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Make IndexMut note apply to more cases

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Previously it was only emitted for assigments, which was an
unnecessary restriction. Now it doesn't care where the mutability
comes from.

This commit also adds `` quotes around the printed type.
This commit is contained in:
Lukas Kalbertodt 2018-08-07 22:38:14 +02:00
parent 9d59c6b76e
commit 764d472b1f
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GPG key ID: 3CBAF4153F818627
1 changed files with 22 additions and 22 deletions
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44
src/librustc_borrowck/borrowck/mod.rs
View file

@ -882,28 +882,6 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
}
}
// We add a special note about `IndexMut`, if the source of this error
// is the fact that `Index` is implemented, but `IndexMut` is not. Needing
// to implement two traits for "one operator" is not very intuitive for
// many programmers.
if err.cmt.note == mc::NoteIndex {
let node_id = self.tcx.hir.hir_to_node_id(err.cmt.hir_id);
let node = self.tcx.hir.get(node_id);
// This pattern probably always matches.
if let hir_map::NodeExpr(
hir::Expr { node: hir::ExprKind::Index(lhs, _), ..}
) = node {
let ty = self.tables.expr_ty(lhs);
db.help(&format!(
"trait `IndexMut` is required to modify indexed content, but \
it is not implemented for {}",
ty
));
}
}
db
}
BorrowViolation(euv::ClosureCapture(_)) => {
@ -924,6 +902,28 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
}
};
// We add a special note about `IndexMut`, if the source of this error
// is the fact that `Index` is implemented, but `IndexMut` is not. Needing
// to implement two traits for "one operator" is not very intuitive for
// many programmers.
if err.cmt.note == mc::NoteIndex {
let node_id = self.tcx.hir.hir_to_node_id(err.cmt.hir_id);
let node = self.tcx.hir.get(node_id);
// This pattern probably always matches.
if let hir_map::NodeExpr(
hir::Expr { node: hir::ExprKind::Index(lhs, _), ..}
) = node {
let ty = self.tables.expr_ty(lhs);
db.help(&format!(
"trait `IndexMut` is required to modify indexed content, but \
it is not implemented for `{}`",
ty
));
}
}
self.note_and_explain_mutbl_error(&mut db, &err, &error_span);
self.note_immutability_blame(
&mut db,