Auto merge of #138458 - petrochenkov:privtup, r=<try>

type privacy: Check constructor types in tuple struct patterns

This fixes a hole in type privacy checker.

In `TupleStruct(something)` expression the `TupleStruct` part has its type recorded and we are checking it, but in patterns only type of the whole pattern is kept, so we were missing the constructor's type in the privacy check.

Author: bors

compiler/rustc_privacy/src/lib.rs

@@ -1302,6 +1302,27 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
             return;
         }
 
+        match pattern.kind {
+            hir::PatKind::TupleStruct(qpath, ..) => {
+                // Tuple struct constructors have to be checked specially.
+                self.span = qpath.span();
+                let def_id = match qpath {
+                    hir::QPath::Resolved(_, path) => path.res.opt_def_id(),
+                    hir::QPath::TypeRelative(..) | hir::QPath::LangItem(..) => self
+                        .maybe_typeck_results
+                        .unwrap_or_else(|| span_bug!(self.span, "`hir::Pat` outside of a body"))
+                        .type_dependent_def_id(pattern.hir_id),
+                };
+
+                if let Some(def_id) = def_id {
+                    if self.visit(self.tcx.type_of(def_id).instantiate_identity()).is_break() {
+                        return;
+                    }
+                }
+            }
+            _ => {}
+        }
+
         intravisit::walk_pat(self, pattern);
     }
 

tests/ui/privacy/private-in-public-tuple-struct-pat.rs

@@ -0,0 +1,36 @@
+mod m {
+    struct Priv;
+
+    #[allow(private_interfaces)]
+    pub struct PubStruct(pub Priv);
+    pub enum PubEnum {
+        #[allow(private_interfaces)]
+        Variant(Priv),
+    }
+
+    impl PubStruct {
+        pub fn new() -> PubStruct {
+            PubStruct(Priv)
+        }
+    }
+    impl PubEnum {
+        pub fn new() -> PubEnum {
+            PubEnum::Variant(Priv)
+        }
+    }
+}
+
+fn main() {
+    match m::PubStruct::new() {
+        m::PubStruct(_) => {} //~ ERROR type `Priv` is private
+        m::PubStruct(..) => {} //~ ERROR type `Priv` is private
+    }
+
+    match m::PubEnum::new() {
+        m::PubEnum::Variant(_) => {} //~ ERROR type `Priv` is private
+        m::PubEnum::Variant(..) => {} //~ ERROR type `Priv` is private
+    }
+
+    let _ = m::PubStruct; //~ ERROR type `Priv` is private
+    let _ = m::PubEnum::Variant; //~ ERROR type `Priv` is private
+}

tests/ui/privacy/private-in-public-tuple-struct-pat.stderr

@@ -0,0 +1,38 @@
+error: type `Priv` is private
+  --> $DIR/private-in-public-tuple-struct-pat.rs:25:9
+   |
+LL |         m::PubStruct(_) => {}
+   |         ^^^^^^^^^^^^ private type
+
+error: type `Priv` is private
+  --> $DIR/private-in-public-tuple-struct-pat.rs:26:9
+   |
+LL |         m::PubStruct(..) => {}
+   |         ^^^^^^^^^^^^ private type
+
+error: type `Priv` is private
+  --> $DIR/private-in-public-tuple-struct-pat.rs:30:9
+   |
+LL |         m::PubEnum::Variant(_) => {}
+   |         ^^^^^^^^^^^^^^^^^^^ private type
+
+error: type `Priv` is private
+  --> $DIR/private-in-public-tuple-struct-pat.rs:31:9
+   |
+LL |         m::PubEnum::Variant(..) => {}
+   |         ^^^^^^^^^^^^^^^^^^^ private type
+
+error: type `Priv` is private
+  --> $DIR/private-in-public-tuple-struct-pat.rs:34:13
+   |
+LL |     let _ = m::PubStruct;
+   |             ^^^^^^^^^^^^ private type
+
+error: type `Priv` is private
+  --> $DIR/private-in-public-tuple-struct-pat.rs:35:13
+   |
+LL |     let _ = m::PubEnum::Variant;
+   |             ^^^^^^^^^^^^^^^^^^^ private type
+
+error: aborting due to 6 previous errors
+