Rollup merge of #102951 - SparrowLii:type_annotation, r=estebank
suggest type annotation for local statement initialed by ref expression In a local statement with a type declaration, if a ref expression is used on the right side and not used on the left side, in addition to removing the `&` and `&mut` on the right side, we can add them on the left side alternatively Fixes #102892
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Dylan DPC
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commit
bf6bfcddf6
@ -714,7 +714,14 @@ pub fn check_ref(
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expr: &hir::Expr<'tcx>,
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checked_ty: Ty<'tcx>,
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expected: Ty<'tcx>,
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) -> Option<(Span, String, String, Applicability, bool /* verbose */)> {
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) -> Option<(
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Span,
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String,
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String,
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Applicability,
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bool, /* verbose */
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bool, /* suggest `&` or `&mut` type annotation */
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)> {
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let sess = self.sess();
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let sp = expr.span;
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@ -746,6 +753,7 @@ pub fn check_ref(
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String::new(),
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Applicability::MachineApplicable,
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true,
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false,
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));
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}
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}
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@ -760,6 +768,7 @@ pub fn check_ref(
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"b".to_string(),
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Applicability::MachineApplicable,
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true,
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false,
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));
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}
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}
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@ -817,6 +826,7 @@ pub fn check_ref(
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sugg.2,
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Applicability::MachineApplicable,
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false,
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false,
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));
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}
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@ -844,6 +854,7 @@ pub fn check_ref(
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format!("{prefix}&mut {sugg_expr}"),
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Applicability::MachineApplicable,
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false,
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false,
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),
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hir::Mutability::Not => (
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sp,
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@ -851,6 +862,7 @@ pub fn check_ref(
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format!("{prefix}&{sugg_expr}"),
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Applicability::MachineApplicable,
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false,
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false,
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),
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});
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}
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@ -880,6 +892,7 @@ pub fn check_ref(
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String::new(),
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Applicability::MachineApplicable,
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true,
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true
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));
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}
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return None;
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@ -893,6 +906,7 @@ pub fn check_ref(
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String::new(),
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Applicability::MachineApplicable,
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true,
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true,
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));
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}
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}
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@ -959,6 +973,7 @@ pub fn check_ref(
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src,
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applicability,
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true,
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false,
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));
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}
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}
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@ -999,6 +1014,7 @@ pub fn check_ref(
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Applicability::MachineApplicable
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},
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true,
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false,
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));
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}
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@ -1050,6 +1066,7 @@ pub fn check_ref(
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suggestion,
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Applicability::MachineApplicable,
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true,
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false,
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));
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}
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}
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@ -327,7 +327,7 @@ pub fn suggest_deref_ref_or_into(
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expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
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) -> bool {
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let expr = expr.peel_blocks();
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if let Some((sp, msg, suggestion, applicability, verbose)) =
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if let Some((sp, msg, suggestion, applicability, verbose, annotation)) =
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self.check_ref(expr, found, expected)
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{
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if verbose {
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@ -335,9 +335,50 @@ pub fn suggest_deref_ref_or_into(
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} else {
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err.span_suggestion(sp, &msg, suggestion, applicability);
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}
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if annotation {
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let suggest_annotation = match expr.peel_drop_temps().kind {
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hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Not, _) => "&",
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hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, _) => "&mut ",
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_ => return true,
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};
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let mut tuple_indexes = Vec::new();
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let mut expr_id = expr.hir_id;
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for (parent_id, node) in self.tcx.hir().parent_iter(expr.hir_id) {
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match node {
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Node::Expr(&Expr { kind: ExprKind::Tup(subs), .. }) => {
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tuple_indexes.push(
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subs.iter()
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.enumerate()
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.find(|(_, sub_expr)| sub_expr.hir_id == expr_id)
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.unwrap()
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.0,
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);
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expr_id = parent_id;
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}
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Node::Local(local) => {
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if let Some(mut ty) = local.ty {
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while let Some(index) = tuple_indexes.pop() {
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match ty.kind {
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TyKind::Tup(tys) => ty = &tys[index],
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_ => return true,
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}
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}
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let annotation_span = ty.span;
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err.span_suggestion(
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annotation_span.with_hi(annotation_span.lo()),
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format!("alternatively, consider changing the type annotation"),
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suggest_annotation,
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Applicability::MaybeIncorrect,
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);
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}
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break;
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}
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_ => break,
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}
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}
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}
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return true;
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} else if self.suggest_else_fn_with_closure(err, expr, found, expected)
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{
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} else if self.suggest_else_fn_with_closure(err, expr, found, expected) {
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return true;
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} else if self.suggest_fn_call(err, expr, found, |output| self.can_coerce(output, expected))
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&& let ty::FnDef(def_id, ..) = &found.kind()
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@ -11,6 +11,10 @@ help: consider removing the borrow
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LL - let a: String = &String::from("a");
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LL + let a: String = String::from("a");
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help: alternatively, consider changing the type annotation
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LL | let a: &String = &String::from("a");
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| +
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error[E0308]: mismatched types
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--> $DIR/format-borrow.rs:4:21
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@ -25,6 +29,10 @@ help: consider removing the borrow
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LL - let b: String = &format!("b");
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LL + let b: String = format!("b");
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help: alternatively, consider changing the type annotation
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LL | let b: &String = &format!("b");
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| +
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error[E0308]: mismatched types
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--> $DIR/format-borrow.rs:6:21
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@ -39,6 +47,10 @@ help: consider removing the borrow
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LL - let c: String = &mut format!("c");
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LL + let c: String = format!("c");
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help: alternatively, consider changing the type annotation
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LL | let c: &mut String = &mut format!("c");
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| ++++
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error[E0308]: mismatched types
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--> $DIR/format-borrow.rs:8:21
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@ -53,6 +65,10 @@ help: consider removing the borrow
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LL - let d: String = &mut (format!("d"));
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LL + let d: String = format!("d"));
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help: alternatively, consider changing the type annotation
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LL | let d: &mut String = &mut (format!("d"));
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| ++++
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error: aborting due to 4 previous errors
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25
src/test/ui/suggestions/issue-102892.rs
Normal file
25
src/test/ui/suggestions/issue-102892.rs
Normal file
@ -0,0 +1,25 @@
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#![allow(dead_code, unused_variables)]
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use std::sync::Arc;
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#[derive(Debug)]
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struct A;
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#[derive(Debug)]
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struct B;
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fn process_without_annot(arc: &Arc<(A, B)>) {
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let (a, b) = **arc; // suggests putting `&**arc` here; with that, fixed!
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}
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fn process_with_annot(arc: &Arc<(A, B)>) {
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let (a, b): (A, B) = &**arc; // suggests putting `&**arc` here too
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//~^ ERROR mismatched types
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}
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fn process_with_tuple_annot(mutation: &mut (A, B), arc: &Arc<(A, B)>) {
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let (a, b): ((A, B), A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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//~^ ERROR mismatched types
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//~| ERROR mismatched types
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}
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fn main() {}
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57
src/test/ui/suggestions/issue-102892.stderr
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57
src/test/ui/suggestions/issue-102892.stderr
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@ -0,0 +1,57 @@
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error[E0308]: mismatched types
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--> $DIR/issue-102892.rs:15:26
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LL | let (a, b): (A, B) = &**arc; // suggests putting `&**arc` here too
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| ------ ^^^^^^ expected tuple, found `&(A, B)`
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| |
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| expected due to this
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= note: expected tuple `(A, B)`
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found reference `&(A, B)`
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help: consider removing the borrow
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LL - let (a, b): (A, B) = &**arc; // suggests putting `&**arc` here too
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LL + let (a, b): (A, B) = **arc; // suggests putting `&**arc` here too
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help: alternatively, consider changing the type annotation
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LL | let (a, b): &(A, B) = &**arc; // suggests putting `&**arc` here too
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| +
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error[E0308]: mismatched types
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--> $DIR/issue-102892.rs:20:32
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LL | let (a, b): ((A, B), A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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| ^^^^^^^^^^^^^^ expected tuple, found `&mut (A, B)`
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= note: expected tuple `(A, B)`
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found mutable reference `&mut (A, B)`
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help: consider removing the borrow
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LL - let (a, b): ((A, B), A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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LL + let (a, b): ((A, B), A) = (*mutation, &(**arc).0); // suggests putting `&**arc` here too
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help: alternatively, consider changing the type annotation
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LL | let (a, b): (&mut (A, B), A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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| ++++
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error[E0308]: mismatched types
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--> $DIR/issue-102892.rs:20:48
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LL | let (a, b): ((A, B), A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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| ^^^^^^^^^^ expected struct `A`, found `&A`
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help: consider removing the borrow
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LL - let (a, b): ((A, B), A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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LL + let (a, b): ((A, B), A) = (&mut *mutation, (**arc).0); // suggests putting `&**arc` here too
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help: alternatively, consider changing the type annotation
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LL | let (a, b): ((A, B), &A) = (&mut *mutation, &(**arc).0); // suggests putting `&**arc` here too
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| +
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0308`.
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