Detect unconstructable re-exported tuple structs

When a tuple-struct is re-exported that has inaccessible fields at the `use` scope, the type's constructor cannot be accessed through that re-export. We now account for this case and extend the resulting resolution error. We also check if the constructor would be accessible directly, not through the re-export, and if so, we suggest using the full path instead.

```
error[E0423]: cannot initialize a tuple struct which contains private fields
  --> $DIR/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs:12:33
   |
LL |             let crate::Foo(x) = crate::Foo(42);
   |                                 ^^^^^^^^^^
   |
note: the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
  --> $DIR/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs:3:9
   |
LL | pub use my_mod::Foo;
   |         ^^^^^^^^^^^
help: the type can be constructed directly, because its fields are available from the current scope
   |
LL |             let crate::Foo(x) = crate::my_mod::Foo(42);
   |                                 ~~~~~~~~~~~~~~~~~~
```

Fix #133343.

3 files changed, 76 insertions, 0 deletions

diff --git a/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.fixed b/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.fixed
new file mode 100644
index 00000000000..63cc3333b6b
--- /dev/null
+++ b/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.fixed
@@ -0,0 +1,20 @@
+#![allow(dead_code, unused_variables)]
+//@ run-rustfix
+pub use my_mod::Foo;
+//~^ NOTE the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
+//~| NOTE the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
+
+mod my_mod {
+    pub struct Foo(u32);
+
+    mod my_sub_mod {
+        fn my_func() {
+            let crate::my_mod::Foo(x) = crate::my_mod::Foo(42);
+            //~^ ERROR cannot initialize a tuple struct which contains private fields
+            //~| HELP the type can be constructed directly, because its fields are available from the current scope
+            //~| ERROR cannot match against a tuple struct which contains private fields
+            //~| HELP the type can be constructed directly, because its fields are available from the current scope
+        }
+    }
+}
+fn main() {}
diff --git a/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs b/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs
new file mode 100644
index 00000000000..0b695f90654
--- /dev/null
+++ b/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs
@@ -0,0 +1,20 @@
+#![allow(dead_code, unused_variables)]
+//@ run-rustfix
+pub use my_mod::Foo;
+//~^ NOTE the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
+//~| NOTE the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
+
+mod my_mod {
+    pub struct Foo(u32);
+
+    mod my_sub_mod {
+        fn my_func() {
+            let crate::Foo(x) = crate::Foo(42);
+            //~^ ERROR cannot initialize a tuple struct which contains private fields
+            //~| HELP the type can be constructed directly, because its fields are available from the current scope
+            //~| ERROR cannot match against a tuple struct which contains private fields
+            //~| HELP the type can be constructed directly, because its fields are available from the current scope
+        }
+    }
+}
+fn main() {}
diff --git a/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.stderr b/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.stderr
new file mode 100644
index 00000000000..6ab324cb32f
--- /dev/null
+++ b/tests/ui/privacy/ctor-not-accessible-due-to-inaccessible-field-in-reexport.stderr
@@ -0,0 +1,36 @@
+error[E0423]: cannot initialize a tuple struct which contains private fields
+  --> $DIR/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs:12:33
+   |
+LL |             let crate::Foo(x) = crate::Foo(42);
+   |                                 ^^^^^^^^^^
+   |
+note: the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
+  --> $DIR/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs:3:9
+   |
+LL | pub use my_mod::Foo;
+   |         ^^^^^^^^^^^
+help: the type can be constructed directly, because its fields are available from the current scope
+   |
+LL |             let crate::Foo(x) = crate::my_mod::Foo(42);
+   |                                        ++++++++
+
+error[E0532]: cannot match against a tuple struct which contains private fields
+  --> $DIR/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs:12:17
+   |
+LL |             let crate::Foo(x) = crate::Foo(42);
+   |                 ^^^^^^^^^^
+   |
+note: the type is accessed through this re-export, but the type's constructor is not visible in this import's scope due to private fields
+  --> $DIR/ctor-not-accessible-due-to-inaccessible-field-in-reexport.rs:3:9
+   |
+LL | pub use my_mod::Foo;
+   |         ^^^^^^^^^^^
+help: the type can be constructed directly, because its fields are available from the current scope
+   |
+LL |             let crate::my_mod::Foo(x) = crate::Foo(42);
+   |                        ++++++++
+
+error: aborting due to 2 previous errors
+
+Some errors have detailed explanations: E0423, E0532.
+For more information about an error, try `rustc --explain E0423`.