Tweak borrow suggestion

compiler/rustc_hir_typeck/src/demand.rs

@@ -1334,52 +1334,55 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         ));
                     }
 
-                    if let Ok(src) = sm.span_to_snippet(sugg_sp) {
+                    let needs_parens = match expr.kind {
-                        let needs_parens = match expr.kind {
+                        // parenthesize if needed (Issue #46756)
-                            // parenthesize if needed (Issue #46756)
+                        hir::ExprKind::Cast(_, _) | hir::ExprKind::Binary(_, _, _) => true,
-                            hir::ExprKind::Cast(_, _) | hir::ExprKind::Binary(_, _, _) => true,
+                        // parenthesize borrows of range literals (Issue #54505)
-                            // parenthesize borrows of range literals (Issue #54505)
+                        _ if is_range_literal(expr) => true,
-                            _ if is_range_literal(expr) => true,
+                        _ => false,
-                            _ => false,
+                    };
-                        };
 
-                        if let Some(sugg) = self.can_use_as_ref(expr) {
+                    if let Some(sugg) = self.can_use_as_ref(expr) {
-                            return Some((
-                                sugg.0,
-                                sugg.1.to_string(),
-                                sugg.2,
-                                Applicability::MachineApplicable,
-                                false,
-                                false,
-                            ));
-                        }
-
-                        let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) {
-                            Some(ident) => format!("{ident}: "),
-                            None => String::new(),
-                        };
-
-                        if let Some(hir::Node::Expr(hir::Expr {
-                            kind: hir::ExprKind::Assign(..),
-                            ..
-                        })) = self.tcx.hir().find_parent(expr.hir_id)
-                        {
-                            if mutability.is_mut() {
-                                // Suppressing this diagnostic, we'll properly print it in `check_expr_assign`
-                                return None;
-                            }
-                        }
-
-                        let sugg_expr = if needs_parens { format!("({src})") } else { src };
                         return Some((
-                            sp,
+                            sugg.0,
-                            format!("consider {}borrowing here", mutability.mutably_str()),
+                            sugg.1.to_string(),
-                            format!("{prefix}{}{sugg_expr}", mutability.ref_prefix_str()),
+                            sugg.2,
                             Applicability::MachineApplicable,
                             false,
                             false,
                         ));
                     }
+
+                    let prefix = match self.maybe_get_struct_pattern_shorthand_field(expr) {
+                        Some(ident) => format!("{ident}: "),
+                        None => String::new(),
+                    };
+
+                    if let Some(hir::Node::Expr(hir::Expr {
+                        kind: hir::ExprKind::Assign(..),
+                        ..
+                    })) = self.tcx.hir().find_parent(expr.hir_id)
+                    {
+                        if mutability.is_mut() {
+                            // Suppressing this diagnostic, we'll properly print it in `check_expr_assign`
+                            return None;
+                        }
+                    }
+
+                    let (sp, sugg_expr, verbose) = if needs_parens {
+                        let src = sm.span_to_snippet(sugg_sp).ok()?;
+                        (sp, format!("({src})"), false)
+                    } else {
+                        (sp.shrink_to_lo(), "".to_string(), true)
+                    };
+                    return Some((
+                        sp,
+                        format!("consider {}borrowing here", mutability.mutably_str()),
+                        format!("{prefix}{}{sugg_expr}", mutability.ref_prefix_str()),
+                        Applicability::MachineApplicable,
+                        verbose,
+                        false,
+                    ));
                 }
             }
             (

tests/ui/argument-suggestions/issue-97484.stderr

@@ -16,7 +16,7 @@ LL | fn foo(a: &A, d: D, e: &E, g: G) {}
 help: consider borrowing here
    |
 LL |     foo(&&A, B, C, D, &E, F, G);
-   |                       ~~
+   |                       +
 help: remove the extra arguments
    |
 LL -     foo(&&A, B, C, D, E, F, G);

tests/ui/async-await/issues/issue-102206.stderr

@@ -2,14 +2,16 @@ error[E0308]: mismatched types
   --> $DIR/issue-102206.rs:6:27
    |
 LL |     std::mem::size_of_val(foo());
-   |     --------------------- ^^^^^
+   |     --------------------- ^^^^^ expected `&_`, found future
-   |     |                     |
+   |     |
-   |     |                     expected `&_`, found future
-   |     |                     help: consider borrowing here: `&foo()`
    |     arguments to this function are incorrect
    |
 note: function defined here
   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
+help: consider borrowing here
+   |
+LL |     std::mem::size_of_val(&foo());
+   |                           +
 
 error: aborting due to previous error
 

tests/ui/coercion/coercion-slice.stderr

@@ -2,11 +2,14 @@ error[E0308]: mismatched types
   --> $DIR/coercion-slice.rs:4:21
    |
 LL |     let _: &[i32] = [0];
-   |            ------   ^^^
+   |            ------   ^^^ expected `&[i32]`, found `[{integer}; 1]`
-   |            |        |
+   |            |
-   |            |        expected `&[i32]`, found `[{integer}; 1]`
-   |            |        help: consider borrowing here: `&[0]`
    |            expected due to this
+   |
+help: consider borrowing here
+   |
+LL |     let _: &[i32] = &[0];
+   |                     +
 
 error: aborting due to previous error
 

tests/ui/inference/deref-suggestion.stderr

@@ -98,19 +98,23 @@ error[E0308]: mismatched types
   --> $DIR/deref-suggestion.rs:40:17
    |
 LL |     let s = S { u };
-   |                 ^
+   |                 ^ expected `&u32`, found integer
-   |                 |
+   |
-   |                 expected `&u32`, found integer
+help: consider borrowing here
-   |                 help: consider borrowing here: `u: &u`
+   |
+LL |     let s = S { u: &u };
+   |                 ++++
 
 error[E0308]: mismatched types
   --> $DIR/deref-suggestion.rs:42:20
    |
 LL |     let s = S { u: u };
-   |                    ^
+   |                    ^ expected `&u32`, found integer
-   |                    |
+   |
-   |                    expected `&u32`, found integer
+help: consider borrowing here
-   |                    help: consider borrowing here: `&u`
+   |
+LL |     let s = S { u: &u };
+   |                    +
 
 error[E0308]: mismatched types
   --> $DIR/deref-suggestion.rs:45:17

tests/ui/issues/issue-11374.stderr

@@ -2,10 +2,8 @@ error[E0308]: mismatched types
   --> $DIR/issue-11374.rs:26:15
    |
 LL |     c.read_to(v);
-   |       ------- ^
+   |       ------- ^ expected `&mut [u8]`, found `Vec<_>`
-   |       |       |
+   |       |
-   |       |       expected `&mut [u8]`, found `Vec<_>`
-   |       |       help: consider mutably borrowing here: `&mut v`
    |       arguments to this method are incorrect
    |
    = note: expected mutable reference `&mut [u8]`
@@ -15,6 +13,10 @@ note: method defined here
    |
 LL |     pub fn read_to(&mut self, vec: &mut [u8]) {
    |            ^^^^^^^            --------------
+help: consider mutably borrowing here
+   |
+LL |     c.read_to(&mut v);
+   |               ++++
 
 error: aborting due to previous error
 

tests/ui/issues/issue-17033.stderr

@@ -2,11 +2,14 @@ error[E0308]: mismatched types
   --> $DIR/issue-17033.rs:2:10
    |
 LL |     (*p)(())
-   |     ---- ^^
+   |     ---- ^^ expected `&mut ()`, found `()`
-   |     |    |
+   |     |
-   |     |    expected `&mut ()`, found `()`
-   |     |    help: consider mutably borrowing here: `&mut ()`
    |     arguments to this function are incorrect
+   |
+help: consider mutably borrowing here
+   |
+LL |     (*p)(&mut ())
+   |          ++++
 
 error: aborting due to previous error
 

tests/ui/issues/issue-18819.stderr

@@ -19,7 +19,7 @@ LL | fn print_x(_: &dyn Foo<Item=bool>, extra: &str) {
 help: consider borrowing here
    |
 LL |     print_x(&X);
-   |             ~~
+   |             +
 help: provide the argument
    |
 LL |     print_x(/* &dyn Foo<Item = bool> */, /* &str */);

tests/ui/issues/issue-46302.stderr

@@ -2,10 +2,12 @@ error[E0308]: mismatched types
   --> $DIR/issue-46302.rs:3:27
    |
 LL |   let u: &str = if true { s[..2] } else { s };
-   |                           ^^^^^^
+   |                           ^^^^^^ expected `&str`, found `str`
-   |                           |
+   |
-   |                           expected `&str`, found `str`
+help: consider borrowing here
-   |                           help: consider borrowing here: `&s[..2]`
+   |
+LL |   let u: &str = if true { &s[..2] } else { s };
+   |                           +
 
 error: aborting due to previous error
 

tests/ui/issues/issue-61106.stderr

@@ -2,10 +2,8 @@ error[E0308]: mismatched types
   --> $DIR/issue-61106.rs:3:9
    |
 LL |     foo(x.clone());
-   |     --- ^^^^^^^^^
+   |     --- ^^^^^^^^^ expected `&str`, found `String`
-   |     |   |
+   |     |
-   |     |   expected `&str`, found `String`
-   |     |   help: consider borrowing here: `&x`
    |     arguments to this function are incorrect
    |
 note: function defined here
@@ -13,6 +11,10 @@ note: function defined here
    |
 LL | fn foo(_: &str) {}
    |    ^^^ -------
+help: consider borrowing here
+   |
+LL |     foo(&x.clone());
+   |         +
 
 error: aborting due to previous error
 

tests/ui/methods/method-self-arg-1.stderr

@@ -2,10 +2,8 @@ error[E0308]: mismatched types
   --> $DIR/method-self-arg-1.rs:11:14
    |
 LL |     Foo::bar(x);
-   |     -------- ^
+   |     -------- ^ expected `&Foo`, found `Foo`
-   |     |        |
+   |     |
-   |     |        expected `&Foo`, found `Foo`
-   |     |        help: consider borrowing here: `&x`
    |     arguments to this function are incorrect
    |
 note: method defined here
@@ -13,6 +11,10 @@ note: method defined here
    |
 LL |     fn bar(&self) {}
    |        ^^^ -----
+help: consider borrowing here
+   |
+LL |     Foo::bar(&x);
+   |              +
 
 error[E0308]: mismatched types
   --> $DIR/method-self-arg-1.rs:13:14

tests/ui/mismatched_types/dont-point-return-on-E0308.stderr

@@ -2,10 +2,8 @@ error[E0308]: mismatched types
   --> $DIR/dont-point-return-on-E0308.rs:11:11
    |
 LL |         f(());
-   |         - ^^
+   |         - ^^ expected `&()`, found `()`
-   |         | |
+   |         |
-   |         | expected `&()`, found `()`
-   |         | help: consider borrowing here: `&()`
    |         arguments to this function are incorrect
    |
 note: function defined here
@@ -13,6 +11,10 @@ note: function defined here
    |
 LL | async fn f(_: &()) {}
    |          ^ ------
+help: consider borrowing here
+   |
+LL |         f(&());
+   |           +
 
 error: aborting due to previous error
 

tests/ui/mut/mut-cross-borrowing.stderr

@@ -2,10 +2,8 @@ error[E0308]: mismatched types
   --> $DIR/mut-cross-borrowing.rs:7:7
    |
 LL |     f(x)
-   |     - ^
+   |     - ^ expected `&mut isize`, found `Box<{integer}>`
-   |     | |
+   |     |
-   |     | expected `&mut isize`, found `Box<{integer}>`
-   |     | help: consider mutably borrowing here: `&mut x`
    |     arguments to this function are incorrect
    |
    = note: expected mutable reference `&mut isize`
@@ -15,6 +13,10 @@ note: function defined here
    |
 LL | fn f(_: &mut isize) {}
    |    ^ -------------
+help: consider mutably borrowing here
+   |
+LL |     f(&mut x)
+   |       ++++
 
 error: aborting due to previous error
 

tests/ui/range/issue-54505-no-literals.fixed

@@ -16,60 +16,60 @@ fn main() {
     take_range(&std::ops::Range { start: 0, end: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::Range { start: 0, end: 1 }
+    //~| SUGGESTION &
 
     take_range(&::std::ops::Range { start: 0, end: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::Range { start: 0, end: 1 }
+    //~| SUGGESTION &
 
     take_range(&std::ops::RangeFrom { start: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeFrom { start: 1 }
+    //~| SUGGESTION &
 
     take_range(&::std::ops::RangeFrom { start: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeFrom { start: 1 }
+    //~| SUGGESTION &
 
     take_range(&std::ops::RangeFull {});
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeFull {}
+    //~| SUGGESTION &
 
     take_range(&::std::ops::RangeFull {});
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeFull {}
+    //~| SUGGESTION &
 
     take_range(&std::ops::RangeInclusive::new(0, 1));
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeInclusive::new(0, 1)
+    //~| SUGGESTION &
 
     take_range(&::std::ops::RangeInclusive::new(0, 1));
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeInclusive::new(0, 1)
+    //~| SUGGESTION &
 
     take_range(&std::ops::RangeTo { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeTo { end: 5 }
+    //~| SUGGESTION &
 
     take_range(&::std::ops::RangeTo { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeTo { end: 5 }
+    //~| SUGGESTION &
 
     take_range(&std::ops::RangeToInclusive { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeToInclusive { end: 5 }
+    //~| SUGGESTION &
 
     take_range(&::std::ops::RangeToInclusive { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeToInclusive { end: 5 }
+    //~| SUGGESTION &
 }

tests/ui/range/issue-54505-no-literals.rs

@@ -16,60 +16,60 @@ fn main() {
     take_range(std::ops::Range { start: 0, end: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::Range { start: 0, end: 1 }
+    //~| SUGGESTION &
 
     take_range(::std::ops::Range { start: 0, end: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::Range { start: 0, end: 1 }
+    //~| SUGGESTION &
 
     take_range(std::ops::RangeFrom { start: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeFrom { start: 1 }
+    //~| SUGGESTION &
 
     take_range(::std::ops::RangeFrom { start: 1 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeFrom { start: 1 }
+    //~| SUGGESTION &
 
     take_range(std::ops::RangeFull {});
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeFull {}
+    //~| SUGGESTION &
 
     take_range(::std::ops::RangeFull {});
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeFull {}
+    //~| SUGGESTION &
 
     take_range(std::ops::RangeInclusive::new(0, 1));
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeInclusive::new(0, 1)
+    //~| SUGGESTION &
 
     take_range(::std::ops::RangeInclusive::new(0, 1));
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeInclusive::new(0, 1)
+    //~| SUGGESTION &
 
     take_range(std::ops::RangeTo { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeTo { end: 5 }
+    //~| SUGGESTION &
 
     take_range(::std::ops::RangeTo { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeTo { end: 5 }
+    //~| SUGGESTION &
 
     take_range(std::ops::RangeToInclusive { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &std::ops::RangeToInclusive { end: 5 }
+    //~| SUGGESTION &
 
     take_range(::std::ops::RangeToInclusive { end: 5 });
     //~^ ERROR mismatched types [E0308]
     //~| HELP consider borrowing here
-    //~| SUGGESTION &::std::ops::RangeToInclusive { end: 5 }
+    //~| SUGGESTION &
 }

tests/ui/range/issue-54505-no-literals.stderr

@@ -2,10 +2,8 @@ error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:16:16
    |
 LL |     take_range(std::ops::Range { start: 0, end: 1 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `Range<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `Range<{integer}>`
-   |     |          help: consider borrowing here: `&std::ops::Range { start: 0, end: 1 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -15,15 +13,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&std::ops::Range { start: 0, end: 1 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:21:16
    |
 LL |     take_range(::std::ops::Range { start: 0, end: 1 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `Range<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `Range<{integer}>`
-   |     |          help: consider borrowing here: `&::std::ops::Range { start: 0, end: 1 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -33,15 +33,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&::std::ops::Range { start: 0, end: 1 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:26:16
    |
 LL |     take_range(std::ops::RangeFrom { start: 1 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeFrom<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeFrom<{integer}>`
-   |     |          help: consider borrowing here: `&std::ops::RangeFrom { start: 1 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -51,15 +53,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&std::ops::RangeFrom { start: 1 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:31:16
    |
 LL |     take_range(::std::ops::RangeFrom { start: 1 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeFrom<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeFrom<{integer}>`
-   |     |          help: consider borrowing here: `&::std::ops::RangeFrom { start: 1 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -69,15 +73,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&::std::ops::RangeFrom { start: 1 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:36:16
    |
 LL |     take_range(std::ops::RangeFull {});
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeFull`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeFull`
-   |     |          help: consider borrowing here: `&std::ops::RangeFull {}`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -87,15 +93,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&std::ops::RangeFull {});
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:41:16
    |
 LL |     take_range(::std::ops::RangeFull {});
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeFull`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeFull`
-   |     |          help: consider borrowing here: `&::std::ops::RangeFull {}`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -105,15 +113,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&::std::ops::RangeFull {});
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:46:16
    |
 LL |     take_range(std::ops::RangeInclusive::new(0, 1));
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeInclusive<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeInclusive<{integer}>`
-   |     |          help: consider borrowing here: `&std::ops::RangeInclusive::new(0, 1)`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -123,15 +133,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&std::ops::RangeInclusive::new(0, 1));
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:51:16
    |
 LL |     take_range(::std::ops::RangeInclusive::new(0, 1));
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeInclusive<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeInclusive<{integer}>`
-   |     |          help: consider borrowing here: `&::std::ops::RangeInclusive::new(0, 1)`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -141,15 +153,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&::std::ops::RangeInclusive::new(0, 1));
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:56:16
    |
 LL |     take_range(std::ops::RangeTo { end: 5 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeTo<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeTo<{integer}>`
-   |     |          help: consider borrowing here: `&std::ops::RangeTo { end: 5 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -159,15 +173,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&std::ops::RangeTo { end: 5 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:61:16
    |
 LL |     take_range(::std::ops::RangeTo { end: 5 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeTo<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeTo<{integer}>`
-   |     |          help: consider borrowing here: `&::std::ops::RangeTo { end: 5 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -177,15 +193,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&::std::ops::RangeTo { end: 5 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:66:16
    |
 LL |     take_range(std::ops::RangeToInclusive { end: 5 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeToInclusive<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeToInclusive<{integer}>`
-   |     |          help: consider borrowing here: `&std::ops::RangeToInclusive { end: 5 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -195,15 +213,17 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&std::ops::RangeToInclusive { end: 5 });
+   |                +
 
 error[E0308]: mismatched types
   --> $DIR/issue-54505-no-literals.rs:71:16
    |
 LL |     take_range(::std::ops::RangeToInclusive { end: 5 });
-   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     ---------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&_`, found `RangeToInclusive<{integer}>`
-   |     |          |
+   |     |
-   |     |          expected `&_`, found `RangeToInclusive<{integer}>`
-   |     |          help: consider borrowing here: `&::std::ops::RangeToInclusive { end: 5 }`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -213,6 +233,10 @@ note: function defined here
    |
 LL | fn take_range(_r: &impl RangeBounds<i8>) {}
    |    ^^^^^^^^^^ -------------------------
+help: consider borrowing here
+   |
+LL |     take_range(&::std::ops::RangeToInclusive { end: 5 });
+   |                +
 
 error: aborting due to 12 previous errors
 

tests/ui/span/coerce-suggestions.stderr

@@ -10,11 +10,14 @@ error[E0308]: mismatched types
   --> $DIR/coerce-suggestions.rs:9:19
    |
 LL |     let x: &str = String::new();
-   |            ----   ^^^^^^^^^^^^^
+   |            ----   ^^^^^^^^^^^^^ expected `&str`, found `String`
-   |            |      |
+   |            |
-   |            |      expected `&str`, found `String`
-   |            |      help: consider borrowing here: `&String::new()`
    |            expected due to this
+   |
+help: consider borrowing here
+   |
+LL |     let x: &str = &String::new();
+   |                   +
 
 error[E0308]: mismatched types
   --> $DIR/coerce-suggestions.rs:12:10

tests/ui/span/issue-39018.stderr

@@ -78,10 +78,12 @@ error[E0308]: mismatched types
   --> $DIR/issue-39018.rs:29:17
    |
 LL |     let _ = a + b;
-   |                 ^
+   |                 ^ expected `&str`, found `String`
-   |                 |
+   |
-   |                 expected `&str`, found `String`
+help: consider borrowing here
-   |                 help: consider borrowing here: `&b`
+   |
+LL |     let _ = a + &b;
+   |                 +
 
 error[E0369]: cannot add `String` to `&String`
   --> $DIR/issue-39018.rs:30:15

tests/ui/str/str-array-assignment.stderr

@@ -10,10 +10,12 @@ error[E0308]: mismatched types
   --> $DIR/str-array-assignment.rs:5:27
    |
 LL |   let u: &str = if true { s[..2] } else { s };
-   |                           ^^^^^^
+   |                           ^^^^^^ expected `&str`, found `str`
-   |                           |
+   |
-   |                           expected `&str`, found `str`
+help: consider borrowing here
-   |                           help: consider borrowing here: `&s[..2]`
+   |
+LL |   let u: &str = if true { &s[..2] } else { s };
+   |                           +
 
 error[E0277]: the size for values of type `str` cannot be known at compilation time
   --> $DIR/str-array-assignment.rs:7:7
@@ -33,11 +35,14 @@ error[E0308]: mismatched types
   --> $DIR/str-array-assignment.rs:9:17
    |
 LL |   let w: &str = s[..2];
-   |          ----   ^^^^^^
+   |          ----   ^^^^^^ expected `&str`, found `str`
-   |          |      |
+   |          |
-   |          |      expected `&str`, found `str`
-   |          |      help: consider borrowing here: `&s[..2]`
    |          expected due to this
+   |
+help: consider borrowing here
+   |
+LL |   let w: &str = &s[..2];
+   |                 +
 
 error: aborting due to 4 previous errors
 

tests/ui/suggestions/suggest-ref-macro.rs

@@ -14,7 +14,7 @@ macro_rules! bla {
     () => {
         x(123);
         //~^ ERROR mismatched types
-        //~| SUGGESTION &mut 123
+        //~| SUGGESTION &mut
     };
     ($v:expr) => {
         x($v)
@@ -25,5 +25,5 @@ fn main() {
     bla!();
     bla!(456);
     //~^ ERROR mismatched types
-    //~| SUGGESTION &mut 456
+    //~| SUGGESTION &mut
 }

tests/ui/suggestions/suggest-ref-macro.stderr

@@ -18,10 +18,8 @@ error[E0308]: mismatched types
   --> $DIR/suggest-ref-macro.rs:15:11
    |
 LL |         x(123);
-   |         - ^^^
+   |         - ^^^ expected `&mut i32`, found integer
-   |         | |
+   |         |
-   |         | expected `&mut i32`, found integer
-   |         | help: consider mutably borrowing here: `&mut 123`
    |         arguments to this function are incorrect
 ...
 LL |     bla!();
@@ -33,6 +31,10 @@ note: function defined here
 LL | fn x(_: &mut i32) {}
    |    ^ -----------
    = note: this error originates in the macro `bla` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider mutably borrowing here
+   |
+LL |         x(&mut 123);
+   |           ++++
 
 error[E0308]: mismatched types
   --> $DIR/suggest-ref-macro.rs:26:10
@@ -41,16 +43,17 @@ LL |         x($v)
    |         - arguments to this function are incorrect
 ...
 LL |     bla!(456);
-   |          ^^^
+   |          ^^^ expected `&mut i32`, found integer
-   |          |
-   |          expected `&mut i32`, found integer
-   |          help: consider mutably borrowing here: `&mut 456`
    |
 note: function defined here
   --> $DIR/suggest-ref-macro.rs:11:4
    |
 LL | fn x(_: &mut i32) {}
    |    ^ -----------
+help: consider mutably borrowing here
+   |
+LL |     bla!(&mut 456);
+   |          ++++
 
 error: aborting due to 3 previous errors
 

tests/ui/type/type-mismatch.stderr

@@ -378,10 +378,8 @@ error[E0308]: mismatched types
   --> $DIR/type-mismatch.rs:47:23
    |
 LL |     want::<&Foo<foo>>(f);
-   |     ----------------- ^
+   |     ----------------- ^ expected `&Foo<foo>`, found `Foo<foo>`
-   |     |                 |
+   |     |
-   |     |                 expected `&Foo<foo>`, found `Foo<foo>`
-   |     |                 help: consider borrowing here: `&f`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&Foo<foo>`
@@ -391,6 +389,10 @@ note: function defined here
    |
 LL | fn want<T>(t: T) {}
    |    ^^^^    ----
+help: consider borrowing here
+   |
+LL |     want::<&Foo<foo>>(&f);
+   |                       +
 
 error[E0308]: mismatched types
   --> $DIR/type-mismatch.rs:48:26
@@ -556,10 +558,8 @@ error[E0308]: mismatched types
   --> $DIR/type-mismatch.rs:61:26
    |
 LL |     want::<&Foo<foo, B>>(f);
-   |     -------------------- ^
+   |     -------------------- ^ expected `&Foo<foo, B>`, found `Foo<foo, B>`
-   |     |                    |
+   |     |
-   |     |                    expected `&Foo<foo, B>`, found `Foo<foo, B>`
-   |     |                    help: consider borrowing here: `&f`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&Foo<foo, B>`
@@ -569,6 +569,10 @@ note: function defined here
    |
 LL | fn want<T>(t: T) {}
    |    ^^^^    ----
+help: consider borrowing here
+   |
+LL |     want::<&Foo<foo, B>>(&f);
+   |                          +
 
 error[E0308]: mismatched types
   --> $DIR/type-mismatch.rs:65:19

tests/ui/typeck/bad-index-due-to-nested.stderr

@@ -42,13 +42,14 @@ error[E0308]: mismatched types
 LL | fn index<'a, K, V>(map: &'a HashMap<K, V>, k: K) -> &'a V {
    |              - this type parameter
 LL |     map[k]
-   |         ^
+   |         ^ expected `&K`, found type parameter `K`
-   |         |
-   |         expected `&K`, found type parameter `K`
-   |         help: consider borrowing here: `&k`
    |
    = note:   expected reference `&K`
            found type parameter `K`
+help: consider borrowing here
+   |
+LL |     map[&k]
+   |         +
 
 error[E0308]: mismatched types
   --> $DIR/bad-index-due-to-nested.rs:20:5
@@ -56,13 +57,14 @@ error[E0308]: mismatched types
 LL | fn index<'a, K, V>(map: &'a HashMap<K, V>, k: K) -> &'a V {
    |                 - this type parameter               ----- expected `&'a V` because of return type
 LL |     map[k]
-   |     ^^^^^^
+   |     ^^^^^^ expected `&V`, found type parameter `V`
-   |     |
-   |     expected `&V`, found type parameter `V`
-   |     help: consider borrowing here: `&map[k]`
    |
    = note:   expected reference `&'a V`
            found type parameter `V`
+help: consider borrowing here
+   |
+LL |     &map[k]
+   |     +
 
 error: aborting due to 4 previous errors
 

tests/ui/typeck/bad-type-in-vec-contains.stderr

@@ -2,16 +2,18 @@ error[E0308]: mismatched types
   --> $DIR/bad-type-in-vec-contains.rs:5:21
    |
 LL |     primes.contains(3);
-   |            -------- ^
+   |            -------- ^ expected `&_`, found integer
-   |            |        |
+   |            |
-   |            |        expected `&_`, found integer
-   |            |        help: consider borrowing here: `&3`
    |            arguments to this method are incorrect
    |
    = note: expected reference `&_`
                    found type `{integer}`
 note: method defined here
   --> $SRC_DIR/core/src/slice/mod.rs:LL:COL
+help: consider borrowing here
+   |
+LL |     primes.contains(&3);
+   |                     +
 
 error: aborting due to previous error
 

tests/ui/typeck/issue-13853.stderr

@@ -20,10 +20,8 @@ error[E0308]: mismatched types
   --> $DIR/issue-13853.rs:37:13
    |
 LL |     iterate(graph);
-   |     ------- ^^^^^
+   |     ------- ^^^^^ expected `&_`, found `Vec<Stuff>`
-   |     |       |
+   |     |
-   |     |       expected `&_`, found `Vec<Stuff>`
-   |     |       help: consider borrowing here: `&graph`
    |     arguments to this function are incorrect
    |
    = note: expected reference `&_`
@@ -33,6 +31,10 @@ note: function defined here
    |
 LL | fn iterate<N: Node, G: Graph<N>>(graph: &G) {
    |    ^^^^^^^                       ---------
+help: consider borrowing here
+   |
+LL |     iterate(&graph);
+   |             +
 
 error: aborting due to 3 previous errors
 

tests/ui/unsized-locals/suggest-borrow.stderr

@@ -16,11 +16,14 @@ error[E0308]: mismatched types
   --> $DIR/suggest-borrow.rs:3:20
    |
 LL |     let x: &[u8] = vec!(1, 2, 3)[..];
-   |            -----   ^^^^^^^^^^^^^^^^^
+   |            -----   ^^^^^^^^^^^^^^^^^ expected `&[u8]`, found `[{integer}]`
-   |            |       |
+   |            |
-   |            |       expected `&[u8]`, found `[{integer}]`
-   |            |       help: consider borrowing here: `&vec!(1, 2, 3)[..]`
    |            expected due to this
+   |
+help: consider borrowing here
+   |
+LL |     let x: &[u8] = &vec!(1, 2, 3)[..];
+   |                    +
 
 error[E0308]: mismatched types
   --> $DIR/suggest-borrow.rs:4:19