follow-up: add tests for 1/n unmatched diagnostics

tests/integrations/basic-fail/tests/actual_tests/diag_not_found_multiple.rs

@@ -0,0 +1,18 @@
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+fn main() {
+    // NOTE: add this so that we don't need `check-pass` (which seems to remove the note about
+    // missed diagnostics) but still get more than 1 missed diagnostics
+    add("42", 3);
+    //~^ E0308
+
+    // NOTE: apparently the "there were n missed diagnostics" message only fires when there are
+    // multiple missed diagnostics on the same line. We couldn't use `add("42", "3")` because that
+    // results in _one_ "arguments to this function are incorrect" diagnostic, not two separate ones.
+    #[rustfmt::skip]
+    {
+        add("42", 3); add("42", 3);
+    };
+}

tests/integrations/basic-fail/tests/actual_tests/diag_not_found_multiple.stderr

@@ -0,0 +1,45 @@
+error[E0308]: mismatched types
+ --> tests/actual_tests/diag_not_found_multiple.rs:8:9
+  |
+8 |     add("42", 3);
+  |     --- ^^^^ expected `usize`, found `&str`
+  |     |
+  |     arguments to this function are incorrect
+  |
+note: function defined here
+ --> tests/actual_tests/diag_not_found_multiple.rs:1:8
+  |
+1 | pub fn add(left: usize, right: usize) -> usize {
+  |        ^^^ -----------
+
+error[E0308]: mismatched types
+  --> tests/actual_tests/diag_not_found_multiple.rs:16:13
+   |
+16 |         add("42", 3); add("42", 3);
+   |         --- ^^^^ expected `usize`, found `&str`
+   |         |
+   |         arguments to this function are incorrect
+   |
+note: function defined here
+  --> tests/actual_tests/diag_not_found_multiple.rs:1:8
+   |
+1  | pub fn add(left: usize, right: usize) -> usize {
+   |        ^^^ -----------
+
+error[E0308]: mismatched types
+  --> tests/actual_tests/diag_not_found_multiple.rs:16:27
+   |
+16 |         add("42", 3); add("42", 3);
+   |                       --- ^^^^ expected `usize`, found `&str`
+   |                       |
+   |                       arguments to this function are incorrect
+   |
+note: function defined here
+  --> tests/actual_tests/diag_not_found_multiple.rs:1:8
+   |
+1  | pub fn add(left: usize, right: usize) -> usize {
+   |        ^^^ -----------
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0308`.

tests/integrations/basic-fail/tests/actual_tests/diag_not_found_one.rs

@@ -0,0 +1,10 @@
+pub fn add(left: usize, right: usize) -> usize {
+    left + right
+}
+
+fn main() {
+    add("42", 3);
+    //~^ E0308
+
+    add("42", 3);
+}

tests/integrations/basic-fail/tests/actual_tests/bad_pattern_multiple.stderr → tests/integrations/basic-fail/tests/actual_tests/diag_not_found_one.stderr

@@ -1,31 +1,31 @@
 error[E0308]: mismatched types
- --> tests/actual_tests/bad_pattern_multiple.rs:4:9
+ --> tests/actual_tests/diag_not_found_one.rs:6:9
   |
-4 |     add("42", 3);
+6 |     add("42", 3);
   |     --- ^^^^ expected `usize`, found `&str`
   |     |
   |     arguments to this function are incorrect
   |
 note: function defined here
- --> $DIR/tests/integrations/basic-fail/src/lib.rs:1:8
+ --> tests/actual_tests/diag_not_found_one.rs:1:8
   |
 1 | pub fn add(left: usize, right: usize) -> usize {
-  |        ^^^
+  |        ^^^ -----------
 
 error[E0308]: mismatched types
-  --> tests/actual_tests/bad_pattern_multiple.rs:6:9
+ --> tests/actual_tests/diag_not_found_one.rs:9:9
   |
-6 |     add("42", 3);
+9 |     add("42", 3);
   |     --- ^^^^ expected `usize`, found `&str`
   |     |
   |     arguments to this function are incorrect
   |
 note: function defined here
-  --> $DIR/tests/integrations/basic-fail/src/lib.rs:LL:CC
+ --> tests/actual_tests/diag_not_found_one.rs:1:8
   |
 1 | pub fn add(left: usize, right: usize) -> usize {
-  |        ^^^
+  |        ^^^ -----------
 
-    error: aborting due to 2 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0308`.