_ref_to_static() {
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return self.report_cannot_move_from_static(move_place, span);
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}
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}
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debug!("report: ty={:?}", ty);
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let mut err = match ty.kind() {
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ty::Array(..) | ty::Slice(..) => {
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self.cannot_move_out_of_interior_noncopy(span, ty, None)
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}
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ty::Closure(def_id, closure_substs)
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if def_id.as_local() == Some(self.mir_def_id()) && upvar_field.is_some() =>
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{
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let closure_kind_ty = closure_substs.as_closure().kind_ty();
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let closure_kind = match closure_kind_ty.to_opt_closure_kind() {
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Some(kind @ (ty::ClosureKind::Fn | ty::ClosureKind::FnMut)) => kind,
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Some(ty::ClosureKind::FnOnce) => {
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bug!("closure kind does not match first argument type")
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}
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None => bug!("closure kind not inferred by borrowck"),
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};
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let capture_description =
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format!("captured variable in an `{}` closure", closure_kind);
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let upvar = &self.upvars[upvar_field.unwrap().index()];
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let upvar_hir_id = upvar.place.get_root_variable();
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let upvar_name = upvar.place.to_string(self.infcx.tcx);
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let upvar_span = self.infcx.tcx.hir().span(upvar_hir_id);
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let place_name = self.describe_any_place(move_place.as_ref());
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let place_description =
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if self.is_upvar_field_projection(move_place.as_ref()).is_some() {
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format!("{}, a {}", place_name, capture_description)
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} else {
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format!("{}, as `{}` is a {}", place_name, upvar_name, capture_description)
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};
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debug!(
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"report: closure_kind_ty={:?} closure_kind={:?} place_description={:?}",
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closure_kind_ty, closure_kind, place_description,
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);
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let mut diag = self.cannot_move_out_of(span, &place_description);
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diag.span_label(upvar_span, "captured outer variable");
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diag.span_label(
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self.body.span,
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format!("captured by this `{}` closure", closure_kind),
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);
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diag
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}
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_ => {
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let source = self.borrowed_content_source(deref_base);
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match (self.describe_place(move_place.as_ref()), source.describe_for_named_place())
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{
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(Some(place_desc), Some(source_desc)) => self.cannot_move_out_of(
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span,
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&format!("`{}` which is behind a {}", place_desc, source_desc),
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),
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(_, _) => self.cannot_move_out_of(
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span,
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&source.describe_for_unnamed_place(self.infcx.tcx),
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),
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}
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}
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};
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let ty = move_place.ty(self.body, self.infcx.tcx).ty;
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let def_id = match *ty.kind() {
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ty::Adt(self_def, _) => self_def.did(),
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ty::Foreign(def_id)
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| ty::FnDef(def_id, _)
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| ty::Closure(def_id, _)
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| ty::Generator(def_id, ..)
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| ty::Opaque(def_id, _) => def_id,
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_ => return err,
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};
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let diag_name = self.infcx.tcx.get_diagnostic_name(def_id);
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if matches!(diag_name, Some(sym::Option | sym::Result))
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&& use_spans.map_or(true, |v| !v.for_closure())
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{
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err.span_suggestion_verbose(
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span.shrink_to_hi(),
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&format!("consider borrowing the `{}`'s content", diag_name.unwrap()),
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".as_ref()".to_string(),
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Applicability::MaybeIncorrect,
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);
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} else if let Some(use_spans) = use_spans {
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self.explain_captures(
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&mut err, span, span, use_spans, move_place, None, "", "", "", false, true,
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);
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}
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err
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}
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fn add_move_hints(&self, error: GroupedMoveError<'tcx>, err: &mut Diagnostic, span: Span) {
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match error {
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GroupedMoveError::MovesFromPlace { mut binds_to, move_from, .. } => {
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if let Ok(snippet) = self.infcx.tcx.sess.source_map().span_to_snippet(span) {
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err.span_suggestion(
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span,
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"consider borrowing here",
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format!("&{}", snippet),
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Applicability::Unspecified,
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);
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}
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if binds_to.is_empty() {
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let place_ty = move_from.ty(self.body, self.infcx.tcx).ty;
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let place_desc = match self.describe_place(move_from.as_ref()) {
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Some(desc) => format!("`{}`", desc),
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None => "value".to_string(),
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};
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self.note_type_does_not_implement_copy(
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err,
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&place_desc,
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place_ty,
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Some(span),
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"",
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);
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} else {
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binds_to.sort();
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binds_to.dedup();
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self.add_move_error_details(err, &binds_to);
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}
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}
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GroupedMoveError::MovesFromValue { mut binds_to, .. } => {
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binds_to.sort();
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binds_to.dedup();
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self.add_move_error_suggestions(err, &binds_to);
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self.add_move_error_details(err, &binds_to);
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}
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// No binding. Nothing to suggest.
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GroupedMoveError::OtherIllegalMove { ref original_path, use_spans, .. } => {
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let span = use_spans.var_or_use();
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let place_ty = original_path.ty(self.body, self.infcx.tcx).ty;
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let place_desc = match self.describe_place(original_path.as_ref()) {
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Some(desc) => format!("`{}`", desc),
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None => "value".to_string(),
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};
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self.note_type_does_not_implement_copy(err, &place_desc, place_ty, Some(span), "");
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use_spans.args_span_label(err, format!("move out of {} occurs here", place_desc));
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}
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}
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}
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fn add_move_error_suggestions(&self, err: &mut Diagnostic, binds_to: &[Local]) {
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let mut suggestions: Vec<(Span, &str, String)> = Vec::new();
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for local in binds_to {
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let bind_to = &self.body.local_decls[*local];
|
|
if let Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
|
|
VarBindingForm { pat_span, .. },
|
|
)))) = bind_to.local_info
|
|
{
|
|
if let Ok(pat_snippet) = self.infcx.tcx.sess.source_map().span_to_snippet(pat_span)
|
|
{
|
|
if let Some(stripped) = pat_snippet.strip_prefix('&') {
|
|
let pat_snippet = stripped.trim_start();
|
|
let (suggestion, to_remove) = if pat_snippet.starts_with("mut")
|
|
&& pat_snippet["mut".len()..].starts_with(rustc_lexer::is_whitespace)
|
|
{
|
|
(pat_snippet["mut".len()..].trim_start(), "&mut")
|
|
} else {
|
|
(pat_snippet, "&")
|
|
};
|
|
suggestions.push((pat_span, to_remove, suggestion.to_owned()));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
suggestions.sort_unstable_by_key(|&(span, _, _)| span);
|
|
suggestions.dedup_by_key(|&mut (span, _, _)| span);
|
|
for (span, to_remove, suggestion) in suggestions {
|
|
err.span_suggestion(
|
|
span,
|
|
&format!("consider removing the `{}`", to_remove),
|
|
suggestion,
|
|
Applicability::MachineApplicable,
|
|
);
|
|
}
|
|
}
|
|
|
|
fn add_move_error_details(&self, err: &mut Diagnostic, binds_to: &[Local]) {
|
|
for (j, local) in binds_to.iter().enumerate() {
|
|
let bind_to = &self.body.local_decls[*local];
|
|
let binding_span = bind_to.source_info.span;
|
|
|
|
if j == 0 {
|
|
err.span_label(binding_span, "data moved here");
|
|
} else {
|
|
err.span_label(binding_span, "...and here");
|
|
}
|
|
|
|
if binds_to.len() == 1 {
|
|
self.note_type_does_not_implement_copy(
|
|
err,
|
|
&format!("`{}`", self.local_names[*local].unwrap()),
|
|
bind_to.ty,
|
|
Some(binding_span),
|
|
"",
|
|
);
|
|
}
|
|
}
|
|
|
|
if binds_to.len() > 1 {
|
|
err.note(
|
|
"move occurs because these variables have types that \
|
|
don't implement the `Copy` trait",
|
|
);
|
|
}
|
|
}
|
|
}
|