diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting.rs
index cc78043b83cc..f3372f6be703 100644
--- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting.rs
+++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting.rs
@@ -37,11 +37,11 @@ enum ConstraintCategory {
 impl fmt::Display for ConstraintCategory {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            ConstraintCategory::Assignment => write!(f, "Assignment"),
-            ConstraintCategory::Return => write!(f, "Return"),
-            ConstraintCategory::Cast => write!(f, "Cast"),
-            ConstraintCategory::CallArgument => write!(f, "Argument"),
-            _ => write!(f, "Free region"),
+            ConstraintCategory::Assignment => write!(f, "assignment"),
+            ConstraintCategory::Return => write!(f, "return"),
+            ConstraintCategory::Cast => write!(f, "cast"),
+            ConstraintCategory::CallArgument => write!(f, "argument"),
+            _ => write!(f, "free region"),
         }
     }
 }
diff --git a/src/test/ui/borrowck/issue-45983.nll.stderr b/src/test/ui/borrowck/issue-45983.nll.stderr
index 9b5fcbc56d5c..a62d81c03333 100644
--- a/src/test/ui/borrowck/issue-45983.nll.stderr
+++ b/src/test/ui/borrowck/issue-45983.nll.stderr
@@ -4,7 +4,7 @@ warning: not reporting region error due to nll
 LL |     give_any(|y| x = Some(y));
    |                           ^
 
-error: Assignment requires that data must outlive free region `'_#2r`
+error: assignment requires that data must outlive free region `'_#2r`
   --> $DIR/issue-45983.rs:17:27
    |
 LL |     give_any(|y| x = Some(y));
diff --git a/src/test/ui/borrowck/regions-escape-bound-fn-2.nll.stderr b/src/test/ui/borrowck/regions-escape-bound-fn-2.nll.stderr
index 91161d6820c3..7a4db0802a84 100644
--- a/src/test/ui/borrowck/regions-escape-bound-fn-2.nll.stderr
+++ b/src/test/ui/borrowck/regions-escape-bound-fn-2.nll.stderr
@@ -4,7 +4,7 @@ warning: not reporting region error due to nll
 LL |     with_int(|y| x = Some(y));
    |                           ^
 
-error: Assignment requires that data must outlive free region `'_#2r`
+error: assignment requires that data must outlive free region `'_#2r`
   --> $DIR/regions-escape-bound-fn-2.rs:18:27
    |
 LL |     with_int(|y| x = Some(y));
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.rs b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.rs
index 248933fc39e1..5a71e75d4b2c 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.rs
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.rs
@@ -31,7 +31,7 @@ fn case1() {
     foo(cell, |cell_a, cell_x| {
         //~^ WARNING not reporting region error due to nll
         cell_a.set(cell_x.get()); // forces 'x: 'a, error in closure
-        //~^ ERROR Argument requires that data must outlive free region
+        //~^ ERROR argument requires that data must outlive free region
     })
 }
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
index 7b1cba1d937f..656c1b46a3ce 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-comparing-against-free.stderr
@@ -4,7 +4,7 @@ warning: not reporting region error due to nll
 LL |     foo(cell, |cell_a, cell_x| {
    |     ^^^
 
-error: Argument requires that data must outlive free region `'_#1r`
+error: argument requires that data must outlive free region `'_#1r`
   --> $DIR/propagate-approximated-shorter-to-static-comparing-against-free.rs:33:20
    |
 LL |         cell_a.set(cell_x.get()); // forces 'x: 'a, error in closure
@@ -17,7 +17,7 @@ LL |       foo(cell, |cell_a, cell_x| {
    |  _______________^
 LL | |         //~^ WARNING not reporting region error due to nll
 LL | |         cell_a.set(cell_x.get()); // forces 'x: 'a, error in closure
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |     })
    | |_____^
    |
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.rs b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.rs
index 4c8c2b1b95bb..b25b0e25df21 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.rs
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.rs
@@ -43,7 +43,7 @@ fn demand_y<'x, 'y>(_cell_x: &Cell<&'x u32>, _cell_y: &Cell<&'y u32>, _y: &'y u3
 #[rustc_regions]
 fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-        //~^ ERROR Argument requires that data must outlive free region
+        //~^ ERROR argument requires that data must outlive free region
 
         // Only works if 'x: 'y:
         demand_y(x, y, x.get()) //~ WARNING not reporting region error due to nll
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
index 8a18af90e195..582417b0da93 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-no-bound.stderr
@@ -9,7 +9,7 @@ note: External requirements
    |
 LL |       establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
    |  _______________________________________________^
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get()) //~ WARNING not reporting region error due to nll
@@ -23,11 +23,11 @@ LL | |     });
    = note: number of external vids: 2
    = note: where '_#1r: '_#0r
 
-error: Argument requires that data must outlive free region `ReStatic`
+error: argument requires that data must outlive free region `ReStatic`
   --> $DIR/propagate-approximated-shorter-to-static-no-bound.rs:45:5
    |
 LL | /     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get()) //~ WARNING not reporting region error due to nll
@@ -39,7 +39,7 @@ note: No external requirements
    |
 LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
 LL | |     establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |
 ...  |
 LL | |     });
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.rs b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.rs
index d9cfea4c891c..db9951bcc0f2 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.rs
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.rs
@@ -46,7 +46,7 @@ fn demand_y<'x, 'y>(_cell_x: &Cell<&'x u32>, _cell_y: &Cell<&'y u32>, _y: &'y u3
 #[rustc_regions]
 fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-        //~^ ERROR Argument requires that data must outlive free region
+        //~^ ERROR argument requires that data must outlive free region
         // Only works if 'x: 'y:
         demand_y(x, y, x.get())
         //~^ WARNING not reporting region error due to nll
diff --git a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
index dda1c44b4d8b..481ba512972f 100644
--- a/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-approximated-shorter-to-static-wrong-bound.stderr
@@ -9,7 +9,7 @@ note: External requirements
    |
 LL |       establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
    |  _______________________________________________^
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |         //~^ WARNING not reporting region error due to nll
@@ -23,11 +23,11 @@ LL | |     });
    = note: number of external vids: 3
    = note: where '_#1r: '_#0r
 
-error: Argument requires that data must outlive free region `ReStatic`
+error: argument requires that data must outlive free region `ReStatic`
   --> $DIR/propagate-approximated-shorter-to-static-wrong-bound.rs:48:5
    |
 LL | /     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |         //~^ WARNING not reporting region error due to nll
@@ -39,7 +39,7 @@ note: No external requirements
    |
 LL | / fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
 LL | |     establish_relationships(&cell_a, &cell_b, |_outlives1, _outlives2, x, y| {
-LL | |         //~^ ERROR Argument requires that data must outlive free region
+LL | |         //~^ ERROR argument requires that data must outlive free region
 LL | |         // Only works if 'x: 'y:
 ...  |
 LL | |     });
diff --git a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.rs b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.rs
index 480461b6b639..316268e7e726 100644
--- a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.rs
+++ b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.rs
@@ -46,7 +46,7 @@ fn supply<'a, 'b>(cell_a: Cell<&'a u32>, cell_b: Cell<&'b u32>) {
         // Only works if 'x: 'y:
         demand_y(x, y, x.get())
         //~^ WARN not reporting region error due to nll
-        //~| ERROR Argument requires that data must outlive free region
+        //~| ERROR argument requires that data must outlive free region
     });
 }
 
diff --git a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
index 00e4c289e7eb..74c0576e03b6 100644
--- a/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
+++ b/src/test/ui/nll/closure-requirements/propagate-fail-to-approximate-longer-no-bounds.stderr
@@ -4,7 +4,7 @@ warning: not reporting region error due to nll
 LL |         demand_y(x, y, x.get())
    |         ^^^^^^^^^^^^^^^^^^^^^^^
 
-error: Argument requires that data must outlive free region `ReFree(DefId(0/1:18 ~ propagate_fail_to_approximate_longer_no_bounds[317d]::supply[0]::{{closure}}[0]), BrAnon(2))`
+error: argument requires that data must outlive free region `ReFree(DefId(0/1:18 ~ propagate_fail_to_approximate_longer_no_bounds[317d]::supply[0]::{{closure}}[0]), BrAnon(2))`
   --> $DIR/propagate-fail-to-approximate-longer-no-bounds.rs:47:9
    |
 LL |         demand_y(x, y, x.get())
@@ -18,7 +18,7 @@ LL |       establish_relationships(&cell_a, &cell_b, |_outlives, x, y| {
 LL | |         // Only works if 'x: 'y:
 LL | |         demand_y(x, y, x.get())
 LL | |         //~^ WARN not reporting region error due to nll
-LL | |         //~| ERROR Argument requires that data must outlive free region
+LL | |         //~| ERROR argument requires that data must outlive free region
 LL | |     });
    | |_____^
    |
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs b/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs
index 5e695f3f7c7d..3832be6288ae 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-closure.rs
@@ -55,7 +55,7 @@ where
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
     //~| ERROR the parameter type `T` may not live long enough
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
@@ -67,7 +67,7 @@ where
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
     //~| ERROR the parameter type `T` may not live long enough
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
@@ -89,7 +89,7 @@ where
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
     //~| ERROR the parameter type `T` may not live long enough
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
index fac0a0b0064c..898c995e09b9 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-closure.stderr
@@ -40,7 +40,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |
    = help: consider adding an explicit lifetime bound `T: ReFree(DefId(0/0:8 ~ projection_one_region_closure[317d]::no_relationships_late[0]), BrNamed(crate0:DefIndex(1:16), 'a))`...
 
-error: Argument requires that data must outlive free region `ReFree(DefId(0/0:8 ~ projection_one_region_closure[317d]::no_relationships_late[0]), BrNamed(crate0:DefIndex(1:16), 'a))`
+error: argument requires that data must outlive free region `ReFree(DefId(0/0:8 ~ projection_one_region_closure[317d]::no_relationships_late[0]), BrNamed(crate0:DefIndex(1:16), 'a))`
   --> $DIR/projection-one-region-closure.rs:55:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -54,7 +54,7 @@ LL | | where
 LL | |     T: Anything<'b>,
 LL | | {
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
@@ -88,7 +88,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |
    = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
 
-error: Argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
+error: argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
   --> $DIR/projection-one-region-closure.rs:67:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -102,7 +102,7 @@ LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
@@ -137,7 +137,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    |
    = help: consider adding an explicit lifetime bound `T: ReEarlyBound(0, 'a)`...
 
-error: Argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
+error: argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
   --> $DIR/projection-one-region-closure.rs:89:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -151,7 +151,7 @@ LL | | where
 LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.rs b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.rs
index 24d1753eea82..da76193459b3 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.rs
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.rs
@@ -46,7 +46,7 @@ where
 {
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
@@ -57,7 +57,7 @@ where
 {
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
@@ -78,7 +78,7 @@ where
 
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
diff --git a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
index 07e65fb40515..be11c6249f0b 100644
--- a/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-one-region-trait-bound-closure.stderr
@@ -31,7 +31,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    = note: number of external vids: 3
    = note: where '_#1r: '_#2r
 
-error: Argument requires that data must outlive free region `ReFree(DefId(0/0:8 ~ projection_one_region_trait_bound_closure[317d]::no_relationships_late[0]), BrNamed(crate0:DefIndex(1:16), 'a))`
+error: argument requires that data must outlive free region `ReFree(DefId(0/0:8 ~ projection_one_region_trait_bound_closure[317d]::no_relationships_late[0]), BrNamed(crate0:DefIndex(1:16), 'a))`
   --> $DIR/projection-one-region-trait-bound-closure.rs:47:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -45,7 +45,7 @@ LL | | where
 LL | |     T: Anything<'b>,
 LL | | {
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
@@ -70,7 +70,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    = note: number of external vids: 4
    = note: where '_#2r: '_#3r
 
-error: Argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
+error: argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
   --> $DIR/projection-one-region-trait-bound-closure.rs:58:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -84,7 +84,7 @@ LL | | where
 LL | |     T: Anything<'b>,
 LL | |     'a: 'a,
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
@@ -110,7 +110,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    = note: number of external vids: 4
    = note: where '_#2r: '_#3r
 
-error: Argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
+error: argument requires that data must outlive free region `ReEarlyBound(0, 'a)`
   --> $DIR/projection-one-region-trait-bound-closure.rs:79:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -124,7 +124,7 @@ LL | | where
 LL | |     T: Anything<'b>,
 LL | |     T::AssocType: 'a,
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
diff --git a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
index 8129f93736b6..5e481a9626f0 100644
--- a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
+++ b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.rs
@@ -107,7 +107,7 @@ where
 {
     with_signature(cell, t, |cell, t| require(cell, t));
     //~^ WARNING not reporting region error due to nll
-    //~| ERROR Argument requires that data must outlive free region
+    //~| ERROR argument requires that data must outlive free region
 }
 
 #[rustc_regions]
diff --git a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
index c778f23a2c45..546384e8545e 100644
--- a/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
+++ b/src/test/ui/nll/ty-outlives/projection-two-region-trait-bound-closure.stderr
@@ -239,7 +239,7 @@ LL |     with_signature(cell, t, |cell, t| require(cell, t));
    = note: number of external vids: 3
    = note: where <T as Anything<ReClosureBound('_#1r), ReClosureBound('_#1r)>>::AssocType: '_#2r
 
-error: Argument requires that data must outlive free region `ReFree(DefId(0/0:13 ~ projection_two_region_trait_bound_closure[317d]::two_regions[0]), BrNamed(crate0:DefIndex(1:43), 'a))`
+error: argument requires that data must outlive free region `ReFree(DefId(0/0:13 ~ projection_two_region_trait_bound_closure[317d]::two_regions[0]), BrNamed(crate0:DefIndex(1:43), 'a))`
   --> $DIR/projection-two-region-trait-bound-closure.rs:108:5
    |
 LL |     with_signature(cell, t, |cell, t| require(cell, t));
@@ -253,7 +253,7 @@ LL | | where
 LL | |     T: Anything<'b, 'b>,
 LL | | {
 ...  |
-LL | |     //~| ERROR Argument requires that data must outlive free region
+LL | |     //~| ERROR argument requires that data must outlive free region
 LL | | }
    | |_^
    |
diff --git a/src/test/ui/underscore-lifetime/dyn-trait-underscore.nll.stderr b/src/test/ui/underscore-lifetime/dyn-trait-underscore.nll.stderr
index 681c0dce7d17..49f9044b19b2 100644
--- a/src/test/ui/underscore-lifetime/dyn-trait-underscore.nll.stderr
+++ b/src/test/ui/underscore-lifetime/dyn-trait-underscore.nll.stderr
@@ -22,7 +22,7 @@ warning: not reporting region error due to nll
 LL |     Box::new(items.iter()) //~ ERROR cannot infer an appropriate lifetime
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
-error: Cast requires that data must outlive free region `'static`
+error: cast requires that data must outlive free region `'static`
   --> $DIR/dyn-trait-underscore.rs:18:5
    |
 LL |     Box::new(items.iter()) //~ ERROR cannot infer an appropriate lifetime