Add `.stderr` files for shadowed labels where the point of the test is to test such cases.

src/test/ui/run-pass/hygiene/hygienic-labels-in-let.stderr

+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:23:9
+   |
+LL |         'x: loop { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: loop {
+   |         -- first declared here
+LL |             // this 'x should refer to the outer loop, lexically
+LL |             loop_x!(break 'x);
+   |             ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:55:9
+   |
+LL |         'x: loop {
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:55:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:23:9
+   |
+LL |         'x: loop { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: loop {
+   |         -- first declared here
+...
+LL |             loop_x!(break 'x);
+   |             ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:23:9
+   |
+LL |         'x: loop { $e }
+   |         ^^
+   |         |
+   |         first declared here
+   |         lifetime 'x already in scope
+...
+LL |             loop_x!(break 'x);
+   |             ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:23:9
+   |
+LL |         'x: loop { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+LL |             // ditto
+LL |             loop_x!(break 'x);
+   |             ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:65:9
+   |
+LL |         'x: loop {
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:65:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:65:9
+   |
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:65:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:30:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: loop {
+   |         -- first declared here
+...
+LL |             while_true!(break 'x);
+   |             ---------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:30:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |             while_true!(break 'x);
+   |             ---------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:30:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+...
+LL |             while_true!(break 'x);
+   |             ---------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:30:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |             while_true!(break 'x);
+   |             ---------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:30:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+LL |             // ditto
+LL |             while_true!(break 'x);
+   |             ---------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:75:9
+   |
+LL |         'x: loop {
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:75:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:75:9
+   |
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:75:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:75:9
+   |
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:75:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 {
+   |         ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: loop {
+   |         -- first declared here
+...
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+...
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+...
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels-in-let.rs:37:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: for _ in 0..1 {
+   |         -- first declared here
+LL |             // ditto
+LL |             run_once!(continue 'x);
+   |             ----------------------- in this macro invocation
+

src/test/ui/run-pass/hygiene/hygienic-labels.stderr

+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:21:9
+   |
+LL |         'x: loop { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+LL |         // this 'x should refer to the outer loop, lexically
+LL |         loop_x!(break 'x);
+   |         ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:46:5
+   |
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+...
+LL |     'x: loop {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:46:5
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |     'x: loop {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:21:9
+   |
+LL |         'x: loop { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+...
+LL |         loop_x!(break 'x);
+   |         ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:21:9
+   |
+LL |         'x: loop { $e }
+   |         ^^
+   |         |
+   |         first declared here
+   |         lifetime 'x already in scope
+...
+LL |         loop_x!(break 'x);
+   |         ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:21:9
+   |
+LL |         'x: loop { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: loop {
+   |     -- first declared here
+LL |         // ditto
+LL |         loop_x!(break 'x);
+   |         ------------------ in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:52:5
+   |
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+...
+LL |     'x: while 1 + 1 == 2 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:52:5
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |     'x: while 1 + 1 == 2 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:52:5
+   |
+LL |     'x: loop {
+   |     -- first declared here
+...
+LL |     'x: while 1 + 1 == 2 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:52:5
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |     'x: while 1 + 1 == 2 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:35:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+...
+LL |         while_x!(break 'x);
+   |         ------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:35:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         while_x!(break 'x);
+   |         ------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:35:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: loop {
+   |     -- first declared here
+...
+LL |         while_x!(break 'x);
+   |         ------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:35:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         while_x!(break 'x);
+   |         ------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:35:9
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: while 1 + 1 == 2 {
+   |     -- first declared here
+LL |         while_x!(break 'x);
+   |         ------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:57:5
+   |
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+...
+LL |     'x: for _ in 0..1 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:57:5
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |     'x: for _ in 0..1 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:57:5
+   |
+LL |     'x: loop {
+   |     -- first declared here
+...
+LL |     'x: for _ in 0..1 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:57:5
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |     'x: for _ in 0..1 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:57:5
+   |
+LL |     'x: while 1 + 1 == 2 {
+   |     -- first declared here
+...
+LL |     'x: for _ in 0..1 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:57:5
+   |
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         -- first declared here
+...
+LL |     'x: for _ in 0..1 {
+   |     ^^ lifetime 'x already in scope
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+...
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: loop {
+   |     -- first declared here
+...
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: loop { $e }
+   |         -- first declared here
+...
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: while 1 + 1 == 2 {
+   |     -- first declared here
+...
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |         'x: while 1 + 1 == 2 { $e }
+   |         -- first declared here
+...
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+
+warning: label name `'x` shadows a label name that is already in scope
+  --> $DIR/hygienic-labels.rs:28:9
+   |
+LL |         'x: for _ in 0..1 { $e }
+   |         ^^ lifetime 'x already in scope
+...
+LL |     'x: for _ in 0..1 {
+   |     -- first declared here
+LL |         // ditto
+LL |         run_once!(continue 'x);
+   |         ----------------------- in this macro invocation
+

src/test/ui/run-pass/macros/macro-lifetime-used-with-labels.stderr

+warning: label name `'b` shadows a label name that is already in scope
+  --> $DIR/macro-lifetime-used-with-labels.rs:31:9
+   |
+LL |         'b: loop {
+   |         ^^ lifetime 'b already in scope
+...
+LL |     'b: loop {
+   |     -- first declared here
+LL |         br2!('b);
+   |         --------- in this macro invocation
+