vars are ?

25 files changed, 199 insertions, 199 deletions

diff --git a/tests/ui/nll/closure-requirements/escape-argument-callee.stderr b/tests/ui/nll/closure-requirements/escape-argument-callee.stderr
index c0d95ddaa07..61233fd8407 100644
--- a/tests/ui/nll/closure-requirements/escape-argument-callee.stderr
+++ b/tests/ui/nll/closure-requirements/escape-argument-callee.stderr
@@ -17,7 +17,7 @@ LL |         let mut closure = expect_sig(|p, y| *p = y);
    |                                       -  -  ^^^^^^ assignment requires that `'1` must outlive `'2`
    |                                       |  |
    |                                       |  has type `&'1 i32`
-   |                                       has type `&'_#2r mut &'2 i32`
+   |                                       has type `&'?2 mut &'2 i32`
 
 note: no external requirements
   --> $DIR/escape-argument-callee.rs:20:1
diff --git a/tests/ui/nll/closure-requirements/escape-upvar-nested.stderr b/tests/ui/nll/closure-requirements/escape-upvar-nested.stderr
index 4fbd5eb19a5..c00a31ef8e1 100644
--- a/tests/ui/nll/closure-requirements/escape-upvar-nested.stderr
+++ b/tests/ui/nll/closure-requirements/escape-upvar-nested.stderr
@@ -7,10 +7,10 @@ LL |             let mut closure1 = || p = &y;
    = note: defining type: test::{closure#0}::{closure#0} with closure substs [
                i16,
                extern "rust-call" fn(()),
-               (&'_#1r mut &'_#2r i32, &'_#3r i32),
+               (&'?1 mut &'?2 i32, &'?3 i32),
            ]
    = note: number of external vids: 4
-   = note: where '_#3r: '_#2r
+   = note: where '?3: '?2
 
 note: external requirements
   --> $DIR/escape-upvar-nested.rs:20:27
@@ -21,10 +21,10 @@ LL |         let mut closure = || {
    = note: defining type: test::{closure#0} with closure substs [
                i16,
                extern "rust-call" fn(()),
-               (&'_#1r mut &'_#2r i32, &'_#3r i32),
+               (&'?1 mut &'?2 i32, &'?3 i32),
            ]
    = note: number of external vids: 4
-   = note: where '_#3r: '_#2r
+   = note: where '?3: '?2
 
 note: no external requirements
   --> $DIR/escape-upvar-nested.rs:13:1
diff --git a/tests/ui/nll/closure-requirements/escape-upvar-ref.stderr b/tests/ui/nll/closure-requirements/escape-upvar-ref.stderr
index bc1ceac5bf0..2d67e6e7d72 100644
--- a/tests/ui/nll/closure-requirements/escape-upvar-ref.stderr
+++ b/tests/ui/nll/closure-requirements/escape-upvar-ref.stderr
@@ -7,10 +7,10 @@ LL |         let mut closure = || p = &y;
    = note: defining type: test::{closure#0} with closure substs [
                i16,
                extern "rust-call" fn(()),
-               (&'_#1r mut &'_#2r i32, &'_#3r i32),
+               (&'?1 mut &'?2 i32, &'?3 i32),
            ]
    = note: number of external vids: 4
-   = note: where '_#3r: '_#2r
+   = note: where '?3: '?2
 
 note: no external requirements
   --> $DIR/escape-upvar-ref.rs:17:1
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
index 5a7b12732df..ba42576d403 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-fail-no-postdom.stderr
@@ -6,20 +6,20 @@ LL |         |_outlives1, _outlives2, _outlives3, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&'_#2r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'_#3r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&'?2 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?3 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#4r
-   = note: late-bound region is '_#5r
-   = note: late-bound region is '_#6r
+   = note: late-bound region is '?4
+   = note: late-bound region is '?5
+   = note: late-bound region is '?6
 
 error: lifetime may not live long enough
   --> $DIR/propagate-approximated-fail-no-postdom.rs:46:13
    |
 LL |         |_outlives1, _outlives2, _outlives3, x, y| {
-   |          ----------              ---------- has type `Cell<&'2 &'_#3r u32>`
+   |          ----------              ---------- has type `Cell<&'2 &'?3 u32>`
    |          |
-   |          has type `Cell<&'_#1r &'1 u32>`
+   |          has type `Cell<&'?1 &'1 u32>`
 ...
 LL |             demand_y(x, y, p)
    |             ^^^^^^^^^^^^^^^^^ argument requires that `'1` must outlive `'2`
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-ref.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-ref.stderr
index db2ecc779ef..9dd6e02081f 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-ref.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-ref.stderr
@@ -6,13 +6,13 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) &'_#2r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) &'?2 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#3r
-   = note: late-bound region is '_#4r
+   = note: late-bound region is '?3
+   = note: late-bound region is '?4
    = note: number of external vids: 5
-   = note: where '_#1r: '_#2r
+   = note: where '?1: '?2
 
 note: no external requirements
   --> $DIR/propagate-approximated-ref.rs:42:1
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
index 1d9dafbe55f..e2f5576d395 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
@@ -6,7 +6,7 @@ LL |     foo(cell, |cell_a, cell_x| {
    |
    = note: defining type: case1::{closure#0} with closure substs [
                i32,
-               for<Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>)),
                (),
            ]
 
@@ -36,11 +36,11 @@ LL |     foo(cell, |cell_a, cell_x| {
    |
    = note: defining type: case2::{closure#0} with closure substs [
                i32,
-               for<Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'_#1r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>)),
                (),
            ]
    = note: number of external vids: 2
-   = note: where '_#1r: '_#0r
+   = note: where '?1: '?0
 
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-comparing-against-free.rs:28:1
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
index 85f7fe35c0a..383fb471ad3 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
@@ -6,13 +6,13 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#2r
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?2
+   = note: late-bound region is '?3
    = note: number of external vids: 4
-   = note: where '_#1r: '_#0r
+   = note: where '?1: '?0
 
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:31:1
@@ -40,7 +40,7 @@ LL | |     });
    | |______`cell_a` escapes the function body here
    |        argument requires that `'a` must outlive `'static`
    |
-   = note: requirement occurs because of the type `Cell<&'_#9r u32>`, which makes the generic argument `&'_#9r u32` invariant
+   = note: requirement occurs because of the type `Cell<&'?9 u32>`, which makes the generic argument `&'?9 u32` invariant
    = note: the struct `Cell<T>` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
index 7194843e203..ac346c0b110 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
@@ -6,13 +6,13 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&'_#2r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&'?2 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#3r
-   = note: late-bound region is '_#4r
+   = note: late-bound region is '?3
+   = note: late-bound region is '?4
    = note: number of external vids: 5
-   = note: where '_#1r: '_#0r
+   = note: where '?1: '?0
 
 note: no external requirements
   --> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:34:1
@@ -40,7 +40,7 @@ LL | |     });
    | |______`cell_a` escapes the function body here
    |        argument requires that `'a` must outlive `'static`
    |
-   = note: requirement occurs because of the type `Cell<&'_#10r u32>`, which makes the generic argument `&'_#10r u32` invariant
+   = note: requirement occurs because of the type `Cell<&'?10 u32>`, which makes the generic argument `&'?10 u32` invariant
    = note: the struct `Cell<T>` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
diff --git a/tests/ui/nll/closure-requirements/propagate-approximated-val.stderr b/tests/ui/nll/closure-requirements/propagate-approximated-val.stderr
index 71f8a1c67c6..b217ae19773 100644
--- a/tests/ui/nll/closure-requirements/propagate-approximated-val.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-approximated-val.stderr
@@ -6,13 +6,13 @@ LL |     establish_relationships(cell_a, cell_b, |outlives1, outlives2, x, y| {
    |
    = note: defining type: test::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'_#2r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?2 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#3r
-   = note: late-bound region is '_#4r
+   = note: late-bound region is '?3
+   = note: late-bound region is '?4
    = note: number of external vids: 5
-   = note: where '_#1r: '_#2r
+   = note: where '?1: '?2
 
 note: no external requirements
   --> $DIR/propagate-approximated-val.rs:35:1
diff --git a/tests/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr b/tests/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr
index e1cb97b1c7d..f31478b6d1c 100644
--- a/tests/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-despite-same-free-region.stderr
@@ -6,12 +6,12 @@ LL |         |_outlives1, _outlives2, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'_#2r u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?2 u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) u32>, std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?3
    = note: number of external vids: 4
-   = note: where '_#1r: '_#2r
+   = note: where '?1: '?2
 
 note: no external requirements
   --> $DIR/propagate-despite-same-free-region.rs:39:1
diff --git a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
index b66e8391c01..1509ade87fa 100644
--- a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
@@ -6,19 +6,19 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'_#1r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?1 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#2r
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?2
+   = note: late-bound region is '?3
 
 error: lifetime may not live long enough
   --> $DIR/propagate-fail-to-approximate-longer-no-bounds.rs:37:9
    |
 LL |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-   |                                                ---------  - has type `&'_#7r Cell<&'1 u32>`
+   |                                                ---------  - has type `&'?7 Cell<&'1 u32>`
    |                                                |
-   |                                                has type `&'_#5r Cell<&'2 &'_#1r u32>`
+   |                                                has type `&'?5 Cell<&'2 &'?1 u32>`
 LL |         // Only works if 'x: 'y:
 LL |         demand_y(x, y, x.get())
    |         ^^^^^^^^^^^^^^^^^^^^^^^ argument requires that `'1` must outlive `'2`
diff --git a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
index 49641fd06fd..c85a9872e21 100644
--- a/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-wrong-bounds.stderr
@@ -6,19 +6,19 @@ LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y
    |
    = note: defining type: supply::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'_#1r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) &'_#2r u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
+               for<Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((&ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) &'?1 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 2, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) &'?2 u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 4, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) u32>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 5, kind: BrAnon(None) }) std::cell::Cell<&ReLateBound(DebruijnIndex(0), BoundRegion { var: 3, kind: BrAnon(None) }) u32>)),
                (),
            ]
-   = note: late-bound region is '_#3r
-   = note: late-bound region is '_#4r
+   = note: late-bound region is '?3
+   = note: late-bound region is '?4
 
 error: lifetime may not live long enough
   --> $DIR/propagate-fail-to-approximate-longer-wrong-bounds.rs:41:9
    |
 LL |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-   |                                                ----------  ---------- has type `&'_#8r Cell<&'2 &'_#2r u32>`
+   |                                                ----------  ---------- has type `&'?8 Cell<&'2 &'?2 u32>`
    |                                                |
-   |                                                has type `&'_#6r Cell<&'1 &'_#1r u32>`
+   |                                                has type `&'?6 Cell<&'1 &'?1 u32>`
 LL |         // Only works if 'x: 'y:
 LL |         demand_y(x, y, x.get())
    |         ^^^^^^^^^^^^^^^^^^^^^^^ argument requires that `'1` must outlive `'2`
diff --git a/tests/ui/nll/closure-requirements/propagate-from-trait-match.stderr b/tests/ui/nll/closure-requirements/propagate-from-trait-match.stderr
index 038a5e11f88..05e274ab220 100644
--- a/tests/ui/nll/closure-requirements/propagate-from-trait-match.stderr
+++ b/tests/ui/nll/closure-requirements/propagate-from-trait-match.stderr
@@ -4,13 +4,13 @@ note: external requirements
 LL |     establish_relationships(value, |value| {
    |                                    ^^^^^^^
    |
-   = note: defining type: supply::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: supply::<'?1, T>::{closure#0} with closure substs [
                i32,
                extern "rust-call" fn((T,)),
                (),
            ]
    = note: number of external vids: 2
-   = note: where T: '_#1r
+   = note: where T: '?1
 
 note: no external requirements
   --> $DIR/propagate-from-trait-match.rs:28:1
@@ -20,7 +20,7 @@ LL | | where
 LL | |     T: Trait<'a>,
    | |_________________^
    |
-   = note: defining type: supply::<'_#1r, T>
+   = note: defining type: supply::<'?1, T>
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/propagate-from-trait-match.rs:43:9
diff --git a/tests/ui/nll/member-constraints/min-choice.rs b/tests/ui/nll/member-constraints/min-choice.rs
index 14b4dae7abf..f4aca69e19f 100644
--- a/tests/ui/nll/member-constraints/min-choice.rs
+++ b/tests/ui/nll/member-constraints/min-choice.rs
@@ -1,5 +1,5 @@
-// Assuming that the hidden type in these tests is `&'_#15r u8`,
-// we have a member constraint: `'_#15r member ['static, 'a, 'b, 'c]`.
+// Assuming that the hidden type in these tests is `&'?15 u8`,
+// we have a member constraint: `'?15 member ['static, 'a, 'b, 'c]`.
 //
 // Make sure we pick up the minimum non-ambiguous region among them.
 // We will have to exclude `['b, 'c]` because they're incomparable,
diff --git a/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs b/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs
index 66ff828a84f..ceb417f84f3 100644
--- a/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs
+++ b/tests/ui/nll/member-constraints/nested-impl-trait-fail.rs
@@ -5,9 +5,9 @@
 trait Cap<'a> {}
 impl<T> Cap<'_> for T {}
 
-// Assuming the hidden type is `[&'_#15r u8; 1]`, we have two distinct member constraints:
-// - '_#15r member ['static, 'a, 'b] // from outer impl-trait
-// - '_#15r member ['static, 'a, 'b] // from inner impl-trait
+// Assuming the hidden type is `[&'?15 u8; 1]`, we have two distinct member constraints:
+// - '?15 member ['static, 'a, 'b] // from outer impl-trait
+// - '?15 member ['static, 'a, 'b] // from inner impl-trait
 // To satisfy both we can choose 'a or 'b, so it's a failure due to ambiguity.
 fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>
 where
diff --git a/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs b/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs
index 15540cb460e..4be0f02acf2 100644
--- a/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs
+++ b/tests/ui/nll/member-constraints/nested-impl-trait-pass.rs
@@ -5,9 +5,9 @@
 trait Cap<'a> {}
 impl<T> Cap<'_> for T {}
 
-// Assuming the hidden type is `[&'_#15r u8; 1]`, we have two distinct member constraints:
-// - '_#15r member ['static, 'a, 'b] // from outer impl-trait
-// - '_#15r member ['static, 'a]     // from inner impl-trait
+// Assuming the hidden type is `[&'?15 u8; 1]`, we have two distinct member constraints:
+// - '?15 member ['static, 'a, 'b] // from outer impl-trait
+// - '?15 member ['static, 'a]     // from inner impl-trait
 // To satisfy both we can only choose 'a.
 fn pass_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a>> + Cap<'b>
 where
diff --git a/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr b/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr
index 4933b934868..4eefb180ee5 100644
--- a/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr
+++ b/tests/ui/nll/ty-outlives/projection-no-regions-closure.stderr
@@ -4,13 +4,13 @@ note: external requirements
 LL |     with_signature(x, |mut y| Box::new(y.next()))
    |                       ^^^^^^^
    |
-   = note: defining type: no_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: no_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '_#2r)>,
+               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '?2)>,
                (),
            ]
    = note: number of external vids: 3
-   = note: where <T as std::iter::Iterator>::Item: '_#2r
+   = note: where <T as std::iter::Iterator>::Item: '?2
 
 note: no external requirements
   --> $DIR/projection-no-regions-closure.rs:21:1
@@ -20,7 +20,7 @@ LL | | where
 LL | |     T: Iterator,
    | |________________^
    |
-   = note: defining type: no_region::<'_#1r, T>
+   = note: defining type: no_region::<'?1, T>
 
 error[E0309]: the associated type `<T as Iterator>::Item` may not live long enough
   --> $DIR/projection-no-regions-closure.rs:25:31
@@ -37,13 +37,13 @@ note: external requirements
 LL |     with_signature(x, |mut y| Box::new(y.next()))
    |                       ^^^^^^^
    |
-   = note: defining type: correct_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: correct_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '_#2r)>,
+               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '?2)>,
                (),
            ]
    = note: number of external vids: 3
-   = note: where <T as std::iter::Iterator>::Item: '_#2r
+   = note: where <T as std::iter::Iterator>::Item: '?2
 
 note: no external requirements
   --> $DIR/projection-no-regions-closure.rs:30:1
@@ -53,7 +53,7 @@ LL | | where
 LL | |     T: 'a + Iterator,
    | |_____________________^
    |
-   = note: defining type: correct_region::<'_#1r, T>
+   = note: defining type: correct_region::<'?1, T>
 
 note: external requirements
   --> $DIR/projection-no-regions-closure.rs:42:23
@@ -61,13 +61,13 @@ note: external requirements
 LL |     with_signature(x, |mut y| Box::new(y.next()))
    |                       ^^^^^^^
    |
-   = note: defining type: wrong_region::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: wrong_region::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '_#3r)>,
+               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '?3)>,
                (),
            ]
    = note: number of external vids: 4
-   = note: where <T as std::iter::Iterator>::Item: '_#3r
+   = note: where <T as std::iter::Iterator>::Item: '?3
 
 note: no external requirements
   --> $DIR/projection-no-regions-closure.rs:38:1
@@ -77,7 +77,7 @@ LL | | where
 LL | |     T: 'b + Iterator,
    | |_____________________^
    |
-   = note: defining type: wrong_region::<'_#1r, '_#2r, T>
+   = note: defining type: wrong_region::<'?1, '?2, T>
 
 error[E0309]: the associated type `<T as Iterator>::Item` may not live long enough
   --> $DIR/projection-no-regions-closure.rs:42:31
@@ -94,13 +94,13 @@ note: external requirements
 LL |     with_signature(x, |mut y| Box::new(y.next()))
    |                       ^^^^^^^
    |
-   = note: defining type: outlives_region::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: outlives_region::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '_#3r)>,
+               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn Anything + '?3)>,
                (),
            ]
    = note: number of external vids: 4
-   = note: where <T as std::iter::Iterator>::Item: '_#3r
+   = note: where <T as std::iter::Iterator>::Item: '?3
 
 note: no external requirements
   --> $DIR/projection-no-regions-closure.rs:47:1
@@ -111,7 +111,7 @@ LL | |     T: 'b + Iterator,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: outlives_region::<'_#1r, '_#2r, T>
+   = note: defining type: outlives_region::<'?1, '?2, T>
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/nll/ty-outlives/projection-one-region-closure.stderr b/tests/ui/nll/ty-outlives/projection-one-region-closure.stderr
index 11ada59c066..986c2bd2182 100644
--- a/tests/ui/nll/ty-outlives/projection-one-region-closure.stderr
+++ b/tests/ui/nll/ty-outlives/projection-one-region-closure.stderr
@@ -4,15 +4,15 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_late::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_late::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?3
    = note: number of external vids: 4
-   = note: where T: '_#2r
-   = note: where '_#1r: '_#2r
+   = note: where T: '?2
+   = note: where '?1: '?2
 
 note: no external requirements
   --> $DIR/projection-one-region-closure.rs:41:1
@@ -22,7 +22,7 @@ LL | | where
 LL | |     T: Anything<'b>,
    | |____________________^
    |
-   = note: defining type: no_relationships_late::<'_#1r, T>
+   = note: defining type: no_relationships_late::<'?1, T>
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/projection-one-region-closure.rs:45:39
@@ -54,14 +54,14 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_early::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where T: '_#3r
-   = note: where '_#2r: '_#3r
+   = note: where T: '?3
+   = note: where '?2: '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-closure.rs:51:1
@@ -72,7 +72,7 @@ LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
    | |___________^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>
+   = note: defining type: no_relationships_early::<'?1, '?2, T>
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/projection-one-region-closure.rs:56:39
@@ -104,13 +104,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: projection_outlives::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where <T as Anything<'_#2r>>::AssocType: '_#3r
+   = note: where <T as Anything<'?2>>::AssocType: '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-closure.rs:62:1
@@ -121,7 +121,7 @@ LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
    | |_____________________^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, T>
+   = note: defining type: projection_outlives::<'?1, '?2, T>
 
 note: external requirements
   --> $DIR/projection-one-region-closure.rs:80:29
@@ -129,14 +129,14 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: elements_outlive::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: elements_outlive::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where T: '_#3r
-   = note: where '_#2r: '_#3r
+   = note: where T: '?3
+   = note: where '?2: '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-closure.rs:74:1
@@ -148,7 +148,7 @@ LL | |     T: 'a,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: elements_outlive::<'_#1r, '_#2r, T>
+   = note: defining type: elements_outlive::<'?1, '?2, T>
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr b/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
index 47d4f2e46c6..25cc60d8141 100644
--- a/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
+++ b/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
@@ -4,14 +4,14 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_late::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_late::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?3
    = note: number of external vids: 4
-   = note: where '_#1r: '_#2r
+   = note: where '?1: '?2
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:33:1
@@ -21,7 +21,7 @@ LL | | where
 LL | |     T: Anything<'b>,
    | |____________________^
    |
-   = note: defining type: no_relationships_late::<'_#1r, T>
+   = note: defining type: no_relationships_late::<'?1, T>
 
 error: lifetime may not live long enough
   --> $DIR/projection-one-region-trait-bound-closure.rs:37:39
@@ -42,13 +42,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_early::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where '_#2r: '_#3r
+   = note: where '?2: '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:42:1
@@ -59,7 +59,7 @@ LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
    | |___________^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>
+   = note: defining type: no_relationships_early::<'?1, '?2, T>
 
 error: lifetime may not live long enough
   --> $DIR/projection-one-region-trait-bound-closure.rs:47:39
@@ -80,13 +80,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: projection_outlives::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where <T as Anything<'_#2r>>::AssocType: '_#3r
+   = note: where <T as Anything<'?2>>::AssocType: '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:52:1
@@ -97,7 +97,7 @@ LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
    | |_____________________^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, T>
+   = note: defining type: projection_outlives::<'?1, '?2, T>
 
 note: external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:69:29
@@ -105,13 +105,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: elements_outlive::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: elements_outlive::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where '_#2r: '_#3r
+   = note: where '?2: '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:64:1
@@ -122,7 +122,7 @@ LL | |     T: Anything<'b>,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: elements_outlive::<'_#1r, '_#2r, T>
+   = note: defining type: elements_outlive::<'?1, '?2, T>
 
 note: external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:81:29
@@ -130,13 +130,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: one_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: one_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
    = note: number of external vids: 3
-   = note: where '_#1r: '_#2r
+   = note: where '?1: '?2
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-closure.rs:73:1
@@ -146,7 +146,7 @@ LL | | where
 LL | |     T: Anything<'a>,
    | |____________________^
    |
-   = note: defining type: one_region::<'_#1r, T>
+   = note: defining type: one_region::<'?1, T>
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr b/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr
index b27186b0537..5a092d7b849 100644
--- a/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr
+++ b/tests/ui/nll/ty-outlives/projection-one-region-trait-bound-static-closure.stderr
@@ -4,12 +4,12 @@ note: no external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_late::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_late::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?3
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-static-closure.rs:32:1
@@ -19,7 +19,7 @@ LL | | where
 LL | |     T: Anything<'b>,
    | |____________________^
    |
-   = note: defining type: no_relationships_late::<'_#1r, T>
+   = note: defining type: no_relationships_late::<'?1, T>
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-static-closure.rs:45:29
@@ -27,9 +27,9 @@ note: no external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_early::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
 
@@ -42,7 +42,7 @@ LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
    | |___________^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, T>
+   = note: defining type: no_relationships_early::<'?1, '?2, T>
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-static-closure.rs:64:29
@@ -50,9 +50,9 @@ note: no external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: projection_outlives::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
 
@@ -65,7 +65,7 @@ LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
    | |_____________________^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, T>
+   = note: defining type: projection_outlives::<'?1, '?2, T>
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-static-closure.rs:73:29
@@ -73,9 +73,9 @@ note: no external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: elements_outlive::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: elements_outlive::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
 
@@ -88,7 +88,7 @@ LL | |     T: Anything<'b>,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: elements_outlive::<'_#1r, '_#2r, T>
+   = note: defining type: elements_outlive::<'?1, '?2, T>
 
 note: no external requirements
   --> $DIR/projection-one-region-trait-bound-static-closure.rs:85:29
@@ -96,9 +96,9 @@ note: no external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: one_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: one_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
 
@@ -110,5 +110,5 @@ LL | | where
 LL | |     T: Anything<'a>,
    | |____________________^
    |
-   = note: defining type: one_region::<'_#1r, T>
+   = note: defining type: one_region::<'?1, T>
 
diff --git a/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr b/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
index 530dd86819d..51283aa8828 100644
--- a/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
+++ b/tests/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
@@ -4,14 +4,14 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_late::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_late::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#4r
+   = note: late-bound region is '?4
    = note: number of external vids: 5
-   = note: where <T as Anything<'_#1r, '_#2r>>::AssocType: '_#3r
+   = note: where <T as Anything<'?1, '?2>>::AssocType: '?3
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:34:1
@@ -21,16 +21,16 @@ LL | | where
 LL | |     T: Anything<'b, 'c>,
    | |________________________^
    |
-   = note: defining type: no_relationships_late::<'_#1r, '_#2r, T>
+   = note: defining type: no_relationships_late::<'?1, '?2, T>
 
-error[E0309]: the associated type `<T as Anything<'_#5r, '_#6r>>::AssocType` may not live long enough
+error[E0309]: the associated type `<T as Anything<'?5, '?6>>::AssocType` may not live long enough
   --> $DIR/projection-two-region-trait-bound-closure.rs:38:39
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                                       ^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as Anything<'_#5r, '_#6r>>::AssocType: 'a`...
-   = note: ...so that the type `<T as Anything<'_#5r, '_#6r>>::AssocType` will meet its required lifetime bounds
+   = help: consider adding an explicit lifetime bound `<T as Anything<'?5, '?6>>::AssocType: 'a`...
+   = note: ...so that the type `<T as Anything<'?5, '?6>>::AssocType` will meet its required lifetime bounds
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:48:29
@@ -38,13 +38,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, '_#3r, T>::{closure#0} with closure substs [
+   = note: defining type: no_relationships_early::<'?1, '?2, '?3, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#4r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?4 ()>, T)),
                (),
            ]
    = note: number of external vids: 5
-   = note: where <T as Anything<'_#2r, '_#3r>>::AssocType: '_#4r
+   = note: where <T as Anything<'?2, '?3>>::AssocType: '?4
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:43:1
@@ -55,16 +55,16 @@ LL | |     T: Anything<'b, 'c>,
 LL | |     'a: 'a,
    | |___________^
    |
-   = note: defining type: no_relationships_early::<'_#1r, '_#2r, '_#3r, T>
+   = note: defining type: no_relationships_early::<'?1, '?2, '?3, T>
 
-error[E0309]: the associated type `<T as Anything<'_#6r, '_#7r>>::AssocType` may not live long enough
+error[E0309]: the associated type `<T as Anything<'?6, '?7>>::AssocType` may not live long enough
   --> $DIR/projection-two-region-trait-bound-closure.rs:48:39
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                                       ^^^^^^^^^^^^^^^^
    |
-   = help: consider adding an explicit lifetime bound `<T as Anything<'_#6r, '_#7r>>::AssocType: 'a`...
-   = note: ...so that the type `<T as Anything<'_#6r, '_#7r>>::AssocType` will meet its required lifetime bounds
+   = help: consider adding an explicit lifetime bound `<T as Anything<'?6, '?7>>::AssocType: 'a`...
+   = note: ...so that the type `<T as Anything<'?6, '?7>>::AssocType` will meet its required lifetime bounds
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:61:29
@@ -72,13 +72,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, '_#3r, T>::{closure#0} with closure substs [
+   = note: defining type: projection_outlives::<'?1, '?2, '?3, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#4r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?4 ()>, T)),
                (),
            ]
    = note: number of external vids: 5
-   = note: where <T as Anything<'_#2r, '_#3r>>::AssocType: '_#4r
+   = note: where <T as Anything<'?2, '?3>>::AssocType: '?4
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:53:1
@@ -89,7 +89,7 @@ LL | |     T: Anything<'b, 'c>,
 LL | |     T::AssocType: 'a,
    | |_____________________^
    |
-   = note: defining type: projection_outlives::<'_#1r, '_#2r, '_#3r, T>
+   = note: defining type: projection_outlives::<'?1, '?2, '?3, T>
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:70:29
@@ -97,13 +97,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: elements_outlive1::<'_#1r, '_#2r, '_#3r, T>::{closure#0} with closure substs [
+   = note: defining type: elements_outlive1::<'?1, '?2, '?3, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#4r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?4 ()>, T)),
                (),
            ]
    = note: number of external vids: 5
-   = note: where <T as Anything<'_#2r, '_#3r>>::AssocType: '_#4r
+   = note: where <T as Anything<'?2, '?3>>::AssocType: '?4
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:65:1
@@ -114,7 +114,7 @@ LL | |     T: Anything<'b, 'c>,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: elements_outlive1::<'_#1r, '_#2r, '_#3r, T>
+   = note: defining type: elements_outlive1::<'?1, '?2, '?3, T>
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:79:29
@@ -122,13 +122,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: elements_outlive2::<'_#1r, '_#2r, '_#3r, T>::{closure#0} with closure substs [
+   = note: defining type: elements_outlive2::<'?1, '?2, '?3, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#4r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?4 ()>, T)),
                (),
            ]
    = note: number of external vids: 5
-   = note: where <T as Anything<'_#2r, '_#3r>>::AssocType: '_#4r
+   = note: where <T as Anything<'?2, '?3>>::AssocType: '?4
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:74:1
@@ -139,7 +139,7 @@ LL | |     T: Anything<'b, 'c>,
 LL | |     'c: 'a,
    | |___________^
    |
-   = note: defining type: elements_outlive2::<'_#1r, '_#2r, '_#3r, T>
+   = note: defining type: elements_outlive2::<'?1, '?2, '?3, T>
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:87:29
@@ -147,14 +147,14 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: two_regions::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: two_regions::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?3
    = note: number of external vids: 4
-   = note: where <T as Anything<'_#1r, '_#1r>>::AssocType: '_#2r
+   = note: where <T as Anything<'?1, '?1>>::AssocType: '?2
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:83:1
@@ -164,7 +164,7 @@ LL | | where
 LL | |     T: Anything<'b, 'b>,
    | |________________________^
    |
-   = note: defining type: two_regions::<'_#1r, T>
+   = note: defining type: two_regions::<'?1, T>
 
 error: lifetime may not live long enough
   --> $DIR/projection-two-region-trait-bound-closure.rs:87:5
@@ -178,7 +178,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ argument requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of the type `Cell<&'_#8r ()>`, which makes the generic argument `&'_#8r ()` invariant
+   = note: requirement occurs because of the type `Cell<&'?8 ()>`, which makes the generic argument `&'?8 ()` invariant
    = note: the struct `Cell<T>` is invariant over the parameter `T`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
@@ -188,13 +188,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: two_regions_outlive::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: two_regions_outlive::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where <T as Anything<'_#2r, '_#2r>>::AssocType: '_#3r
+   = note: where <T as Anything<'?2, '?2>>::AssocType: '?3
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:92:1
@@ -205,7 +205,7 @@ LL | |     T: Anything<'b, 'b>,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: two_regions_outlive::<'_#1r, '_#2r, T>
+   = note: defining type: two_regions_outlive::<'?1, '?2, T>
 
 note: external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:109:29
@@ -213,13 +213,13 @@ note: external requirements
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |                             ^^^^^^^^^
    |
-   = note: defining type: one_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: one_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
    = note: number of external vids: 3
-   = note: where <T as Anything<'_#1r, '_#1r>>::AssocType: '_#2r
+   = note: where <T as Anything<'?1, '?1>>::AssocType: '?2
 
 note: no external requirements
   --> $DIR/projection-two-region-trait-bound-closure.rs:101:1
@@ -229,7 +229,7 @@ LL | | where
 LL | |     T: Anything<'a, 'a>,
    | |________________________^
    |
-   = note: defining type: one_region::<'_#1r, T>
+   = note: defining type: one_region::<'?1, T>
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr b/tests/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr
index 2c4a0597554..04616f9b702 100644
--- a/tests/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr
+++ b/tests/ui/nll/ty-outlives/ty-param-closure-approximate-lower-bound.stderr
@@ -6,11 +6,11 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
    |
    = note: defining type: generic::<T>::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) T)),
+               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) T)),
                (),
            ]
    = note: number of external vids: 2
-   = note: where T: '_#1r
+   = note: where T: '?1
 
 note: no external requirements
   --> $DIR/ty-param-closure-approximate-lower-bound.rs:22:1
@@ -28,12 +28,12 @@ LL |     twice(cell, value, |a, b| invoke(a, b));
    |
    = note: defining type: generic_fail::<T>::{closure#0} with closure substs [
                i16,
-               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'_#1r &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) T)),
+               for<Region(BrAnon(None)), Region(BrAnon(None))> extern "rust-call" fn((std::option::Option<std::cell::Cell<&'?1 &ReLateBound(DebruijnIndex(0), BoundRegion { var: 0, kind: BrAnon(None) }) ()>>, &ReLateBound(DebruijnIndex(0), BoundRegion { var: 1, kind: BrAnon(None) }) T)),
                (),
            ]
-   = note: late-bound region is '_#2r
+   = note: late-bound region is '?2
    = note: number of external vids: 3
-   = note: where T: '_#1r
+   = note: where T: '?1
 
 note: no external requirements
   --> $DIR/ty-param-closure-approximate-lower-bound.rs:28:1
diff --git a/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.rs b/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.rs
index 4343c3aee53..72b18c16732 100644
--- a/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.rs
+++ b/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.rs
@@ -19,8 +19,8 @@ where
     // Here, the closure winds up being required to prove that `T:
     // 'a`.  In principle, it could know that, except that it is
     // type-checked in a fully generic way, and hence it winds up with
-    // a propagated requirement that `T: '_#2`, where `'_#2` appears
-    // in the return type. The caller makes the mapping from `'_#2` to
+    // a propagated requirement that `T: '?2`, where `'?2` appears
+    // in the return type. The caller makes the mapping from `'?2` to
     // `'a` (and subsequently reports an error).
 
     with_signature(x, |y| y)
diff --git a/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr b/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr
index 35979c8bf51..d580774ff8c 100644
--- a/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr
+++ b/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-return-type.stderr
@@ -4,13 +4,13 @@ note: external requirements
 LL |     with_signature(x, |y| y)
    |                       ^^^
    |
-   = note: defining type: no_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: no_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn std::fmt::Debug + '_#2r)>,
+               extern "rust-call" fn((std::boxed::Box<T>,)) -> std::boxed::Box<(dyn std::fmt::Debug + '?2)>,
                (),
            ]
    = note: number of external vids: 3
-   = note: where T: '_#2r
+   = note: where T: '?2
 
 note: no external requirements
   --> $DIR/ty-param-closure-outlives-from-return-type.rs:15:1
@@ -20,7 +20,7 @@ LL | | where
 LL | |     T: Debug,
    | |_____________^
    |
-   = note: defining type: no_region::<'_#1r, T>
+   = note: defining type: no_region::<'?1, T>
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/ty-param-closure-outlives-from-return-type.rs:26:27
diff --git a/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr b/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr
index 4c97db58c6c..3d4c11a3c54 100644
--- a/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr
+++ b/tests/ui/nll/ty-outlives/ty-param-closure-outlives-from-where-clause.stderr
@@ -6,12 +6,12 @@ LL |     with_signature(a, b, |x, y| {
    |
    = note: defining type: no_region::<T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#1r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?1 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#2r
+   = note: late-bound region is '?2
    = note: number of external vids: 3
-   = note: where T: '_#1r
+   = note: where T: '?1
 
 note: no external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:26:1
@@ -38,13 +38,13 @@ note: external requirements
 LL |     with_signature(a, b, |x, y| {
    |                          ^^^^^^
    |
-   = note: defining type: correct_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: correct_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
    = note: number of external vids: 3
-   = note: where T: '_#2r
+   = note: where T: '?2
 
 note: no external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:38:1
@@ -54,7 +54,7 @@ LL | | where
 LL | |     T: 'a,
    | |__________^
    |
-   = note: defining type: correct_region::<'_#1r, T>
+   = note: defining type: correct_region::<'?1, T>
 
 note: external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:63:26
@@ -62,14 +62,14 @@ note: external requirements
 LL |     with_signature(a, b, |x, y| {
    |                          ^^^^^^
    |
-   = note: defining type: wrong_region::<'_#1r, T>::{closure#0} with closure substs [
+   = note: defining type: wrong_region::<'?1, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#2r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?2 ()>, T)),
                (),
            ]
-   = note: late-bound region is '_#3r
+   = note: late-bound region is '?3
    = note: number of external vids: 4
-   = note: where T: '_#2r
+   = note: where T: '?2
 
 note: no external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:59:1
@@ -79,7 +79,7 @@ LL | | where
 LL | |     T: 'b,
    | |__________^
    |
-   = note: defining type: wrong_region::<'_#1r, T>
+   = note: defining type: wrong_region::<'?1, T>
 
 error[E0309]: the parameter type `T` may not live long enough
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:65:9
@@ -98,13 +98,13 @@ note: external requirements
 LL |     with_signature(a, b, |x, y| {
    |                          ^^^^^^
    |
-   = note: defining type: outlives_region::<'_#1r, '_#2r, T>::{closure#0} with closure substs [
+   = note: defining type: outlives_region::<'?1, '?2, T>::{closure#0} with closure substs [
                i32,
-               extern "rust-call" fn((std::cell::Cell<&'_#3r ()>, T)),
+               extern "rust-call" fn((std::cell::Cell<&'?3 ()>, T)),
                (),
            ]
    = note: number of external vids: 4
-   = note: where T: '_#3r
+   = note: where T: '?3
 
 note: no external requirements
   --> $DIR/ty-param-closure-outlives-from-where-clause.rs:71:1
@@ -115,7 +115,7 @@ LL | |     T: 'b,
 LL | |     'b: 'a,
    | |___________^
    |
-   = note: defining type: outlives_region::<'_#1r, '_#2r, T>
+   = note: defining type: outlives_region::<'?1, '?2, T>
 
 error: aborting due to 2 previous errors