diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index 30b0503668877..1f792ecc2da90 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -1548,6 +1548,19 @@ impl Expr {
}
}
}
+
+ /// If `Self.kind` is `ExprKind::DropTemps(expr)`, drill down until we get a non-`DropTemps`
+ /// `Expr`. This is used in suggestions to ignore this `ExprKind` as it is semantically
+ /// silent, only signaling the ownership system. By doing this, suggestions that check the
+ /// `ExprKind` of any given `Expr` for presentation don't have to care about `DropTemps`
+ /// beyond remembering to call this function before doing analysis on it.
+ pub fn peel_drop_temps(&self) -> &Self {
+ let mut expr = self;
+ while let ExprKind::DropTemps(inner) = &expr.kind {
+ expr = inner;
+ }
+ expr
+ }
}
impl fmt::Debug for Expr {
diff --git a/src/librustc_typeck/check/demand.rs b/src/librustc_typeck/check/demand.rs
index 78bd4508e21a4..d92ea7fd49a72 100644
--- a/src/librustc_typeck/check/demand.rs
+++ b/src/librustc_typeck/check/demand.rs
@@ -115,6 +115,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
Err(e) => e
};
+ let expr = expr.peel_drop_temps();
let cause = self.misc(expr.span);
let expr_ty = self.resolve_type_vars_with_obligations(checked_ty);
let mut err = self.report_mismatched_types(&cause, expected, expr_ty, e);
@@ -355,6 +356,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
};
let is_macro = sp.from_expansion() && !is_desugaring;
+ // `ExprKind::DropTemps` is semantically irrelevant for these suggestions.
+ let expr = expr.peel_drop_temps();
+
match (&expr.kind, &expected.kind, &checked_ty.kind) {
(_, &ty::Ref(_, exp, _), &ty::Ref(_, check, _)) => match (&exp.kind, &check.kind) {
(&ty::Str, &ty::Array(arr, _)) |
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index aa26c74967a1e..ad46a443b8ffa 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -87,12 +87,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
if let Some(mut err) = self.demand_suptype_diag(expr.span, expected_ty, ty) {
+ let expr = expr.peel_drop_temps();
self.suggest_ref_or_into(&mut err, expr, expected_ty, ty);
-
- let expr = match &expr.kind {
- ExprKind::DropTemps(expr) => expr,
- _ => expr,
- };
extend_err(&mut err);
// Error possibly reported in `check_assign` so avoid emitting error again.
err.emit_unless(self.is_assign_to_bool(expr, expected_ty));
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index f130ee821d17c..7475b9cc3b327 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -4216,20 +4216,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pub fn suggest_mismatched_types_on_tail(
&self,
err: &mut DiagnosticBuilder<'tcx>,
- expression: &'tcx hir::Expr,
+ expr: &'tcx hir::Expr,
expected: Ty<'tcx>,
found: Ty<'tcx>,
cause_span: Span,
blk_id: hir::HirId,
) -> bool {
- self.suggest_missing_semicolon(err, expression, expected, cause_span);
+ let expr = expr.peel_drop_temps();
+ self.suggest_missing_semicolon(err, expr, expected, cause_span);
let mut pointing_at_return_type = false;
if let Some((fn_decl, can_suggest)) = self.get_fn_decl(blk_id) {
pointing_at_return_type = self.suggest_missing_return_type(
err, &fn_decl, expected, found, can_suggest);
}
- self.suggest_ref_or_into(err, expression, expected, found);
- self.suggest_boxing_when_appropriate(err, expression, expected, found);
+ self.suggest_ref_or_into(err, expr, expected, found);
+ self.suggest_boxing_when_appropriate(err, expr, expected, found);
pointing_at_return_type
}
diff --git a/src/test/ui/if/if-no-match-bindings.stderr b/src/test/ui/if/if-no-match-bindings.stderr
index 53b7aafc430a2..0936f3b9e38e8 100644
--- a/src/test/ui/if/if-no-match-bindings.stderr
+++ b/src/test/ui/if/if-no-match-bindings.stderr
@@ -29,7 +29,7 @@ LL | if &true {}
| ^^^^^
| |
| expected bool, found &bool
- | help: consider dereferencing the borrow: `*&true`
+ | help: consider removing the borrow: `true`
|
= note: expected type `bool`
found type `&bool`
@@ -41,7 +41,7 @@ LL | if &mut true {}
| ^^^^^^^^^
| |
| expected bool, found &mut bool
- | help: consider dereferencing the borrow: `*&mut true`
+ | help: consider removing the borrow: `true`
|
= note: expected type `bool`
found type `&mut bool`
@@ -77,7 +77,7 @@ LL | while &true {}
| ^^^^^
| |
| expected bool, found &bool
- | help: consider dereferencing the borrow: `*&true`
+ | help: consider removing the borrow: `true`
|
= note: expected type `bool`
found type `&bool`
@@ -89,7 +89,7 @@ LL | while &mut true {}
| ^^^^^^^^^
| |
| expected bool, found &mut bool
- | help: consider dereferencing the borrow: `*&mut true`
+ | help: consider removing the borrow: `true`
|
= note: expected type `bool`
found type `&mut bool`
diff --git a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
index 619f9c85b24db..ad4686c1915d6 100644
--- a/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
+++ b/src/test/ui/rfc-2497-if-let-chains/disallowed-positions.stderr
@@ -520,7 +520,7 @@ LL | if &let 0 = 0 {}
| ^^^^^^^^^^
| |
| expected bool, found &bool
- | help: consider dereferencing the borrow: `*&let 0 = 0`
+ | help: consider removing the borrow: `let 0 = 0`
|
= note: expected type `bool`
found type `&bool`
@@ -708,7 +708,7 @@ LL | while &let 0 = 0 {}
| ^^^^^^^^^^
| |
| expected bool, found &bool
- | help: consider dereferencing the borrow: `*&let 0 = 0`
+ | help: consider removing the borrow: `let 0 = 0`
|
= note: expected type `bool`
found type `&bool`