Account for better recovery in two cases.

src/test/ui/parser/pat-lt-bracket-6.rs

@@ -1,3 +1,6 @@
 fn main() {
     let Test(&desc[..]) = x; //~ ERROR: expected one of `)`, `,`, or `@`, found `[`
+    //~^ ERROR cannot find value `x` in this scope
+    //~| ERROR cannot find tuple struct/variant `Test` in this scope
+    //~| ERROR subslice patterns are unstable
 }

src/test/ui/parser/pat-lt-bracket-6.stderr

@@ -4,5 +4,28 @@ error: expected one of `)`, `,`, or `@`, found `[`
 LL |     let Test(&desc[..]) = x;
    |                   ^ expected one of `)`, `,`, or `@` here
 
-error: aborting due to previous error
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/pat-lt-bracket-6.rs:2:27
+   |
+LL |     let Test(&desc[..]) = x;
+   |                           ^ not found in this scope
 
+error[E0531]: cannot find tuple struct/variant `Test` in this scope
+  --> $DIR/pat-lt-bracket-6.rs:2:9
+   |
+LL |     let Test(&desc[..]) = x;
+   |         ^^^^ not found in this scope
+
+error[E0658]: subslice patterns are unstable
+  --> $DIR/pat-lt-bracket-6.rs:2:20
+   |
+LL |     let Test(&desc[..]) = x;
+   |                    ^^
+   |
+   = note: for more information, see https://github.com/rust-lang/rust/issues/62254
+   = help: add #![feature(slice_patterns)] to the crate attributes to enable
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0425, E0658.
+For more information about an error, try `rustc --explain E0425`.

src/test/ui/parser/pat-lt-bracket-7.rs

@@ -1,3 +1,5 @@
 fn main() {
     for thing(x[]) in foo {} //~ ERROR: expected one of `)`, `,`, or `@`, found `[`
+    //~^ ERROR cannot find value `foo` in this scope
+    //~| ERROR cannot find tuple struct/variant `thing` in this scope
 }

src/test/ui/parser/pat-lt-bracket-7.stderr

@@ -4,5 +4,18 @@ error: expected one of `)`, `,`, or `@`, found `[`
 LL |     for thing(x[]) in foo {}
    |                ^ expected one of `)`, `,`, or `@` here
 
-error: aborting due to previous error
+error[E0425]: cannot find value `foo` in this scope
+  --> $DIR/pat-lt-bracket-7.rs:2:23
+   |
+LL |     for thing(x[]) in foo {}
+   |                       ^^^ not found in this scope
 
+error[E0531]: cannot find tuple struct/variant `thing` in this scope
+  --> $DIR/pat-lt-bracket-7.rs:2:9
+   |
+LL |     for thing(x[]) in foo {}
+   |         ^^^^^ not found in this scope
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0425`.