Rollup merge of #49160 - estebank:issue-47457-missing-fields, r=oli-obk

Reduce the diagnostic spam when multiple fields are missing in pattern

Fix #47457.

src/test/ui/error-codes/E0026-teach.stderr

@@ -2,7 +2,7 @@ error[E0026]: struct `Thing` does not have a field named `z`
   --> $DIR/E0026-teach.rs:21:23
    |
 LL |         Thing { x, y, z } => {}
-   |                       ^ struct `Thing` does not have field `z`
+   |                       ^ struct `Thing` does not have this field
    |
    = note: This error indicates that a struct pattern attempted to extract a non-existent field from a struct. Struct fields are identified by the name used before the colon : so struct patterns should resemble the declaration of the struct type being matched.
            

src/test/ui/error-codes/E0026.stderr

@@ -2,7 +2,7 @@ error[E0026]: struct `Thing` does not have a field named `z`
   --> $DIR/E0026.rs:19:23
    |
 LL |         Thing { x, y, z } => {}
-   |                       ^ struct `Thing` does not have field `z`
+   |                       ^ struct `Thing` does not have this field
 
 error: aborting due to previous error
 

src/test/ui/missing-fields-in-struct-pattern.rs

@@ -0,0 +1,19 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct S(usize, usize, usize, usize);
+
+fn main() {
+    if let S { a, b, c, d } = S(1, 2, 3, 4) {
+    //~^ ERROR struct `S` does not have fields named `a`, `b`, `c`, `d` [E0026]
+    //~| ERROR pattern does not mention fields `0`, `1`, `2`, `3` [E0027]
+        println!("hi");
+    }
+}

src/test/ui/missing-fields-in-struct-pattern.stderr

@@ -0,0 +1,18 @@
+error[E0026]: struct `S` does not have fields named `a`, `b`, `c`, `d`
+  --> $DIR/missing-fields-in-struct-pattern.rs:14:16
+   |
+LL |     if let S { a, b, c, d } = S(1, 2, 3, 4) {
+   |                ^  ^  ^  ^ struct `S` does not have these fields
+
+error[E0027]: pattern does not mention fields `0`, `1`, `2`, `3`
+  --> $DIR/missing-fields-in-struct-pattern.rs:14:12
+   |
+LL |     if let S { a, b, c, d } = S(1, 2, 3, 4) {
+   |            ^^^^^^^^^^^^^^^^ missing fields `0`, `1`, `2`, `3`
+   |
+   = note: trying to match a tuple variant with a struct variant pattern
+
+error: aborting due to 2 previous errors
+
+Some errors occurred: E0026, E0027.
+For more information about an error, try `rustc --explain E0026`.

src/test/ui/numeric-fields.stderr

@@ -10,7 +10,7 @@ error[E0026]: struct `S` does not have a field named `0x1`
   --> $DIR/numeric-fields.rs:17:17
    |
 LL |         S{0: a, 0x1: b, ..} => {}
-   |                 ^^^^^^ struct `S` does not have field `0x1`
+   |                 ^^^^^^ struct `S` does not have this field
 
 error: aborting due to 2 previous errors
 

src/test/ui/type-check/issue-41314.stderr

@@ -2,7 +2,7 @@ error[E0026]: variant `X::Y` does not have a field named `number`
   --> $DIR/issue-41314.rs:17:16
    |
 LL |         X::Y { number } => {} //~ ERROR does not have a field named `number`
-   |                ^^^^^^ variant `X::Y` does not have field `number`
+   |                ^^^^^^ variant `X::Y` does not have this field
 
 error[E0027]: pattern does not mention field `0`
   --> $DIR/issue-41314.rs:17:9

src/test/ui/union/union-fields-2.stderr

@@ -52,7 +52,7 @@ error[E0026]: union `U` does not have a field named `c`
   --> $DIR/union-fields-2.rs:28:19
    |
 LL |     let U { a, b, c } = u; //~ ERROR union patterns should have exactly one field
-   |                   ^ union `U` does not have field `c`
+   |                   ^ union `U` does not have this field
 
 error: union patterns should have exactly one field
   --> $DIR/union-fields-2.rs:28:9