Rollup merge of #85068 - luqmana:78708-xcrate-diag, r=estebank

Fix diagnostic for cross crate private tuple struct constructors

Fixes #78708.

There was already some limited support for certain cross-crate scenarios but that didn't handle a tuple struct rexported from an inner module for example (e.g. the NonZero* types as seen in #85049).

```Rust
➜  cat bug.rs
fn main() {
    let _x = std::num::NonZeroU32(12);
    let n = std::num::NonZeroU32::new(1).unwrap();
    match n {
        std::num::NonZeroU32(i) => {},
    }
}
```

**Before:**
<details>

```Rust
➜  rustc +nightly bug.rs
error[E0423]: expected function, tuple struct or tuple variant, found struct `std::num::NonZeroU32`
   --> bug.rs:2:14
    |
2   |       let _x = std::num::NonZeroU32(12);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^ help: use struct literal syntax instead: `std::num::NonZeroU32 { 0: val }`
    |
   ::: /home/luqman/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/nonzero.rs:148:1
[snip]
error[E0532]: expected tuple struct or tuple variant, found struct `std::num::NonZeroU32`
   --> bug.rs:5:9
    |
5   |           std::num::NonZeroU32(i) => {},
    |           ^^^^^^^^^^^^^^^^^^^^^^^ help: use struct pattern syntax instead: `std::num::NonZeroU32 { 0 }`
    |
   ::: /home/luqman/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/nonzero.rs:148:1
[snip]

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0423, E0532.
For more information about an error, try `rustc --explain E0423`.
```
</details>

**After:**
<details>

```Rust
➜  /rust/build/x86_64-unknown-linux-gnu/stage1/bin/rustc bug.rs
error[E0423]: cannot initialize a tuple struct which contains private fields
   --> bug.rs:2:14
    |
2   |     let _x = std::num::NonZeroU32(12);
    |              ^^^^^^^^^^^^^^^^^^^^
    |
note: constructor is not visible here due to private fields
   --> /rust/library/core/src/num/nonzero.rs:148:1
[snip]
error[E0532]: cannot match against a tuple struct which contains private fields
 --> bug.rs:5:9
  |
5 |         std::num::NonZeroU32(i) => {},
  |         ^^^^^^^^^^^^^^^^^^^^
  |
note: constructor is not visible here due to private fields
 --> bug.rs:5:30
  |
5 |         std::num::NonZeroU32(i) => {},
  |                              ^ private field

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0423, E0532.
For more information about an error, try `rustc --explain E0423`.
```
</details>

One question is if we should only collect the needed info for the cross-crate case after encountering an error instead of always doing it. Perf run perhaps to gauge the impact.

4 files changed, 41 insertions, 4 deletions

diff --git a/src/test/ui/issues/auxiliary/issue-75907.rs b/src/test/ui/issues/auxiliary/issue-75907.rs
index 0b70452a24d..389c9c35101 100644
--- a/src/test/ui/issues/auxiliary/issue-75907.rs
+++ b/src/test/ui/issues/auxiliary/issue-75907.rs
@@ -3,3 +3,15 @@ pub struct Bar(pub u8, u8, u8);
 pub fn make_bar() -> Bar {
     Bar(1, 12, 10)
 }
+
+mod inner {
+    pub struct Foo(u8, pub u8, u8);
+
+    impl Foo {
+        pub fn new() -> Foo {
+            Foo(1, 12, 10)
+        }
+    }
+}
+
+pub use inner::Foo;
diff --git a/src/test/ui/issues/issue-75907_b.rs b/src/test/ui/issues/issue-75907_b.rs
index a775845279e..e3074778233 100644
--- a/src/test/ui/issues/issue-75907_b.rs
+++ b/src/test/ui/issues/issue-75907_b.rs
@@ -3,9 +3,12 @@
 
 extern crate issue_75907 as a;
 
-use a::{make_bar, Bar};
+use a::{make_bar, Bar, Foo};
 
 fn main() {
     let Bar(x, y, z) = make_bar();
     //~^ ERROR cannot match against a tuple struct which contains private fields
+
+    let Foo(x, y, z) = Foo::new();
+    //~^ ERROR cannot match against a tuple struct which contains private fields
 }
diff --git a/src/test/ui/issues/issue-75907_b.stderr b/src/test/ui/issues/issue-75907_b.stderr
index 8884484e18d..b82d08473c8 100644
--- a/src/test/ui/issues/issue-75907_b.stderr
+++ b/src/test/ui/issues/issue-75907_b.stderr
@@ -2,8 +2,30 @@ error[E0532]: cannot match against a tuple struct which contains private fields
   --> $DIR/issue-75907_b.rs:9:9
    |
 LL |     let Bar(x, y, z) = make_bar();
-   |         ^^^ constructor is not visible here due to private fields
+   |         ^^^
+   |
+note: constructor is not visible here due to private fields
+  --> $DIR/issue-75907_b.rs:9:16
+   |
+LL |     let Bar(x, y, z) = make_bar();
+   |                ^  ^ private field
+   |                |
+   |                private field
+
+error[E0532]: cannot match against a tuple struct which contains private fields
+  --> $DIR/issue-75907_b.rs:12:9
+   |
+LL |     let Foo(x, y, z) = Foo::new();
+   |         ^^^
+   |
+note: constructor is not visible here due to private fields
+  --> $DIR/issue-75907_b.rs:12:13
+   |
+LL |     let Foo(x, y, z) = Foo::new();
+   |             ^     ^ private field
+   |             |
+   |             private field
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0532`.
diff --git a/src/test/ui/rfc-2008-non-exhaustive/struct.stderr b/src/test/ui/rfc-2008-non-exhaustive/struct.stderr
index e2ee8d6a6fe..d023ba3096e 100644
--- a/src/test/ui/rfc-2008-non-exhaustive/struct.stderr
+++ b/src/test/ui/rfc-2008-non-exhaustive/struct.stderr
@@ -2,7 +2,7 @@ error[E0423]: cannot initialize a tuple struct which contains private fields
   --> $DIR/struct.rs:20:14
    |
 LL |     let ts = TupleStruct(640, 480);
-   |              ^^^^^^^^^^^ constructor is not visible here due to private fields
+   |              ^^^^^^^^^^^
 
 error[E0423]: expected value, found struct `UnitStruct`
   --> $DIR/struct.rs:29:14